Question

sickle-cell anemia is caused by a mutation in the gene encoding hemoglobin, causing red blood cells to appear
○ a) long and stringy.
○ b) spherical.
○ c) like discs.
○ d) half-moon shaped.

question 19 (5 points)
listen
in a series of experiments, hershey and chase radioactively labeled dna and protein
in viruses and then used labeled viruses to infect bacteria. hershey and chases
experiments definitively showed that
○ a) protein and not dna is the genetic material.
○ b) dna and not protein is the genetic material.
○ ...

Explanation:

First Question (Sickle - cell anemia)

Sickle - cell anemia is a genetic disorder. The mutation in the hemoglobin - encoding gene leads to red blood cells having a sickle (half - moon) shape instead of the normal biconcave disc shape. Option A is incorrect as they are not long and stringy. Option B is incorrect as normal red blood cells are not spherical (spherical red blood cells are seen in some other disorders like spherocytosis). Option C is the shape of normal red blood cells, not sickle - celled ones.

Second Question (Hershey and Chase experiment)

Hershey and Chase used radioactive isotopes to label DNA (with $^{32}P$) and protein (with $^{35}S$) in bacteriophages. When the phages infected bacteria, they found that the radioactive DNA entered the bacterial cells, while the radioactive protein remained outside. This experiment provided strong evidence that DNA, not protein, is the genetic material that is passed on to the next generation during viral infection of bacteria. Option A is incorrect as the results showed the opposite.

Answer:

D) half - moon shaped.