Q: Which of the following best describes the central dogma of molecular biology?

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

Question 1

Which of the following best describes the relationship between genotype and phenotype in a cell?

Accepted Answer

Genotype is the genetic makeup that determines the phenotype, which is the observable traits.

Question 2

Which of the following statements about prokaryotic and eukaryotic genomes is correct?

Accepted Answer

Eukaryotic genomes are organized into linear chromosomes with histones, while prokaryotic genomes are usually circular and have histone-like proteins.

Question 3

Which of the following is a correct pairing of nitrogenous bases in DNA, and how many hydrogen bonds are formed between them?

Accepted Answer

Adenine and Thymine; 2 hydrogen bonds

Question 4

Which enzyme is responsible for unwinding the DNA double helix during replication?

Accepted Answer

Helicase

Question 5

During DNA replication, why is the lagging strand synthesized in fragments?

Accepted Answer

Because the lagging strand is synthesized in the opposite direction of the replication fork movement, requiring multiple primers and discontinuous synthesis.

Question 6

Which of the following best describes the central dogma of molecular biology?

Accepted Answer

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

Question 7

Which of the following is a function of the enzyme ligase during DNA replication?

Accepted Answer

Joins Okazaki fragments together on the lagging strand

Question 8

A mutation changes a codon from $$	ext{UAC} ($$tyrosine) to $$	ext{UAA} ($$stop). What type of mutation is this?

Accepted Answer

Nonsense mutation

Question 9

Which of the following is a key difference between prokaryotic and eukaryotic gene expression?

Accepted Answer

Prokaryotic translation can begin before transcription is complete, but eukaryotic translation cannot.

Question 10

Which of the following best describes the function of small noncoding RNAs (such as miRNA or siRNA) in post-transcriptional regulation?

Accepted Answer

They bind to mRNA and either tag it for destruction or prevent its translation.

Question 11

Which of the following is true about plasmids in bacteria?

Accepted Answer

They are small, circular DNA molecules that can carry genes for antibiotic resistance.

Question 12

Which process allows bacteria to take up naked DNA from their environment, and what is the term for cells capable of this process?

Accepted Answer

Transformation; competent cells

Question 13

A mutation that does not change the amino acid sequence of a protein is called:

Accepted Answer

Silent mutation

Question 14

Which of the following is an example of an inducible operon and under what condition is it activated?

Accepted Answer

lac operon; activated when lactose is present and glucose is absent

Question 15

Which of the following best explains the effect of DNA methylation on gene expression?

Accepted Answer

It silences genes by preventing the binding of transcription factors.

Question 16

Which of the following is a real-world example of horizontal gene transfer with significant medical implications?

Accepted Answer

The spread of antibiotic resistance genes among bacteria via conjugation

Question 17

Which of the following best describes a frameshift mutation?

Accepted Answer

A mutation caused by insertion or deletion of nucleotides not in multiples of three, altering the reading frame

Question 18

Which of the following is a feature of the genetic code that helps minimize the effects of mutations?

Accepted Answer

The code is redundant, so multiple codons can specify the same amino acid.

Question 19

Which of the following is a post-translational modification that can affect protein function?

Accepted Answer

Addition of a phosphate group to a protein

Question 20

Which of the following best describes the role of the Ames test in microbiology?

Accepted Answer

It detects chemicals that increase mutation rates and may be carcinogens.

Microbial Genetics: Structure, Function, and Regulation

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