DNA/RNA/Protein/Gene Practice Questions

What is the central dogma of molecular biology?

• A) RNA → DNA → Protein

• B) DNA → RNA → Protein

• C) Protein → RNA → DNA

• D) DNA → Protein → RNA

B) DNA → RNA → Protein

Which nucleotide is found in RNA but not in DNA?

• A) Thymine

• B) Cytosine

• C) Adenine

• D) Uracil

D) Uracil

Which enzyme is responsible for synthesizing RNA from a DNA template?

• A) DNA polymerase

• B) RNA polymerase

• C) Ligase

• D) Helicase

B) RNA polymerase

What is the role of transfer RNA (tRNA) in protein synthesis?

• A) Synthesizes RNA from DNA

• B) Carries amino acids to ribosomes

• C) Serves as a template for transcription

• D) Provides structural framework for ribosomes

B) Carries amino acids to ribosomes

Which structure of the ribosomal RNA is responsible for binding the mRNA?

• A) A site

• B) P site

• C) E site

• D) Small subunit

D) Small subunit

What is the start codon for translation in mRNA?

• A) UAA

• B) AUG

• C) UAG

• D) UGA

B) AUG

Which of the following molecules prevents the degradation of mRNA and helps in its export from the nucleus?

• A) The 5' cap

• B) Poly-A tail

• C) Introns

• D) Exons

B) Poly-A tail

In DNA, what base pairs with guanine (G)?

• A) Thymine (T)

• B) Adenine (A)

• C) Cytosine (C)

• D) Uracil (U)

C) Cytosine (C)

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

• A) Carrying amino acids to ribosomes

• B) Acting as a template for protein synthesis

• C) Providing the structural framework for ribosomes

• D) Binding the promoter region for transcription

C) Providing the structural framework for ribosomes

Which base pairing is correct for RNA?

• A) A-T, G-C

• B) A-T, G-U

• C) A-U, G-C

• D) A-G, T-C

C) A-U, G-C

What is the function of histone acetyltransferases (HATs) in chromatin remodeling?

• A) Tightens the interaction between DNA and histones

• B) Loosens the interaction between DNA and histones

• C) Initiates DNA replication

• D) Methylates DNA for transcriptional silencing

B) Loosens the interaction between DNA and histones

Which of the following statements about DNA replication is correct?

• A) It is conservative, with both parent strands remaining intact.

• B) DNA replication is semiconservative, with each new double helix containing one parent strand and one daughter strand.

• C) Replication occurs in the 3' to 5' direction.

• D) DNA replication occurs independently of base pairing.

B) DNA replication is semiconservative, with each new double helix containing one parent strand and one daughter strand.

What does the enzyme DNA polymerase III do during replication?

• A) Corrects errors in base pairing

• B) Adds nucleotides to the growing DNA strand

• C) Joins the Okazaki fragments

• D) Unwinds the DNA helix

B) Adds nucleotides to the growing DNA strand

Which process removes introns and retains exons in mRNA?

• A) Translation

• B) Replication

• C) RNA splicing

• D) Transcription

C) RNA splicing

Which molecule is responsible for bringing amino acids to the ribosome during

translation?

• A) rRNA

• B) mRNA

• C) tRNA

• D) DNA

C) tRNA

Which enzyme is involved in the transcription of mRNA from DNA?

• A) RNA polymerase II

• B) RNA polymerase I

• C) DNA polymerase

• D) RNA ligase

A) RNA polymerase II

Which genetic phenomenon allows for the production of structurally related proteins from the same gene?

• A) RNA splicing

• B) Polyadenylation

• C) Alternate splicing

• D) RNA degradation

C) Alternate splicing

Which of the following occurs during transcription?

• A) DNA is synthesized from RNA

• B) RNA is synthesized from a DNA template

• C) Proteins are synthesized from RNA

• D) tRNA brings amino acids to the ribosome

B) RNA is synthesized from a DNA template

Which of the following statements about the lagging strand during DNA replication is true?

• A) It is synthesized continuously.

• B) It is synthesized discontinuously in short fragments.

• C) It is synthesized from the 5’ to 3’ direction toward the replication fork.

• D) It does not require DNA ligase.

B) It is synthesized discontinuously in short fragments.

What role does the 5' cap play in mRNA?

• A) Helps RNA polymerase bind to DNA

• B) Stabilizes mRNA and aids in ribosome recognition

• C) Promotes the degradation of mRNA

• D) Initiates protein folding

B) Stabilizes mRNA and aids in ribosome recognition

What is the role of the enzyme RNA polymerase I?

• A) Synthesizes mRNA

• B) Synthesizes tRNA

• C) Synthesizes rRNA

• D) Corrects errors in transcription

C) Synthesizes rRNA

Which statement describes the function of DNA ligase during replication?

