Genetics Two Question

Genetics Two Question.

Genetics 303 Dr. Joe Staton

Fourth exam—take home

Answer on separate paper, show all work, and be neat in the reporting of answers. STAPLE YOUR RESULTS!

 

1. In a human population, the genotype frequencies at one locus are 0.75 AA, 0.22 Aa, and 0.03 aa. What is the frequency

of the A allele [f(A)] and a allele [f(a)] for the population? Are they in Hardy-Weinberg equilibrium?

 

2. Calculate the number of heterozygotes in a population with p = 0.65 and q = 0.35 (at time = 0). After 4 generations of

inbreeding between siblings (F = 0.25) in a population of 1000.

 

3. Human albinism is an autosomal recessive trait. Suppose that you find an isolated village in the Andes where seven

people are albino. If the population size of the village was 1777 and the population is in Hardy-Weinberg

equilibrium with respect to this trait, how many individuals are expected to be carriers (heterozygotes)?

 

4. A boatload of Swedish tourists, all of whom bear the MM blood group, is marooned on Haldane Island, where they are

met by an equally sized population of Islanders, all bearing blood group NN. In time, the castaways become

integrated into Island society. Assuming random mating, no mutation, no selection (based on blood group), and no

genetic drift, what would you expect the blood group distribution to be among 5000 progeny of the new Haldane

Island population?

 

5. You identify a population of mice (Peromyscus maniculatus) on an island. Their coat color is controlled by a single

gene: BB mice are black, Bb mice are gray, and bb mice are white. You take a census of the population and record

the following numbers of mice:

Black 432

Gray 576

White 192

(a) What are the frequencies of the two alleles?

(b) What are the Hardy-Weinberg equilibrium frequencies for these three phenotypes?

(c) A heat wave hits the island. All mice with black fur die from heat stroke, but the other mice survive. What are the new

allele frequencies for the population?

(d) If the population suffers no further cataclysms after the heat wave, and the surviving animals mate randomly, what will

be the frequency of mice with black fur in the next generation?

(e) If the climate is altered permanently, so that mice with black fur die before reproducing, which following statement is

correct?

(1) At Hardy-Weinberg equilibrium, f(B) will equal 0.135.

(2) The fitness of mice with gray fur (ωBb) must be equal to 0.5.

(3) The fitness of mice with black fur (ωBB) is 0.

(4) The B allele will disappear from the population in one generation.

(5) The B allele will disappear from the population in two generations.

 

6. Which of the following are requirements for evolution by natural selection? Explain your answer.

I Environmental change

II Differential survival and reproduction

III Heritability of phenotypic variation

IV Variation in phenotype

V Sexual reproduction

 

A) II, III, V B) II, III, IV C) I, II, IV D) III, IV, V E) II, IV, V

 

 

 

7. Which of the following processes is the source (origin) of genetic variation within populations?

A) Reproductive Isolation

B) Asexual reproduction

C) Selection

D) Mutation

E) Genetic drift

Explain your answer including a description of what the others do to variation.

 

8. If the population (14,926 in 2013) of folks in Perry, GA, have an f(a) = 0.1 and folks in Valdosta, GA, has a f(a) = 0.5,

then how many people from Valdosta, GA, would have to migrate to Perry to increase the population to at least

f(a) = 0.15?

 

9. What is the Ne of a population with the following annual censuses, [note the drop in size due to 2004 being an extreme

drought year]?

2001: 9,700

2002: 8,800

2003: 4,600

2004: 400

2005: 2,400

2006: 3,800

2007: 7,650

2008: 9,400

2009: 10,700

2010: 12,110

2011: 17,060

2012: 19,471

2013: 22,834

2014: 25,891

 

10. Consider the following populations that have the genotypes shown in the following table:

Population AA Aa aa

1 1.0 0.0 0.0

2 0.0 1.0 0.0

3 0.25 0.50 0.25

4 0.25 0.25 0.50

5 0.32 0.36 0.32

6 0.04 0.32 0.64

7 0.9025 0.095 0.0025

a. What are p and q for each population?

