study guide for genetics

Question 1

Q: The diagram represents a molecule of:

A: A) DNA

B: RNA

C: Protein

D: Fat

Explanation: The double-helix shape in the image is specific to DNA.

Question 2

Q: Which DNA strand is complementary to the strand shown?

A: A) GTACGATG

B: TACGCTAG

C: GUACGAUG

D: CATGCTAC

Explanation: Complementary base pairing: C–G, A–T, T–A, G–C, C–G, T–A, A–T, C–G → GTACGATG

Question 3

Q: Which parts of the diagram make up a nucleotide?

A: A) A, B, and C

B: B, C, and D

C: A, C, and D

D: A, B, and D

Explanation: A nucleotide consists of a phosphate group (A), a sugar (B), and a nitrogen base (C).

Question 4

Q: How many nucleotides are shown in the diagram?

A: A) 8

B: 2

C: 6

D: 4

Explanation: The diagram shows 4 complete nucleotides, each consisting of a sugar, phosphate, and base.

Question 5

Q: The letter X represents two nitrogen bases that are:

A: A) Identical and joined by hydrogen bonds

B: Complementary and joined by hydrogen bonds

C: Identical and joined by ionic bonds

D: Complementary and joined by ionic bonds

Explanation: Base pairs like A–T and C–G are complementary and held together by hydrogen bonds.

Question 6

Q: The mRNA codon for methionine is:

A: A) TAC

B: UAC

C: ATG

D: AUG

Explanation: AUG is the universal start codon and codes for methionine.

Question 7

Q: A change in the DNA base sequence is called a:

A: A) Bacterial transformation

B: Chromosomal replication

C: Gene mutation

D: Protein synthesis

Explanation: A gene mutation involves a change in the nucleotide sequence of DNA.

Question 8

Q: Which nucleic acid molecule carries instructions from the nucleus to the cytoplasm?

A: A) DNA only

B: Messenger RNA only

C: Transfer RNA only

D: DNA, mRNA, and tRNA

Explanation: DNA provides the template, mRNA carries the instructions, and tRNA brings amino acids during protein synthesis.

Question 9

Q: Which sequence of events happens during protein synthesis?

A: A) B → E → A → C → D

  • B: DNA serves as a template for RNA

  • E: RNA moves to cytoplasm

  • A: mRNA attaches to a ribosome

  • C: tRNA bonds to a codon

  • D: Amino acids are bonded
    Explanation: This sequence represents the correct order of events from transcription to translation.

Question 10

Q: The biochemical process shown is most closely associated with what organelle?

A: A) Nucleolus

B: Ribosome

C: Chloroplast

D: Mitochondrion

Explanation: Ribosomes are the sites of protein synthesis where translation occurs.

Question 11

Q: Molecule 3 (a protein) is formed as a result of:

A: A) Deamination

B: Dehydration synthesis

C: Enzymatic hydrolysis

D: Oxidation

Explanation: Dehydration synthesis links amino acids together by removing water molecules.

Question 12

Q: The correct order of molecules in protein synthesis is:

A: A) mRNA, tRNA, DNA, polypeptide

B: DNA, mRNA, polypeptide, tRNA

C: tRNA, polypeptide, DNA, mRNA

D: DNA, mRNA, tRNA, polypeptide

Explanation: DNA is transcribed into mRNA, which is translated with the help of tRNA to form a polypeptide.

Question 13

Q: What is the function of tRNA during protein synthesis?

A: A) Carries the genetic code from the nucleus

B: Synthesizes DNA

C: Transfers amino acids to the ribosome

D: Forms the ribosome structure

Explanation: tRNA brings specific amino acids to the ribosome during translation.

Question 14

Q: Which process converts DNA into RNA?

A: A) Replication

B: Transcription

C: Translation

D: Mutation

Explanation: Transcription is the process of synthesizing RNA from a DNA template.

Question 15

Q: What amino acid does the codon AUG code for?

A: A) Glycine

B: Valine

C): Serine

D: Methionine

Explanation: AUG is the start codon and codes for methionine.

Question 16

Q: Which molecule brings amino acids to the ribosome?

A: A) mRNA

B: rRNA

C: tRNA

D: DNA

Explanation: tRNA transports amino acids to the ribosome for protein assembly.