Mendelian Genetics Test REVIEW

Mendelian Genetics Test REVIEW

PreAP Biology – 2009

The information below and on the attachments is intended to help guide you through the studying process. It is not a guarantee of everything that is on the test. You are responsible for preparing for the test based on the handouts, reading assignments, and written assignments we have completed. Only chapter 8 is on this test.

Vocabulary:

Allele

Autosomal

Blood typing

Carrier

Codominance

Continuous variation (polygenic inheritance)

Cross-pollinate

Dihybrid

Dominant

Genotype

Genotypic ratio

Heredity

Heterozygous

Homozygous

Incomplete dominance

Mendel’s law of independent assortment

Mendel’s law of segregation

Monohybrid

Phenotype

Phenotypic ratio

Probability

Punnett square

Recessive

Self-pollinate

Sex-linked

Test cross

Below is the key to the review pages attached. This is how to use this review:

First, DON’T LOOK AT THE KEY!!!!
Begin, by working through all of the problems to the very best of your ability. Look up the things you don’t know in your notes or book.
Check your work against the key!
Then, work in a group – since you have the key this is obviously NOT for a grade – and DISCUSS the things you don’t understand with each other.
Next, COME IN FOR TUTORIALS BEFORE the day before the test and ask about the things you don’t understand.
Finally, the night before the test you should have a completed, correct review sheet to use as a guide to reviewing your notes, your book, and your assignments.

You should have the following:

Genetics Basics – Vocabulary Notes

Genetics Terminology Worksheet (kept as notes)

Genetics Problems Notes & homework worksheet

Other Genetics worksheets and quizzes

Genetics Review 2009

Why do genetic counselors use pedigrees?

How do you find the genotype of individuals on a pedigree?

What represents a man, woman, marriage, child or someone with a disorder?

When studying a pedigree, how do scientists determine if a trait is dominant or recessive?

What does it mean if a disorder is sex-linked?

Can a male be a carrier for a sex-linked disorder?

Why does a male determine the sex of the offspring?

What is the chance a couple will have a baby boy?

What is the study of heredity?

What is the scientific name and common name of the specimen that Mendel studied?

Differentiate between incomplete dominance and codominance and give an example of each.

Genetics Problems:

Monohybrid Crosses—Autosomal Single-Gene Traits:

Given: Black fur (B)is dominant over white (b) fur in rabbits.

1. Cross a homozygous black rabbit with a homozygous white rabbit.

a. What are the genotypes of the mom and dad rabbits? _____ x _____

Show your work with a Punnett square to the right 

b. What are the genotypes of the offspring? ______

c. What’s the ratio or percentage of each?______

d. What are the phenotypes of the offspring? ______

e. What’s the ratio or percentage of each? ______

2. Cross a heterozygous black rabbit with a heterozygous black rabbit.

a. What are the genotypes of the mom and dad rabbits? _____ x _____

Show your work with a Punnett square to the right 

b. What are the genotypes of the offspring? ______

c. What’s the ratio or percentage of each?______

d. What are the phenotypes of the offspring? ______

e. What’s the ratio or percentage of each? ______

B. Monohybrid Crosses—Autosomal Intermediate Inheritance: Incomplete Dominance

Sponge Bob and his pal Patrick love to go jellyfishing at Jellyfish Fields! The fields are home to a special type of green jellyfish known as Goobers and only really great jellyfishermen are lucky enough to catch some on every trip. Many of the jellyfish are yellow (YY) or blue (BB), but some end up green as a result of incomplete dominance. Use this information to help you complete each section below.

3. What would happen if SpongeBob and Patrick crossed two “goobers” or green jellyfish? Complete a

Punnett square to the right to help you determine the probability for each color of jellyfish.

(a) Give the possible genotypes and phenotypes for the offspring.

(b) What percentage of the offspring would be yellow? _____%

(d) What percentage would be “goobers” (green)? _____ %

4. What would happen if they crossed a yellow jellyfish with a goober? Complete a Punnett square to help

you determine the probability for each color of jellyfish.

(a) Give the possible genotypes and phenotypes for the offspring.