b. Which of the populations are in Hardy-Weinberg equilibrium?

c. Populations 1 and 2 have a tree fall across their islands so that individuals can cross. If equal numbers of the

individuals occur on each island, what is the new population’s allele frequencies and genotype frequencies

after one generation of random mating?

d. In population 3, the a allele is less fit than the A allele, and the A allele is incompletely dominant. The result

is that AA is perfectly fit (= 1.0), Aa has a fitness of 0.85, and aa has a fitness of 0.65. With no mutation or

migration, graph the allele frequency of the a allele for 10 generations under selection (e.g., Time 0 = q above,

Time 1 = first generation after selection)

e. In population 8, the population size gets radically reduced to 200 individuals, total. What is the most likely

fate of the “a” allele, and what genetic principle would lead you to believe that the case?

 

 

 

11. You are given the following genetic data matrix of distances for crustaceans calculated for a region of the mtDNA

called the 16S rDNA: Brine Shrimp Striped-leg hermit King Crab Soldier crab Flat-claw hermit Long-clawed hermit

Brine Shrimp ─

Striped-leg hermit 0.354 ─

King Crab 0.309 0.260 ─

Soldier crab (hermit) 0.321 0.268 0.067 ─

Flat-claw hermit 0.337 0.245 0.108 0.111 ─

Long-clawed hermit 0.312 0.249 0.090 0.096 0.044 ─

 

Calculate the average distance and draw the resulting UPGMA tree based on these distances. Write a brief interpretation

of the branching pattern in the tree.

 

12. You digest a linear piece of DNA with two restriction enzymes, BamH1 & Sma1, and get the following sized

fragments (in kb [kilobases]):

 

BamHI SmaI BamHI & SmaI

13 kb 11 kb 10 kb

6 kb 5 kb 5 kb

3 kb 3 kb

1 kb

Draw the appropriate restriction fragment map based on this data labeling all restriction sites.

Genetics Two Question

 
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BIOLOGY HELP

BIOLOGY HELP. 1-The final shape of a protein is very important to its function. When proteins undergo an irreversible change in shape called ________________ they ________________ perform their usual functions.

  naturation/can
  naturation/cannot
  denaturation/can
  denaturation/cannot
  dehydration reaction/cannot

 

 

2-Which group of lipids will contain hydrophilic heads that face outwards and hydrophobic tails that face inwards that will form a barrier?

  phospholipids
  steroids
  triglycerides
  saturated acids
  trans-fatty acids

 

3-DNA codes for the sequence of amino acids in the primary structure of a protein, but not for sugars or lipids. This is because

  only proteins are involved in living metabolic reactions.
  sugars and lipids code for their own replication.
  sugars and lipids are ever present in the living environment and are not used in living structures.
  other hereditary molecules code for sugars and lipids.
  proteins are the main structural and functional components of cells.

 

4-Which statement about the cellular nucleic acids DNA and RNA is incorrect?

  DNA is double-stranded, and RNA is single-stranded.
  The sugar in DNA is deoxyribose, and in RNA the sugar is ribose.
  DNA has a helix shape; RNA does not.
  RNA and DNA have the same four nitrogen-containing bases.
  Both DNA and RNA are polymers of nucleotides.

 

5-All carbohydrate molecules

  contain amino acids.
  contain nitrogen and phosphate.
  are organic acids.
  are composed of atoms of C, H, and the functional group -OH.
  are composed of atoms of C, H, O, and N.

 

6-Two molecules of glucose combine to form a disaccharide molecule during a(n) ________ reaction.

  dehydration
  hydrolysis
  hydrogen bond
  ionic bond
  inert

 

7-One carbon atom can form covalent bonds with up to ___ other atoms to form an organic molecule.

  2
  3
  4
  6
  8

 

8-Enzymes are organic compounds classified as

  nucleic acids.
  carbohydrates.
  lipids.
  steroids.
  proteins.

 

9-Organic molecules

  always contain carbon.
  always contain hydrogen.
  always contain carbon and hydrogen.
  are found only in organisms, hence their name.
  are always food molecules.

