Question 1

The manufacture of proteins from RNA and amino acids is referred to as
A) transcription.
B) translation.
C) transformation.
D) activation.
E) replication.

Accepted Answer

Translation is the process by which the sequence of bases in mRNA is converted into the sequence of amino acids in a protein, involving the assembly of proteins on ribosomes using mRNA and amino acids.

Question 2

A sequence of three RNA bases can function as a(n)
A) gene only.
B) codon only.
C) codon or anticodon.
D) anticodon only.

Accepted Answer

A sequence of three RNA bases can function as a codon in mRNA or as an anticodon in tRNA.

Question 3

What molecule is responsible for translation of the four-letter ʺnucleic acid languageʺ (A, T, G, and C nucleotides) into the 20 ʺamino acid languageʺ of proteins by bringing in amino acids to the ribosome?
A) Transfer RNA
B) Ribosomal RNA
C) DNA
D) Messenger RNA

Accepted Answer

Transfer RNA (tRNA) is responsible for translating the four-letter nucleic acid language into the 20 amino acid language of proteins by bringing amino acids to the ribosome during protein synthesis.

Question 4

Which point mutation would be most likely to have a catastrophic effect?
A) A base insertion near the end of the coding sequence
B) The deletion of three bases near the start of the coding sequence
C) A base deletion near the end of the coding sequence
D) A base deletion near the start of the coding sequence
E) A base substitution

Accepted Answer

A base deletion near the start of the coding sequence can cause a frameshift mutation, altering the entire amino acid sequence downstream of the mutation, potentially leading to a nonfunctional protein. This can have more severe effects compared to the other options, which might result in less drastic changes to the protein structure or function.

Question 5

Which of the following has anticodons?
A) DNA
B) Messenger RNA
C) RNA polymerase
D) Transfer RNA
E) Ribosomal RNA

Accepted Answer

Transfer RNA (tRNA) contains anticodons, which are sequences of three nucleotides complementary to the codons in messenger RNA (mRNA). These anticodons are crucial for the correct alignment and incorporation of amino acids during the process of protein synthesis.

Question 6

Which of the following is a protein made up of amino acids?
A) Uracil
B) Messenger RNA
C) RNA polymerase
D) Transfer RNA
E) DNA

Accepted Answer

RNA polymerase is a protein composed of amino acids, responsible for synthesizing RNA from a DNA template.

Question 7

A gene can be mutated with no resulting functional change in the protein that is produced from that gene if
A) an entire codon has been removed.
B) RNA polymerase can edit the mutation from the mRNA produced during translation.
C) a codon has changed, but it codes for the same amino acid as the original codon.
D) the mutation alters the active site of an enzyme.

Accepted Answer

This is because of the redundancy in the genetic code, where multiple codons can code for the same amino acid. This phenomenon is known as "silent mutation."

Question 8

What kind of mutation occurs when one base is changed to another at a single location in the DNA?
A) Deletion
B) Substitution
C) Neutral
D) Insertion

Accepted Answer

Substitution mutations occur when one base is changed to another at a single location in the DNA.

Question 9

Suppose the template DNA strand of a ʺmini-geneʺ has the base sequence TACCCGGATTCA. The anticodon of the tRNA that carries the first amino acid to the ribosome will be
A) AGU.
B) UAG.
C) UCA.
D) AUG.
E) UAC.

Accepted Answer

The template DNA strand is TACCCGGATTCA, so the mRNA sequence transcribed from it would be AUGGGCCUAAGU. The first codon (AUG) codes for the first amino acid, and the anticodon that pairs with this codon on the tRNA is UAC. However, the question asks for the anticodon that carries the first amino acid, which is methionine (Met), and its codon is AUG. The anticodon is written in the 3' to 5' direction, opposite to the codon, so the correct anticodon for the tRNA carrying the first amino acid (methionine) is UAC, but due to the options provided and the nature of the question, the correct interpretation is that it seeks the anticodon complementary to the mRNA. Thus, the confusion arises from the interpretation of the question's wording. Given the options and re-evaluating the context, the correct answer aligns with the mRNA's start codon AUG, which is not directly listed as an anticodon option. The question's phrasing might have led to an initial misunderstanding. The correct approach is to identify the anticodon that pairs with the mRNA's codon, but the options and explanation seem to have mixed the direct answer. The anticodon corresponding to the mRNA sequence AUG (which codes for Methionine, the first amino acid in a protein) would indeed be UAC in a direct pairing scenario. However, the question's framing about the "first amino acid" and the provided options might lead to confusion, as it seems to ask for the anticodon matching the mRNA's start codon. Given the options, none directly represent the anticodon for AUG (which would be UAC in direct tRNA-mRNA pairing). The explanation aimed to clarify this misunderstanding, acknowledging the mix-up in interpreting the question's intent and the provided answer choices.

Question 10

For a mutation to affect the evolution of an animal species, it must occur within
A) somatic cells.
B) gametes.
C) prokaryotic cells.
D) diploid cells.

Accepted Answer

Mutations in gametes (sperm or eggs) can be passed on to offspring, affecting the genetic diversity and evolution of a species. Mutations in somatic cells do not get passed to offspring and thus do not contribute to evolution.

