Question

question 63
what is the difference between a somatic cell mutation and a germ - line mutation?
a only mutations in germ - line cells can be passed on to offspring and mutations in somatic cell are not.
b only mutations in somatic cells can be passed on to offspring.
c somatic cell mutations cannot lead to disease, but germ - line mutations can.
d germ - line mutations do not involve dna, but somatic cell mutations do.
e somatic cell mutations do not involve dna, but germ - line mutations do.
1 point
question 64
the type of mutation where a nucleotide is added to sequence that changes all the amino acid sequence after that addition:
a missense mutation
b silent mutation
c nonsense mutation
d frameshift mutation
e inversion mutation

Explanation:

• Question 63:
• Somatic cells are body cells (not involved in reproduction). Mutations in somatic cells affect only the individual organism (e.g., can cause cancer in that individual).
• Germ - line cells (gametes - sperm and egg) are involved in reproduction. Mutations in germ - line cells can be passed on to offspring as they contribute to the genetic material of the next generation.
• Option B is wrong because somatic cell mutations are not passed to offspring. Option C is incorrect as somatic cell mutations (e.g., in cells related to cell growth regulation) can lead to diseases like cancer. Options D and E are wrong because both somatic and germ - line mutations involve DNA changes.
• Question 64:
• A missense mutation changes a single amino acid (due to a single nucleotide change in a non - frameshift way). A silent mutation does not change the amino acid sequence (due to the degeneracy of the genetic code). A nonsense mutation introduces a premature stop codon.
• An inversion mutation is a rearrangement of DNA segments. A frameshift mutation (caused by insertion or deletion of nucleotides not in multiples of three) changes the reading frame, so all amino acids after the insertion/deletion are affected. When a nucleotide is added (an insertion) and it changes all amino acids after the addition, it is a frameshift mutation.

Answer:

• Question 63: A. Only mutations in germ - line cells can be passed on to offspring and mutations in somatic cell are not.
• Question 64: D. frameshift mutation