(b) What percentage of the offspring would be yellow? _____%

(d) What percentage would be “goobers” (green)? _____ %

C. Monohybrid Crosses—Autosomal Intermediate Inheritance: Multiple Alleles & Codominance

Give the genotypes for type A= ____ (Heterozygous) or _____ (homozygous). Type B = ____ (hetero) or _____ (homo); AB = _____; type O = _____.
List the possible blood types of offspring if Mom is heterozygous for type A and Dad is homozygous for type B.

If a person has type AB blood and marries a person with type O blood, could they have a child with type O blood? Prove with a punnett square.

D. Dihybrid Cross.

Cross a heterozygous tall,blue flower with a heterozygous tall, blue flower.

The letter for blue is B. The letter for white is b. The letter for tall is T. The letter for short is t.

a. The genotypes of the parent flowers are ______x ______

Show your work in a Punnett square:

d. What are the phenotypes of the offspring? ______

e. What’s the ratio or percentage of each? ______

***Study Genetics Vocabulary Notes, Genetics Problems Notes, Pedigrees, and Genetics Problems WS***

Vocabulary Review

In the space provided, write the letter of the description that best matches the term or phrase.

_____1. heredity

_____2. genetics

_____3. monohybrid cross

_____4. true-breeding

_____5. P generation

_____6. F1 generation

_____7. F2 generation

_____8. alleles

_____9. dominant

_____10. recessive

_____11. homozygous

_____12. heterozygous

_____13. genotype

_____14. phenotype

_____15. law of segregation

_____16. law of independent assortment

the alleles of a particular gene are different
the two alleles for a trait separate when gametes are formed
the alleles of different genes separate independently of one another during gamete formation
not expressed when the dominant form of the trait is present
passing of traits from parents to offspring
all the offspring display only one form of a particular trait
the expressed form of a trait
first two individuals crossed in a breeding experiment
physical appearance of a trait
cross that considers one pair of contrasting traits
offspring of the F1 generation
when the two alleles of a particular gene are the same
branch of biology that studies heredity
different versions of a gene
offspring of the P generation
set of alleles that an individual has

Write the correct term from the list below in the space next to its definition.

Codominance

Incomplete dominance

Multiple alleles

Pedigree

Polygenic trait

Probability

Punnett square

Sex-linked trait

Test cross

______17. diagram that predicts the outcomes of a genetic cross

______18. cross of a homozygous recessive individual with an individual with a dominant phenotype of unknown genotype

______19. the likelihood that a specific event will occur

______20. a family history that shows how a trait is inherited

______21. trait whose allele is located on the X chromosome

______22. when several genes influence a trait

______23. when an individual displays a trait that is intermediate between the two parents

______24. two dominant alleles are expressed at the same time

______25. genes with three or more alleles

Pedigree Practice

B. Huntington disease, a disease of the nervous system, is caused by an autosomal dominant gene. The pedigree chart below illustrates a family with individuals who have Huntington disease. Use the chart to answer the questions that follow. HINT: Write the genotypes for each individual in the pedigree before you start answering the questions.

A B

C D E FG H I

J K L M N O

6. What is the probable genotype of individual D? Explain your answer. ______

______

7. What are the probable genotypes of individuals H and I? Explain your answer. ___

______

8. What is the probability that N will not have Huntington disease? ______

9. Which individuals can be determined to have Huntington disease? ______

10. Identify the individuals whose genotypes cannot be determined without more information. ______

Use the space below to work any Punnett squares you may find necessary to answer the questions above.

Making and Interpreting Pedigree Studies

Determining Genotypes from a Pedigree

Nearsightedness – or myopia – is a recessive trait. The shaded regions show individuals who are homozygous recessive for myopia. They exhibit the trait being studied.

Label the generationsI., II., III., and IV. Label the individuals in each generation A., B., etc. Start over with A with each generation. Use the symbols E and e to label each of the individuals in the pedigree below.

Free ear lobes is a dominant trait. Attached ear lobes is a recessive trait. The shaded regions show individuals who are homozygous recessive for attached ear lobes. They exhibit the trait being studied. They have attached ear lobes.