Question

for a parental mutation to be passed onto offspring, the mutation has to occur in which type of cell? (1 point)
a gamete (sex cell)
a somatic cell (body cell)
either a gamete or a somatic cell
a stem cell
ultimately, what is the source of all genetic variation? (1 point)
mutations
mitosis
pollutants
biological clones

Explanation:

First Question (Parental Mutation Inheritance)

To determine the cell type for a parental mutation to pass to offspring, we analyze:

• Gametes (sex cells: sperm/egg) fuse during fertilization to form the zygote (offspring's first cell). Mutations in gametes are in the genetic material passed to offspring.
• Somatic cells (body cells) mutations affect only the individual, not offspring (since they don't contribute to the next generation's genetic makeup).
• "Either" is incorrect (somatic mutations aren't inherited). Stem cells can be somatic or germ - line, but the key is gametes for inheritance.

To identify the source of all genetic variation:

• Mutations are changes in DNA sequence. They create new alleles/genetic material, which is the ultimate source (other variation sources like recombination shuffle existing mutations).
• Mitosis (cell division for growth/repair) doesn't create new genetic variation (it replicates DNA).
• Pollutants can cause mutations but aren't the source of all variation (variation exists without pollutants, and pollutants are just one mutagen).
• Biological clones are genetically identical, so they don't introduce variation.

Answer:

A. A gamete (sex cell)

Second Question (Source of All Genetic Variation)