Which of the following is the genetic material in most viruses?
a) DNA
b) RNA
c) Protein
d) Lipid
Answer: b) RNA
What is the main function of ribosomes in a cell?
a) DNA replication
b) Protein synthesis
c) Lipid metabolism
d) Energy production
Answer: b) Protein synthesis
Which of the following processes results in the formation of messenger RNA (mRNA)?
a) Translation
b) Transcription
c) Replication
d) Translocation
Answer: b) Transcription
What is the role of tRNA in protein synthesis?
a) Transcribes DNA to RNA
b) Carries amino acids to the ribosome
c) Synthesizes proteins
d) Processes mRNA
Answer: b) Carries amino acids to the ribosome
Which enzyme is responsible for unwinding the DNA double helix during replication?
a) DNA polymerase
b) Helicase
c) Ligase
d) Topoisomerase
Answer: b) Helicase
What is the purpose of PCR (Polymerase Chain Reaction) in molecular biology?
a) To sequence DNA
b) To amplify DNA
c) To edit DNA
d) To degrade DNA
Answer: b) To amplify DNA
Which type of mutation involves a change in a single nucleotide base?
a) Deletion
b) Insertion
c) Frameshift
d) Point mutation
Answer: d) Point mutation
What is the primary function of the enzyme reverse transcriptase?
a) Synthesizes RNA from a DNA template
b) Synthesizes DNA from an RNA template
c) Repairs DNA
d) Degrades RNA
Answer: b) Synthesizes DNA from an RNA template
Which process describes the uptake of naked DNA by a bacterial cell?
a) Conjugation
b) Transduction
c) Transformation
d) Transfection
Answer: c) Transformation
What are plasmids?
a) Large chromosomal DNA
b) Small, circular DNA molecules
c) RNA molecules
d) Protein complexes
Answer: b) Small, circular DNA molecules
Which technique separates DNA fragments based on size?
a) PCR
b) Gel electrophoresis
c) DNA sequencing
d) Cloning
Answer: b) Gel electrophoresis
Which type of RNA carries the genetic code from DNA to the ribosome?
a) mRNA
b) tRNA
c) rRNA
d) miRNA
Answer: a) mRNA
What is the role of ligase in DNA replication?
a) Synthesizes new DNA strands
b) Unwinds the DNA helix
c) Joins Okazaki fragments
d) Adds RNA primers
Answer: c) Joins Okazaki fragments
Which structure contains the genetic material in prokaryotic cells?
a) Nucleus
b) Plasmid
c) Nucleoid
d) Mitochondria
Answer: c) Nucleoid
What is the function of RNA polymerase?
a) Synthesizes DNA
b) Synthesizes RNA
c) Degrades RNA
d) Degrades DNA
Answer: b) Synthesizes RNA
Which of the following is not a stop codon in mRNA translation?
a) UAA
b) UAG
c) UGA
d) AUG
Answer: d) AUG
Which type of horizontal gene transfer involves the direct transfer of DNA between two bacterial cells?
a) Transformation
b) Transduction
c) Conjugation
d) Transfection
Answer: c) Conjugation
What is the role of CRISPR-Cas9 in molecular genetics?
a) DNA amplification
b) Gene editing
c) Protein synthesis
d) RNA interference
Answer: b) Gene editing
What is a bacteriophage?
a) A type of bacterium
b) A virus that infects bacteria
c) A fungal spore
d) A bacterial plasmid
Answer: b) A virus that infects bacteria
Which molecule is the main carrier of genetic information in cells?
a) RNA
b) DNA
c) Protein
d) Lipid
Answer: b) DNA
What is the function of the promoter region in a gene?
a) Encodes the protein
b) Terminates transcription
c) Initiates transcription
d) Splices RNA
Answer: c) Initiates transcription
What is the difference between a genotype and a phenotype?
a) Genotype is the physical trait; phenotype is the genetic makeup
b) Genotype is the genetic makeup; phenotype is the physical trait
c) Both are the same
d) Genotype is RNA; phenotype is DNA
Answer: b) Genotype is the genetic makeup; phenotype is the physical trait
Which process converts mRNA into a protein?
a) Transcription
b) Replication
c) Translation
d) Translocation
Answer: c) Translation
What is the function of the lac operon in E. coli?
a) Metabolism of lactose
b) Replication of DNA
c) Synthesis of proteins
d) Degradation of RNA
Answer: a) Metabolism of lactose
Which structure in eukaryotic cells is responsible for producing ribosomal RNA (rRNA)?
a) Nucleus
b) Nucleolus
c) Endoplasmic reticulum
d) Golgi apparatus
Answer: b) Nucleolus
Which of the following is a purine base in DNA?