 

10-The water strider is an insect that skates across the water without sinking. The tips of its feet must be coated with molecules that are

  ions.
  hydrophilic.
  hydrophobic.
  basic.
  acidic.

 

11-Nucleic acids are polymers of

  amino acids.
  nucleotides.
  glycerol.
  monosaccharides.
  fatty acids.

 

12-DNA codes for the sequence of amino acids in the primary structure of a protein, but not for sugars or lipids. This is because

  only proteins are involved in living metabolic reactions.
  sugars and lipids code for their own replication.
  sugars and lipids are ever present in the living environment and are not used in living structures.
  other hereditary molecules code for sugars and lipids.
  proteins are the main structural and functional components of cells.

 

 

13-The moon lacks life and varies dramatically in temperature. If we could keep a layer of water spread on the surface of the moon, what effect would it have?

  Life would be possible but it would have to withstand these extremes in temperature.
  Water would absorb and hold heat and moderate the temperature extremes.
  The temperatures would drop to the lower extremes.
  Because water has a high heat of vaporization, the temperatures would rise to the upper extremes.
  Physical conditions would remain the same.

 

 

14-____ is a polysaccharide that is found in plant cell walls and accounts for their strength.

  Cellulose
  Chitin
  Glycogen
  Starch
  Cholesterol

 

 

 

15-The primary function of carbohydrates is

  quick fuel and short-term energy storage.
  structural reinforcement of plant and fungal cell walls.
  encoding the hereditary information.
  to speed chemical reactions in cells.
  to transport molecules across cell membranes.

 

16-Which of the following types of lipid is the most abundant constituent of cell membranes?

  cholesterol
  phospholipid
  triglyceride
  neutral fat
  fa

BIOLOGY HELP

 
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Fatty Acids, Nutrition and Health Exercise

Fatty Acids, Nutrition and Health Exercise. Scenario

 

Fatty Acids, Nutrition and Health

 

Students please note : It is assumed that you have an understanding of organic molecules as presented in your text book. If not, you should read chapter 3 in your text book dealing with organic molecules. At a minimum, you need to look over the sections associated with lipids. At the end of the scenario, there are some links listed to web sites that you might find useful.

 

 

Its time for your annual physical examination…

 

Suppose that you were visiting your doctor for an annual physical examination. While you were in the waiting room, you picked up and began to read a pamphlet about dietary fats (lipids) and their impacts on health. In order to remember them later, you typed some of the important points into a file on your laptop. To refresh your memory, and for your convenience (and the rest of the class), these notes can be seen below.

 

Notes on Lipids and Health

 

True lipids (triglycerides)

· composed of a glycerol molecule covalently bound to three fatty acid side chains

· hydrophobic molecules, meaning they are non-polar and don’t mix with water

· a group of triglycerides is called a fat

 

Saturated fats

· solid at room temperature (think of fat on an uncooked steak)

· hydrocarbon chains in fatty acids have no carbon-carbon double covalent bonds

· maximum number of hydrogens are covalently bound to the carbons, thereby “saturating” them

· ( Saturated Fatty Acid )animal fats such as lard and butter are usually high in saturated fatty acids

 

 

 

 

Unsaturated fats

· liquid (oils) at room temperature

· hydrocarbon chains of the fatty acids have at least one (monounsaturated) or more (polyunsaturated) carbon-carbon double covalent bonds

· double bonds cause bends in the molecules and also leave them “unsaturated” with hydrogens

· unsaturated fats are found in plant oils such as olive or canola oil

( Monounsaturated Fatty Acid )

 

Dietary fatty acids

· fatty acids are a necessary component of a complete diet

· fatty acids are found in foods such as fatty meats, plant oils and dairy products

· certain polyunsaturated fatty acids (called essential fatty acids) cannot be synthesized by the human body and must come from the diet

· one such essential fatty acid is linoleic acid which can be found in foods such as sunflower oil and almonds

· both monounsaturated and polyunsaturated fatty acids can be found in plant oils

 

( Polyunsaturated Fatty Acid )

 

 

