Foundations of Biological Sciences I Evolutionary Agents

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Foundations of Biological Sciences I Evolutionary Agents.

Foundations of Biological Sciences I Evolutionary Agents – 1

A quick recap…. There are several terms that need to be clarified so that you can more easily follow the exercise. A gene is a

piece of DNA that directs the expression of a particular characteristic (trait). Genes are located on

chromosomes, and the location where a particular gene is found is referred to as the locus (plural: loci) of that

gene. An allele is a gene for which there is an alternative expression, which can lead to the alterative form of a

trait. For example, a diploid organism carries the allele “A” on one homologous chromosome, and the allele “A”

on the other. The genotype of this organism is then AA and it is said to be homozygous. An organism may also

carry two different alleles. For example on one chromosome it could carry the allele “A” and on the other it

could carry the allele “a”. The genotype of such an organisms is then Aa, and it is described as heterozygous for

this chromosomal locus.

The genotype of an organism is the listing of the two alleles for each trait that it possesses. The phenotype of an

organism is a description of the way a trait is displayed in the structure, behavior, or physiology of the organism.

Some alleles are dominant to others and mask the presence of other alleles. The dominant condition is indicated

by uppercase letters (e.g., “A”). The alleles that are masked are called recessive alleles. The recessive condition

is indicated by lowercase letters (e.g., “a”). When both dominants are present in the genotype (AA), the organism

is said to be homozygous dominant for the trait, and the organisms will show the dominant phenotype (trait

expression A). When both recessives are present in the genotype (aa), the organism is said to be homozygous

recessive for the trait, and the organisms will show the recessive phenotype (trait expression a). In the case of

complete dominance, the dominant allele completely masks the recessive allele, and an organism with a

heterozygous genotype (Aa) will show the dominant phenotype (trait expression A).

 

Evolutionary Agents

Evolution is a process resulting in changes in gene frequencies (= the genetic make-up) of a population over

time. The mechanisms of evolution include selection (which can cause change over time & adaptation), and

forces that provide variation and cause change over time (but not adaptation). Factors that change gene

frequencies over time are referred to as evolutionary agents.

A powerful way to detect the presence of evolutionary agents is the use of the Hardy–Weinberg model. This

model can be applied to traits that are influenced by several loci; the simplest case is for a trait that is regulated

by one locus with two alleles.

With the Hardy–Weinberg model, the frequency of genotypes in the population can be predicted from the

probability of encounters between gametes bearing the different alleles. With alleles R and B occurring at

frequencies p and q, respectively, the frequency of genotypes in the population is described by the formula:

 

p 2

+ 2pq + q 2

= 1

Hardy-Weinberg

equilibrium

If p is the frequency of one allele, and q

is the frequency of the other allele, then:

 

p + q = 1

 

 

Foundations of Biological Sciences I Evolutionary Agents – 2

If certain conditions are met, the proportions of genotypes that make

up a population remain constant from generation to generation, and

can be predicted from the Hardy-Weinberg equilibrium.

For example, if flower color is controlled by two alleles (R & B),

and the allele for red color is present in the population 80% of the

time, than the other allele for blue color must be present 20% of the

time. Consequently, the allele frequencies in the population are p =

0.8 and q = 0.2. (0.8 + 0.2 = 1).

From this we can calculate the expected genotype frequencies in the

population. Since p = 0.8, we would expect 64% of the flowers in

the populations to be homozygous for red flower color (expected

genotype frequency for p 2

= 0.8 x 0.8 =0.64). 32% of the

populations would be heterozygous for flower color. They would

have one R allele (p = 0.8) and one B allele (q = 0.2), and if neither

allele were dominant they would appear purple. The expected

genotype frequency of these purple individuals is 2pq = 2 x 0.8 x 0.2 = 0.32. Finally, 4% of the population would be homozygous for the

blue flower color (q 2

= 0.2 x 0.2 = 0.04).

The Hardy–Weinberg model applies

when the following conditions are met:

1) No genetic drift

2) No selection

3) No mutation

4) No migration

 

By contrast, there will be change in gene

frequencies in a population when at least

one of these conditions occur:

1) Genetic drift

2) Selection

3) Mutation

4) Migration

 

In today’s lab, you will do a series of exercises that illustrate the effect of the different evolutionary agents on the

genetic structure of a model population. You will work with populations composed of individuals that are

represented by colored beads. White beads represent individuals that are homozygous for the white allele (WW);

red beads are individuals that are homozygous for the red allele (RR), and pink beads are heterozygous (WR).

These beads live in a habitat – a plastic dishpan filled with smaller beads. The larger beads of our population will

be retained by the mesh, while the smaller beads pass through the mesh.

When the individuals are recovered with the help of the mesh, the frequencies of the color alleles are determined

using the Hardy-Weinberg model. The alleles in our populations are codominant – each white individual

possesses two white alleles, each red individual two red alleles, and the pink individuals have one red and one

white allele. Consequently, the total number of color alleles in a population of 40 individuals is 80. If such a

population contains 10 white individuals, 20 pink individuals, and 10 red individuals, the frequency of white

alleles (p) is

(2 x number white beads) + number pink beads

p = —————————————————————-

(2 x number of beads total)

(2 x 10) + 20

p = ———————– = 0.5

80

Because p + q = 1, the frequency of the red allele (q) must also be 0.5.

1. NAT URAL S E L E CT I O N

Natural selection disturbs the Hardy-Weinberg equilibrium by discriminating between individuals with respect to

their ability to survive and reproduce. Individuals that are better at surviving to produce young will contribute

more genes to the next generation; they are said to have greater fitness than those individuals that leave no or

fewer offspring.

In this experiment you will test the hypothesis that individuals are more likely to survive and reproduce when

their coloration makes it easier to hide from predators in the environment.

 

 

Foundations of Biological Sciences I Evolutionary Agents – 3

1. Work in groups of four. Each group member assumes one of the following roles

Predator: Search for prey (large beads)

Data Recorder / Timer: record numerical results and time the predation sessions

Calculator: use a calculator to calculate the allele frequencies

Caretaker: look after and manipulate the experimental setup

2. Create a white habitat by filling the dishpan with small white beads. Establish an initial population by

adding 10 large white beads, 20 large pink beads and 10 large red beads into the habitat. “Hide” the

individuals in the habitat by mixing the large and small beads. The predator will prey on the large beads,

removing as many individuals as possible in a set amount of time. The survivors will reproduce a new

generation, upon which the predator will prey again. This cycle will be repeated several times. Make a

prediction as to how the frequency of red alleles in the populations will change over time.

Prediction:

 

3. The predator hunts for prey (large beads) in the habitat, and uses the pair of forceps to catch as many prey

items as possible in 30 seconds.

