Master Molecular Biology Fundamentals: A Comprehensive Guide for Medical Students

Question 1

Which of the following is NOT a nitrogenous base found in DNA?

Accepted Answer

Cytosine

Answer

Adenine

Answer

Thymine

Answer

Guanine

Question 2

What is the complementary strand to the following DNA sequence: 5'-ATCG-3'?

Accepted Answer

3'-TAGC-5'

Answer

3'-ATCG-5'

Answer

5'-TAGC-3'

Answer

5'-ATCG-3'

Question 3

What type of bond links amino acids in a polypeptide chain?

Accepted Answer

Covalent bond

Answer

Ionic bond

Answer

Hydrogen bond

Answer

Van der Waals force

Question 4

Which of the following is a nonpolar amino acid?

Accepted Answer

Leucine

Answer

Glutamic acid

Answer

Arginine

Answer

Serine

Question 5

What is the process by which genetic material is duplicated prior to cell division?

Accepted Answer

Replication

Answer

Transcription

Answer

Translation

Answer

Mutation

Question 6

Which enzyme is responsible for unwinding and separating DNA strands during replication?

Accepted Answer

Helicase

Answer

DNA polymerase

Answer

RNA polymerase

Answer

Ligase

Question 7

Which of the following best describes the genetic code?

Accepted Answer

The sequence of nucleotides in DNA that codes for specific amino acids

Answer

The sequence of amino acids in a protein

Answer

The order of genes on a chromosome

Answer

The pairing of alleles in a diploid organism

Question 8

What type of mutation introduces a premature stop codon?

Accepted Answer

Nonsense mutation

Answer

Missense mutation

Answer

Frameshift mutation

Answer

Silent mutation

Question 9

What is the primary function of polymerases in molecular biology?

Accepted Answer

To synthesize new nucleic acid molecules (DNA or RNA)

Answer

To degrade nucleic acid molecules (DNA or RNA)

Answer

To modify the structure of nucleic acid molecules (DNA or RNA)

Answer

To transport nucleic acid molecules (DNA or RNA)

Question 10

Which of the following is NOT a type of RNA molecule?

Accepted Answer

Small nuclear RNA (snRNA)

Answer

Messenger RNA (mRNA)

Answer

Transfer RNA (tRNA)

Answer

Ribosomal RNA (rRNA)

Question 11

Which nitrogenous base is NOT present in DNA?

Accepted Answer

Uracil

Answer

Adenine

Answer

Thymine

Answer

Guanine

Question 12

RNA plays a central role in protein synthesis. What is its primary function in this process?

Accepted Answer

Transporting amino acids to the ribosome

Answer

Storing genetic information

Answer

Catalyzing biochemical reactions

Answer

Assembling ribosomes

Question 13

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

Accepted Answer

Helicase

Answer

DNA polymerase

Answer

Topoisomerase

Answer

Ligase

Question 14

Which type of mutation results in a premature stop codon and potentially truncated protein?

Accepted Answer

Nonsense mutation

Answer

Missense mutation

Answer

Frameshift mutation

Answer

Silent mutation

Question 15

The central dogma of molecular biology describes the fundamental flow of genetic information. Which of the following accurately represents this flow?

Accepted Answer

DNA → RNA → Protein

Answer

Protein → RNA → DNA

Answer

RNA → DNA → Protein

Answer

DNA → Protein → RNA

Question 16

What type of chemical force plays a dominant role in stabilizing the double helix structure of DNA?

Accepted Answer

Hydrogen bonds

Answer

Ionic bonds

Answer

Covalent bonds

Answer

Van der Waals forces

Question 17

In protein synthesis, the structure responsible for assembling amino acids into a polypeptide chain is the:

Accepted Answer

Ribosome

Answer

Nucleus

Answer

Mitochondria

Answer

Golgi apparatus

Question 18

Which type of RNA molecule carries the genetic information from the nucleus to the cytoplasm for protein synthesis?

Accepted Answer

mRNA

Answer

rRNA

Answer

tRNA

Answer

snRNA

Question 19

Transcription and translation are two fundamental processes in gene expression. What is the key difference between them?

