BIOD 210 / BIOL 210 Module 5 Exam – Genetics (Portage Learning) – 200 Practice Questions with Verified Answers

BIOD 210 / BIOL 210 Module 5 Exam – Genetics (Portage Learning) –
200 Practice Questions with Verified Answers

QUESTIONS 1–200
Topic 1: The Central Dogma and Genetic Code


1. The Central Dogma of molecular biology describes the flow of genetic information as:
A) Protein → RNA → DNA
B) DNA → RNA → Protein
C) RNA → DNA → Protein
D) Protein → DNA → RNA
Answer B: DNA → RNA → Protein
Rationale: The Central Dogma states that genetic information flows from DNA to RNA (transcription) to
protein (translation).




2. Which of the following best describes the function of the genetic code?
A) It determines the sequence of amino acids in DNA
B) It specifies the relationship between codons in mRNA and amino acids in proteins
C) It determines the sequence of nucleotides in RNA
D) It specifies the relationship between genes and chromosomes
Answer B: It specifies the relationship between codons in mRNA and amino acids in proteins
Rationale: The genetic code is a set of rules by which information encoded in mRNA codons is translated
into amino acids.




3. How many nucleotides make up a codon?
A) 1
B) 2
C) 3
D) 4
Answer C: 3

,Rationale: A codon consists of three consecutive nucleotides that specify a single amino acid.




4. How many possible codons exist in the standard genetic code?
A) 20
B) 32
C) 64
D) 128
Answer C: 64
Rationale: There are 64 possible codons (4³), with 61 coding for amino acids and 3 serving as stop codons.




5. The start codon is:
A) UAA
B) UAG
C) UGA
D) AUG
Answer D: AUG
Rationale: AUG is the start codon, coding for methionine and initiating translation.




6. Which of the following are stop codons?
A) AUG, UAA, UAG
B) UAA, UAG, UGA
C) UAA, UGA, AUG
D) UAG, UGA, AUG
Answer B: UAA, UAG, UGA
Rationale: UAA, UAG, and UGA are stop codons that terminate translation.




7. The genetic code is said to be degenerate because:
A) Each codon codes for multiple amino acids
B) Multiple codons can code for the same amino acid
C) Each amino acid codes for multiple codons
D) The code varies between organisms
Answer B: Multiple codons can code for the same amino acid

,Rationale: Degeneracy means that most amino acids are encoded by more than one codon.




8. The wobble hypothesis explains:
A) Why the genetic code is universal
B) Why the third base of a codon can pair with multiple bases in the anticodon
C) Why DNA replication is semiconservative
D) Why mutations occur
Answer B: Why the third base of a codon can pair with multiple bases in the anticodon
Rationale: The wobble hypothesis accounts for the flexibility in base-pairing at the third position of a codon.




9. The anticodon is found on:
A) mRNA
B) tRNA
C) rRNA
D) DNA
Answer B: tRNA
Rationale: The anticodon is a three-nucleotide sequence on tRNA that complementary base-pairs with the
mRNA codon.




10. Which of the following is true about the genetic code?
A) It is different in prokaryotes and eukaryotes
B) It is nearly universal across all organisms
C) It is not redundant
D) It contains 20 stop codons
Answer B: It is nearly universal across all organisms
Rationale: The genetic code is nearly universal, with only minor variations in some organisms. --- ### Topic
2: Transcription




11. Transcription is the process by which:
A) RNA is synthesized from a DNA template
B) Protein is synthesized from RNA
C) DNA is replicated from DNA

, D) RNA is replicated from RNA
j0 j0 j0 j0 j0




Answer A: RNA is synthesized from a DNA template
j0 j0 j0 j0 j0 j0 j0 j0




Rationale: Transcription uses DNA as a template to synthesize RNA.
j0 j0 j0 j0 j0 j0 j0 j0 j0




12. Which enzyme catalyzes transcription?
j0 j0 j0 j0




A) DNA polymerase
j0 j0




B) RNA polymerase
j0 j0




C) Helicase
j0




D) Ligase
j0




Answer B: RNA polymerase
j0 j0 j0




Rationale: RNA polymerase synthesizes RNA from a DNA template during transcription.
j0 j0 j0 j0 j0 j0 j0 j0 j0 j0




13. During transcription, the DNA strand that is used as a template is called the:
j0 j0 j0 j0 j0 j0 j0 j0 j0 j0 j0 j0 j0 j0




A) Coding strand
j0 j0




B) Template strand (antisense strand)
j0 j0 j0 j0




C) Sense strand
j0 j0




D) Leading strand
j0 j0




Answer B: Template strand (antisense strand)
j0 j0 j0 j0 j0




Rationale: The template strand is complementary to the RNA being synthesized.
j0 j0 j0 j0 j0 j0 j0 j0 j0 j0




14. The coding strand of DNA has the same sequence as the RNA transcript except that:
j0 j0 j0 j0 j0 j0 j0 j0 j0 j0 j0 j0 j0 j0 j0




A) RNA contains uracil instead of adenine
j0 j0 j0 j0 j0 j0




B) RNA contains uracil instead of thymine
j0 j0 j0 j0 j0 j0




C) RNA contains thymine instead of uracil
j0 j0 j0 j0 j0 j0




D) RNA contains guanine instead of cytosine
j0 j0 j0 j0 j0 j0




Answer B: RNA contains uracil instead of thymine
j0 j0 j0 j0 j0 j0 j0




Rationale: RNA uses uracil (U) in place of thymine (T) found in DNA.
j0 j0 j0 j0 j0 j0 j0 j0 j0 j0 j0 j0




15. The promoter is a DNA sequence that:
j0 j0 j0 j0 j0 j0 j0




A) Signals where transcription should begin
j0 j0 j0 j0 j0




B) Signals where transcription should end
j0 j0 j0 j0 j0




C) Encodes the protein
j0 j0 j0