Exam 1

Question 1

The chemical group at the 3’ end of a single polynucleotide chain is

Answer 1

Hydroxyl group

Question 2

If a single gene has three alleles how many different genotypes are possible in a diploid organism?

Answer 2

6

Question 3

Define true breeding

Answer 3

When an organism passes down a certain phenotypic trait to its offspring

Question 4

A cross between two true breeding lines (one with dark blue and one with white flowers) produces F1 progeny with a 1:2:1 ratio of dark blue: light blue: white flowers. What genetic phenomenon is consistent with these results?

Answer 4

Incomplete dominance

Question 5

The coding region of a mRNA (from initiation to termination codon) has 300 nucleotides. The initiation codon is located closer to the ___ end of the mRNA and the polypeptide encoded by this mRNA will be approximately ___ amino acids

Answer 5

5’

100

Question 6

Both PKU and AKU are caused by rare recessive alleles. A person affected by PKU marries a person affected by AKU. What phenotype do you expect for their children?

Answer 6

All normal

Question 7

The allele causing achondroplasia is lethal when homozygpus. n both parents are affected by achondroplasia, the probability of a child with achondroplastic short stature among the children that survive can be estimated as:

Answer 7

2/3

Question 8

When DNA fragments are separated in an agarose gel under an electric field

Answer 8

They are separated according to size; shorter fragments move faster

Question 9

A 9:3:3:1 ratio refers to

Answer 9

The phenotypic ratio in the F2 progeny of a dihybrid cross

Question 10

In peas, the yellow allele is dominant. If a plant with yellow peas is crossed to a plant with green peas, the resulting plants are 50% yellow and 50% green. What is the genotype of the parents in this cross?

Answer 10

Yy and yy

Question 11

What phenotypic ratio would you expect as a result of a test cross between a dihybrid organism and one that is homozygous recessive for alleles at two independent loci?

Answer 11

1:1:1:1

Question 12

Idnetify 3 possible components of a DNA nucleotide:

Answer 12

deoxyribose, cytosine, phosphate group

Question 13

A give protein is 210 amino acids long. The mRNA encoding the protein is at least

Answer 13

630 nucleotides long

Question 14

A mRNA is translated ____

Answer 14

5’ to 3’

Question 15

Polypeptide synthesis begins at the ___ and ends at the ____ end

Answer 15

Amino

Carboxyl

Question 16

Black skin color is dominant to pink skin color in pigs. Two heterozygous black pigs are crossed. If these pigs produce a total of three piglets what is the probability that two will be pink and one will be black?

Answer 16

3/64

Question 17

Dihybrid wild type males and females of Drosphelia are crossed. A vestigial wing and ebony body are inherited at independent loci and are recessive to full wing and gray body. 800 progeny are produced. How many are expected to have vestigial wings and gray bodies?

Answer 17

150