Question 1

Codons are base pair sequences that
A)signal the start of DNA synthesis.
B)signal the end of DNA synthesis.
C)code for amino acids.
D)signal the start of RNA synthesis.
E)code for one or more bases in mRNA.

Accepted Answer

Codons are sequences of three base pairs that code for a specific amino acid during protein synthesis.

Question 2

During protein synthesis, the codon for an amino acid is found on
A)DNA.
B)rRNA.
C)tRNA.
D)mRNA.
E)sRNA.

Accepted Answer

The codon for an amino acid is found on mRNA, which is transcribed from DNA and carries the genetic information to the ribosome where it is translated into a polypeptide chain. rRNA and tRNA are involved in the translation process, but they do not carry the codon for the amino acid. sRNA is not involved in protein synthesis.

Question 3

A tRNA is activated when it
A)attaches to mRNA.
B)attaches to its specific amino acid.
C)attaches to the ribosome.
D)leaves the ribosome.
E)releases its specific amino acid.

Accepted Answer

A tRNA is activated when it attaches to its specific amino acid, which occurs through the action of an enzyme called aminoacyl-tRNA synthetase. The activated tRNA can then bring the amino acid to the ribosome during translation.

Question 4

Some sections of a DNA molecule do not code for protein synthesis. These segments are called
A)codons.
B)anticodons.
C)Okazaki fragments.
D)introns.
E)exons.

Accepted Answer

The segments of DNA that do not code for protein synthesis are called introns.

Question 5

In the synthesis of mRNA, an adenine in the DNA pairs with
A)uracil.
B)adenine.
C)guanine.
D)thymine.
E)cytosine.

Accepted Answer

In RNA synthesis, uracil pairs with adenine instead of thymine. Therefore, when an adenine is present in the DNA, it will pair with uracil in the mRNA.

Question 6

In transcription
A)the mRNA produced is identical to the parent DNA.
B)a double helix containing one parent strand and one daughter strand is produced.
C)uracil pairs with thymine.
D)both strands of the DNA are copied.
E)the mRNA produced is complementary to one strand of the DNA.

Accepted Answer

During transcription, the DNA sequence is used as a template to synthesize a single-stranded RNA molecule. The mRNA produced is complementary to one strand of DNA, which serves as the template, and not identical to the parent DNA. Uracil does pair with adenine, not thymine. Only one strand of the double-stranded DNA serves as the template, and the other is not copied.

Question 7

Which of the following types of RNA carries the genetic information from DNA in the nucleus to the cytoplasm for protein synthesis?
A)mRNA
B)histone RNA
C)rRNA
D)tRNA
E)sRNA

Accepted Answer

mRNA (messenger RNA) carries the genetic information from DNA in the nucleus to the cytoplasm for protein synthesis.

Question 8

A set of directions in the DNA base sequence for the synthesis of a protein is a(n)
A)structural gene.
B)promotor.
C)operator.
D)codon.
E)regulatory gene.

Accepted Answer

A structural gene is a segment of DNA that contains the necessary information to code for a protein, providing the directions for its synthesis.

Question 9

The anticodon is
A)identical to the codon on DNA.
B)complementary to the codon on DNA.
C)identical to the codon on mRNA.
D)complementary to the codon on mRNA.
E)complementary to the codon on tRNA.

Accepted Answer

The anticodon is a three-nucleotide sequence on tRNA that is complementary to the three-nucleotide codon on mRNA during protein synthesis. Therefore, the anticodon is complementary to the codon on mRNA, making choice D the correct answer.

Question 10

Mutations are the result of
A)alterations in the phosphate of the DNA backbone.
B)exposure to water in utero.
C)physical trauma in the mother's childhood.
D)alterations in the sugar component of the DNA backbone.
E)alterations in the DNA base sequence.

Accepted Answer

Mutations are alterations in the sequence of DNA bases, which can occur through errors during DNA replication or exposure to mutagens such as radiation or certain chemicals. Changes to the phosphate or sugar components of the DNA backbone do not necessarily result in mutations. Water in utero or physical trauma in the mother's childhood are not known to cause mutations.

Question 11

The codon is found on ________, and the anticodon is found on ________.
A)mRNA; tRNA
B)tRNA; mRNA
C)rRNA; tRNA
D)ribosomes; tRNA
E)mRNA; rRNA

Accepted Answer

The codon, which consists of three nucleotides that encode for a specific amino acid, is found on mRNA. The anticodon, which is a sequence of three nucleotides that binds to the codon on mRNA during protein synthesis, is found on tRNA. Therefore, choice A is the correct answer.

Question 12

Which of the following is a section of mRNA produced from the DNA template below? 3' A-A-G-C-G-A-A 5'
A)5' A-T-A-G-C-T-A 3'
B)5' A-U-A-G-C-U-A 3'
C)5' U-A-U-C-G-A-U 3'
D)5' U-U-U-G-C-U-U 3'
E)5' T-A-T-C-G-A-T 3'

Accepted Answer

The answer of Which of the following is a section...