4. After the predation (selection) episode, strain the habitat with the sieve and count the remaining red, pink

and red individuals. Record the numbers in the second row in Table 1. Calculate the frequencies of the white

(p) and red (q) alleles remaining in the population, and record them in Table 2 (under First generation). For

example, if 6 white, 8 pink and 8 red individuals remain, the frequency of the white alleles is

To calculate p, use the observed numbers of each color within the formula:

(2 x number white beads) + number pink beads

p = ——————————————————–

(2 x number of beads total)

(2 x 6) + 8

p = ———————– = 0.45

44

 

Table 1: Large- Bead counts before and after four rounds of Natural Selection (Predation)

 

Population

White Beads

Pink Beads

Red Beads

Total Beads

 

Initial

Before 10 20 10 40

After

 

Second Generation

Before

After

 

Third Generation

Before

After

 

Fourth Generation

Before

After

 

 

Foundations of Biological Sciences I Evolutionary Agents – 4

Table 2: Allele and genotype frequencies due to Natural Selection (Predation)

Population p q p 2

2pq q 2

Initial 0.5 0.5 0.25 0.5 0.25

 

First Generation

 

Second Generation

 

Third Generation

 

Fourth Generation

 

5. Based on the new values (after selection) for allele frequencies, calculate the genotype frequencies for the

homozygous white (p 2 ) and red (q

2 ) individuals, and for the heterozygous pink individuals (2pq). Record the

new allele frequencies in Table 2. For example, if p now equals 0.43, the frequency of the homozygous

white individuals is

p 2

= (0.48) 2

= 0.23

6. Assuming that 40 individuals comprise the next and all succeeding generations, calculate the number of

white, red and pink individuals to create the next generation, and record the numbers in the Before row

under Second generation in Table 1. For this, and all future calculations, round up or down to the nearest

whole number. For example, if p 2 =0.23, the number of white individuals for the next generation is

p 2

x 40 = 0.23 x 40 = 9.2 or 9 white individuals

7. Calculate the numbers of white, red and pink individuals you need to construct the new generation, and

introduce them into the habitat for a new round of selection.

8. Repeat the selection and reproduction steps for three more rounds, filling in the remaining rows in Tables 1

and 2. When you are done, use the frequencies of the red allele from Table 2 to construct a histogram in the

appropriate space in Figure 1 below. Remember to label your axes and complete the figure caption.

Figure 1: Changes in frequency of the red allele (q) due to selection. ……………………………………………………………………..

……………………………………………………………………………………………………………………………………………………………………………….

……………………………………………………………………………………………………………………………………………………………………………….

 

 

 

 

 

 

 

 

 

 

0 1 2 3 4

1.0

0.5

0.0

 

 

Foundations of Biological Sciences I Evolutionary Agents – 5

What is your conclusion as to the prediction you made in point 2?

There are 3 different patterns of selection. Directional selection favors one extreme phenotype over the other and

causes allele frequencies to change in a predictable direction. Stabilizing selection favors an intermediate

phenotype, rather than one at the extremes. Disruptive selection disfavors intermediate phenotypes, and favors

the extreme ones. Which kind of selection is illustrated by predation of white, pink and red individuals in a white

habitat?

 

If two identical populations inhabited different environments (e.g. white and red habitats), how would the

frequency of the color genes in each habitat compare after a large number of generations?

 

When two populations become genetically different through time (divergence), individuals can lose the ability

to interbreed, and two new species are formed. This process is called speciation.

 

2. EFFECT OF GENE FLOW ON NATURAL SELECTION

New members may join populations (immigrations) or leave the population (emigration). As they do, the

frequencies of alleles in the population change. This gene flow due to migration can be a powerful force in

evolution.

1. Establish a new population as described in the previous section.

2. Begin the selection process as before, but this time 5 red individuals will immigrate into the population

before the new allele frequencies are determined. Write down a prediction of the hypothesis that gene flow

resulting from migration of individuals into a population undergoing predation affects the change in allele

frequencies expected from selection alone. Focus your prediction on the change in the frequency of red

alleles in the population.

3. Conduct 4 cycles of predation with migration. For each generation, write down the number of surviving

individuals in Table 3, and the allele frequencies in Table 4. When you are done, use the frequencies of the

red allele from Table 4 to construct a histogram as your homework.

Homework: Write a hypothesis and prediction for this evolutionary model based on your understanding of

gene flow. Create a histogram that displays the change through four generations of natural selection with

migration. Remember to include a figure caption and axis labels (10 pts). *Hint: see Figure 1

 

 

Foundations of Biological Sciences I Evolutionary Agents – 6

 

Table 3:

Large- Bead counts before and after four rounds of simulated Natural Selection and Gene Flow

 

Population

White Beads

Pink Beads

Red Beads

Total Beads

 

Initial

Before 10 20 10 40

After (First Gen) (survivors + 5)

 

Second Generation

Before

After (survivors + 5)

 

Third Generation

Before _________ _________ __________ _________

After _________ _________ (survivors + 5)

 

Fourth Generation

Before _________ _________ __________ _________

After _________ _________ (survivors + 5)

Table 4: Allele and Genotype frequencies due to Natural Selection and Gene Flow

Population p q p 2

2pq q 2

Initial

First Generation

Second Generation

Third Generation

Fourth Generation

 

How did migration influence the effectiveness of selection in this example?

If white individuals would have immigrated into the population instead of the red ones – how would this have

influenced the change in gene frequencies?

 

Through immigration, new genetic information is introduced into the population. Gene flow thus maintains

genetic variation in a population. Barriers to gene flow can decrease genetic variation within populations, and

also accelerate divergence between populations.

 

 

Foundations of Biological Sciences I Evolutionary Agents – 7

3. MUTATION

New genetic information can also be introduced into a population through mutation.

1. Establish a new population by placing 10 large white beads, 10 large red beads and 20 large pink beads in

the bowl. Do not add the small beads this time.

2. Designate one group member to pick 20 large beads from the bowl (without looking!). Use these 20 beads to establish a new generation. Then replace one white bead with a silver bead. This represents a mutation in the

gamete that one parent contributes to this generation.

3. Calculate the allele frequencies of the new generation, including the frequency of the new color allele (r),

and write them down in Table 5.

 

Table 5: Change in Allele Frequencies due to Mutation

Population p

q

r

 

Initial

 

New Generation

 

After the mutation, three alleles are present in the population (p + q + r = 1). Consequently, the Hardy-Weinberg

equation must be expanded to

p 2 + 2pq + q

2 + 2pr + 2qr + r

2 = 1.0.

In addition to white, pink and red phenotypes, there are now silver, silver-red, and in subsequent generation

potentially black phenotypes. If the next generation contains 50 individuals, how many offspring of each

phenotype would be found in the population? Use Table 6 to calculate the genotype and phenotype frequencies.

 

Table 6: Phenotypes two generations after a mutation

 

Phenotype Genotype Frequency

x 50

 

# Individuals

White p 2

 

 

Pink 2pq

Red q 2

 

 

Silver 2pr

Silver-Red 2qr

Black r 2

 

 

Imagine a population made up of individuals of the color phenotypes in these proportions. What effect will

natural selection have on the phenotypes in a white habitat?

 

Under which conditions would a rare black allele be favored?

 

 

Foundations of Biological Sciences I Evolutionary Agents – 8

4. GENETIC DRIFT

Gene frequencies can change over generations as a result of chance (Genetic Drift). Genetic drift is often a

problem for small populations, because it can result in a loss of genetic variability. In very small populations,

chance can even eliminate an allele from a population.

1. Establish a new population by placing 10 large white beads, 10 large red beads and 20 large pink beads in

the bowl. Do not add the small beads this time.

2. If all 40 members of this population have an equal chance of getting to reproduce, the allele frequencies for

the colors in the population are p = 0.5 and q = 0.5 (see first column of Table 7).

3. Now let’s see what happens when only a subset of the population gets a chance to reproduce. Choose,

without looking, 10 beads from the bowl. They will make up a small group of individuals that reproduce.

Record the allele frequencies in this cluster in the second column of Table 7.

4. Replace the 10 beads to the population and mix well. Then pick 30 new beads. They represent a larger group

of individuals that get to reproduce. Calculate the allele frequencies in this group, and add them to the third

column in Table 7.

 

 

Table 7: Allele frequencies resulting from Genetic Drift

Observed Frequency in

Expected Frequency Small Group Large Group

n

40

 

p

0.5

 

q

0.5

 

Compare the allele frequencies of the three groups of reproducing individuals. How does group size affect the

makeup of the next generation?

