Midterm #4

Question 1

John and Mary do NOT have cystic fibrosis, but their first child DOES have the condition. What do we know about the genotypes of John and Mary?

Answer 1

Both John and Mary are carriers

Question 2

Which enzyme plays a key role in CRISPR technology for genome editing?

Answer 2

CAS9

Question 3

Red-green color blindness is an X-linked recessive trait in humans. Two people with normal color vision have a son with colorblindness. Given this information, the genotypes of the parents are

Answer 3

XNXn and XNY

Question 4

Suppose a double-stranded DNA molecule was shown to have 22% guanine bases. What would be the expected percentage of adenine bases in that molecule?

Answer 4

28%

Question 5

The two antiparallel strands of nucleotides that form the DNA double helix are held together by

Answer 5

Hydrogen bonds between nucleotide bases

Question 6

Patient X has Type A blood and needs a blood transfusion. Which of the following donor blood types would you administer?

Answer 6

Blood w/Type B antibodies

Question 7

For DNA screening, we identify specific alleles in a sample by allowing the sample DNA to hybridize to:

Answer 7

Complimentary DNA strands on a DNA Chip

Question 8

Imagine a locus with four different alleles for fur color in an animal, Da, Db, Dc, Dd. If you crossed two heterozygotes, DaDb and DcDd, what genotype proportions would you expect in the offspring?

Answer 8

25% DaDc, 25% DaDd, 25% DbDc, 25% DbDd

Question 9

John, and Carol are both married, and both of their parents are carriers of cystic fibrosis. What is the probability that John, AND Carol are carriers, AND the baby is homozygous recessive?

Answer 9

1/9

Question 10

When using recombinant DNA techniques to insert a human insulin gene into bacteria, scientists first had to cut the donor genome into pieces using a:

Answer 10

Restriction enzyme

Question 11

After a dihybrid cross you will find the following ratios of offspring with flower colors: 9/16 Dark Red flowers; 3/16 Red flowers; 4/16 white flowers. How are these ratios best explained?

Answer 11

Epistasis

Question 12

Is/are “carriers for an X-linked recessive trait”

Answer 12

Female heterozygotes

Question 13

Which of the following attributes of DNA is most crucial to its accurate duplication?

Answer 13

It’s specific base pairing through hydrogen bonds.

Question 14

Monomers for the synthesis of DNA are called

Answer 14

Nucleotides

Question 15

Which order of the following steps correct describes adding in the human insulin gene into a bacterium?

I. Transform bacteria with a recombinant DNA molecule.
II. Cut the plasmid DNA using restriction enzymes.
III. Expect plasmid DNA from bacterial cells.
IV. Add plasmid DNA to human insulin DNA fragment.
V. Add DNA ligase to seal plasmid DNA to Human insulin DNA fragment.

Answer 15

III, II, IV, V, I

Question 16

A man heterozygous with Type B blood, and a woman heterozygous with Type A blood have the potential of producing children with the following phenotype combinations:

Answer 16

Type A, Type B, Type AB, or Type O

Question 17

When attempting to introduce a foreign DNA fragment into the genome of an animal cell which of the following methods would be most successful?

Answer 17

CRISPR/Cas9 genetic engineering

Question 18

In tigers, the recessive allele from one gene causes both an absence of fur pigmentation (white tiger) phenotype and a cross-eyed phenotype. In this species, the heterozygotes for this gene are phenotypically normal tigers. This example demonstrates:

Answer 18

Pleiotropy

Question 19

Is/are “carriers” for an autosomal recessive trait.

Answer 19

Male and female heterozygotes

Question 20

John, age 47, has just been diagnosed with Huntington’s disease, which is caused by a rare dominant allele. His daughter, age 25, has a 2-year-old son. No one else in the family has the disease. Without knowing anything about the 25-year-old daughter’s genotype, what is the probability that the 2-year-old son will eventually develop the disease?

Answer 20

50%

Question 21

ABO blood type in humans exhibits codominance and multiple alleles. What is the likelihood of a type A father and a type A mother having a type O child?

Answer 21

25% if both parents are heterozygous

Question 22

Which of the following is true regarding PCR?

Answer 22

All the answer choices are correct

Question 23

Which of the following describes a stem cell’s ability to differentiate or mature into any cell type?

Answer 23

Pluripotent

Question 24

A woman has heterozygous blood type A, and a man has heterozygous blood type B, what is the probability that they will have a son with blood type A?

Answer 24

12.5%

Question 25

During the replication of DNA,

Answer 25

both strands of a molecule act as templates

Question 26

Consider the replicated bubble diagram. Which letters represent leading strands?

5’ L M 3’
3’ N O 5’

Answer 26

L and O

Question 27

Heterozygote individuals for sickle cell anemia have both round, and sickle shaped red blood cells. This indicates that the sickle cell anemia trait is inherited as a _ trait.

Answer 27

Codominant

Question 28

_ synthesizes an RNA primer at 5’end of leading strand.

Answer 28

D - Primase

Question 29

Which of the following is NOT used in PCR?

Answer 29

RNA Polymerase

Question 30

A genetic counselor is working with a couple who have just had a child who has Tay-Sachs disease. Neither parent has Tay-Sachs, nor does anyone in their families. What should the counselor say to this couple?

Answer 30

“Because you have had one child with Tay-Sachs, you must each carry the allele. Any child you have has a 25% chance of having the disease.”

Question 31

A STR can be used for DNA profiling, and makes use of the fact that individuals have:

Answer 31

Different number of tandem DNA repeats at non-coding sites in the genome.

Question 32

How do the leading and the lagging strands differ?

Answer 32

The leading strand is synthesized in the same direction as the movement of the replication fork, whereas the lagging strand is synthesized in the opposite direction.

Question 33

Which of the following individuals is a universal blood recipient?

Answer 33

Man with AB blood type.

Question 34

Which of the following correctly describes blood from a universal blood donor?

Answer 34

Red blood cell with no carbohydrates.

Question 35

Consider the replication bubble diagrammed at the right. Which letters represent places where one could find Okazaki fragments?

5’ L M 3’
3’ N O 5’

Answer 35

M and N

Question 36

The template strand of a given DNA molecule includes the sequence 3’-GCCACGTATCA-5’. What is the sequence of the nontemplate strand?

Answer 36

5’-CGGTGCATAGT-3’

Question 37

A man has 6 fingers on each hand, and 6 toes on each foot. His wife and daughter have 5 fingers, and toes on their hands, and feet. Extra digits is a dominant trait. What is the chance that the man’s next child would have extra digits?

Answer 37

50%