Q: During translation, how does the ribosome know where to stop synthesizing the polypeptide chain?

It encounters a stop codon ($$\text{UAA}$$, $$\text{UAG}$$, or $$\text{UGA}) on $$the mRNA

Question 1

A couple, both with blood type AB, are planning to have a child. What is the probability that their child will have blood type A? Use a Punnett square to determine your answer.

Accepted Answer

$$\frac{1}{2}$$

Question 2

Which of the following genotypes corresponds to the universal donor blood type?

Accepted Answer

ii

Question 3

If a person with genotype IAi (blood type A) has children with a person with genotype IBi (blood type B), what is the expected phenotypic ratio of their offspring's blood types?

Accepted Answer

1 A : 1 B : 1 AB : 1 O

Question 4

During transcription, which enzyme is responsible for synthesizing the mRNA strand from the DNA template?

Accepted Answer

RNA polymerase

Question 5

Given the DNA template strand 5'-TACGGTACG-3', what is the sequence of the transcribed mRNA?

Accepted Answer

5'-AUGCCAUGC-3'

Question 6

Which structure is responsible for translating the mRNA into a polypeptide chain?

Accepted Answer

Ribosome

Question 7

How many different amino acids are encoded by the genetic code?

Accepted Answer

20

Question 8

A codon is defined as:

Accepted Answer

A sequence of three nucleotides in mRNA that codes for a specific amino acid

Question 9

Which codon signals the start of translation in most mRNA molecules?

Accepted Answer

$$	ext{AUG}$$

Question 10

Which of the following is NOT a stop codon in the genetic code?

Accepted Answer

$$	ext{AUG}$$

Question 11

If the mRNA sequence is 5'-AUGUUUCCU-3', what is the corresponding amino acid sequence? (Use the standard genetic code)

Accepted Answer

Met-Phe-Pro

Question 12

Which blood type is considered the universal recipient, and why?

Accepted Answer

AB, because individuals with this blood type do not produce anti-A or anti-B antibodies

Question 13

A woman with genotype IAi (blood type A) and a man with genotype ii (blood type O) have a child. What is the probability that the child will have blood type O?

Accepted Answer

$$\frac{1}{2}$$

Question 14

Which statement best describes the difference between the DNA template and coding (nontemplate) strands during transcription?

Accepted Answer

The template strand is used by RNA polymerase to synthesize mRNA, while the coding strand has the same sequence as the mRNA (except T is replaced by U)

Question 15

If a gene has the coding strand sequence 5'-ATG GAA TGC-3', what is the mRNA sequence transcribed from the template strand?

Accepted Answer

5'-AUG GAA UGC-3'

Question 16

Which of the following best explains why individuals with blood type O are considered universal donors?

Accepted Answer

Their red blood cells lack A and B antigens, so they do not trigger an immune response in recipients of any blood type

Question 17

A man with genotype IBIB (blood type B) and a woman with genotype IAi (blood type A) have a child. What is the probability that the child will have blood type AB?

Accepted Answer

$$\frac{1}{2}$$

Question 18

Which of the following is a correct statement about the genetic code?

Accepted Answer

It is universal, redundant, and unambiguous

Question 19

During translation, how does the ribosome know where to stop synthesizing the polypeptide chain?

Accepted Answer

It encounters a stop codon ($$	ext{UAA}$$, $$	ext{UAG}$$, or $$	ext{UGA}) on $$the mRNA

Genetics and Molecular Biology: Study Guide for Lab Quiz 4

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