Honor Bio 11.3

Question 1

Autosomal dominant

Answer 1

Trait appears in every generation; only one copy of the allele is needed.

Question 2

Autosomal recessive

Answer 2

Skips generations; two copies of the allele are needed.

Question 3

Sex-linked dominant

Answer 3

More females affected; one X-linked allele causes the trait.

Question 4

Sex-linked recessive

Answer 4

More males affected; two X-linked alleles needed in females, one in males.

Question 5

Carrier

Answer 5

A person with one copy of a recessive allele who does not express the trait.

Question 6

X-inactivation

Answer 6

One of the X chromosomes in females becomes inactive (Barr body).

Question 7

Pedigree

Answer 7

A diagram showing genetic relationships and trait inheritance in families.

Question 8

Differences between autosomal dominant and autosomal recessive

Answer 8

Dominant appears every generation with one allele; recessive requires two alleles and can skip generations.

Question 9

Differences between sex-linked dominant and sex-linked recessive

Answer 9

Dominant affects both sexes but more females; recessive affects mostly males.

Question 10

Example of a cross involving a sex-linked trait

Answer 10

XᴺXⁿ (carrier female) × XᴺY (normal male) → 25% affected son, 25% carrier daughter.

Question 11

How to rule out inheritance types on a pedigree

Answer 11

Look for affected sexes, generational skipping, and carrier patterns to determine autosomal vs. sex-linked and dominant vs. recessive.