a) Cytosine
b) Thymine
c) Adenine
d) Uracil
Answer: c) Adenine
What is the role of the operator in an operon?
a) Binds RNA polymerase
b) Binds repressor proteins
c) Encodes proteins
d) Splices RNA
Answer: b) Binds repressor proteins
Which of the following is a post-transcriptional modification in eukaryotic cells?
a) RNA splicing
b) DNA methylation
c) Protein folding
d) RNA replication
Answer: a) RNA splicing
What is the term for a segment of DNA that can move from one location to another in the genome?
a) Plasmid
b) Transposon
c) Intron
d) Exon
Answer: b) Transposon
Which enzyme is used in the process of transcription?
a) DNA polymerase
b) RNA polymerase
c) Ligase
d) Helicase
Answer: b) RNA polymerase
What is a codon?
a) A protein
b) A sequence of three nucleotides
c) A ribosome
d) An enzyme
Answer: b) A sequence of three nucleotides
What is the term for the DNA sequence where replication begins?
a) Promoter
b) Origin of replication
c) Terminator
d) Operator
Answer: b) Origin of replication
Which molecule is synthesized during transcription?
a) DNA
b) mRNA
c) Protein
d) Lipid
Answer: b) mRNA
What type of bond holds the two strands of DNA together?
a) Ionic bonds
b) Covalent bonds
c) Hydrogen bonds
d) Peptide bonds
Answer: c) Hydrogen bonds
Which of the following is a characteristic of prokaryotic cells?
a) Presence of a nucleus
b) Presence of membrane-bound organelles
c) Absence of a nucleus
d) Absence of ribosomes
Answer: c) Absence of a nucleus
What is the function of restriction enzymes in molecular genetics?
a) To synthesize DNA
b) To cut DNA at specific sequences
c) To join DNA fragments
d) To replicate RNA
Answer: b) To cut DNA at specific sequences
Which phase of the cell cycle involves DNA replication?
a) G1 phase
b) S phase
c) G2 phase
d) M phase
Answer: b) S phase
What is the primary role of histones in the cell?
a) Synthesizing DNA
b) Packing DNA into chromatin
c) Degrading RNA
d) Facilitating protein synthesis
Answer: b) Packing DNA into chromatin
Which of the following is an RNA virus?
a) Hepatitis B virus
b) HIV
c) Smallpox virus
d) Herpes simplex virus
Answer: b) HIV
What is an operon?
a) A single gene
b) A cluster of genes under the control of a single promoter
c) A regulatory protein
d) A segment of RNA
Answer: b) A cluster of genes under the control of a single promoter
Which structure in the cell is the site of protein synthesis?
a) Nucleus
b) Ribosome
c) Mitochondrion
d) Golgi apparatus
Answer: b) Ribosome
What is the role of microRNAs (miRNAs) in gene expression?
a) Enhancing transcription
b) Degrading mRNA
c) Initiating translation
d) Splicing RNA
Answer: b) Degrading mRNA
Which of the following describes a lysogenic cycle in bacteriophages?
a) Immediate lysis of the host cell
b) Integration of viral DNA into the host genome
c) Production of viral proteins
d) Release of new viruses
Answer: b) Integration of viral DNA into the host genome
What is the function of telomerase?
a) Synthesizes ribosomal RNA
b) Adds repetitive sequences to the ends of chromosomes
c) Unwinds the DNA helix
d) Joins Okazaki fragments
Answer: b) Adds repetitive sequences to the ends of chromosomes
What type of mutation is caused by the insertion or deletion of a nucleotide in a DNA sequence?
a) Point mutation
b) Silent mutation
c) Frameshift mutation
d) Missense mutation
Answer: c) Frameshift mutation
What is the main purpose of Southern blotting in molecular genetics?
a) To amplify DNA
b) To sequence DNA
c) To detect specific DNA sequences
d) To edit genes
Answer: c) To detect specific DNA sequences
Which bacterial structure is involved in motility?
a) Pilus
b) Flagellum
c) Capsule
d) Plasmid
Answer: b) Flagellum
Which process is used to introduce foreign DNA into bacterial cells?
a) Electrophoresis
b) Electroporation
c) PCR
d) Cloning
Answer: b) Electroporation
Which of the following is a feature of eukaryotic mRNA but not prokaryotic mRNA?
a) 5′ cap and poly-A tail
b) Exons and introns
c) Polycistronic nature
d) Ribosome binding site
Answer: a) 5′ cap and poly-A tail
What is the primary function of the CRISPR-Cas9 system in bacteria?
a) RNA synthesis
b) DNA repair
c) Immune defense against viruses
d) Protein synthesis
Answer: c) Immune defense against viruses