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.