Question 13

Which of the following is not a step in protein synthesis?
A)activation of tRNA
B)initiation
C)elongation
D)termination
E)unwinding of two strands of mRNA

Accepted Answer

Unwinding of two strands of mRNA is not a step in protein synthesis. The correct sequence of steps in protein synthesis is activation of tRNA, initiation, elongation, and termination. During initiation, the mRNA strand is bound to the ribosome, and during elongation, the ribosome moves along the mRNA strand, reading the codons and adding the appropriate amino acids to the growing peptide chain. Unwinding of the two strands of DNA occurs during transcription, which is the process by which mRNA is synthesized from a DNA template.

Question 14

Translation is the process whereby
A)DNA is synthesized from DNA.
B)DNA is synthesized from mRNA.
C)protein is synthesized from DNA.
D)protein is synthesized from mRNA.
E)mRNA is synthesized from DNA.

Accepted Answer

Translation is the process by which proteins are synthesized from mRNA templates. The mRNA carries the genetic code for the protein synthesis, and deciphered by ribosomes which translate the code into the language of amino acids, the building blocks for proteins. Therefore, option D is the correct answer.

Question 15

The anticodon of U-A-G is
A)A-T-C.
B)U-A-G.
C)A-A-C.
D)A-U-C.
E)G-A-U.

Accepted Answer

The answer of The anticodon of U-A-G is
A)A-T-C.
B)U-A-G.
C)A-A-C.
D)A-U-C.
E)G-A-U....

Question 16

Which one of these base pairs is found in RNA?
A)guanine-cytosine
B)adenine-cytosine
C)adenine-thymine
D)adenine-guanine
E)guanine-thymine

Accepted Answer

In RNA, the base pairs are adenine-uracil and guanine-cytosine. Guanine-cytosine is the correct pair found in both DNA and RNA.

Question 17

When mRNA is synthesized using the information from DNA, the process is called
A)transportation.
B)transposition.
C)transcription.
D)translation.
E)transliteration.

Accepted Answer

The process when mRNA is synthesized using the information from DNA is called transcription.

Question 18

Which of the following is a section of mRNA produced from the DNA template below? 3' A-T-A-G-C-T-A 5'
A)5' A-T-A-G-C-T-A 3'
B)5' A-U-A-G-C-U-A 3'
C)5' U-A-U-C-G-A-U 3'
D)5' U-U-U-G-C-U-U 3'
E)5' T-A-T-C-G-A-T 3'

Accepted Answer

The mRNA sequence will be complementary to the DNA template, except that thymine (T) will be replaced with uracil (U). So, the mRNA sequence will be 5' U-A-U-C-G-A-U 3'. Choice A has the same sequence as the DNA template and choices B, D and E contain incorrect nucleotide sequences. Therefore, the correct answer is C.

Question 19

A DNA template having the base sequence 3' A-G-A-T-G-A 5' would produce a mRNA with a base sequence of
A)5' A-G-A-T-G-A 3'.
B)5' U-C-U-A-C-U 3'.
C)5' T-C-T-U-C-T 3'.
D)5' T-C-T-A-C-A 3'.
E)5' A-C-A-U-C-A 3'.

Accepted Answer

DNA to mRNA transcription follows the base pairing rule where A pairs with U, T pairs with A, C pairs with G and G pairs with C. 
So, the complementary base sequence of the given DNA template would be: 
5' T-C-A-T-C-T 3'. 
Thus, the mRNA sequence would be: 
5' U-C-A-U-C-U 3'. 
Therefore, the correct answer is B.

Question 20

Which of the following types of RNA has a large subunit and a small subunit?
A)mRNA
B)histone RNA
C)rRNA
D)tRNA
E)sRNA

Accepted Answer

The answer of Which of the following types of RNA...

Quiz 21: Nucleic Acids and Protein Synthesis

Codons are base pair sequences that

During protein synthesis, the codon for an amino acid is found on

A tRNA is activated when it

Some sections of a DNA molecule do not code for protein synthesis. These segments are called

In the synthesis of mRNA, an adenine in the DNA pairs with

In transcription

Which of the following types of RNA carries the genetic information from DNA in the nucleus to the cytoplasm for protein synthesis?

A set of directions in the DNA base sequence for the synthesis of a protein is a(n)

The anticodon is

Mutations are the result of

The codon is found on , and the anticodon is found on .

Which of the following is a section of mRNA produced from the DNA template below? 3' A-A-G-C-G-A-A 5'

Which of the following is not a step in protein synthesis?

Translation is the process whereby

The anticodon of U-A-G is

Which one of these base pairs is found in RNA?

When mRNA is synthesized using the information from DNA, the process is called

Which of the following is a section of mRNA produced from the DNA template below? 3' A-T-A-G-C-T-A 5'

A DNA template having the base sequence 3' A-G-A-T-G-A 5' would produce a mRNA with a base sequence of

Which of the following types of RNA has a large subunit and a small subunit?