Trans fats

· are triglycerides that contain trans fatty acids

· Trans means “across” so…

· a trans fatty acid is an unsaturated one in which the hydrogens attached to adjacent carbons in a carbon-carbon double covalent bond are on opposite sides of the molecule

· produced by the process of adding hydrogens to unsaturated vegetable oils

· hydrogenation decreases the number of carbon-carbon double covalent bonds in the molecules and creates what are known as “hydrogenated” or “partially hydrogenated” vegetable oils

· trans configuration gives the fatty acids chemical properties more similar to saturated fatty acids (such as lack of bends in the molecules) and can also lead to some accumulation of “bad” types of cholesterol when consumed

· trans fats are found in any hydrogenated oils, so margarines and shortening made from vegetable oils are major sources

· since they are made from plant oils, these were once touted as being much healthier than saturated animal fats

 

 

· in cis fatty acids, the hydrogens attached to adjacent carbons in a carbon-carbon double covalent bond are on the same side of the molecule.

· Almost all naturally occurring unsaturated fatty acids are cis isomers

 

 

 

 

So, the doctor says your cholesterol is too high…

 

When you were finally called back to a room, your doctor said that a standard analysis of your blood showed that your total cholesterol level was 250mg/dL (a dL=deciliter, or 1/10 of a liter, 100mL). He/she explained that a total cholesterol level of 240mg/dL or above is considered high and is a risk factor for coronary artery disease (CAD).

 

In continuing conversations with your physician, you learned that as a general rule cholesterol is not always “bad.” In fact, cholesterol is a necessary component of cell membranes and is a vital part of normal metabolic processes, including formation of other steroids. In addition to looking at total cholesterol concentration in your blood, your doctor emphasized that it is important to take notice of high density lipoprotein (HDL) cholesterol and low density lipoprotein (LDL) cholesterol, which make up major fractions of the total cholesterol and may be more accurate indicators of CAD risk.

 

Your LDL fraction was found to be 195mg/dL which is considered very high.

 

After seeing your very high LDL number, your physician went on to say that the role of LDLs is to carry cholesterol around in the bloodstream and deposit it where it is needed. Unfortunately, if the level of LDLs becomes too high they can also deposit the cholesterol in arteries, forming “plaques” and clogging the arteries. On the other hand, HDLs are responsible for carrying excess cholesterol away from the arteries to the liver where it can be metabolized or “reprocessed” for other purposes. So, with this in mind, cholesterol bound in LDLs is often called “bad cholesterol” and cholesterol bound in HDLs is called “good cholesterol”. In order to avoid CAD, the average person should attempt to raise the level of HDLs in their blood and lower the level of LDLs, although both are needed at some level in the blood.

 

At this point, your doctor strongly urged you to exercise regularly and watch your diet because consumption of fats can have a profound effect on cholesterol levels in the body. However, it turns out that it is probably the types of fat, not the total amount of fat that you eat that may determine incidence of CAD. In fact, a 2001 study by Frank Hu and colleagues at the Harvard School of Public Health showed that different parts of the world with similar total fat intake had very different amounts of death from CAD. Individuals in countries where the fats eaten were mainly in the form of saturated fats and trans fats had much higher incidences of death from CAD than individuals in countries where the fats were mainly consumed in the form of polyunsaturated fats containing omega-3 fatty acids. In general, the study showed that consumption of saturated fats and trans fats tended to increase LDL cholesterol while consumption of polyunsaturated fats tended to both decrease LDL cholesterol and increase HDL cholesterol.

 

References

Hu, FB, Manson, JE, and Willett, WC. 2001. Types of Dietary Fat and Risk of Coronary Heart Disease: A Critical Review. Journal of the American College of Nutrition 20:5-19.

 

Useful Links:

More explanation about trans fats from the FDA

http://www.fda.gov/Food/LabelingNutrition/ConsumerInformation/ucm109832.htm#unhide

 

Understanding cholesterol numbers website

http://www.webmd.com/cholesterol-management/guide/understanding-numbers

 

Government information about reading nutrition labels

http://www.fda.gov/Food/LabelingNutrition/ConsumerInformation/ucm078889.htm

 

 

Pre-Activity Assignment: Fatty Acids, Nutrition and Health ________________________ Name

Read the Fatty Acids, Nutrition and Health reading and Chapter 3 in the text book and then answer the following questions before class.

