Question

question #13
sickle cell anemia is an autosomal recessive disorder. if each parent carries one sickle cell allele, what
are the chances that their child will have sickle cell anemia?
a no chance
b one in four
c two in four
d three in four
question #14
the diagram below shows a change that occurred in a pair of chromosomes during meiosis.
after fertilization, the alteration that occurred will most likely

Explanation:

Question #11 Solution (Step-by-Step Format)

Step 1: Identify Parental Genotypes

Both parents are carriers of the sickle cell allele, so their genotypes are \( Aa \) (heterozygous, with \( A \) = normal allele, \( a \) = sickle cell allele).

Step 2: Set Up the Punnett Square

For a cross \( Aa \times Aa \), the possible gametes from each parent are \( A \) and \( a \). The Punnett square is:

	\( A \)	\( a \)
\( a \)	\( Aa \)	\( aa \)

Step 3: Calculate Probability of \( aa \)

Sickle cell anemia requires the homozygous recessive genotype \( aa \). From the Punnett square, only 1 of the 4 possible genotypes is \( aa \). Thus, the probability is \( \frac{1}{4} \) (one in four).

Answer:

B. one in four

Question #15 (Incomplete, but if we assume the diagram shows a chromosomal alteration like crossing over or translocation):

(Note: The question is cut off, but if it involves chromosomal changes during meiosis (e.g., crossing over, translocation, or nondisjunction), the alteration (e.g., a mutation or rearrangement) would most likely be passed to the offspring after fertilization, as meiosis produces gametes, and fertilization combines gametes. However, without the full question, a precise answer cannot be provided. If you share the complete question, I can assist further.)