Question 1

The fact that some tRNA molecules do not have to pair exactly is called _______.

Accepted Answer

The answer of The fact that some tRNA molecules do...

Question 2

Which of the following statements about RNA polymerase is false?

Accepted Answer

RNA polymerase synthesizes mRNA in a 5´-to-3´ direction, reading the DNA strand 3´ to 5´. Choice A is true. RNA polymerase also binds at the promoter and unwinds the DNA (choice C) and does not require a primer to initiate transcription (choice D). RNA polymerase uses only one strand of DNA as a template for synthesizing RNA (choice E). However, choice B is false as RNA polymerase synthesizes mRNA in a 5´-to-3´ direction, not 3´-to-5´.

Question 3

Translation of messenger RNA into protein occurs in a _______ direction, and from _______ terminus to _______ terminus.

Accepted Answer

Translation of messenger RNA into protein occurs in a 5´-to-3´ direction, and from N terminus to C terminus. This means that the ribosome reads the mRNA in the 5´-to-3´ direction and synthesizes the corresponding protein from the N terminus to the C terminus. The other answer choices are incorrect as they either have the wrong direction or the wrong order of termini.

Question 4

The portion of the tRNA molecule that complementary base-pairs with the mRNA is called the _______.

Accepted Answer

The answer of The portion of the tRNA molecule that...

Question 5

Translate the following mRNA: 
3´ - G A U G G U U U U A A A G U A - 5´

Accepted Answer

The answer of Translate the following mRNA: 
3´ - G...

Question 6

Refer to the diagram below showing the process of gene expression in prokaryotes. The molecule responsible for carrying and delivering amino acids in the proper sequence is/are

Accepted Answer

The molecule responsible for carrying and delivering amino acids in the proper sequence is tRNA, as it contains anticodons that match up with codons on the mRNA during translation. Both rRNA and mRNA play important roles in gene expression, but they are not responsible for carrying and delivering amino acids. DNA is involved in transcription, but not in the actual process of translating the genetic code into protein.

Question 7

Transcription in prokaryotic cells

Accepted Answer

Prokaryotic transcription is initiated at a promoter region on the DNA and uses only one strand of DNA (the template strand) to synthesize a complementary RNA strand. The process does not occur in the nucleus, and translation, not transcription, occurs in the cytoplasm. Initiation factors and the small subunit of the ribosome are involved in translation, not transcription. Transcription is terminated at termination sequences, not stop codons, and ori sites are involved in DNA replication, not transcription.

Question 8

The synthesis of DNA from RNA is called _______.

Accepted Answer

The answer of The synthesis of DNA from RNA is...

Question 9

The addition of phosphate groups to polypeptide chains following translation is called _______.

Accepted Answer

The answer of The addition of phosphate groups to polypeptide...

Question 10

If codons were read two bases at a time instead of three bases at a time, how many different possible amino acids could be specified?

Accepted Answer

With two bases per codon, there are 4^2 = 16 possible combinations, as each base can be one of four (A, T, C, G).

Question 11

Peptidyl transferase is an

Accepted Answer

Peptidyl transferase is a ribozyme (catalytic RNA) found in the large subunit of the ribosome, responsible for catalyzing peptide bond formation during protein synthesis.

Question 12

If the following synthetic RNA were added to a test tube containing all the components necessary for protein translation to occur, what would the amino acid sequence be? 5´ - A U A U A U A U A U A U - 3´

Accepted Answer

The answer of If the following synthetic RNA were added...

Question 13

A tRNA that has bonded to an amino acid is referred to as _______ tRNA.

Accepted Answer

The answer of A tRNA that has bonded to an...

Question 14

The excess of codons (64) over amino acids (20) indicates that the genetic code is _______.

Accepted Answer

The answer of The excess of codons (64) over amino...

Question 15

An mRNA molecule with several ribosomes attached is called a(n) _______.

Accepted Answer

The answer of An mRNA molecule with several ribosomes attached...

Question 16

The part of a protein that determines whether translation will continue in the cytosol or at the endoplasmic reticulum is the _______ sequence.

Accepted Answer

The answer of The part of a protein that determines...

Question 17

Small ribosomal subunits will disperse into smaller components when placed in a detergent solution. Upon removal of the detergent, the components will interact to create new intact subunits by a process called _______.

Accepted Answer

The answer of Small ribosomal subunits will disperse into smaller...

Question 18

What would happen if a mutation occurred in DNA such that the second codon of the resulting mRNA was changed from UGG to UAG?

Accepted Answer

The codon UAG is a stop codon, also known as a nonsense codon. When a stop codon is encountered in the mRNA, translation is terminated and no further amino acids are added to the growing peptide chain. Therefore, if the second codon in the mRNA is changed from UGG to UAG, translation will stop at the second codon and no functional protein will be made.

Question 19

Which part of the tRNA base-pairs with the codon in the mRNA?

Accepted Answer

The anticodon of the tRNA base-pairs with the codon in the mRNA, ensuring the correct amino acid is incorporated into the growing polypeptide chain during translation.

Question 20

A noncoding base sequence found in eukaryotic cells is called a(n) _______.

Accepted Answer

The answer of A noncoding base sequence found in eukaryotic...

Quiz 14: From Dna to Protein: Gene Expression