Question 1

A recessive allele in dogs causes white spots. If two solid-colored dogs are mated and produce a spotted offspring, what is the percentage chance their next puppy would be solid colored? Use the following: Let $$S be $$the dominant allele (solid color) and $$s be $$the recessive allele (spotted).

Accepted Answer

75%

Question 2

In humans, cystic fibrosis is a recessive disorder controlled by a single gene. A couple goes to see a genetic counselor before having children because the husband's brother has cystic fibrosis. It is determined that the husband is heterozygous and carries the allele. What is the likelihood that one of his gametes contains the recessive allele?

Accepted Answer

50%

Question 3

The gene for blood group determination has three alleles in the population. How many alleles does each person have for this gene?

Accepted Answer

2

Question 4

If a mother is heterozygous for a recessive sex-linked trait and her husband has the dominant allele, which of the following is true about the probabilities for their children?

Accepted Answer

Half of their sons will have the recessive trait.

Question 5

Sherry has O type blood and her son, Jack, has B type blood. Which of the following phenotypes could be the phenotype of Jack's biological father? Select all that apply.

Accepted Answer

B

Question 6

If the sequence in the mRNA for a particular amino acid is $$5' AGU 3'$$, then the anticodon on the corresponding tRNA would be ______.

Accepted Answer

$$5' UCA 3'$$

Question 7

Which of the following levels of gene expression allows the most rapid response to environmental change?

Accepted Answer

Translational control

Question 8

A tRNA carrying the anticodon $$3' ACC 5'$$ will base pair with the codon _____ and be carrying the amino acid _____.

Accepted Answer

$$5' UGG 3'$$; Trp

Question 9

An operon in E. coli called the Suc operon encodes proteins responsible for metabolism of sucrose. In the absence of glucose, similar to the regulation of the lac operon, the 2 genes of the operon are under the control of a single promoter and operator. The repressor protein, SucR, binds to the operator. Under what conditions do you expect the repressor to be bound to the operator?

Accepted Answer

Low sucrose

Question 10

What type of operon is the Suc operon described above?

Accepted Answer

Inducible

Question 11

Glucose suddenly becomes abundant in an E. coli culture that was previously growing on lactose. Predict whether transcription of the lac operon increases, decreases, or stays the same. Explain why by describing both negative and positive regulation.

Accepted Answer

Transcription decreases because glucose reduces cAMP, lowering CAP activation (positive regulation), and the repressor is not bound (negative regulation).

Question 12

A missense mutation most likely results in which of the following outcomes?

Accepted Answer

One amino acid in the protein is changed to a different one.

Question 13

A woman who is a carrier for hemophilia (an X-linked recessive disorder) and a man without hemophilia have a son. What is the probability that their son will have hemophilia?

Accepted Answer

50%

Question 14

Which of the following best describes the function of an operon in prokaryotic gene regulation?

Accepted Answer

A group of genes regulated together by a single promoter and operator.

Question 15

If a mutation changes the codon $$5' UAU 3' ($$which codes for tyrosine) to $$5' UAA 3'$$, what type of mutation has occurred?

Accepted Answer

Nonsense mutation

Question 16

Which of the following is true about the relationship between genotype and phenotype?

Accepted Answer

Genotype interacts with the environment to produce phenotype.

Question 17

A man with blood type AB and a woman with blood type O have a child. What are the possible blood types of their child?

Accepted Answer

A or B

Question 18

Which of the following best explains why the genetic code is described as 'degenerate'?

Accepted Answer

Multiple codons can code for the same amino acid.

Question 19

Which of the following is a real-world example of a frameshift mutation causing disease?

Accepted Answer

Cystic fibrosis (most common mutation, $$	riangleF508)$$

Genetics and Gene Expression: Study Notes for General Biology

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