Molecular Biology MCQ Quiz With Answers

22 Questions | By Astosich | Updated: Sep 4, 2022 | Attempts: 4006

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Molecular Biology MCQ Quiz With Answers - Quiz

Do you know all about DNA and RNA? Check out this molecular Biology MCQ quiz with answers and review your knowledge of DNA and RNA structure, replication, transcription & translation. Molecular biology is a branch of Biology that is concerned with studying chemical structures and biological phenomenon processes. It is mostly focused on nucleic acids (DNA and RNA) and proteins. This is an advanced-level test, so questions might be hard for you. Answer the questions carefully. Play the quiz now.

Questions and Answers

1.

DNA nucleotides have three components. Which one of these is NOT part of a DNA nucleotide?
- A.
  
  Phosphate
- B.
  
  Deoxyribose sugar
- C.
  
  Ribose sugar
- D.
  
  A nitrogenous base
2.

When considering DNA replication, the best way to describe it is:
- A.
  
  Semiconservative (half old, half new)
- B.
  
  Conservative (original remains, a new one is formed)
- C.
  
  Semipermeable (letting some molecules through)
- D.
  
  All of these
3.

In DNA replication, the enzyme responsible for untwisting & 'unzipping' the DNA strands is....
- A.
  
  Helicase & gyrase
- B.
  
  Ligase
- C.
  
  DNA Polymerase III
- D.
  
  Primase
- E.
  
  RNAse H (DNA Polymerase I)
4.

During DNA Replication, a short segment of RNA must form before DNA synthesis can begin. This is done by which enzyme?
- A.
  
  Helicase & gyrase
- B.
  
  DNA Polymerase III
- C.
  
  Ligase
- D.
  
  RNAse H (DNA Polymerase I)
- E.
  
  Primase
5.

Small discontinuous fragments of DNA, called Okazaki Fragments, need to be joined together to form a complete strand. Which enzyme carries out this reaction?
- A.
  
  Helicase & gyrase
- B.
  
  DNA Polymerase III
- C.
  
  Ligase
- D.
  
  RNAse H (DNA Polymerase I)
- E.
  
  Primase
6.

A new strand of DNA forms when nucleotides are linked together by phosphodiester bonds. The enzyme that enables this is...
- A.
  
  Helicase & gyrase
- B.
  
  DNA Polymerase III
- C.
  
  Ligase
- D.
  
  RNAse H (DNA Polymerase I)
- E.
  
  Primase
7.

During DNA replication, there are two other proteins involved that aren't enzymes. These are the SSB's and the "sliding clamp" protein. What are their jobs?
- A.
  
  To speed up the copying of DNA & make sure it happens correctly
- B.
  
  To prevent annealing (closing) of 'unzipped' DNA + increase processivity
- C.
  
  To ensure that any errors in copying are excised before they become permanent
- D.
  
  To bring the correct nucleotides to their correct complementary partners
8.

During DNA Transcription, only one strand is copied. This strand is the 3' -- 5' strand, and is called the _______________ strand.
- A.
  
  Leading
- B.
  
  Lagging
- C.
  
  Template
- D.
  
  Adenine
9.

During DNA replication, one strand is copied in a nice, smooth, continuous manner. This strand is called the ______________ strand.
- A.
  
  Leading
- B.
  
  Lagging
- C.
  
  Template
- D.
  
  Adenine
10.

During DNA replication, one strand is made discontinously, in short fragments, little by little. This is called the ____________________ strand.
- A.
  
  Leading
- B.
  
  Lagging
- C.
  
  Template
- D.
  
  Adenine
11.

During transcription, a segment of DNA coding AACGGATTATAT would be transcribed to....
- A.
  
  TTGCCTAATATA
- B.
  
  AACGGATTATAT
- C.
  
  AACGGAUUAUAU
- D.
  
  UUGCCUAAUAUA
12.

Although there are only 20 amino acids, there are 64 possible codons in the Genetic Code. This is because of a property of the code called....
- A.
  
  Redundancy
- B.
  
  Repetitiveness
- C.
  
  Recombination
- D.
  
  Frequency
13.

Because the mRNA codon, AUG, stands for an amino acid, it means that technically, every protein begins with which amino acid?
- A.
  
  Isoleucine
- B.
  
  Proline
- C.
  
  Methionine
- D.
  
  Tryptophan
14.

A sequence of DNA codes: AAAAAAAAAAAAAAAAAAAAA After transcription and translation, it would yield which of the following?
- A.
  
  Nothing.... that's ridiculous!
- B.
  
  A polypeptide composed of 7 Lysines
- C.
  
  A polypeptide composed of 7 Phenylalanines
- D.
  
  A polypeptide composed of 6 Lysines
15.

Where in the cell does transcription of DNA occur?
- A.
  
  The nucleus
- B.
  
  The cytoplasm
- C.
  
  Anywhere there is a ribosome
- D.
  
  All of these
16.

Where in the cell does translation of mRNA happen?
- A.
  
  The nucleus
- B.
  
  The cytoplasm
- C.
  
  Anywhere there is a ribosome
- D.
  
  All of these
17.

If an mRNA has a codon which is CGC, then the tRNA anticodon will be...
- A.
  
  CGC
- B.
  
  GCG
- C.
  
  UAU
- D.
  
  ATA
18.

Which of the following is NOT true about the Ribosome?
- A.
  
  It is composed of two subunits, large & small
- B.
  
  It is a vital participant in both transcription & translation
- C.
  
  It has three sites (E, P, A) that accomodate tRNA's
- D.
  
  It is the cell's protein maker
19.

A tRNA molecule picks up a Cysteine amino acid. The anticodon loop of this tRNA might have which of the following sequences?
- A.
  
  UGU, UGC
- B.
  
  ACA, ACG
- C.
  
  TGT, TGC
- D.
  
  All of these
20.

The 'rough draft' version of an mRNA, the Primary Transcript, needs to be 'cleaned up' or edited before translation can occur. This editing involves....
- A.
  
  Removal of exons
- B.
  
  Removal of introns
- C.
  
  Complementary pairing
- D.
  
  Secondary pairing
21.

If the DNA sequence of a gene is TACCCATGTAAGGGC, then the final amino acid sequence produced from it, after transcription and translation, will be
- A.
  
  TRP - PHE - LYS - ILE - LEU
- B.
  
  MET - GLY - SER - PHE - SER
- C.
  
  GLY - ASP - GLU - MET - MET
- D.
  
  None of the above
22.

When cells transcribe & translate their DNA, the term we use for this is...
- A.
  
  Gene expression
- B.
  
  Genetic mutation
- C.
  
  General mayhem
- D.
  
  Genetic coding