Q: If a DNA sequence $$5'\text{TAC}3' is $$transcribed and translated, what is the corresponding mRNA codon and amino acid?

mRNA: $$5'\text{AUG}3'$$, Amino acid: Methionine

Q: Which of the following statements about the genetic code is correct?

The codon $$\text{AUG}$$ serves as both a start codon and codes for methionine.

Question 1

Which of the following statements best describes the difference between the leading and lagging strands during DNA replication in bacteria?

Accepted Answer

The leading strand is synthesized continuously in the 5' to 3' direction, while the lagging strand is synthesized discontinuously in the 5' to 3' direction as Okazaki fragments.

Question 2

A mutation changes the DNA sequence from $$5'	ext{ACTGATT}3' to$$ $$5'	ext{ACTAATT}3'. $$What type of mutation is this, and what is a possible consequence?

Accepted Answer

It is a point mutation (substitution), which may result in a missense, nonsense, or silent mutation.

Question 3

Which enzyme is targeted by antibiotics such as ciprofloxacin due to its unique presence in bacteria and its role in DNA replication?

Accepted Answer

DNA gyrase

Question 4

During transcription in bacteria, which of the following is NOT required for the synthesis of mRNA?

Accepted Answer

DNA ligase

Question 5

A bacterial cell acquires resistance to penicillin after exposure to DNA fragments from a dead cell. Which genetic process is responsible for this event?

Accepted Answer

Transformation

Question 6

Which of the following codons signals the termination of translation in protein synthesis?

Accepted Answer

$$	ext{UAA}$$

Question 7

If a DNA sequence $$5'	ext{TAC}3' is $$transcribed and translated, what is the corresponding mRNA codon and amino acid?

Accepted Answer

mRNA: $$5'	ext{AUG}3'$$, Amino acid: Methionine

Question 8

Which of the following best explains why a frameshift mutation often results in a non-functional protein?

Accepted Answer

It alters the reading frame, changing the sequence of most amino acids downstream from the mutation.

Question 9

Which type of plasmid is responsible for the transfer of antibiotic resistance genes between bacteria?

Accepted Answer

R plasmid

Question 10

A bacteriophage accidentally packages bacterial DNA instead of its own during assembly. What is the name of this process?

Accepted Answer

Transduction

Question 11

Which of the following statements about the genetic code is correct?

Accepted Answer

The codon $$	ext{AUG}$$ serves as both a start codon and codes for methionine.

Question 12

Which of the following is a real-world consequence of horizontal gene transfer in bacteria?

Accepted Answer

Rapid spread of antibiotic resistance among pathogenic bacteria.

Question 13

Which enzyme is responsible for joining Okazaki fragments on the lagging strand during DNA replication?

Accepted Answer

DNA ligase

Question 14

A bacterial cell with an F plasmid (F+) mates with a cell lacking the plasmid (F-). What is the result of this conjugation?

Accepted Answer

Both cells become F+

Question 15

Which of the following best describes the role of tRNA during translation?

Accepted Answer

It brings specific amino acids to the ribosome based on the mRNA codon sequence.

Question 16

Which of the following is a possible outcome of a silent mutation?

Accepted Answer

The amino acid sequence of the protein remains unchanged.

Question 17

Which of the following is NOT a component of a DNA nucleotide?

Accepted Answer

A ribose sugar

Question 18

Which process is responsible for the vertical transfer of genetic information from a parent bacterial cell to its daughter cells?

Accepted Answer

Replication

Question 19

Which of the following best explains why DNA is described as 'antiparallel'?

Accepted Answer

One strand runs 5' to 3' and the other runs 3' to 5'.

Question 20

Which of the following is a function of rRNA in the cell?

Accepted Answer

It forms the structural and catalytic core of the ribosome.

Microbial Genetics: Structure, Function, and Transfer of Genetic Material

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