Q: If a DNA coding strand has the sequence 5'-ATG GCC AAT GAC TTT CAA TAA-3', what is the corresponding mRNA sequence?

$$5'\text{AUG GCC AAU GAC UUU CAA UAA}3'$$

Question 1

Which of the following best describes the Central Dogma of molecular biology?

Accepted Answer

DNA is transcribed into mRNA, which is then translated into proteins.

Question 2

If a DNA coding strand has the sequence 5'-ATG GCC AAT GAC TTT CAA TAA-3', what is the corresponding mRNA sequence?

Accepted Answer

$$5'	ext{AUG GCC AAU GAC UUU CAA UAA}3'$$

Question 3

How many different amino acids can be specified by a 3-base codon system, given 4 different RNA bases?

Accepted Answer

$$4^3 = 64$

Question 4

Which of the following statements about RNA polymerase is TRUE?

Accepted Answer

RNA polymerase synthesizes RNA in the 5' to 3' direction.

Question 5

During eukaryotic RNA processing, which of the following modifications occurs to the primary transcript?

Accepted Answer

Addition of a 5' cap and a poly(A) tail

Question 6

Which of the following is the correct sequence of events during transcription initiation in bacteria?

Accepted Answer

Sigma binds to the promoter, RNA polymerase binds to sigma, transcription begins

Question 7

A mutation changes the DNA sequence from 5'-ATG GCC AAT GAC TTT CAA TAA-3' to 5'-ATG GCC AAA GAC TTT CAA TAA-3'. What is the effect on the protein sequence?

Accepted Answer

The asparagine (Asn) is replaced by lysine (Lys).

Question 8

Which of the following best explains why E. coli does not produce β-galactosidase when both glucose and lactose are present?

Accepted Answer

Glucose inhibits the expression of the gene for β-galactosidase.

Question 9

Which site on the ribosome holds the tRNA with the growing polypeptide chain during translation?

Accepted Answer

P site

Question 10

What is the role of snRNPs in eukaryotic cells?

Accepted Answer

They splice introns out of the primary RNA transcript.

Question 11

A tRNA has the anticodon 5'-UGA-3'. Which mRNA codon will it recognize, and which amino acid will it carry if the genetic code is used?

Accepted Answer

5'-ACU-3', Serine

Question 12

Which of the following is a post-translational modification that can regulate protein activity?

Accepted Answer

Addition of a phosphate group

Question 13

Which of the following statements about translation in prokaryotes is correct?

Accepted Answer

Translation and transcription are coupled and can occur simultaneously.

Question 14

Which codon serves as the start codon for translation in most organisms?

Accepted Answer

$$	ext{AUG}$$

Question 15

What would be the effect of a mutation that prevents the formation of the hairpin loop in bacterial transcription termination?

Accepted Answer

Transcription would not terminate properly, leading to longer RNA transcripts.

Question 16

Which of the following best describes the function of the spliceosome?

Accepted Answer

It removes introns from pre-mRNA and joins exons together.

Question 17

If the mRNA codon is 5'-GAA-3', what is the corresponding anticodon on the tRNA?

Accepted Answer

$$3'	ext{CUU}5'$$

Question 18

Which of the following is NOT a function of the 5' cap added to eukaryotic mRNA?

Accepted Answer

Acts as a signal for RNA splicing

Question 19

Which of the following scenarios would most likely result in the production of a nonfunctional protein?

Accepted Answer

A mutation introduces a premature stop codon in the coding region.

Gene Function: Transcription, Translation, and the Genetic Code

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