 

1. A trans fatty acid is one

a. that has no carbon-carbon double bonds directly adjacent to each other.

b. that is a major component of phospholipids in cell membranes.

c. in which the hydrogens attached to adjacent carbons in a carbon-carbon double covalent bond are on opposite sides of the molecule.

d. in which the hydrogens attached to adjacent carbons in a carbon-carbon double covalent bond are on the same side of the molecule.

e. that is saturated with hydrogens.

 

2. Types of polyunsaturated fatty acids that are necessary in the human diet because they cannot be synthesized by the body are called _____________ fatty acids.

a. essential

b. important

c. trans

d. omega-3

e. hydrophobic

 

3. Generations of Americans were introduced to trans fats in their diet in the form of ____________ which was hailed as a healthy alternative to the saturated fats found in butter and lard.

a. Coconut oil

b. Olive oil

c. Margarine

d. Canola oil

e. Beef tallow

 

4. HDL stands for

a. Highly dense lipid.

b. Hydrogenated dark lipid.

c. High density lipid.

d. Hydrogenated dense lipoprotein.

e. High density lipoprotein.

 

5. In the next class meeting you will work in small collaborative groups to answer four question sets. Each person in the group will act as the ‘facilitator’ for one question set, leading the group discussion, promoting input from each of the other students (who will be acting as ‘discussants’) and formalizing the group response. In the role of a discussant, students provide their knowledge, experience and perspectives, compare and contrast the inputs of other members of the group and collaborate in the formulation of the group response. At the end of the activity, you may be called on to present your group’s answers to one of the question sets (not necessarily the one you were the facilitator for). You will act as both a facilitator and a discussant in the activity.

Make sure you have critically analyzed the Fatty Acids, Nutrition and Health scenario and chapter 3 in the text book so that you are prepared to participate in all aspects of the group activity. Bring the scenario with you to the next class meeting.

 

Activity—Fatty Acids, Nutrition and Health (Critical Question Sets)

1. Plaque Formation in Arteries: High levels of LDL cholesterol in the bloodstream can lead to formation of “plaques” in the arteries.

 

_________________________________

Facilitator

 

 

· What are the potential health consequences of coronary arteries being clogged by “plaques”?

 

 

 

 

 

· Name some specific foods that might lead to increased LDL cholesterol in the bloodstream.

 

 

 

 

 

· What do these foods contain that could cause this?

 

 

 

 

2. Nutrition Labels: Analyze the nutrition label below and answer the following questions.

 

______ ___________________________

Facilitator

 

· How much total fat, saturated fat and trans fat does this product contain per serving?

 

 

 

 

· How many grams of total fat would a person consume if he/she ate the whole container?

 

 

· How many calories are from fat per serving?

 

 

 

· Calculate the percentage of the total calories per serving that come from total fat?

 

 

 

 

· Based on a 2,000 calorie diet, what percent of the USDA’s percent daily value for total fat would be consumed per serving? Calculate the percent if the whole container was consumed?

 

 

 

· Based on what you know about trans fats, do you think there are hydrogenated oils in this product? Explain.

 

 

 

3. Hydrogenation of Oils: Answer the following questions about hydrogenation of vegetable oils.

_________ _____________ ___________

Facilitator

 

· What is the reason behind hydrogenating vegetable oils? What effect does the hydrogenation process have on their chemical and physical properties?

 

 

 

 

 

· Draw both a cis isomer and a trans isomer of a polyunsaturated fatty acid. Which would be produced by the hydrogenation process?

 

 

 

 

 

 

 

 

 

4. Cholesterol Profiles: Answer the following question using what you know about cholesterol and the tables to the right that show health categories based on blood levels of different fractions of cholesterol.

 

___________ _____________________

Facilitator

 

 

· Circle the blood cholesterol profile below that you think would be most desirable? What about this profile made you choose it over the others? Explain why you didn’t choose each of the other two.

