Question

practice it!
which of the following statements about mutations are correct?
select the correct answer(s).
mutations always make organisms stronger or better adapted to their environment.
mutations can affect a single gene or an entire chromosome.
mutations never change how proteins work in the body.
the mutation that causes sickle cell is harmful, but can result in beneficial effects.
all mutations are harmful and cause diseases.

Explanation:

• Mutations can be harmful, beneficial, or neutral. So, "Mutations always make organisms stronger or better adapted to their environment" and "All mutations are harmful and cause diseases" are incorrect.
• Mutations can range from affecting a single gene (point mutations) to an entire chromosome (chromosomal aberrations). So, "Mutations can affect a single gene or an entire chromosome" is correct.
• Mutations can change the amino - acid sequence of proteins (e.g., in sickle - cell anemia, the mutation changes the hemoglobin protein), so "Mutations never change how proteins work in the body" is incorrect.
• The sickle - cell mutation is harmful as it causes sickle - cell disease, but in areas with malaria, heterozygous individuals (carriers) have some resistance to malaria, so "The mutation that causes sickle cell is harmful, but can result in beneficial effects" is correct.

Answer:

Mutations can affect a single gene or an entire chromosome.
The mutation that causes sickle cell is harmful, but can result in beneficial effects.