Q: Which of the following sequences correctly represents the flow of genetic information according to the central dogma of molecular biology?

$$\text{DNA} \rightarrow \text{RNA} \rightarrow \text{Protein}$$

Question 1

Which of the following best describes the difference between DNA replication and transcription in eukaryotic cells?

Accepted Answer

DNA replication produces two identical DNA molecules, while transcription produces a complementary RNA strand from a DNA template.

Question 2

A scientist observes that a bacterial cell can acquire antibiotic resistance after being exposed to DNA from a dead, resistant bacterium. This process is best described as:

Accepted Answer

Transformation

Question 3

Which of the following bonds is primarily responsible for holding the two strands of DNA together?

Accepted Answer

Hydrogen bonds between complementary nitrogenous bases

Question 4

During DNA replication, which enzyme is responsible for synthesizing the new DNA strand by adding nucleotides to the 3' end?

Accepted Answer

DNA polymerase

Question 5

A mutation changes a codon from $$	ext{UAC} ($$tyrosine) to $$	ext{UAA} ($$stop codon). What type of mutation is this, and why is it likely to be deleterious?

Accepted Answer

Nonsense mutation; it introduces a premature stop codon, truncating the protein.

Question 6

Which of the following is a post-transcriptional control of gene expression in eukaryotes?

Accepted Answer

Alternative splicing of pre-mRNA

Question 7

What is the main difference between prokaryotic and eukaryotic gene expression?

Accepted Answer

In eukaryotes, transcription and translation are separated by the nuclear envelope; in prokaryotes, they occur simultaneously.

Question 8

Which of the following best describes the role of telomeres in eukaryotic chromosomes?

Accepted Answer

They protect chromosome ends from deterioration during replication.

Question 9

A eukaryotic cell is observed to have a high level of histone acetylation in a region of DNA. What is the most likely effect on gene expression in this region?

Accepted Answer

Increased gene expression due to relaxed chromatin structure

Question 10

Which of the following sequences correctly represents the flow of genetic information according to the central dogma of molecular biology?

Accepted Answer

$$	ext{DNA} ightarrow 	ext{RNA} ightarrow 	ext{Protein}$$

Question 11

Which of the following events occurs during meiosis I but not during mitosis?

Accepted Answer

Homologous chromosomes pair up and undergo crossing over.

Question 12

A cell undergoes meiosis and produces four cells. Which of the following statements is true about the resulting cells?

Accepted Answer

They are haploid and genetically different from each other.

Question 13

Which of the following is a major source of genetic variation during meiosis?

Accepted Answer

Crossing over between homologous chromosomes

Question 14

Which of the following best describes an exon?

Accepted Answer

A coding region of a gene that is expressed in the final mRNA

Question 15

If a DNA template strand has the sequence $$5'	ext{-ATG CCG TAA-}3'$$, what is the corresponding mRNA sequence produced during transcription?

Accepted Answer

$$5'	ext{-AUG CCG UAA-}3'$$

Question 16

Which of the following is required for DNA polymerase to begin synthesizing a new DNA strand during replication?

Accepted Answer

A short RNA primer synthesized by primase

Question 17

Which of the following is an example of epigenetic inheritance?

Accepted Answer

Transmission of DNA methylation patterns that affect gene expression without changing the DNA sequence

Question 18

Which of the following mechanisms can decrease the lifespan of an mRNA molecule in the cytoplasm, thus reducing protein production?

Accepted Answer

RNA interference (RNAi)

Question 19

A cell is observed to have a mutation in the gene encoding ubiquitin. Which process is most likely to be affected?

Accepted Answer

Protein degradation after translation

Question 20

Which of the following statements about homologous chromosomes is correct?

Accepted Answer

They carry the same genes but may have different alleles.

Molecular Genetics and Cell Division: DNA Structure, Gene Expression, and Meiosis

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