 

 

 

 

(a) (b) (c)

 

 

 

Post-Activity Assignment: Fatty Acids, Nutrition and Health ________________________

Name

 

6. Which one of the following diagrams represents a trans fatty acid?

 

 

a.

 

 

 

 

 

 

 

 

b.

 

 

 

 

 

 

 

c.

 

 

 

d.

 

 

 

 

 

 

 

7. Which one of the following would be solid at room temperature?

a. Cis fatty acids

b. Corn oil

c. Peanut oil

d. Saturated fats such as lard (pig fat)

e. Unsaturated fats

 

 

 

8. A true lipid is composed of glycerol and three fatty acids. What type of reaction is used to link each of the fatty acids to a glycerol molecule?

a. Dehydration

b. Hydrolysis

c. Dehydrohalogenation

d. Hydrogenation

e. Hydroxylation

 

9. Food companies can tag their products on the nutrition label as having 0g of trans fats if they have <0.5g of trans fat per serving. What could be found in the ingredients list that is probably a better indicator of the presence of trans fats in foods than the trans fat line on the nutrition label?

a. Lard

b. Hydrogenated oils

c. Palm oil

d. Olive oil

e. Almonds

 

10. Consumption of which of the following is most likely to raise your HDL and also lower your LDL levels?

a. Trans fats

b. Saturated fats

c. Lard

d. Polyunsaturated fats

e. Margarine

 

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Fatty Acids, Nutrition and Health Exercise

 
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Lab 5: Meiosis INSTRUCTIONS: And 3425

Lab 5: Meiosis INSTRUCTIONS: And 3425. lab biology questions
BiolLab_5.docx
BiolLab_5.docx

Your Full Name:

102/103
Lab 5: Meiosis
INSTRUCTIONS:

and submit it via the Assignments Folder by the date listed in the Course
Schedule (under Syllabus).

To conduct your laboratory exercises, use the Laboratory Manual located under
Course Content. Read the introduction and the directions for each exercise/experiment
carefully before completing the exercises/experiments and answering the questions.

Save your Lab 5 Answer Sheet in the following format: LastName_Lab5 (e.g.,
Smith_Lab5).

You should submit your document as a Word (.doc or .docx) or Rich Text Format
(.rtf) file for best compatibility.

© eScience Labs, LLC 2014

Pre-Lab Questions
1. Compare and contrast mitosis and meiosis.

2. What major event occurs during interphase?

Experiment 1: Following Chromosomal DNA Movement
through Meiosis
Data Tables and Post-Lab Assessment
Trial 1 – Meiotic Division Beads Diagram:
Prophase I

© eScience Labs, LLC 2014

Metaphase I

Anaphase I

Telophase I

Prophase II

Metaphase II

Anaphase II

Telophase I

Cytokinesis

© eScience Labs, LLC 2014

Trial 2 – Meiotic Division Beads Diagram:
Prophase I

Metaphase I

Anaphase I

Telophase I

Prophase II

Metaphase II

Anaphase II

Telophase I

© eScience Labs, LLC 2014

Cytokinesis

Post-Lab Questions
1. What is the ploidy of the DNA at the end of meiosis I? What about at the end of meiosis

II?

2. How are meiosis I and meiosis II different?

© eScience Labs, LLC 2014

3. Why do you use non-sister chromatids to demonstrate crossing over?

4. What combinations of alleles could result from a crossover between BD and bd

chromosomes?

© eScience Labs, LLC 2014

5. How many chromosomes were present when meiosis I started?

6. How many nuclei are present at the end of meiosis II? How many chromosomes are in

each?

© eScience Labs, LLC 2014

7. Identify two ways that meiosis contributes to genetic recombination.

8. Why is it necessary to reduce the number of chromosomes in gametes, but not in other

cells?

© eScience Labs, LLC 2014

9. Blue whales have 44 chromosomes in every cell. Determine how many chromosomes

you would expect to find in the following:

a.i.

Sperm Cell:

a.ii.

Egg Cell:

a.iii.

Daughter Cell from Mitosis:

© eScience Labs, LLC 2014

a.iv.

