Questions on the Genetic Code
Multiple Choice Questions: Genetic Code
1. What is the genetic code?
A) A set of genes that regulate metabolism
B) A language made of sugars
C) The sequence of DNA bases that determines the sequence of amino acids in a protein
D) The shape of chromosomes
E) The organization of nucleosomes
2. Each set of three nucleotide bases in mRNA that codes for an amino acid is called a:
A) Gene
B) Codon
C) Anticodon
D) Triphosphate
E) Ribosome
3. How many different codons are possible in the genetic code?
A) 3
B) 16
C) 20
D) 64
E) 128
4. How many amino acids are coded for by the genetic code?
A) 4
B) 16
C) 20
D) 64
E) 128
5. Which molecule carries the anticodon?
A) mRNA
B) DNA
C) rRNA
D) tRNA
E) Enzyme
6. Which of the following is a start codon?
A) UAA
B) AUG
C) UGA
D) UAG
E) GUA
7. Which amino acid is encoded by the start codon AUG?
A) Tryptophan
B) Alanine
C) Methionine
D) Serine
E) Glycine
8. Which of the following are stop codons?
A) AUG, UGG, AUA
B) UAA, UAG, UGA
C) AAA, AAG, AAC
D) CGA, CGC, CGG
E) GUA, GUC, GUG
9. What is meant by the term “degenerate” in reference to the genetic code?
A) It decays over time
B) It is the same in all species
C) Multiple codons can code for the same amino acid
D) It is random
E) It mutates easily
10. The genetic code is said to be “universal” because:
A) It has different rules in each organism
B) All organisms use different amino acids
C) Most organisms use the same codons for the same amino acids
D) It is only found in eukaryotes
E) It applies only to humans
11. Which RNA molecule contains the codons?
A) rRNA
B) tRNA
C) mRNA
D) snRNA
E) siRNA
12. Which RNA molecule contains the anticodons?
A) rRNA
B) mRNA
C) tRNA
D) snRNA
E) hnRNA
13. Which organelle reads the genetic code during translation?
A) Nucleus
B) Lysosome
C) Ribosome
D) Golgi apparatus
E) Endoplasmic reticulum
14. Which of the following correctly matches the codon UUU with its amino acid?
A) Leucine
B) Phenylalanine
C) Serine
D) Tyrosine
E) Glutamine
15. What is the role of a stop codon?
A) Start transcription
B) Begin translation
C) Signal end of translation
D) Add a methyl cap
E) Signal splicing
16. Which property of the genetic code prevents changes in a single base from always changing the amino acid?
A) Universality
B) Redundancy
C) Polarity
D) Reversibility
E) Flexibility
17. Which of the following is true of codons and anticodons?
A) Both are found in DNA
B) Codons pair with ribosomes
C) Codons and anticodons pair during replication
D) Anticodons in tRNA pair with codons in mRNA
E) Codons and anticodons are always the same sequence
18. How many nucleotides are required to code for one amino acid?
A) 1
B) 2
C) 3
D) 4
E) 6
19. Which statement is true about the genetic code in mitochondria?
A) It is identical to the nuclear code
B) It is non-functional
C) It has slight variations from the universal code
D) It uses DNA polymerase to read RNA
E) It has no stop codons
20. What happens if a codon mutates into a stop codon?
A) Protein synthesis speeds up
B) Translation continues normally
C) Protein is completed successfully
D) Premature termination occurs
E) DNA repair is initiated
- Questions on Transcription in Molecular Biology
- Questions on RNA Structure and Replication
- Questions on DNA Structure and Replication
Answer Key:
1. C
2. B
3. D
4. C
5. D
6. B
7. C
8. B
9. C
10. C
11. C
12. C
13. C
14. B
15. C
16. B
17. D
18. C
19. C
20. D
Dive into the groundbreaking science of neurotransmitters—your brain’s invisible architects—in Chemical Harmony: How Neurotransmitters Shape Our Lives (2025). This meticulously researched book reveals how serotonin, dopamine, GABA, and other brain chemicals silently orchestrate every aspect of your existence, from decision-making and relationships to mental health and emotional resilience.Click here to buy
👉 +3000 Biology Questions with Answers Key.
Share Online!
