Genetics & Molecular Biology for Competitive Exams

Genetics & Molecular Biology

Q. What is the main advantage of using plasmids as vectors in cloning?

A. They are large and complex
B. They replicate independently of chromosomal DNA
C. They are difficult to manipulate
D. They do not carry antibiotic resistance genes

Solution

Plasmids can replicate independently of chromosomal DNA, making them ideal vectors for cloning.

Correct Answer: B — They replicate independently of chromosomal DNA

Q. What is the main outcome of gene expression?

A. DNA replication
B. Protein synthesis
C. RNA degradation
D. Cell division

Solution

Gene expression primarily results in the synthesis of proteins based on the information encoded in DNA.

Correct Answer: B — Protein synthesis

Q. What is the main purpose of cloning in biotechnology?

A. To create genetically identical copies of an organism
B. To sequence the entire genome
C. To mutate genes
D. To analyze gene expression

Solution

Cloning is used to create genetically identical copies of an organism or specific cells.

Correct Answer: A — To create genetically identical copies of an organism

Q. What is the primary function of mRNA in the cell?

A. To store genetic information
B. To catalyze biochemical reactions
C. To transfer amino acids during protein synthesis
D. To carry genetic information from DNA to ribosomes

Solution

mRNA carries genetic information from DNA to ribosomes for protein synthesis.

Correct Answer: D — To carry genetic information from DNA to ribosomes

Q. What is the primary function of mRNA in the central dogma of molecular biology?

A. To replicate DNA
B. To carry genetic information from DNA to ribosomes
C. To synthesize proteins
D. To form the structure of ribosomes

Solution

mRNA serves as the intermediary that conveys genetic information from DNA to the ribosomes, where proteins are synthesized.

Correct Answer: B — To carry genetic information from DNA to ribosomes

Q. What is the primary function of mRNA in the process of gene expression?

A. To carry amino acids to the ribosome
B. To serve as a template for protein synthesis
C. To replicate DNA
D. To form the ribosome

Solution

mRNA serves as a template for protein synthesis by carrying the genetic information from DNA to the ribosome.

Correct Answer: B — To serve as a template for protein synthesis

Q. What is the primary function of mRNA?

A. To store genetic information
B. To transport amino acids
C. To carry genetic information from DNA to ribosomes
D. To catalyze biochemical reactions

Solution

mRNA carries genetic information from DNA to ribosomes for protein synthesis.

Correct Answer: C — To carry genetic information from DNA to ribosomes

Q. What is the primary function of PCR (Polymerase Chain Reaction)?

A. To amplify DNA sequences
B. To sequence DNA
C. To cut DNA at specific sites
D. To synthesize RNA

Solution

PCR is used to amplify specific DNA sequences, making millions of copies of a particular segment.

Correct Answer: A — To amplify DNA sequences

Q. What is the primary function of ribosomes in cells?

A. DNA replication
B. RNA synthesis
C. Protein synthesis
D. Lipid synthesis

Solution

Ribosomes are the cellular structures responsible for protein synthesis, translating messenger RNA (mRNA) into polypeptide chains.

Correct Answer: C — Protein synthesis

Q. What is the primary function of RNA polymerase during transcription?

A. To synthesize DNA from RNA
B. To synthesize RNA from a DNA template
C. To degrade RNA molecules
D. To replicate DNA

Solution

RNA polymerase synthesizes RNA by using a DNA template during the process of transcription.

Correct Answer: B — To synthesize RNA from a DNA template

Q. What is the primary function of the ribosome in the cell?

A. DNA replication
B. RNA synthesis
C. Protein synthesis
D. Gene regulation

Solution

The primary function of the ribosome is to synthesize proteins by translating mRNA.

Correct Answer: C — Protein synthesis

Q. What is the primary purpose of PCR (Polymerase Chain Reaction) in molecular biology?

A. To sequence DNA
B. To amplify specific DNA sequences
C. To splice genes
D. To transcribe RNA

Solution

PCR is a technique used to amplify specific DNA sequences, making millions of copies of a particular segment of DNA.

Correct Answer: B — To amplify specific DNA sequences

Q. What is the primary purpose of PCR (Polymerase Chain Reaction)?

A. To sequence DNA
B. To amplify DNA
C. To cut DNA
D. To visualize DNA

Solution

PCR is used to amplify specific DNA sequences, making millions of copies of a particular segment.

Correct Answer: B — To amplify DNA

Q. What is the primary purpose of the polymerase chain reaction (PCR)?

A. To amplify a specific DNA segment
B. To sequence DNA
C. To clone DNA fragments
D. To analyze gene expression

Solution

PCR is primarily used to amplify a specific DNA segment, making millions of copies for further analysis.

Correct Answer: A — To amplify a specific DNA segment

Q. What is the primary structure of DNA composed of?

A. A double helix of nucleotides
B. A single strand of amino acids
C. A triple helix of sugars
D. A circular structure of lipids

Solution

The primary structure of DNA is composed of a double helix formed by nucleotides, which consist of a sugar, phosphate group, and nitrogenous base.