 

When members of an old population emigrate to establish a new population, the allele frequencies in the new

population can be heavily influenced by chance.

5. Reestablish the old 10/20/10 beads population you have worked with before. Then pick (without looking) 6

individuals which will represent the 6 founding members of a new population.

6. Move these individuals to a new habitat. Calculate the allele frequencies and record them in Table 8.

 

Table 8: Allele Frequencies in a Founder Population

 

Allele Frequency

Initial population Founder Population

 

p

0.5

 

q

0.5

 

How do the allele frequencies of the small founder population compare to the larger original population?

Foundations of Biological Sciences I Evolutionary Agents

 
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Monohybrid crosses

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Monohybrid crosses. How to Proceed

  • Read through the introductory materials below.
  • Open the Unit 6 Experiment Answer Sheet and complete the following Experiment exercises this unit:
    • Experiment 6 Exercise 1 – Monohybrid crosses (~45 min)
    • Experiment 6 Exercise 2 – Dihybrid crosses (~30 min)
    • Experiment 6 Exercise 3 – Inheritance of Human Traits (~30 min)
  • Save your completed Unit 6 Experiment Answer Sheet and submit it no later than Sunday midnight (CT).

Monhybrid and Dihybrid Crosses – Introduction

Mendel crossed true-breeding pea plants in order to develop and understanding of how traits are inherited. True-breeding means that if a plant was crossed with itself, it always generated offspring that looked like the parent. Although Mendel didn’t know this at the time, it meant that the parent plant was homozygous or had two copies of the same allele that controlled the appearance of the trait.

Mendel noticed that when he crossed two true-breeding plants exhibiting different versions of a trait (e.g., green and yellow); the offspring (F1) always looked like only one of the parent plants. We know now that the F1 individuals looked like the parent that carried the dominant trait. But what surprised Mendel, was that when he crossed the F1 individuals with each other, the F2 offspring exhibited BOTH traits! Based on this observation, he concluded that the F1 individuals were hybrids, meaning they carried both alleles for a given trait. Only the dominant trait was expressed in the F1 individuals and the recessive trait, although present, was masked.

A monohybrid cross is when you are interested in crossing individuals that vary in only a single trait (e.g., flower color, seed color, stem length). In a dihybrid cross, we are crossing individuals that differ at two traits (e.g., flower color and seed color, flower color and stem length). Obviously, the more traits that vary, the more complex the crosses become!

By examining the distribution of the various traits obtained following different types of crosses, Mendel was able to describe the general pattern of genetic inheritance. Be sure to review the online lecture this unit on Genetics and pp 146-153 in your book before starting these first two exercises.

We will be using the following website for the first exercise. Be sure that you can access it and use it before beginning:

Glencoe-McGraw Hill. No date. Punnett Squares
http://glencoe.mcgraw-hill.com/sites/dl/free/0078759864/383934/BL_05.html (Links to an external site.)

You will need to complete the Tables and answer the questions in the Unit 6 Experiment Answer Sheet for Exercises 1 and 2.

Inheritance of Human Traits – Introduction

Some human traits are controlled by a single gene that has only two alternative alleles. If a characteristic is determined by the dominant allele, one or both parents express that trait and many of the children will as well. Dominant characteristics will most likely be present in every generation, since the expression of these traits requires only one of the dominant alleles in order to be expressed. If the characteristic is determined by the recessive allele, then neither parent may express the trait nor few of the children. This is because two copies of the recessive allele must be present in order for the recessive trait to be expressed. If a trait is X-linked recessive; meaning the gene for the trait is found on the X chromosome, it will be expressed primarily in males.

The application of human genotypes in medicine and genetic counseling is becoming more and more necessary as we discover more about the human genome. Despite our increasing ability to decipher the chromosomes and their genes, an accurate family history remains one of the best sources of information concerning the individual. In this exercise you will determine your genotype for certain characteristics that are controlled by a single gene with two alleles based on your phenotype. We will not be looking at any X-linked traits in this exercise.

Use the information about the traits of interest in the Unit 6 Experiment Answer Sheet to answer the questions found there.

WEEK 6 EXPERIMENT ANSWER SHEET Please submit to the Week 6 Experiment dropbox no later than Sunday midnight.

SUMMARY OF ACTIVITIES FOR WEEK 6 EXPERIMENT ASSIGNMENT

· Experiment 6 Exercise 1 – Monhybrid Crosses

· Experiment 6 Exercise 2 – Dihybrid Cross

· Experiment 6 Exercise 3 – Inheritance of Human Traits

Experiment 6 Exercise 1: Monohybrid Crosses

You will be conducting monohybrid crosses using fruit flies. Open in the following website:

Glencoe-McGraw Hill. No date. Punnett Squares http://glencoe.mcgraw-hill.com/sites/dl/free/0078759864/383934/BL_05.html

Procedure

A. Open the above website and click on the VCR to listen to the introduction. Close the window when done.

B. Click on the Lab Notebook on the lab bench. A breeding scenario will be presented to you that you will need to carry out. Here are the possible phenotypes and genotypes you will using:

a. Normal wings (LL or Ll) or vestigial wings (ll)

b. Gray body (GG or Gg) or black body (gg)

C. Enter the Scenario number in Table 1 below.

D. Based on the Scenario, use the down arrows beneath the Parent 1 and Parent 2 boxes to select the appropriate parents. Look carefully at the flies so that you know which ones to select.

E. Before proceeding, click on the Check Parents button. If necessary, make corrections. If you are correct, the maternal and paternal alleles will be added to the Punnett Square.

F. Next, drag the correct allele combinations and the corresponding fly types to the boxes in the Punnett Square.

G. When you are done, click on Check Offspring. If necessary, make corrections.

H. Record your data in Table 1 below. An example has been given, but note that the example is not using the genotypes and phenotypes used in this exercise.

I. Click on Reset. Repeat steps B – H four more times for a total of five crosses. If a scenario is presented that has already been completed, click Reset again. DO NOT REPEAT a given scenario!

Note that the scenario number you need to record in the Table below is the number associated with the specific scenario you completed.

Table 1. Results of crosses.

 

 Parent Genotypes Offspring Genotypes Offspring Phenotype
Scenario # Parent 1 Parent 2 # % # %
Example Rr rr 2 Rr

2 rr

 50% Rr

50% rr

 2 red

2 white

 50% red

50% white
             
             
             
             
             

Questions

1. Which type of cross gave you the greatest number of genotypes? Was the number of phenotypes the same as the number of genotypes or different? If different, why (2 pts)?

2. Can the genotype for a gray-bodied fly be determined? If so, how? (3 pts)?

Experiment 6 Exercise 2: Dihybrid Cross

We will continue to use flies for our crosses, but this time we will examine the inheritance of TWO different traits: body color (gray or black) and wing type (long or vestigial). As with our first crosses, the gray body color is dominant (GG or Gg) over the black body color (gg). And the long wing type is dominant (LL or Ll) over vestigial (ll). Be sure you have reviewed our online Genetics lecture and this week’s reading before proceeding. An example of a dihybrid cross is shown on p 150 in your book.

Recall our flies from the previous exercise. We have the following traits:

· Gray body (GG or Gg) is dominant over black body (gg)

· Long wings (LL or Li) is dominant over vestigial wings (ll)

We will cross a gray bodied fly with long wings which has the genotype GGLl with a gray bodied fly with long wings with a genotype of GgLl . Note that even though the phenotypes are the same, the genotypes of the two parents are different.

