Q: Which of the following best describes the Central Dogma of Molecular Biology?

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

Question 1

Which experiment provided the first strong evidence that DNA is the genetic material, and what was the key result?

Accepted Answer

Griffith's transformation experiment; non-virulent R strain bacteria became virulent when mixed with heat-killed S strain

Question 2

Which of the following best describes the Central Dogma of Molecular Biology?

Accepted Answer

$$	ext{DNA} 	o 	ext{RNA} 	o 	ext{Protein}$$

Question 3

Which component is NOT part of a nucleotide in DNA?

Accepted Answer

Ribose sugar

Question 4

What is the correct complementary base pairing in DNA?

Accepted Answer

Adenine–Thymine, Guanine–Cytosine

Question 5

During DNA replication, which enzyme is responsible for joining Okazaki fragments on the lagging strand?

Accepted Answer

Ligase

Question 6

A mutation changes a codon from $$	ext{GAA} to$$ $$	ext{GUA} in $$the mRNA. Using the genetic code, what type of mutation is this and what is the likely effect on the protein?

Accepted Answer

Missense mutation; changes glutamic acid to valine

Question 7

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

Accepted Answer

The code is redundant, with some amino acids coded by more than one codon

Question 8

In eukaryotic cells, what must happen to mRNA before it can be translated?

Accepted Answer

It must be exported from the nucleus and undergo splicing to remove introns

Question 9

Which of the following best explains why sickle-cell anemia is considered a molecular disease?

Accepted Answer

It results from a single nucleotide substitution that changes one amino acid in the hemoglobin protein

Question 10

Which process is responsible for synthesizing RNA from a DNA template?

Accepted Answer

Transcription

Question 11

A scientist mutates the promoter region of a gene in a prokaryote. What is the most likely immediate effect?

Accepted Answer

RNA polymerase may not bind efficiently, reducing or preventing transcription

Question 12

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

Accepted Answer

tRNA carries amino acids to the ribosome and matches them to the mRNA codons

Question 13

If a DNA strand has the sequence $$5'	ext{-ATG CCG TAA-}3'$$, what is the sequence of the mRNA transcribed from it?

Accepted Answer

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

Question 14

Which of the following is a property of DNA that allows for evolution?

Accepted Answer

Its stability and mutability

Question 15

A frameshift mutation is most likely to result from which of the following?

Accepted Answer

An insertion or deletion of nucleotides not in multiples of three

Question 16

Which enzyme is responsible for synthesizing the new DNA strand during replication?

Accepted Answer

DNA polymerase

Question 17

Which of the following best explains why the genetic code is described as 'universal'?

Accepted Answer

The same codons specify the same amino acids in almost all organisms

Question 18

Which of the following statements about genotype and phenotype is correct?

Accepted Answer

Genotype is the heritable information in the nucleotide sequence, while phenotype is the observable traits

Question 19

A patient has a mutation that introduces a premature stop codon in a gene. What is the most likely result?

Accepted Answer

A truncated, likely nonfunctional protein

Question 20

Which of the following best describes the role of ribosomes in the cell?

Accepted Answer

They are the site of protein synthesis, translating mRNA into polypeptides

Molecular Biology: DNA Structure, Replication, Gene Expression, and Mutation

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