• A) Adds new nucleotides to the growing DNA strand

• B) Unwinds the DNA helix for replication

• C) Joins Okazaki fragments on the lagging strand

• D) Proofreads the newly synthesized DNA for errors

C) Joins Okazaki fragments on the lagging strand

Which of the following best describes a codon?

• A) A sequence of three nucleotides in DNA that codes for an amino acid

• B) A sequence of two nucleotides that terminates translation

• C) A molecule that carries amino acids to the ribosome

• D) A binding site for ribosomes on mRNA

A) A sequence of three nucleotides in DNA that codes for an amino acid

What is the start codon for the translation of mRNA into protein?

• A) UAA

• B) UAG

• C) AUG

• D) UGA

C) AUG

Which molecule binds to the A-site on the ribosome during protein synthesis?

• A) mRNA

• B) tRNA with an amino acid

• C) rRNA

• D) DNA polymerase

B) tRNA with an amino acid

Which process refers to the synthesis of proteins from an mRNA template?

• A) Transcription

• B) Replication

• C) Translation

• D) Splicing

C) Translation

Which of the following statements is true about prion diseases?

• A) PrP Sc proteins assist in DNA replication.

• B) PrP Sc proteins resist proteolytic digestion and form aggregates.

• C) PrP Sc proteins degrade misfolded proteins.

• D) PrP Sc proteins prevent protein aggregation.

B) PrP Sc proteins resist proteolytic digestion and form aggregates.

Which of the following best describes semiconservative DNA replication?

• A) Both original strands are copied, and new strands form independently.

• B) Each new DNA molecule contains one original and one new strand.

• C) One DNA strand is replicated, while the other is discarded.

• D) DNA is copied in reverse order.

B) Each new DNA molecule contains one original and one new strand.

Which enzyme is responsible for synthesizing rRNA?

• A) RNA polymerase I

• B) RNA polymerase II

• C) RNA polymerase III

• D) DNA polymerase

A) RNA polymerase I

Which molecule serves as the template for transcription?

• A) mRNA

• B) DNA

• C) rRNA

• D) tRNA

B) DNA

What role does prion protein PrP Sc play in prion diseases?

• A) It synthesizes new proteins

• B) It acts as a template to fold other prion proteins

• C) It degrades misfolded proteins

• D) It assists in protein folding

B) It acts as a template to fold other prion proteins

What type of bonds connect nucleotides in a DNA or RNA strand?

• A) Hydrogen bonds

• B) Peptide bonds

• C) Phosphodiester bonds

• D) Glycosidic bonds

C) Phosphodiester bonds

Which of the following is an exception to the central dogma?

• A) Ribosomes synthesizing proteins from RNA

• B) Retroviruses like HIV

• C) DNA replication

• D) RNA splicing

B) Retroviruses like HIV

In DNA, the sugar is _____, whereas in RNA it is ______. DNA occurs as ______, but RNA is ______

1. deoxyribose 2. ribose 3. double-stranded 4. single-stranded

True or False? DNA is more stable than RNA

True

Which of the following enzymes catalyzes the joining of Okazaki fragments during DNA replication?

• A) DNA polymerase III

• B) Helicase

• C) DNA ligase

• D) RNA polymerase

C) DNA ligase

What does DNA polymerase I do during DNA replication?

• A) Joins Okazaki fragments

• B) Synthesizes new DNA strands

• C) Removes mismatched nucleotides and corrects errors

• D) Unwinds the DNA double helix

C) Removes mismatched nucleotides and corrects errors

Release factors bind to any ribosome with a stop codon positioned in the

• A-site

• P-site

• E-site

• All of the above

A-site

“Redundancy” or “degeneration” of the genetic code occurs during which of the following step of protein synthesis.

• Transcription

• DNA replication

• Translation

• None of the above

Translation

Write the nucleotide of daughter DNA strand during replication if parent is represented with the following nucleotide sequence

3’ ATCGTTTCATA 5’ Parent strand (DNA)

5’ TAGCAAAGTAT 3’ Daughter strand .

• New strand formation is ALWAYS from 5’ prime- to 3’ end.

Write the nucleotide sequence of RNA strand during transcription if DNA template strand is represented with the following nucleotide sequence

3’ ATCGTTTCATA 5’ strand (DNA)

5’ UAGCAAAGUAU 3’

True or False? Transcriptional activators or repressors binding to the regulatory region can affect gene transcription.

True

Transcriptional activators binding to the regulatory region can ______ while Transcriptional repressors ______ can affect gene transcription.

• Enhances, suppress

• Suppress,Enhance

• No effect

• None of the above.

Enhances, suppress

Keeping start and stop codon in mind, identify how many amino acids will be translated theoratically if the RNA codons reads as

-----GCUAAUG ATG GAU UGG CGA GGA CCA UGA GGC

7