Daughter Cell from Meiosis II:

10. Research and find a disease that is caused by chromosomal mutations. When does the

mutation occur? What chromosomes are affected? What are the consequences?

11. Diagram what would happen if sexual reproduction took place for four generations using

diploid (2n) cells.

© eScience Labs, LLC 2014

Experiment 2: The Importance of Cell Cycle Control
Data Tables and Post-Lab Assessment
1.

2.

3.

4.

5.

Post-Lab Questions
1. Record your hypothesis from Step 1 in the Procedure section here.

2. What do your results indicate about cell cycle control?

3. Suppose a person developed a mutation in a somatic cell which diminishes the

performance of the body’s natural cell cycle control proteins. This mutation resulted in
© eScience Labs, LLC 2014

cancer, but was effectively treated with a cocktail of cancer-fighting techniques. Is it possible
for this person’s future children to inherit this cancer-causing mutation? Be specific when
you explain why or why not.

4. Why do cells which lack cell cycle control exhibit karyotypes which look physically

different than cells with normal cell cycle.

5. What are HeLa cells? Why are HeLa cells appropriate for this experiment?

Experiment 1:
Following
Chromosomal DNA
Movement through
Meiosis
In this experiment, you
will model the movement
of the chromosomes
through meiosis I and II to
create gametes.

© eScience Labs, LLC 2014

Materials

2 Sets of Different Colored Pop-it® Beads (32 of e
may be any color)
8 5-Holed Pop-it® Beads (used as centromeres)
Procedure:
Part 1: Modeling Meiosis
without Crossing Over
As prophase I begins, the
replicated chromosomes
coil and condense…
1.

Build a pair of
replicated,
homologous
chromosomes. 10
beads should be
used to create each
individual sister
chromatid (20
beads per
chromosome pair).
Two five-holed
beads represent
each centromere.
To do this…

© eScience Labs, LLC 2014

Figure 3: Bead set-up. The blue beads
represent one pair of sister chromatids
and the black beads represent a second
pair of sister chromatids. The black and
blue pair are homologous.
a.

Start with
20 beads of
the same
color to
create your
first sister
chromatid
pair. Five
beads must
be snapped
together for
each of the
four
different
strands.
Two
strands
create the
first
chromatid,
and two
strands
create the
second
chromatid
with a 5holed bead
at the
center of
each
chromatid.
This creates
an “I”
© eScience Labs, LLC 2014

shape.
b.

Connect the
“I” shaped
sister
chromatids
by the 5holed beads
to create
an “X”
shape.

c.

Repeat this
process
using 20
new beads
(of a
different
color) to
create the
second
sister
chromatid
pair.

2.

Assemble a second
pair of replicated
sister chromatids;
this time using 12
beads, instead of
20, per pair (six
beads per each
complete sister
chromatid strand).

3.

Pair up the
homologous
chromosome pairs
created in Step 1
and 2. DO NOT
SIMULATE
© eScience Labs, LLC 2014

CROSSING
OVER IN THIS
TRIAL. You will
simulate crossing
over in Part 2.
4.

Configure the
chromosomes as
they would appear
in each of the
stages of meiotic
division (prophase
I and II, metaphase
I and II, anaphase I
and II, telophase I
and II, and
cytokinesis).

5.

Diagram the
corresponding
images for each
stage in the
sections titled
“Trial 1 – Meiotic
Division Beads
Diagram”. Be sure
to indicate the
number of
chromosomes
present in each cell
for each phase.

© eScience Labs, LLC 2014

Figure 4: Second set of replicated
chromosomes.
6.

Disassemble the
beads used in Part
1. You will need to
recycle these beads
for a second
meiosis trial in
Steps 8 – 13.

Part 1 – Meiotic Division
Beads Diagram
Prophase I
Metaphase I
Anaphase I
Telophase I
Prophase II
Metaphase II
Anaphase II

© eScience Labs, LLC 2014

Telophase II
Cytokinesis
Part 2: Modeling Meiosis
with Crossing Over
7.