Question 11

A gene mutation is defined as change in the
A) structure of ribosomes.
B) nucleotide sequence of DNA.
C) activation of a gene.
D) nucleotide sequence of RNA.

Accepted Answer

A gene mutation refers to a change in the nucleotide sequence of DNA, which can affect the structure and function of proteins encoded by the gene.

Question 12

Which of the following contains codons?
A) Messenger RNA
B) Transfer RNA
C) DNA
D) Ribosomal RNA
E) RNA polymerase

Accepted Answer

Messenger RNA (mRNA) contains codons, which are sequences of three nucleotides that correspond to specific amino acids or stop signals during protein synthesis.

Question 13

Which of the following attaches to specific amino acids?
A) DNA
B) Messenger RNA
C) Ribosomal RNA
D) RNA polymerase
E) Transfer RNA

Accepted Answer

Transfer RNA (tRNA) is responsible for bringing amino acids to the ribosome during protein synthesis, where they are added to the growing polypeptide chain. Each tRNA molecule is specific to one amino acid.

Question 14

A mutation that results in a change in the codon-reading pattern could result from
A) a base substitution only.
B) either an insertion or a deletion of a base.
C) a base insertion only.
D) a base deletion only.

Accepted Answer

Either an insertion or a deletion of a base can result in a frameshift mutation, which changes the codon-reading pattern from the point of mutation onwards.

Question 15

A tRNA that carries a specific amino acid enters the protein -synthesizing machinery at the ribosomes and pairs with the appropriate
A) codon.
B) amino acid.
C) charge.
D) anticodon.

Accepted Answer

A tRNA pairs with the appropriate codon on the mRNA strand during protein synthesis, ensuring that the correct amino acid is added to the growing polypeptide chain.

Question 16

A tRNA molecule brings_________ to the ribosome during protein synthesis.
A) an amino acid
B) a polypeptide
C) RNA polymerase
D) mRNA

Accepted Answer

tRNA molecules are responsible for bringing amino acids to the ribosome during protein synthesis, where they are added to the growing polypeptide chain.

Question 17

In a wild-type strain of fruit flies, the length of a gene from the start to the stop codon is 2,000 DNA bases. Suppose an experiment indicated that the mRNA molecule transcribed from this gene is much shorter (only 1,200 bases). What is the most likely explanation for this?
A) The first 800 bases of DNA are always cut out as it is transcribed into mRNA.
B) A mutation caused the formation of an extra stop codon in the gene.
C) There are introns in the DNA that were cut out of the mRNA.
D) The mRNA was prematurely degraded.

Accepted Answer

Introns are non-coding sequences in a gene that are removed during the process of mRNA splicing, resulting in a shorter mRNA molecule compared to the original DNA sequence.

Question 18

Which of the following synthesizes RNA molecules in the nucleus?
A) Messenger RNA
B) DNA
C) Ribosomal RNA
D) Transfer RNA
E) RNA polymerase

Accepted Answer

RNA polymerase is the enzyme responsible for synthesizing RNA molecules from a DNA template in the nucleus, a process known as transcription.

Question 19

A random change in a DNA nucleotide base sequence
A) is never apparent in the organism.
B) always kills the cell.
C) represents a mutation.
D) cannot have an influence on genetic variation.
E) is never beneficial to the organism.

Accepted Answer

Mutations are defined as changes in the nucleotide sequence of DNA, which can occur randomly and have various effects on an organism, ranging from harmful to beneficial or neutral.

Question 20

Which of the following binds to codons?
A) Messenger RNA
B) DNA
C) RNA polymerase
D) Transfer RNA

Accepted Answer

Transfer RNA (tRNA) binds to codons on the messenger RNA (mRNA) during protein synthesis by matching its anticodon with the codon on the mRNA.

Quiz 13: Gene Expression and Regulation

The manufacture of proteins from RNA and amino acids is referred to as

A sequence of three RNA bases can function as a(n)

What molecule is responsible for translation of the four-letter ʺnucleic acid languageʺ (A, T, G, and C nucleotides) into the 20 ʺamino acid languageʺ of proteins by bringing in amino acids to the ribosome?

Which point mutation would be most likely to have a catastrophic effect?

Which of the following has anticodons?

Which of the following is a protein made up of amino acids?

A gene can be mutated with no resulting functional change in the protein that is produced from that gene if

What kind of mutation occurs when one base is changed to another at a single location in the DNA?

Suppose the template DNA strand of a ʺmini-geneʺ has the base sequence TACCCGGATTCA. The anticodon of the tRNA that carries the first amino acid to the ribosome will be

For a mutation to affect the evolution of an animal species, it must occur within

A gene mutation is defined as change in the

Which of the following contains codons?

Which of the following attaches to specific amino acids?

A mutation that results in a change in the codon-reading pattern could result from

A tRNA that carries a specific amino acid enters the protein -synthesizing machinery at the ribosomes and pairs with the appropriate

A tRNA molecule brings_________ to the ribosome during protein synthesis.

In a wild-type strain of fruit flies, the length of a gene from the start to the stop codon is 2,000 DNA bases. Suppose an experiment indicated that the mRNA molecule transcribed from this gene is much shorter (only 1,200 bases) . What is the most likely explanation for this?

Which of the following synthesizes RNA molecules in the nucleus?

A random change in a DNA nucleotide base sequence

Which of the following binds to codons?