Question

1.In fruit flies, eye color is an X-linked trait. Red eyes (X^R) are dominant over white eyes (X^r)A homozygous dominant female mates with a white-eyed male. What is the phenotypic ratio among males?

a.1:0 (all male offspring will have red eyes)

b.1:1 (half of the male offspring will have red eyes and half will have white eyes)

c.0:1 (all male offspring will have white eyes)

2.In fruit flies, eye color is an X-linked trait. Red eyes (X^R) are dominant over white eyes (X^r).

A homozygous dominant female mates with a white-eyed male. What is the phenotypic ratio among females?

A. 1:0 (all female offspring will have red eyes)

B.1:1 (half of the female offspring will have red eyes and half will have white eyes)

C.0:1 (all female offspring will have white eyes)

3.In sheep, horns are sex linked; H = horns and h = no horns. What cross do you recommend if a farmer wants to produce hornless males?

A.Cross 1:   X^HY x  X^HX^H

B.Cross 2:   X^hY x  X^HX^h

C.Cross 3:   X^HY x  X^hX^h

D.Cross 4:   X^HY x  X^HXh

4.

A = adenine

T = thymine

C = cytosine

G = guanine

U = uracil

A DNA strand is used as a template to make an RNA strand. Write out the complementary RNA bases for the following DNA sequence: A C G G T T             

5. Name the process that makes an mRNA strand from a DNA template strand.

6.Name the process that requires tRNA, mRNA, and a ribosome.

7.In pea plants the purple flower allele (P) is dominant to the white flower allele (p).

If there is a population of 10 pea plants homozygous for purple flowers, 20 heterozygous, and 10 pea plants with white; what is the frequency of the P allele in the population.

A.0.25

B.0.33  

C.0.05

D.0.75  

E.0.50

8.In pea plants the purple flower allele (P) is dominant to the white flower allele (p).

If all of the pea plants with white flowers are eaten, what is the new frequency of the p allele?

A.0.33

B.0.25

C.0.75  

D.0.5

9.True or False. Natural selection CAUSES mutations.

A.True

B.False

10.Is a population bottleneck an example of genetic drift?

A.no

B.yes

Answer 1

1. Answer: a

Representation:

Considering trait of eye color: X-liked

Red = R = Dominant

White = r= Recessive

· Red eyed male Male= X^RY

· White eyed male = X^rY

· Red eyed Female= X^R X^R (Homozygous), X^R X^r (Heterozygous)

· White eyed Female= X^r X^r

Cross: Red eyed (homozygous)Female with white eyed male:

	Female
Male	XR	XR	F2
Xr	XR Xr	XR Xr	Female
Y	XRY	XR Y	Male

All males are red eyed = X^RY

2. Answer: A

All females are red eyed (heterozygous dominant) = X^R X^r

3. Answer: C

X^HY x X^hX^h

	Female
Male	Xh	Xh	F1
XH	XHXh	XHXh	Female
Y	Xh Y	Xh Y	Male

All males are hornless = X^h Y

4.

• 5’ to 3’ strand of DNA serve as coding strand.
• 3’ to 5’ strand of DNA act as template strand.
• RNA is synthesized by complementary base pairing with the template strand.
• Thus, the RNA will have same sequence as coding strand (only T is replaced by U) and is oriented in 5’ to 3’ direction.

Given template strand :3' A C G G T T 5'

Complementary DNA strand (Sense strand):5' TGCCAA3'

mRNA: 5’ UGCCAA 3’