Identify the four possible gametes produced by these two individuals. Note that each gamete must consist of two alleles (G or g and L or l):

Parent 1 Parent 2

image1.png image2.png

GGLl GgLl

Parent 1 (GGLl) Gametes: _______ ______ _______ _______ (1 pts)

Parent 2 (GgLl) Gametes: _______ ______ _______ _______ (1 pts)

Create a Punnett square to show the outcome of a cross between these two individuals (GGLl and GgLl) using the gametes you identified above (3 pts).

    Parent 1
           
Parent 2          
           
           
           

Questions

1. What are the possible F1 genotypes (these must now have four alleles) and their percentages (4 pts)?

2. Recall that GG and Gg individuals are gray bodied, while gg individuals are black bodied and that LL and Li individuals have long wings, while ll individuals have vestigial wings. What are the phenotypes of the resulting offspring and what are the percentages of these phenotypes (2 pts)?

Experiment 6 Exercise 3: Inheritance of Human Traits

Read over the Inheritance of Human Traits Introduction under the Week 6 Experiment link in our course before beginning.

Procedure

A. For each of the heritable traits describe below, determine which form you have (dominant form or recessive form). This is your phenotype.

B. Record your phenotype information in Table 2 below. Then, enter the possible genotype(s) you have based on your phenotype.

C. Answer the questions found following Table 2 below.

Description of Heritable Traits

Trait Possible Alleles Dominant Form Recessive

Form

 Examples
Ear lobes E or e Detached (Free) Attached  

image3.png 
Hairline W or w Widows peak Straight image4.jpg Widow’s peak Straight
Tongue rolling T or t Able to roll Unable to roll image5.jpg
Hand folding R or r Right thumb on top Left thumb on top image6.jpg
Chin C or c Cleft chin No cleft chin image7.jpg
Tongue folding F or f Can fold tongue backwards Cannot fold tongue backwards image8.jpg
Thumb H or h Straight thumb (cannot bend backwards) Hitchhiker’s thumb (can bend it backwards) image9.jpg
Little Finger B or b Bent inwards Straight image10.jpg
Mid-digital hair M or m Hair on fingers No hair on fingers  

image11.png 

An example is shown as to what should be entered in RED. Please correct the entry for “Ear lobes” based on your personal data. For the Genotypes, please use the letters provided above (8 pts).

Table 2. Your phenotypes and genotypes.

Trait Phenotype Genotype
Ear lobes Unattached OR Detached EE/Ee OR

ee
Hairline    
Tongue Rolling    
Hand Folding    
Chin    
Tongue Folding    
Thumb    
Little Finger    
Mid-digital Hair    

Questions

1.  Which traits did you have that were dominant (1 pts)?

2.  Which traits did you have that were recessive (1 pts)?

3. What does it mean to be homozygous for a trait? Cite source(s) used (1 pts).

4.  What does it mean to be heterozygous for a trait? Cite source(s) used (1 pts).

5.  Define genotype and phenotype? Cite source(s) used (1 pts).

6.  Which traits do you know for sure that you were homozygous (1 pts)?

Week 6 Experiment Grading Rubric

Component Expectation Points
Experiment 6 Exercise 1 Correctly perform and record the outcome of five monohybrid crosses (Table 1).

 5
 

 Demonstrate an understanding of the possible outcomes of monohybrid crosses with respect to genotypes and phenotypes (Questions 1-2).

 5
Experiment 6 Exercise 2 Determine the correct parental gametes and conduct a dihybrid cross.

 5
 

 Correctly evaluate the outcome of a dihybrid cross (Questions 1-2).

 6
Experiment 6 Exercise 3

 Correctly recognize one’s phenotype and assigns the correct genotype (Table 2).

 8
 

 Demonstrate an understanding of dominant and recessive traits, genotype vs phenotype and homozygous vs heterozygous (Questions 1-6).

 6
TOTAL  

 35 pts

Updated October 2013

Monohybrid crosses

 
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Gene BioEthics

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Gene BioEthics. Part 1:

 

Directions: Explore the attached article and videos.  Answer the associated questions with a few short sentences.  Each question is worth 1 point unless otherwise noted for a total of 35 points.   Please submit under the “journals” tab under the heading “DNA: Gene therapy and cloning”.

 

 

DNA : Gene therapy and cloning

Directions: Explore the attached article and videos below. Answer the associated questions with a few short sentences. Each question is worth 1 point unless otherwise noted for a total of 35 points. Please submit under the “journals” tab under the heading “DNA: Gene therapy and cloning”.

Picture courtesy of http://img.timeinc.net/time/2001/stemcells/images/stemcells.jpg

 

What are the ethical issues surrounding the stem cell debate?

“Human embryonic stem cell (HESC) research offers much hope for alleviating the human suffering brought on by the ravages of disease and injury. HESCs are characterized by their capacity for self-renewal and their ability to differentiate into all types of cells of the body. The main goal of HESC research is to identify the mechanisms that govern cell differentiation and to turn HESCs into specific cell types that can be used for treating debilitating and life-threatening diseases and injuries….”

(#1) Ethics of Stem Cell Research: http://plato.stanford.edu/entries/stem-cells/ (5 points)

1. The standard view of those that oppose Human Stem Cell Research is that a human being begins to exist with the emergence of what?

2. Why do Smith and Brogard (2003) and McMahan (2002) reject the stipulation that the early human embryo is a human being?

3. What are some of the capacities that are necessary for the right to Life?

4. How does the article morally distinguish the creation of embryos for reproductive purposes from the creation of embryos for research and therapeutic reasons? (2 points)

(#2) The Ethical Questions of Stem Cell Research (6 minutes) (4 points)

https://www.youtube.com/watch?v=f5d0ieWfKlI

1. What were the first guidelines available in the United States for governing the use of stem cells in research?

2. What is the Hinxton group?

3. Under the National Academy of Science, What does ESCROC stand for?

4. Who is involved in ESCROC?

 

What is the technology behind our understanding of gene transfer and cloning?

http://www.intechopen.com/source/html/44748/media/image4.jpeg Image result for clones

Pictures courtesy of: http://www.wnd.com/files/2012/12/babies-cloning-340×255.jpg

http://www.intechopen.com/source/html/44748/media/image4.jpeg

(#3)Eyes of Nye: Cloning (24 minutes) (11 points)

http://www.bing.com/videos/search?q=eyes+of+nye+cloning&&view=detail&mid=80D719E65E993F03C22880D719E65E993F03C228&FORM=VRDGAR

1. What are some of the benefits to therapeutic cloning?

2. Describe the process of somatic cell nuclear transfer. (2 points)

3. The first patent for cloning was given to the scientists who cloned Dolly the sheep. What did this provide for the company?

4. Dr. Billie Swalla uses stem cell research to study how genes do what?

5. Why does reproductive cloning not work very well?

6. Dolly died at the age of 7 indicating what about the nucleus used?

7. Dr. Hans Keirstead works with human embryonic stem cells in hopes of treating what kinds of injuries?

8. What evidence is shown (with the rats) that human embryonic stem cells have great therapeutic hope for the future?

9. What is happening inside the rat with the injected stem cells?

10. Where does Dr. Jeffery Kahn stand with regard to moral rights of the embryo?

11. Is there a law in the United States that prohibits that prohibits cloning?

 

 

 

(#4) Stem Cells- The Future: An Introduction to iPS cells (16 minutes) (5 points)

http://www.bing.com/videos/search?q=stem+cells+the+future+videos&FORM=HDRSC3#view=detail&mid=42240DF444901218969542240DF4449012189695

1. What are some of the benefits for using iPS cells? (2 points)

2. What types of patients does Dr. Shinyayamanaka hope to help with his technology?

3. What are the new ethical questions that arise with this technology? (2 points)

 

http://img2.timeinc.net/people/i/2007/archive/covers/95/6_12_95_205x273.jpg https://kinoimages.files.wordpress.com/2012/06/christopherreeve-herb-ritts.jpg

Images courtesy of: http://img2.timeinc.net/people/i/2007/archive/covers/95/6_12_95_205x273.jpg https://kinoimages.files.wordpress.com/2012/06/christopherreeve-herb-ritts.jpg

(#5) Cloning Humans? – (30 minutes) (10 points)

https://www.youtube.com/watch?v=R4JoRy_vNEw

1. What is the difference between reproductive cloning and therapeutic cloning?

2. The Eugenics movement in the first part of the 20th century resulted in sterilization of certain members of the population whose genes were determined to not be desirable. How is cloning related to this movement? (3 points)

3. Dr. Brent Blackwelder (President of “Friends of the Earth”) claims that genetic engineering will be similar to “invasive species” which could harm the environment. True or false?

