- What is the basic unit of genetic information in DNA?
a) Gene
b) Nucleotide
c) Chromosome
d) Protein
Answer: b) Nucleotide - Which enzyme is responsible for unwinding the DNA double helix during replication?
a) DNA polymerase
b) Ligase
c) Helicase
d) Topoisomerase
Answer: c) Helicase - What is the central dogma of molecular biology?
a) DNA → RNA → Protein
b) RNA → DNA → Protein
c) Protein → DNA → RNA
d) DNA → Protein → RNA
Answer: a) DNA → RNA → Protein - Which process involves the synthesis of RNA from a DNA template?
a) Replication
b) Translation
c) Transcription
d) Replication
Answer: c) Transcription - What type of RNA carries amino acids to the ribosome during protein synthesis?
a) mRNA
b) tRNA
c) rRNA
d) siRNA
Answer: b) tRNA - Which component of the cell is the site of protein synthesis?
a) Nucleus
b) Mitochondria
c) Ribosome
d) Golgi apparatus
Answer: c) Ribosome - What is the role of ribosomal RNA (rRNA)?
a) Carrying genetic information
b) Catalyzing peptide bond formation
c) Transporting amino acids
d) Regulating gene expression
Answer: b) Catalyzing peptide bond formation - Which process involves the conversion of mRNA into a protein?
a) Replication
b) Transcription
c) Translation
d) Duplication
Answer: c) Translation - What is the role of DNA polymerase in DNA replication?
a) Unwinding the DNA double helix
b) Synthesizing the new DNA strand
c) Repairing DNA damage
d) Binding to RNA primer
Answer: b) Synthesizing the new DNA strand - In which part of the cell does transcription occur?
a) Cytoplasm
b) Nucleus
c) Mitochondria
d) Ribosome
Answer: b) Nucleus - Which type of mutation results in a premature stop codon in the protein sequence?
a) Silent mutation
b) Missense mutation
c) Nonsense mutation
d) Frameshift mutation
Answer: c) Nonsense mutation - What is the function of spliceosomes in eukaryotic cells?
a) Synthesizing DNA
b) Modifying RNA transcripts
c) Replicating RNA
d) Translating proteins
Answer: b) Modifying RNA transcripts - What is a codon?
a) A sequence of three nucleotides in RNA that codes for an amino acid
b) A sequence of two nucleotides in DNA
c) A protein synthesis factor
d) An enzyme involved in DNA replication
Answer: a) A sequence of three nucleotides in RNA that codes for an amino acid - Which enzyme seals the gaps between Okazaki fragments on the lagging strand during DNA replication?
a) DNA polymerase
b) Helicase
c) Ligase
d) Topoisomerase
Answer: c) Ligase - Which term describes a change in the DNA sequence that does not alter the amino acid sequence of the protein?
a) Silent mutation
b) Missense mutation
c) Nonsense mutation
d) Frameshift mutation
Answer: a) Silent mutation - What is the primary function of transfer RNA (tRNA)?
a) Carrying genetic information from DNA to the ribosome
b) Carrying amino acids to the ribosome for protein synthesis
c) Synthesizing mRNA
d) Splicing introns from pre-mRNA
Answer: b) Carrying amino acids to the ribosome for protein synthesis - What is the role of the promoter region in gene expression?
a) Binding of RNA polymerase to initiate transcription
b) Binding of ribosomes to initiate translation
c) Splicing of introns from mRNA
d) Modification of amino acids in proteins
Answer: a) Binding of RNA polymerase to initiate transcription - Which of the following is NOT a component of a nucleotide?
a) Phosphate group
b) Sugar
c) Amino acid
d) Nitrogenous base
Answer: c) Amino acid - What is the purpose of a DNA microarray?
a) To analyze the protein content of cells
b) To measure gene expression levels
c) To replicate DNA sequences
d) To visualize chromosomal abnormalities
Answer: b) To measure gene expression levels - Which process involves the removal of introns from pre-mRNA?
a) Splicing
b) Transcription
c) Translation
d) Replication
Answer: a) Splicing - What is the significance of the 5′ cap on mRNA?
a) Protects mRNA from degradation
b) Facilitates the binding of tRNA
c) Signals the start of transcription
d) Inhibits translation
Answer: a) Protects mRNA from degradation - Which structure is responsible for holding together the two strands of DNA?
a) Hydrogen bonds
b) Phosphodiester bonds
c) Ionic bonds
d) Covalent bonds
Answer: a) Hydrogen bonds - What is the purpose of polymerase chain reaction (PCR)?
a) To amplify specific DNA sequences
b) To separate proteins based on size
c) To sequence RNA molecules
d) To visualize gene expression
Answer: a) To amplify specific DNA sequences - Which process converts genetic information from DNA into a complementary RNA sequence?
a) Replication
b) Transcription
c) Translation
d) Mutation
Answer: b) Transcription - What is the role of the ribosome in protein synthesis?
a) To replicate DNA
b) To synthesize RNA
c) To translate mRNA into a protein
d) To splice RNA
Answer: c) To translate mRNA into a protein - Which of the following is a function of the endoplasmic reticulum in a eukaryotic cell?
a) Synthesizing lipids and proteins
b) Performing cellular respiration
c) Replicating DNA
d) Modifying RNA transcripts
Answer: a) Synthesizing lipids and proteins - What is the function of topoisomerase during DNA replication?
