Question 1

Which of the following best describes the structure of DNA in most bacteria?

Accepted Answer

One circular chromosome located in the nucleoid region

Question 2

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

Accepted Answer

Operons allow for coordinated expression of multiple related genes from a single promoter

Question 3

A mutation occurs in the operator region of the lac operon, preventing the repressor from binding. What is the most likely outcome?

Accepted Answer

The lac operon will be constitutively expressed, even in the absence of lactose

Question 4

Which of the following is a function of plasmids in bacteria?

Accepted Answer

Encoding genes for antibiotic resistance and virulence factors

Question 5

Which equation correctly represents the complementary base pairing in DNA?

Accepted Answer

$$A + G = T + C$$

Question 6

What is the main role of microRNAs (miRNAs) in eukaryotic cells?

Accepted Answer

They regulate gene expression by silencing target mRNAs

Question 7

Which of the following best explains why eukaryotic genomes are generally larger and more complex than prokaryotic genomes?

Accepted Answer

Eukaryotic genomes contain large amounts of non-coding DNA, including introns and regulatory regions

Question 8

Which process is responsible for removing introns from pre-mRNA in eukaryotic cells?

Accepted Answer

Splicing

Question 9

A bacterial cell loses all its plasmids but retains its main chromosome. What is the most likely consequence?

Accepted Answer

The cell will lose accessory traits such as antibiotic resistance

Question 10

Which of the following is a key difference between DNA and RNA?

Accepted Answer

RNA contains ribose sugar, while DNA contains deoxyribose sugar

Question 11

Which of the following best describes the evolutionary process of chromosomization?

Accepted Answer

A plasmid gains essential genes and becomes indispensable, eventually functioning as a secondary chromosome

Question 12

Which of the following is true about the packaging of DNA in eukaryotes?

Accepted Answer

DNA is wrapped around histone proteins to form nucleosomes

Question 13

Which of the following is a function of introns in eukaryotic genomes?

Accepted Answer

They allow for alternative splicing, increasing protein diversity

Question 14

Which of the following statements about secondary chromosomes in bacteria is correct?

Accepted Answer

They contain housekeeping genes and are essential for survival

Question 15

Which of the following best describes the role of the operator in an operon?

Accepted Answer

It is the binding site for regulatory proteins that control transcription

Question 16

Which of the following is a similarity between archaeal and eukaryotic chromosomes?

Accepted Answer

Both use histone or histone-like proteins for DNA packaging

Question 17

A mutation in the spliceosome prevents recognition of the GU sequence at the start of introns. What is the most likely effect?

Accepted Answer

Introns will not be removed, resulting in abnormal mRNA

Question 18

Which of the following best explains why bacteria can rapidly adapt to antibiotics?

Accepted Answer

Plasmids can carry antibiotic resistance genes and be transferred between bacteria via horizontal gene transfer

Question 19

Which of the following is a direct result of alternative splicing in eukaryotes?

Accepted Answer

One gene can produce multiple protein isoforms

Question 20

Which of the following best describes the function of the RNA-induced silencing complex (RISC) in gene regulation?

Accepted Answer

It binds to miRNA and targets complementary mRNA for degradation or translational repression

lec 18:Bacterial Genomes and Replication: Structure, Organization, and Regulation

Study Guide - Practice Questions