4. According to the video, before researchers can use cloning in their research they must do what (in the code of practice)?

5. What was the cloning scandal that occurred in Korea?

6. What are some of the risks involved in therapeutic cloning? (2 points)

7. According to the video, the media has misled the public leading them to believe that only embryonic stem cells could be used to cure certain diseases (such as Parkinsons, or spinal cord defects). True or False?

 

 

 

Part 2:

Post a brief blog / response to ONE selected article from http://www.bioethics.com.  This response should be approximately 350-450 words, roughly 4 -6 paragraphs. You should be able to defend your viewpoint using one of the ethical approaches described in the “Framework for Ethical Decision Making” guide (attached in the Introduction to Bioethics link above).

Please follow the format and detailed rubric (below). Please post to the “Blogs” tab under “Tools”. This blog is worth 25 points.

 

Bioethics essay Rubric Point value
What is the issue or topic of concern and why is this issue controversial? 2
What is the procedure, activity, research or technology used for?

What is the goal?

What studies are being conducted?

 3
What are the pros and cons? 3
What parties are affected?

What moral rights do the affected parties have?

How are these rights being violated?

 3
What role has the media or education system played (if any) in reporting this issue and how has it affected the public?

Do you feel the reporting has been fair and unbiased?

 2
What treatment (policy or decision) do you support?

Which method (below) will you use to arrive at this decision?

1. What leads to the best overall consequences? (Utilitarian approach)

2. Which course of action best respects all parties’ rights? (rights approach)

3. Which course of action treats everyone the same and does not show discrimination? (The fairness or justice approach)

4. Which course of action advances the common good (common good approach)

5. Which course of action develops moral virtues (The virtue approach)

 5
Post the link to  another article that discusses similar technology  – Describe the similarities (or differences) in the research 2
Respectfully respond to one other student blog 5
Total points 25

 

 

 

 

 

INTRODUCTION:

 

THINKING ETHICALLY A Framework for Moral Decision Making

 

***This article updates several previous pieces from Issues in Ethics by Manuel Velasquez – Dirksen Professor of Business Ethics at Santa Clara University and former Center director – and Claire Andre, associate Center director. “Thinking Ethically” is based on a framework developed by the authors in collaboration with Center Director Thomas Shanks, S.J., Presidential Professor of Ethics and the Common Good Michael J. Meyer, and others. The framework is used as the basis for many programs and presentations at the Markkula Center for Applied Ethics.

TAKEN FROM : http://www.scu.edu/ethics/practicing/decision/framework.html

 

 

 

 

Moral issues greet us each morning in the newspaper, confront us in the memos on our desks, nag us from our children’s soccer fields, and bid us good night on the evening news. We are bombarded daily with questions about the justice of our foreign policy, the morality of medical technologies that can prolong our lives, the rights of animals or perhaps the fairness of our children’s teachers dealing with diverse students in their classrooms.

 

Dealing with these moral issues is often perplexing. How, exactly, should we think through an ethical issue? What questions should we ask? What factors should we consider?

 

WHAT IS ETHICS?

 

Simply stated, ethics refers to standards of behavior that tell us how human beings ought to act in the many situations in which they find themselves-as friends, parents, children, citizens, businesspeople, teachers, professionals, and so on.

 

According to The National Institute of Health: “Ethics seeks to determine what a person should do, or the best course of action, and provides reasons why. It also helps people decide how to behave and treat one another, and what kinds of communities would be good to live in.”

“Bioethics is a subfield of ethics that explores ethical questions related to the life sciences. Bioethical analysis helps people make decisions about their behavior and about policy questions that governments, organizations, and communities must face when they consider how best to use new biomedical knowledge and innovation”.

 

WHAT ETHICS IS NOT:

 

• Ethics is not the same as feelings. Feelings provide important information for our ethical choices. Some people have highly developed habits that make them feel bad when they do something wrong, but many people feel good even though they are doing something wrong. And often our feelings will tell us it is uncomfortable to do the right thing if it is hard.

 

Ethics is not religion. Many people are not religious, but ethics applies to everyone. Most religions do advocate high ethical standards but sometimes do not address all the types of problems we face.

 

• Ethics is not following the law. A good system of law does incorporate many ethical standards, but law can deviate from what is ethical. Law can become ethically corrupt, as some totalitarian regimes have made it. Law can be a function of power alone and designed to serve the interests of narrow groups. Law may have a difficult time designing or enforcing standards in some important areas, and may be slow to address new problems.

 

• Ethics is not following culturally accepted norms. Some cultures are quite ethical, but others become corrupt -or blind to certain ethical concerns (as the United States was to slavery before the Civil War). “When in Rome, do as the Romans do” is not a satisfactory ethical standard.

 

• Ethics is not science. Social and natural science can provide important data to help us make better ethical choices. But science alone does not tell us what we ought to do. Science may provide an explanation for what humans are like. But ethics provides reasons for how humans ought to act. And just because something is scientifically or technologically possible, it may not be ethical to do it.

 

THINKING LIKE A BIOETHICIST: MAKING ETHICAL DECISIONS

 

The first step in analyzing moral issues is obvious but not always easy: Get the facts. Some moral issues create controversies simply because we do not bother to check the facts. This first step, although obvious, is also among the most important and the most frequently overlooked.

 

But having the facts is not enough. Facts by themselves only tell us what is; they do not tell us what ought to be. In addition to getting the facts, resolving an ethical issue also requires an appeal to values.

 

Philosophers have developed five different approaches to values to deal with moral issues.

 

1. The Utilitarian Approach Utilitarianism was conceived in the 19th century by Jeremy Bentham and John Stuart Mill to help legislators determine which laws were morally best. Both Bentham and Mill suggested that ethical actions are those that provide the greatest balance of good over evil.

To analyze an issue using the utilitarian approach, we first identify the various courses of action available to us. Second, we ask who will be affected by each action and what benefits or harms will be derived from each. And third, we choose the action that will produce the greatest benefits and the least harm. The ethical action is the one that provides the greatest good for the greatest number.

 

2. The Rights Approach The second important approach to ethics has its roots in the philosophy of the 18th-century thinker Immanuel Kant and others like him, who focused on the individual’s right to choose for herself or himself. According to these philosophers, what makes human beings different from mere things is that people have dignity based on their ability to choose freely what they will do with their lives, and they have a fundamental moral right to have these choices respected. People are not objects to be manipulated; it is a violation of human dignity to use people in ways they do not freely choose.

Of course, many different, but related, rights exist besides this basic one. These other rights (an incomplete list below) can be thought of as different aspects of the basic right to be treated as we choose.

· The right to the truth: We have a right to be told the truth and to be informed about matters that significantly affect our choices.

· The right of privacy: We have the right to do, believe, and say whatever we choose in our personal lives so long as we do not violate the rights of others.

· The right not to be injured: We have the right not to be harmed or injured unless we freely and knowingly do something to deserve punishment or we freely and knowingly choose to risk such injuries.

