Question

multiple choice questions:

1- What fraction of the progeny will show a recessive phenotype for just one gene in a cross

between AaBbCc x AaBbCc?

A. 7/16

B. 9/64                

C. ¼                      

D. 27/64              

E. 26/64

2- Siblings share what percentage of their alleles?

A. ½

B. ¼                      

C. 1/8                    

D. 1/10                  

E. 1/16

3- In a heterozygote, one allele conceals the presence of another. This is Mendel's:

A. principle of segregation.

B. principle of independent assortment.

C. principle of dominance.

D. principle of dihybrid crosses.

E. principle of monohybrid crosses.

4- A dihybrid cross is:

A. crossing individuals of two different species together.

B. selfing an individual.

C. crossing two individuals with two different alleles for the same trait.

D. crossing two individuals that differ in two different traits.

E. crossing two individuals with two different alleles in the same two traits.

5- How many different kinds of gametes can a DdGgww individual form?

A. 10

B. 4                       

C. 2                        

D. 5                       

E. 3

6- A cross between two heterozygotes for one trait yields a phenotypic ratio of 2:1. What is the best explanation?

A. The dominant trait is lethal in its homozygous form.

B. The trait forms sterile progeny.

C. Either the dominant or the recessive allele in its homozygous form is lethal.

D. The trait causes semisterility in one of the parents.

E. The recessive allele for the trait is lethal in its homozygous form.

F. A and D.

7- Below is a list of possible environmental effects on the expression of genes. Which are valid?

A. A small temperature change effects viability.

B. phenylketonuria

C. cystic fibrosis

D. A and B         

E. A, B, and C

8- Two white flowers were cross fertilized. The resulting F₁ only contained purple flowers. What is a plausible explanation?

A. The gene coding for white mutated.

B. There is an epistatic interaction.

C. The parental varieties had complementary genotypes allowing purple to be expressed.

D. Four different genes were involved.

E. B and C.

F. B and D.

9- Which of the following can effect the expression of a phenotype?

A. environment

B. epistasis

C. incomplete penetrance        

D. variable expressivity

E. all of the above

10- Humans with the disorder PKU develop light colored hair. What kind of genetic effect is this?

A. epistatic

B. pleiotropic                  

C. phenotypic                 

D. variable expressivity                                                                                             

E. incomplete penetrance

11- The ability to produce the M and N antigens is determined by a gene with two alleles. Heterozygotes for the trait produce both kinds of antigens. What is this an example of?

A. incomplete dominance

B. partial dominance                  

C. codominance                                                                             

D. semidominance                        

E. A and B

12- A man has inherited an allele that codes for blue hair, but his hair is brown. This is a possible example of:

A. variable expressivity.

B. incomplete penetrance.       

C. an environmental interaction.

D. an epistatic interaction.

E. all of the above

13- Which of the following is not a feature of continuous traits?

A. environment influences phenotype

B. Effect of environment can vary with genotype.

C. Mendel's laws do not apply to these traits.

D. Two or more genes are often involved.

E. all of the above

14- Determining the number of genes controlling a continuous trait can be difficult because:

A. Environmental effect may vary with genotype.

B. Linked genes may act as if they are a single unit.

C. Physiological basis is impossible to determine.

D. Some loci may contribute more to phenotype than others.

E. Such traits are hard to measure.

F. A, B, C

G. B, C, D

H. A, B, D

15- Knowledge of heritability is important for:

A. developing conservation strategies for natural populations.

B. developing goal oriented selective breeding programs.

C. developing health care programs (for high blood pressure, etc.).

D. understanding how natural populations evolve.

E. all of the above

Answer 1