Accepted Answer

Transcription produces mRNA, while translation produces protein

Answer

Transcription uses RNA polymerase, while translation uses DNA polymerase

Answer

Transcription occurs in the cytoplasm, while translation occurs in the nucleus

Answer

Transcription is template-independent, while translation is template-dependent

Question 20

Which of the following is the correct hierarchical order of molecular structure, from smallest to largest?

Accepted Answer

Nucleotide -> Codon -> Gene -> Chromosome

Answer

Codon -> Nucleotide -> Gene -> Chromosome

Answer

Chromosome -> Gene -> Codon -> Nucleotide

Answer

Nucleotide -> Gene -> Codon -> Chromosome

Question 21

The process by which RNA is synthesized using a DNA template is known as:

Accepted Answer

Transcription

Answer

Replication

Answer

Translation

Answer

Mutation

Question 22

Which of the following molecules serves as the primary genetic material in most living organisms?

Accepted Answer

Double-stranded DNA

Answer

Single-stranded DNA

Answer

Single-stranded RNA

Answer

Double-stranded RNA

Question 23

Which of the following options correctly describes the primary function of codons?

Accepted Answer

Specify the sequence of amino acids in proteins

Answer

Initiate transcription

Answer

Terminate translation

Answer

Remove non-coding regions from mRNA

Question 24

The process responsible for duplicating DNA, prior to cell division, is called:

Accepted Answer

Replication

Answer

Transcription

Answer

Translation

Answer

Mutation

Question 25

Which level of protein structure primarily determines its three-dimensional shape?

Accepted Answer

Tertiary structure

Answer

Primary structure

Answer

Secondary structure

Answer

Quaternary structure

Question 26

The genetic code refers to the relationship between codons and amino acids and is best described as:

Accepted Answer

Universal across all living organisms

Answer

Specific to each species

Answer

Different between prokaryotes and eukaryotes

Answer

Dependent on the environment

Question 27

A change in the DNA sequence of an organism, potentially affecting its traits, is referred to as:

Accepted Answer

Mutation

Answer

Deletion

Answer

Insertion

Answer

Transversion

Question 28

Which nitrogenous base is NOT found in DNA?

Accepted Answer

Uracil

Answer

Adenine

Answer

Thymine

Answer

Guanine

Question 29

What is the primary function of RNA polymerase in molecular biology?

Accepted Answer

To synthesize RNA from DNA

Answer

To synthesize DNA from RNA

Answer

To translate RNA into proteins

Answer

To replicate DNA

Question 30

Which type of RNA is NOT involved in protein synthesis?

Accepted Answer

snRNA

Answer

mRNA

Answer

tRNA

Answer

rRNA

Question 31

How do codons and anticodons differ in their sequences?

Accepted Answer

A codon is a sequence of three nucleotides on mRNA, while an anticodon is a sequence of three nucleotides on tRNA

Answer

A codon is a sequence of three nucleotides on DNA, while an anticodon is a sequence of three nucleotides on mRNA

Answer

A codon is a sequence of three nucleotides on tRNA, while an anticodon is a sequence of three nucleotides on DNA

Answer

Codons and anticodons are identical sequences of nucleotides

Question 32

What is the primary function of a promoter in gene expression?

Accepted Answer

To initiate transcription

Answer

To terminate transcription

Answer

To splice RNA

Answer

To translate mRNA

Question 33

What is the significance of the CRISPR-Cas9 system?

Accepted Answer

It enables precise genome editing

Answer

It is used for DNA sequencing

Answer

It is a method for protein synthesis

Answer

It is a diagnostic tool for genetic diseases

Question 34

Which type of bond forms between complementary nucleotide bases in DNA?

Accepted Answer

(A) Hydrogen bonds

Answer

(B) Covalent bonds

Answer

(C) Ionic bonds

Answer

(D) Van der Waals forces

Question 35

What is the primary function of a promoter in gene expression?

Accepted Answer

(A) Initiates transcription

Answer

(B) Terminates transcription

Answer

(C) Enhances translation

Answer

(D) Regulates gene expression

Question 36

Which key difference distinguishes prokaryotic and eukaryotic cells in terms of gene expression?

Accepted Answer

(D) All of the above

Answer

(A) Eukaryotes undergo splicing, while prokaryotes do not.