· The right to what is agreed: We have a right to what has been promised by those with whom we have freely entered into a contract or agreement.

 

In deciding whether an action is moral or immoral using this second approach, then, we must ask, Does the action respect the moral rights of everyone? Actions are wrong to the extent that they violate the rights of individuals; the more serious the violation, the more wrongful the action.

 

3. The Fairness or Justice Approach The fairness or justice approach to ethics has its roots in the teachings of the ancient Greek philosopher Aristotle, who said that “equals should be treated equally and unequals unequally.” The basic moral question in this approach is: How fair is an action? Does it treat everyone in the same way, or does it show favoritism and discrimination?

Favoritism gives benefits to some people without a justifiable reason for singling them out; discrimination imposes burdens on people who are no different from those on whom burdens are not imposed. Both favoritism and discrimination are unjust and wrong.

 

4. The Common-Good Approach This approach to ethics assumes a society comprising individuals whose own good is inextricably linked to the good of the community. Community members are bound by the pursuit of common values and goals.

The common good is a notion that originated more than 2,000 years ago in the writings of Plato, Aristotle, and Cicero. More recently, contemporary ethicist John Rawls defined the common good as “certain general conditions that are…equally to everyone’s advantage.”

In this approach, we focus on ensuring that the social policies, social systems, institutions, and environments on which we depend are beneficial to all. Examples of goods common to all include affordable health care, effective public safety, peace among nations, a just legal system, and an unpolluted environment.

Appeals to the common good urge us to view ourselves as members of the same community, reflecting on broad questions concerning the kind of society we want to become and how we are to achieve that society. While respecting and valuing the freedom of individuals to pursue their own goals, the common-good approach challenges us also to recognize and further those goals we share in common.

 

 

 

5. The Virtue Approach The virtue approach to ethics assumes that there are certain ideals toward which we should strive, which provide for the full development of our humanity. These ideals are discovered through thoughtful reflection on what kind of people we have the potential to become.

Virtues are attitudes or character traits that enable us to be and to act in ways that develop our highest potential. They enable us to pursue the ideals we have adopted. Honesty, courage, compassion, generosity, fidelity, integrity, fairness, self-control, and prudence are all examples of virtues.

Virtues are like habits; that is, once acquired, they become characteristic of a person. Moreover, a person who has developed virtues will be naturally disposed to act in ways consistent with moral principles. The virtuous person is the ethical person.

In dealing with an ethical problem using the virtue approach, we might ask, What kind of person should I be? What will promote the development of character within myself and my community?

 

 

Putting the Approaches Together

Each of the approaches helps us determine what standards of behavior can be considered ethical. There are still problems to be solved, however.

 

The first problem is that we may not agree on the content of some of these specific approaches. We may not all agree to the same set of human and civil rights .We may not agree on what constitutes the common good. We may not even agree on what is a good and what is a harm.

 

The second problem is that the different approaches may not all answer the question “What is ethical?” in the same way. Nonetheless, each approach gives us important information with which to determine what is ethical in a particular circumstance. And much more often than not, the different approaches do lead to similar answers.

 

Ethical Problem Solving ** Students should be familiar with these five steps in ethical problem solving These five approaches suggest that once we have ascertained the facts, we should ask ourselves five questions when trying to resolve a moral issue:

 

1. What benefits and what harms will each course of action produce, and which alternative will lead to the best overall consequences? (The Utilitarian Approach)

2. What moral rights do the affected parties have, and which course of action best respects those rights? (The Rights Approach)

3. Which course of action treats everyone the same, except where there is a morally justifiable reason not to, and does not show favoritism or discrimination? (The Fairness or Justice Approach)

4. Which course of action advances the common good? (The Common Good Approach)

5. Which course of action develops moral virtues? (The Virtue Approach)

This method, of course, does not provide an automatic solution to moral problems. It is not meant to. The method is merely meant to help identify most of the important ethical considerations. In the end, we must deliberate on moral issues for ourselves, keeping a careful eye on both the facts and on the ethical considerations involved.

 

 

 

 

WEIGHING ETHICAL CONSIDERATIONS

Please Note: Sometimes it is not easy or even possible to act in accordance with all the relevant considerations at the same time.

For example, you might want to show respect for your grandmother by allowing her to continue driving, even when her eyesight is failing, but to minimize harm, you might feel a responsibility to take her keys away. In a case like that, it’s hard both to show respect for her desire to move around freely and to protect her and others from the harm that might be caused by a car accident. Which of these core ethical considerations should count more (respect for persons, which motivates you to allow her to keep driving, or minimizing harms, which motivates you to take her keys away)? How should you decide?

When an ethical problem arises, each individual may prioritize and choose which considerations should be favored in a different way. Often, there is no one right answer. In addition, people can emphasize different ethical considerations in the process of ethical analysis but arrive at the same decision about what should be done

Gene BioEthics

 
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Nutrition

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Nutrition. Create a PowerPoint presentation of no more than 15 slides that reflect your understanding of the three macronutrients discussed in this module: Carbohydrates, Lipids, and Proteins. Be creative!
Each slide should include information about each macronutrient.

  • Definition of the macronutrient inclusive of its      function and structure
  • Where they are digested and absorbed
  • Types and their purpose
  • Special characteristics and function
  • Clinical applications as they relate to health and      diets

Use APA Editorial Format for citations and references used other than the textbook.

Macronutrients – Carbohydrates, Lipids, and Proteins

Macronutrients

In this module nutrients are introduced with a discussion about how they work in the body. There are six classes of nutrients:

  • Energy yielding macronutrients: Carbohydrates, Lipids      or Fats, and Proteins
  • Non-energy yielding micronutrients: Vitamins (water soluble      and fat soluble) and Minerals (macrominerals and microminerals) and Water

In this module the focus will be on energy yielding macronutrients. In the next module the non-energy micronutrients are discussed.

Let’s start with an overview by viewing the Gastrointestinal Tract in Action http://www.dnatube.com/video/1104/Gastrointestinal-tract-in-action and you may find the following CDC Nutrition for Everyone website helpful http://www.cdc.gov/nutrition/everyone/index.html

Carbohydrates: Structure and Sources

A carbohydrate is an organic compound (a substance that contains carbon bonded to hydrogen) that provides energy. Chemically, all carbohydrates contain carbon, hydrogen, and oxygen in the same proportion as water (H2O). A carbohydrate is measured in calories or “kilocalories.”

A kilocalorie (C) is a unit of energy. Note the capital C means these are kilocalories and not calories. Carbohydrates provide 4 Calories/gram and are an immediate source of energy for the body. For example, to find the number of carbohydrate kilocalories, find the amount of carbohydrates per serving and multiply this number by four to get the amount of carbohydrate kilocalories. Example: 20g carbohydrates x 4 = 80 kilocalories of carbohydrates. So keep this in mind when teaching clients.

Carbohydrates include starches, fiber, and sugars (glucose). Carbohydrates can be found in rice, pasta, cereals, starchy vegetables (corn, potatoes, green beans) and bread. Fiber-rich carbohydrates include berries, kidney beans, and broccoli. Carbohydrates with a large amount of sugars are baked goods, cookies, cakes, soda, syrups, and honey. You can think of carbohydrates as anything with “white” ingredients (white flour, white sugar). Fruits are also considered carbohydrates with sugar as well as alcohol. This is helpful to remember when conducting client teaching. You help them to distinguish between high calorie, high starch, and high sugar carbohydrates.