Build a pair of
replicated,
homologous
chromosomes. 10
beads should be
used to create each
individual sister
chromatid (20
beads per
chromosome pair).
Two five-holed
beads represent
each centromere.
To do this…
a.

Start with
20 beads of
the same
color to
create your
first sister
chromatid
pair. Five
beads must
be snapped
together for
each of the
four
different
strands.
Two

© eScience Labs, LLC 2014

strands
create the
first
chromatid,
and two
strands
create the
second
chromatid
with a 5holed bead
at the
center of
each
chromatid.
This creates
an “I”
shape.
b.

Connect the
“I” shaped
sister
chromatids
by the 5holed beads
to create
an “X”
shape.

c.

Repeat this
process
using 20
new beads
(of a
different
color) to
create the
second
sister
chromatid
© eScience Labs, LLC 2014

pair.
8.

Assemble a second
pair of replicated
sister chromatids;
this time using 12
beads, instead of
20, per pair (six
beads per each
complete sister
chromatid strand).
Snap each of the
four pieces into a
new five-holed
bead to complete
the set up.

9.

Pair up the
homologous
chromosomes
created in Step 8
and 9.

10.

SIMULATE
CROSSING
OVER. To do this,
bring the two
homologous pairs
of sister
chromatids
together (creating
the chiasma) and
exchange an equal
number of beads
between the two.
This will result in
chromatids of the
same original
length, there will
now be new

© eScience Labs, LLC 2014

combinations of
chromatid colors.
11.

Configure the
chromosomes as
they would appear
in each of the
stages of meiotic
division (prophase
I and II, metaphase
I and II, anaphase I
and II, telophase I
and II, and
cytokinesis).

12.

Diagram the
corresponding
images for each
stage in the section
titled “Trial 2 Meiotic Division
Beads Diagram”.
Be sure to indicate
the number of
chromosomes
present in each cell
for each phase.
Also, indicate how
the crossing over
affected the genetic
content in the
gametes from Part1
versus Part 2.

Part 2 – Meiotic Division
Beads Diagram:
Prophase I
Metaphase I

© eScience Labs, LLC 2014

Anaphase I
Telophase I
Prophase II
Metaphase II
Anaphase II
Telophase II
Cytokinesi

Experiment 2: The Importance of Cell Cycle Control
Some environmental factors can cause genetic mutations which result in a
lack of proper cell cycle control (mitosis). When this happens, the possibility
for uncontrolled cell growth occurs. In some instances, uncontrolled growth
can lead to tumors, which are often associated with cancer, or other biological
diseases.
In this experiment, you will review some of the karyotypic differences which
can be observed when comparing normal, controlled cell growth and
abnormal, uncontrolled cell growth. A karyotype is an image of the complete
set of diploid chromosomes in a single cell.
Procedure
© eScience Labs, LLC 2014

Materials
*Computer Access
*Internet Access

1.

*You Must Provide

Begin by constructing a hypothesis to explain what differences you
might observe when comparing the karyotypes of human cells which
experience normal cell cycle control versus cancerous cells (which
experience abnormal, or a lack of, cell cycle control). Record your
hypothesis in Post-Lab Question 1.
Note: Be sure to include what you expect to observe, and why you think
you will observe these features. Think about what you know about
cancerous cell growth to help construct this information

2.

Go online to find some images of abnormal karyotypes, and normal
karyotypes. The best results will come from search terms such as
“abnormal karyotype”, “HeLa cells”, “normal karyotype”, “abnormal
chromosomes”, etc. Be sure to use dependable resources which have
been peer-reviewed

3.

Identify at least five abnormalities in the abnormal images. Then, list and
draw each image in the Data section at the end of this experiment. Do
these abnormalities agree with your original hypothesis?
Hint: It may be helpful to count the number of chromosomes, count the
number of pairs, compare the sizes of homologous chromosomes, look
for any missing or additional genetic markers/flags, etc.

Data
1.
2.
3.

© eScience Labs, LLC 2014

4.
5.
Click here to download and solve a few questions.

© eScience Labs, LLC 2014

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Lab 5: Meiosis
INSTRUCTIONS:

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