Answer

(B) Prokaryotes have operons, while eukaryotes do not.

Answer

(C) Eukaryotes have a nucleus, while prokaryotes do not.

Question 37

What is the fundamental principle described by the central dogma of molecular biology?

Accepted Answer

(A) DNA → RNA → Protein

Answer

(B) Protein → RNA → DNA

Answer

(C) RNA → DNA → Protein

Answer

(D) DNA → Protein → RNA

Question 38

Which technique is commonly used to amplify a specific DNA sequence?

Accepted Answer

(A) Polymerase Chain Reaction (PCR)

Answer

(B) Gel electrophoresis

Answer

(C) Southern blotting

Answer

(D) Restriction enzyme digestion

Question 39

What is the primary function of RNA polymerase in gene expression?

Accepted Answer

To synthesize new RNA molecules

Answer

To unwind the DNA double helix

Answer

To cut and splice RNA molecules

Answer

To translate RNA into proteins

Question 40

Which of the following amino acids is classified as non-polar?

Accepted Answer

Leucine

Answer

Serine

Answer

Tyrosine

Answer

Glutamine

Question 41

What is the process by which genetic information from DNA is transferred to RNA?

Accepted Answer

Transcription

Answer

Replication

Answer

Translation

Answer

Mutation

Question 42

Which type of covalent bond is formed between amino acids?

Accepted Answer

Peptide bond

Answer

Hydrogen bond

Answer

Disulfide bond

Answer

Ionic bond

Question 43

What is the name of the enzyme that catalyzes the unwinding of DNA during replication?

Accepted Answer

Helicase

Answer

Polymerase

Answer

Ligase

Answer

Primase

Question 44

Which type of mutation involves the insertion or deletion of a single nucleotide?

Accepted Answer

Frameshift mutation

Answer

Missense mutation

Answer

Nonsense mutation

Answer

Silent mutation

Question 45

What is the primary function of the ribosome in protein synthesis?

Accepted Answer

To assemble amino acids into proteins

Answer

To store genetic information

Answer

To synthesize new RNA molecules

Answer

To modify and transport proteins

Question 46

What is the name of the process by which RNA molecules are processed to remove non-coding sequences?

Accepted Answer

RNA editing

Answer

Transcription

Answer

Translation

Answer

Reverse transcription

Question 47

Which of the following is the primary structure of DNA, consisting of a chain of nucleotides linked by phosphodiester bonds?

Accepted Answer

A chain of nucleotides linked by phosphodiester bonds

Answer

A complex of DNA, RNA, and protein

Answer

A double helix

Question 48

Which of the following proteins is the primary initiator of DNA unwinding to facilitate the replication process?

Accepted Answer

Helicase

Answer

Ligase

Answer

Topoisomerase

Answer

Polymerase

Question 49

Which of the following processes is primarily responsible for the synthesis of new proteins?

Accepted Answer

Translation

Answer

Transcription

Answer

Recombination

Answer

Replication

Question 50

Which of the following characteristics is most closely associated with a strong intermolecular bond?

Accepted Answer

High bond energy

Answer

Solubility in water

Answer

Low bond length

Answer

Reversibility

Question 51

Identify the type of intermolecular bond where partially positive hydrogen atoms of polar molecules are attracted to partially negative oxygen or nitrogen atoms of other molecules:

Accepted Answer

Hydrogen bond

Answer

Metallic bond

Answer

Ionic bond

Answer

Covalent bond

Question 52

Which of the following is a notable property of water?

Accepted Answer

High specific heat capacity

Answer

Low boiling point

Answer

Poor solvent

Answer

Low density

Question 53

Which of the following is NOT a known function of proteins?

Accepted Answer

None of the above

Answer

Transporting molecules

Answer

Providing structural support

Answer

Catalyzing reactions

Question 54

Which of the following represents the most fundamental level of protein structure?

Accepted Answer

Primary

Answer

Quaternary

Answer

Atomic

Answer

Molecular

Question 55

Which of the following biomolecules carries genetic information?

Accepted Answer

DNA

Answer

Carbohydrate

Answer

Lipid

Answer

Amino acid