Carbohydrates: Role in the Body and Health Effects

The number one role carbohydrates play is to supply energy (4 C/gram). Carbohydrates are specifically important to neurologic function (brain) and physical exercise. Also, carbohydrates save protein use in the body by using carbohydrates for energy rather than growth and maintenance of body tissues and prevent ketosis. Growth and maintenance of body tissues is best done by proteins. Carbohydrates provide fiber from whole grains. Fiber reduces the risk of obesity, heart disease, type 2 diabetes, and high cholesterol. Fiber is needed to prevent constipation which can lead to hemorrhoids, and gastrointestinal disorders such as diverticulosis and colon cancer. Our bodies need 45-65% carbohydrate intake of our total energy intake (the Acceptable Macronutrient Distribution Range or AMDR). Adequate Intake of fiber is 25 grams per day for women and 38g for men.

An important point for nurses to remember about carbohydrates is that a low carbohydrate high protein diet can lead to keto-acidosis and damage to the heart, liver, and kidneys because the body will break down proteins (and muscle) if there is not enough glucose in the body for energy. Another important point is that the liver converts all molecules to glucose. So for those diabetic clients on oral anti-diabetic medications, always consider liver function. Hypoglycemia is another disease process to recognize concerning carbohydrates. Lastly, lactose intolerance is considered when discussing carbohydrates because dairy products contain lactose, a sugar and form of carbohydrates.

Lipids: Structure and Sources

A lipid is also an organic compound that provides an important energy source during rest and low intensity exercise. Chemically all fats contain carbon, hydrogen, and oxygen much less proportionately to water. A lipid also contains phospholipids, phosphorus, and occasionally nitrogen. Lipids include triglycerides, phospholipids, and sterols. Lipids are insoluble in water. Think of a lipid when making a salad dressing; the oil or fat stays on top of the water.

Lipids provide 9 Calories/gram and are a later source of energy for the body after carbohydrate calories have been used. Lipids contain the most concentrated amount of energy for the body. To find the number of lipid kilocalories, find the amount of fats per serving and multiply this number by nine to get the amount of fat kilocalories. For example, 20g fat x 9 = 180 kilocalories of fats.

Food sources include: oils, shortening, butter, margarine, mayonnaise, salad dressings, table cream, and sour cream. Triglycerides are the most common form of fats found in foods and contain fatty acids. Some fatty acids increase the risk of chronic disease and some fatty acids prevent disease and protect our health. Phospholipids contain phosphate and are found in only a few foods. Cholesterol is an example of a phospholipid. Cholesterol is found in any animal product. If it comes from an animal and has fat, it is cholesterol. Meat, eggs, dairy, and eggs are all examples of foods that contain cholesterol.

Lipids: Role in the Body and Health Effects

Lipids carry important fat soluble vitamins A, D, E, and K. They also provide a sense of fullness and satisfaction since they take longer to digest. There are three types of triglycerides and are important to distinguish because of their health effects. Saturated fatty acids (coconut oil, butter, cheese, whole milk, cream, lard, and beef fat) can cause high cholesterol, heart disease, and atherosclerosis, and contribute to obesity since fat is stored in adipose tissue. But Mono and Poly unsaturated fats such as olive oil, nuts, canola oil, corn, and safflower oils help prevent high cholesterol. Therefore, animal fats are saturated and contribute to high cholesterol, cardiovascular disease, and cancer, while plant fats are good and help lower the risk of disease. Also, saturated fats are solid at room temperature, while unsaturated fats are liquid at room temperature. This is an important point when teaching clients about fat in the diet. Essential fatty acids cannot be synthesized by the body and must be consumed in the diet (linoleic acid and alpha-linolenic acid).

There is one exception to the saturated fat classification, coconut oil. In years past, coconut oil was viewed as an artery clogging fat and placed in the same category as animal fat. When reexamined by experts this medium chain fatty acid is now seen as a heart healthy fat that fights disease. This fat is not stored in the body as adipose tissue, but rather metabolized by the liver immediately and used as energy. For this reason, experts say it speeds up metabolism and promotes weight loss. This beneficial oil is involved in research around the globe for medical conditions such as Alzheimer’s, Diabetes Mellitus Types I and II, Coronary Artery Disease, and numerous skin disorders.

An important point to know about lipids is to be aware of what cholesterol numbers mean. See http://www.cdc.gov/cholesterol/ldl_hdl.htm and review the National Lipid Association recommendations for patient-centered management of dyslipidemia: Part 1 – executive summary http://www.lipidjournal.com/article/S1933-2874(14)00274-8/fulltext#sec1.1

Proteins: Structure and Sources

A protein is also an organic compound that supports tissue growth, repair, and maintenance. Chemically all proteins contain carbon, hydrogen, and oxygen and differ from carbs and lipids in that they contain nitrogen. Proteins contain amino acids. The body will break down food proteins into amino acids and then rebuild the amino acids to build protein for the body, such as in the muscles and blood. Essential amino acids are only obtained from food, the body cannot make them. Non-essential amino acids are made by the body and do not need to be consumed in the diet. Proteins provide 4 Calories/gram for energy.

Food sources of proteins include: meat, poultry, fish, eggs, milk, yogurt, cheese, dried beans and peas, and nuts and nut butters. A small amount of protein can sometimes be found in whole grains and vegetables.
Proteins: Role in the Body and Health Effects

Proteins are essential for tissue growth, repair, and maintenance. A diet with the appropriate amount of protein promotes healing in any plan of care. If clients are not consuming enough carbohydrates and lipids, the body will use protein as an energy source. This can lead to problems such as poor healing, ketoacidosis, and muscle damage to include heart, kidneys, and liver. Protein can be used for energy in times of low carb intake and/or starvation. The body will break down protein for essential glucose to provide energy to the brain. Proteins have so many functions it is impossible to discuss them all. Here are the other functions to pay attention to in your readings: enzymes and hormones, maintaining fluid and electrolyte balance, acid-base balance, building a strong immune system, neurotransmission, and the transport and storage of other nutrients. Also the effects of consuming too much protein is not what you might think given many Americans think high protein diets are essential to weight loss and do not realize the health effects such as high cholesterol, bone loss, and kidney disease.

Note that according to the Institute of Medicine, a balanced diet will consist of between 20 to 35 percent calories from fat, 10 to 35 percent from protein and 45 to 65 percent from carbohydrates. Aim for 30 percent, 20 percent and 50 percent of your calories from fat, protein and carbohydrates, respectively.

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Create a PowerPoint presentation of no more than 15 slides that reflect your understanding of the three macronutrients discussed in this module: Carbohydrates, Lipids, and Proteins. Be creative!  Each slide should include information about each macronutrient.

· Definition of the macronutrient inclusive of its function and structure

· Where they are digested and absorbed

· Types and their purpose

· Special characteristics and function

· Clinical applications as they relate to health and diets

Use APA Editorial Format for citations and references used other than the textbook.

 

Macronutrients – Carbohydrates, Lipids, and Proteins

Macronutrients

In this module nutrients are introduced with a discussion about how they work in the body. There are six classes of nutrients:

· Energy yielding macronutrients: Carbohydrates, Lipids or Fats, and Proteins

· Non-energy yielding micronutrients: Vitamins (water soluble and fat soluble) and Minerals (macrominerals and microminerals) and Water

In this module the focus will be on energy yielding macronutrients. In the next module the non-energy micronutrients are discussed.

Let’s start with an overview by viewing the Gastrointestinal Tract in Action http://www.dnatube.com/video/1104/Gastrointestinal-tract-in-action and you may find the following CDC Nutrition for Everyone website helpful http://www.cdc.gov/nutrition/everyone/index.html

Carbohydrates: Structure and Sources

A carbohydrate is an organic compound (a substance that contains carbon bonded to hydrogen) that provides energy. Chemically, all carbohydrates contain carbon, hydrogen, and oxygen in the same proportion as water (H2O). A carbohydrate is measured in calories or “kilocalories.”