a) To unwind the DNA double helix
b) To synthesize new DNA strands
c) To relieve torsional strain in the DNA
d) To seal DNA fragments
Answer: c) To relieve torsional strain in the DNA - What type of mutation results in a shift in the reading frame of the mRNA?
a) Silent mutation
b) Missense mutation
c) Nonsense mutation
d) Frameshift mutation
Answer: d) Frameshift mutation - Which process involves the conversion of an mRNA sequence into a protein sequence?
a) Replication
b) Transcription
c) Translation
d) Splicing
Answer: c) Translation - Which type of RNA carries genetic information from the nucleus to the cytoplasm?
a) tRNA
b) rRNA
c) mRNA
d) snRNA
Answer: c) mRNA - What is the role of introns in eukaryotic genes?
a) Coding for proteins
b) Regulating gene expression
c) Coding for tRNA
d) Intervening sequences that are removed from pre-mRNA
Answer: d) Intervening sequences that are removed from pre-mRNA - Which of the following best describes a gene?
a) A sequence of nucleotides that codes for a protein or RNA molecule
b) A protein that binds to DNA
c) A structure that synthesizes RNA
d) A molecule that transports amino acids
Answer: a) A sequence of nucleotides that codes for a protein or RNA molecule - What is the primary function of DNA ligase?
a) To unwind the DNA double helix
b) To synthesize new DNA strands
c) To seal gaps between DNA fragments
d) To degrade RNA molecules
Answer: c) To seal gaps between DNA fragments - What is the role of the 3′ poly-A tail on mRNA?
a) Facilitates the export of mRNA from the nucleus
b) Protects mRNA from degradation
c) Assists in ribosome binding
d) Signals the end of transcription
Answer: b) Protects mRNA from degradation - Which process involves the synthesis of a new DNA strand using an existing DNA strand as a template?
a) Replication
b) Transcription
c) Translation
d) Splicing
Answer: a) Replication - What is the function of a primer in DNA replication?
a) To unwind the DNA double helix
b) To provide a starting point for DNA synthesis
c) To repair DNA damage
d) To remove RNA primers
Answer: b) To provide a starting point for DNA synthesis - Which of the following is an example of a post-translational modification?
a) Splicing of introns
b) Addition of a 5′ cap
c) Phosphorylation of proteins
d) Transcription of DNA
Answer: c) Phosphorylation of proteins - What does the term ‘genetic code’ refer to?
a) The sequence of DNA nucleotides
b) The set of rules that defines how mRNA sequences are translated into proteins
c) The sequence of amino acids in proteins
d) The arrangement of nucleotides in RNA
Answer: b) The set of rules that defines how mRNA sequences are translated into proteins - Which of the following is a characteristic of prokaryotic DNA replication?
a) DNA replication occurs in the nucleus
b) Replication is bidirectional
c) Multiple origins of replication
d) Presence of histones
Answer: b) Replication is bidirectional - What is the purpose of the Chi-square test in genetics?
a) To compare observed and expected frequencies of genetic traits
b) To measure the mutation rate
c) To determine the nucleotide sequence
d) To identify gene expression levels
Answer: a) To compare observed and expected frequencies of genetic traits - Which of the following is NOT a type of RNA involved in protein synthesis?
a) mRNA
b) tRNA
c) rRNA
d) DNA
Answer: d) DNA - What is the role of the 5′ untranslated region (UTR) of mRNA?
a) Coding for proteins
b) Regulating mRNA stability and translation initiation
c) Encoding tRNA
d) Splicing of introns
Answer: b) Regulating mRNA stability and translation initiation - What is the main function of the Golgi apparatus in relation to proteins?
a) Synthesizing proteins
b) Modifying and packaging proteins for secretion
c) Replicating DNA
d) Splicing RNA
Answer: b) Modifying and packaging proteins for secretion - Which type of gene mutation changes a single nucleotide but does not change the amino acid sequence?
a) Silent mutation
b) Missense mutation
c) Nonsense mutation
d) Frameshift mutation
Answer: a) Silent mutation - Which process involves the addition of a methyl group to DNA?
a) Acetylation
b) Phosphorylation
c) Methylation
d) Ubiquitination
Answer: c) Methylation - What is the function of a repressor protein in gene regulation?
a) To enhance gene expression
b) To inhibit gene expression
c) To modify RNA transcripts
d) To synthesize proteins
Answer: b) To inhibit gene expression - What is the role of the TATA box in transcription?
a) Binding site for RNA polymerase
b) Enhancing translation efficiency
c) Splicing of pre-mRNA
d) Stabilizing mRNA
Answer: a) Binding site for RNA polymerase - Which type of genetic mutation results in a change in the reading frame of the mRNA?
a) Point mutation
b) Silent mutation
c) Frameshift mutation
d) Inversion
Answer: c) Frameshift mutation - What is the role of chaperone proteins in the cell?
a) Synthesizing DNA
b) Assisting in protein folding and assembly
c) Degrading damaged proteins
d) Transcribing mRNA
Answer: b) Assisting in protein folding and assembly - Which term describes the phenomenon where multiple codons code for the same amino acid?
a) Redundancy
b) Universality
c) Specificity
d) Fidelity
Answer: a) Redundancy