Correct Answer: A — A double helix of nucleotides

Q. What is the probability of obtaining a heterozygous offspring from a cross between two heterozygous parents (Aa x Aa)?

A. 0
B. 1/4
C. 1/2
D. 3/4

Solution

The probability of obtaining a heterozygous offspring (Aa) from a cross of Aa x Aa is 1/2.

Correct Answer: C — 1/2

Q. What is the probability of obtaining a homozygous recessive offspring from a cross between two heterozygous parents (Aa x Aa)?

A. 0.25
B. 0.50
C. 0.75
D. 1.00

Solution

The probability of obtaining a homozygous recessive offspring (aa) from a cross of Aa x Aa is 0.25 or 25%.

Correct Answer: A — 0.25

Q. What is the process of converting mRNA into a protein called?

A. Transcription
B. Translation
C. Replication
D. Translocation

Solution

The process of converting mRNA into a protein is called translation.

Correct Answer: B — Translation

Q. What is the purpose of a Punnett square?

A. To determine the DNA sequence
B. To predict the genotype ratios of offspring
C. To analyze protein structure
D. To measure gene expression

Solution

A Punnett square is used to predict the genotype ratios of offspring from a genetic cross.

Correct Answer: B — To predict the genotype ratios of offspring

Q. What is the purpose of gel electrophoresis in molecular biology?

A. To amplify DNA
B. To separate DNA fragments by size
C. To clone DNA
D. To synthesize RNA

Solution

Gel electrophoresis separates DNA fragments based on size, allowing for analysis and visualization.

Correct Answer: B — To separate DNA fragments by size

Q. What is the purpose of using restriction enzymes in molecular biology?

A. To amplify DNA
B. To cut DNA at specific sequences
C. To synthesize RNA
D. To visualize proteins

Solution

Restriction enzymes cut DNA at specific sequences, allowing for the manipulation and cloning of DNA fragments.

Correct Answer: B — To cut DNA at specific sequences

Q. What is the purpose of using restriction enzymes in recombinant DNA technology?

A. To amplify DNA
B. To cut DNA at specific sequences
C. To synthesize RNA
D. To clone entire genomes

Solution

Restriction enzymes cut DNA at specific sequences, allowing for the insertion of foreign DNA into vectors.

Correct Answer: B — To cut DNA at specific sequences

Q. What is the purpose of using reverse transcriptase in molecular biology?

A. To synthesize DNA from RNA
B. To amplify DNA
C. To cut DNA at specific sites
D. To clone DNA

Solution

Reverse transcriptase is used to synthesize complementary DNA (cDNA) from an RNA template.

Correct Answer: A — To synthesize DNA from RNA

Q. What is the role of a vector in recombinant DNA technology?

A. To amplify RNA
B. To carry foreign DNA into a host cell
C. To cut DNA at specific sites
D. To synthesize proteins

Solution

A vector is a DNA molecule used to carry foreign DNA into a host cell for replication and expression.

Correct Answer: B — To carry foreign DNA into a host cell

Q. What is the role of messenger RNA (mRNA) in gene expression?

A. To replicate DNA
B. To carry genetic information from DNA to ribosomes
C. To form the structure of ribosomes
D. To transport amino acids

Solution

mRNA carries genetic information from DNA to ribosomes, where proteins are synthesized.

Correct Answer: B — To carry genetic information from DNA to ribosomes

Q. What is the role of messenger RNA (mRNA)?

A. To store genetic information
B. To transport amino acids
C. To carry genetic information from DNA to ribosomes
D. To form the structure of ribosomes

Solution

Messenger RNA (mRNA) carries genetic information from DNA to the ribosomes for protein synthesis.

Correct Answer: C — To carry genetic information from DNA to ribosomes

Q. What is the role of mRNA in gene expression?

A. To replicate DNA
B. To transport amino acids
C. To carry genetic information from DNA to ribosomes
D. To form the ribosome structure

Solution

mRNA carries the genetic information from DNA to the ribosomes for protein synthesis.

Correct Answer: C — To carry genetic information from DNA to ribosomes

Q. What is the role of restriction enzymes in molecular biology?

A. To cut DNA at specific sequences
B. To synthesize RNA
C. To amplify DNA
D. To repair DNA

Solution

Restriction enzymes cut DNA at specific sequences, which is essential for cloning and recombinant DNA technology.

Correct Answer: A — To cut DNA at specific sequences

Q. What is the role of ribosomal RNA (rRNA) in the cell?

A. To carry amino acids to the ribosome
B. To catalyze protein synthesis
C. To store genetic information
D. To transcribe DNA

Solution

Ribosomal RNA (rRNA) plays a crucial role in catalyzing protein synthesis at the ribosome.

Correct Answer: B — To catalyze protein synthesis

Q. What is the role of ribosomes in gene expression?

A. DNA replication
B. RNA synthesis
C. Protein synthesis
D. RNA degradation

Solution

Ribosomes are the cellular machinery that synthesizes proteins during the process of translation.

Correct Answer: C — Protein synthesis

Showing 61 to 90 of 186 (7 Pages)