A kilocalorie (C) is a unit of energy. Note the capital C means these are kilocalories and not calories. Carbohydrates provide 4 Calories/gram and are an immediate source of energy for the body. For example, to find the number of carbohydrate kilocalories, find the amount of carbohydrates per serving and multiply this number by four to get the amount of carbohydrate kilocalories. Example: 20g carbohydrates x 4 = 80 kilocalories of carbohydrates. So keep this in mind when teaching clients.

Carbohydrates include starches, fiber, and sugars (glucose). Carbohydrates can be found in rice, pasta, cereals, starchy vegetables (corn, potatoes, green beans) and bread. Fiber-rich carbohydrates include berries, kidney beans, and broccoli. Carbohydrates with a large amount of sugars are baked goods, cookies, cakes, soda, syrups, and honey. You can think of carbohydrates as anything with “white” ingredients (white flour, white sugar). Fruits are also considered carbohydrates with sugar as well as alcohol. This is helpful to remember when conducting client teaching. You help them to distinguish between high calorie, high starch, and high sugar carbohydrates.

Carbohydrates: Role in the Body and Health Effects

The number one role carbohydrates play is to supply energy (4 C/gram). Carbohydrates are specifically important to neurologic function (brain) and physical exercise. Also, carbohydrates save protein use in the body by using carbohydrates for energy rather than growth and maintenance of body tissues and prevent ketosis. Growth and maintenance of body tissues is best done by proteins. Carbohydrates provide fiber from whole grains. Fiber reduces the risk of obesity, heart disease, type 2 diabetes, and high cholesterol. Fiber is needed to prevent constipation which can lead to hemorrhoids, and gastrointestinal disorders such as diverticulosis and colon cancer. Our bodies need 45-65% carbohydrate intake of our total energy intake (the Acceptable Macronutrient Distribution Range or AMDR). Adequate Intake of fiber is 25 grams per day for women and 38g for men.

An important point for nurses to remember about carbohydrates is that a low carbohydrate high protein diet can lead to keto-acidosis and damage to the heart, liver, and kidneys because the body will break down proteins (and muscle) if there is not enough glucose in the body for energy. Another important point is that the liver converts all molecules to glucose. So for those diabetic clients on oral anti-diabetic medications, always consider liver function. Hypoglycemia is another disease process to recognize concerning carbohydrates. Lastly, lactose intolerance is considered when discussing carbohydrates because dairy products contain lactose, a sugar and form of carbohydrates.

Lipids: Structure and Sources

A lipid is also an organic compound that provides an important energy source during rest and low intensity exercise. Chemically all fats contain carbon, hydrogen, and oxygen much less proportionately to water. A lipid also contains phospholipids, phosphorus, and occasionally nitrogen. Lipids include triglycerides, phospholipids, and sterols. Lipids are insoluble in water. Think of a lipid when making a salad dressing; the oil or fat stays on top of the water.

Lipids provide 9 Calories/gram and are a later source of energy for the body after carbohydrate calories have been used. Lipids contain the most concentrated amount of energy for the body. To find the number of lipid kilocalories, find the amount of fats per serving and multiply this number by nine to get the amount of fat kilocalories. For example, 20g fat x 9 = 180 kilocalories of fats.

Food sources include: oils, shortening, butter, margarine, mayonnaise, salad dressings, table cream, and sour cream. Triglycerides are the most common form of fats found in foods and contain fatty acids. Some fatty acids increase the risk of chronic disease and some fatty acids prevent disease and protect our health. Phospholipids contain phosphate and are found in only a few foods. Cholesterol is an example of a phospholipid. Cholesterol is found in any animal product. If it comes from an animal and has fat, it is cholesterol. Meat, eggs, dairy, and eggs are all examples of foods that contain cholesterol.

Lipids: Role in the Body and Health Effects

Lipids carry important fat soluble vitamins A, D, E, and K. They also provide a sense of fullness and satisfaction since they take longer to digest. There are three types of triglycerides and are important to distinguish because of their health effects. Saturated fatty acids (coconut oil, butter, cheese, whole milk, cream, lard, and beef fat) can cause high cholesterol, heart disease, and atherosclerosis, and contribute to obesity since fat is stored in adipose tissue. But Mono and Poly unsaturated fats such as olive oil, nuts, canola oil, corn, and safflower oils help prevent high cholesterol. Therefore, animal fats are saturated and contribute to high cholesterol, cardiovascular disease, and cancer, while plant fats are good and help lower the risk of disease. Also, saturated fats are solid at room temperature, while unsaturated fats are liquid at room temperature. This is an important point when teaching clients about fat in the diet. Essential fatty acids cannot be synthesized by the body and must be consumed in the diet (linoleic acid and alpha-linolenic acid).

There is one exception to the saturated fat classification, coconut oil. In years past, coconut oil was viewed as an artery clogging fat and placed in the same category as animal fat. When reexamined by experts this medium chain fatty acid is now seen as a heart healthy fat that fights disease. This fat is not stored in the body as adipose tissue, but rather metabolized by the liver immediately and used as energy. For this reason, experts say it speeds up metabolism and promotes weight loss. This beneficial oil is involved in research around the globe for medical conditions such as Alzheimer’s, Diabetes Mellitus Types I and II, Coronary Artery Disease, and numerous skin disorders.

An important point to know about lipids is to be aware of what cholesterol numbers mean. See http://www.cdc.gov/cholesterol/ldl_hdl.htm and review the National Lipid Association recommendations for patient-centered management of dyslipidemia: Part 1 – executive summary http://www.lipidjournal.com/article/S1933-2874(14)00274-8/fulltext#sec1.1

Proteins: Structure and Sources

A protein is also an organic compound that supports tissue growth, repair, and maintenance. Chemically all proteins contain carbon, hydrogen, and oxygen and differ from carbs and lipids in that they contain nitrogen. Proteins contain amino acids. The body will break down food proteins into amino acids and then rebuild the amino acids to build protein for the body, such as in the muscles and blood. Essential amino acids are only obtained from food, the body cannot make them. Non-essential amino acids are made by the body and do not need to be consumed in the diet. Proteins provide 4 Calories/gram for energy.

Food sources of proteins include: meat, poultry, fish, eggs, milk, yogurt, cheese, dried beans and peas, and nuts and nut butters. A small amount of protein can sometimes be found in whole grains and vegetables. Proteins: Role in the Body and Health Effects

Proteins are essential for tissue growth, repair, and maintenance. A diet with the appropriate amount of protein promotes healing in any plan of care. If clients are not consuming enough carbohydrates and lipids, the body will use protein as an energy source. This can lead to problems such as poor healing, ketoacidosis, and muscle damage to include heart, kidneys, and liver. Protein can be used for energy in times of low carb intake and/or starvation. The body will break down protein for essential glucose to provide energy to the brain. Proteins have so many functions it is impossible to discuss them all. Here are the other functions to pay attention to in your readings: enzymes and hormones, maintaining fluid and electrolyte balance, acid-base balance, building a strong immune system, neurotransmission, and the transport and storage of other nutrients. Also the effects of consuming too much protein is not what you might think given many Americans think high protein diets are essential to weight loss and do not realize the health effects such as high cholesterol, bone loss, and kidney disease.

Note that according to the Institute of Medicine, a balanced diet will consist of between 20 to 35 percent calories from fat, 10 to 35 percent from protein and 45 to 65 percent from carbohydrates. Aim for 30 percent, 20 percent and 50 percent of your calories from fat, protein and carbohydrates, respectively.

Nutrition

 
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