Biology

Molecular Genetics

917 Questions

Molecular genetics explores the mechanisms of genetic information transfer, including DNA replication, transcription, and translation. It is a core component of biology syllabi. These concepts frequently appear in general science sections of major competitive exams.

DNA replicationTranscription processTranslation processRNA typesCentral dogma

Molecular Genetics Questions

Multiple choice biology enzymes classification of enzyme enzymes classification and cofactors the origin of cells and cell division

Telomerase is an enzyme which is a

  1. Simple protein

  2. RNA

  3. Ribonucleoprotein

  4. Repetitive DNA
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation
Telomerase is a ribonucleoprotein enzyme which adds bases at the 3' end of one strand of telomere as directed by the RNA sequence of RNA component of this enzyme.
So, the correct answer is 'Ribonucleoprotein'
Multiple choice enzymes classification of enzyme enzymes classification and cofactors the origin of cells and cell division

Ribozyme is

  1. RNA with additional phosphate.

  2. RNA without sugar.

  3. RNA without uracil.

  4. RNA acting as enzyme.
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation

Most of the enzymes are large protein molecules except for a small category of catalytic RNA molecules. The catalytic RNA molecules are called Ribozymes. Ribozymes play an important role in intron splicing and other reactions during processing of RNA. The ribozymes are an important example of self catalytic (RNA) molecules, i.e., one type of RNA (ribozyme) acting on another type of RNA (like mRNA). Some of the introns are self splicing which catalyze their own splicing.

Multiple choice

Why is an RNA primer necessary in DNA replication?

  1. Provides a 3' end that DNA polymerase can add nucleotides to

  2. To support the unwinding of DNA by DNA gyrase

  3. To support the unwinding of DNA by Helicase

  4. Provides a 5' end that DNA polymerase can add nucleotides to
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

DNA polymerase cannot initiate synthesis on a bare template strand; it requires an existing 3' end to attach new nucleotides. The RNA primer provides this necessary 3' hydroxyl group.

Multiple choice botany cell and cellular organization cell theory microscope cell and its discovery

Dry weight of macromolecules like RNA, proteins and DNA can be known through which method?

  1. Fluorescent microscopy

  2. Dark field microscopy

  3. Phase contrast microscopy

  4. Differential interference contrast microscopy.
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation

Differential interference contrast (DIC) microscopy is often used to study the physical properties of biological samples, including mass and density, which can relate to the dry weight of cellular components.

Multiple choice

the enzyme that creates mRNA from the DNA is called?

  1. DNA polymerase 1

  2. RNA polymerase

  3. DNA polymerase 3

  4. Ligase
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

RNA polymerase is the primary enzyme responsible for transcription, where it reads a DNA template strand to synthesize a complementary mRNA molecule. DNA polymerases, on the other hand, are involved in DNA replication, and ligase joins DNA fragments.

Multiple choice

What does the Central Dogma state when it comes to process of flow

  1. DNA to RNA to Protein

  2. Protein to RNA to DNA

  3. RNA to DNA to Protein

  4. Protein to DNA to RNA
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

The Central Dogma of molecular biology describes the two-step flow of genetic information: transcription of DNA into RNA, followed by translation of RNA into proteins.

Multiple choice

DNA & RNA are both

  1. Carbohydrate

  2. Protein

  3. Lipid

  4. Nucleic Acid
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation

DNA (Deoxyribonucleic Acid) and RNA (Ribonucleic Acid) are polymers composed of nucleotide monomers, which classifies them as nucleic acids. They are responsible for storing and transmitting genetic information, unlike carbohydrates, proteins, or lipids.

Multiple choice

After transcription, the mRNA moves to the ?

  1. Golgi apparatus

  2. Cytoplasm

  3. Nucleus

  4. Mitochondria
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

Transcription occurs in the nucleus of eukaryotic cells. Once the mRNA molecule is synthesized and processed, it leaves the nucleus through nuclear pores and enters the cytoplasm, where translation takes place on ribosomes.

Multiple choice

Which of the following is NOT a role of RNA Polymerase?

  1. Create RNA nucleotides within the nucleus

  2. Unwind the DNA double helix

  3. Create covalent bonds between RNA nucleotides

  4. Add complimentary RNA nucleotides to DNA with hydrogen bonds
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

RNA polymerase does not synthesize or create individual RNA nucleotides from scratch; these free nucleotides are already present in the nucleoplasm. Instead, RNA polymerase unwinds DNA, aligns complementary RNA nucleotides, and catalyzes the formation of covalent phosphodiester bonds to link them into an mRNA strand.

Multiple choice

Which enzyme builds mRNA by adding complimentary RNA nucleotides?

  1. DNA polymerase

  2. RNA polymerase

  3. DNAse

  4. RNAse
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

RNA polymerase is the primary enzyme responsible for transcription, binding to DNA and assembling a complementary RNA strand by adding RNA nucleotides. DNA polymerase is involved in DNA replication, while nucleases like DNAse and RNAse break down nucleic acids.

Multiple choice

mRNA is built by adding ?

  1. Complimentary DNA nucleotides

  2. Complimentary tRNA

  3. Complimentary rRNA

  4. Complimentary RNA nucleotides
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation

Messenger RNA (mRNA) is a polymer of RNA nucleotides. During transcription, RNA polymerase links complementary RNA nucleotides (A, U, C, G) together based on the DNA template.

Multiple choice

What occurs during the very beginning of the transcription process?

  1. Thymine is converted to uracil

  2. mRNA is built using RNA polymerase

  3. DNA is unwound

  4. DNA is wound back up
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

Before RNA polymerase can read the template strand to build mRNA, the DNA double helix must be unwound and separated at the promoter region to expose the bases. Once unwound, the enzyme can begin synthesizing the complementary RNA strand.