Cats Normally Have a Total of 18 Toes, 5 on Each

question 35

Multiple Choice

Cats normally have a total of 18 toes, 5 on each front paw and 4 on each back paw. But some cats express the dominant phenotype for polydactyly, which results in the development of extra toes on one or more paws. Jake, a Canadian tabby cat, has 28 toes and is recognized by the Guinness Book of World Records as the cat with the most toes.
Suppose that Jake mates with a female cat, Lucy, who has 18 total toes. Over several years, they have multiple litters and a total of 16 kittens (10 males and 6 females) . The total number of toes on each kitten ranges from 21 to 25.
-Along with having a variable number of toes, some kittens from Jake and Lucy's litter had a white spot on their nose. In fact, out of the 16 kittens, all 10 males had the white spot, but none of the 6 females had the white spot. Jake has a white spot on his nose, but Lucy does not. What can you conclude from this information?

• A) A sex-linked gene that controls the expression of the white spot is found on the Y chromosome.
• B) A sex-linked gene that controls the expression of the white spot is found on the X chromosome.
• C) The genes for the white spot and for polydactyly are linked.
• D) The genes for the white spot and for polydactyly are not linked.

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Definitions:

Aromatic Ring

A cyclic molecule with conjugated pi electrons that exhibits enhanced stability, typified by the benzene ring.

Deactivator

A chemical group or substituent attached to an aromatic ring that decreases its reactivity in electrophilic aromatic substitution reactions.

Friedel-Crafts Acylation

A chemical reaction that introduces an acyl group into an aromatic ring, facilitated by a Lewis acid catalyst, used in synthetic chemistry.

Benzophenone

An organic compound used primarily as a photoinitiator in polymer chemistry and as a flavor or fragrance additive, characterized by its ketone attached to two benzene rings.