Chapter 2 quiz-part 1

Identical twins are produced from the same sperm and egg (which splits after the first mitotic division), whereas fraternal twins are produced from separate sperm and separate egg cells. If two parents with brown eyes (a dominant trait) produce a boy with blue eyes.What is the probability that both parents are heterozygous?

1

Identical twins are produced from the same sperm and egg (which splits after the first mitotic division), whereas fraternal twins are produced from separate sperm and separate egg cells. If two parents with brown eyes (a dominant trait) produce a boy with blue eyes.What is the probability that their second child being brown eye?

3/4

Identical twins are produced from the same sperm and egg (which splits after the first mitotic division), whereas fraternal twins are produced from separate sperm and separate egg cells. If two parents with brown eyes (a dominant trait) produce a boy with blue eyes. What is the probability that their next child will have blue eyes?

1/4

A cross between a heterozygous tall pea plant (Tt) and a homozygous short plant (tt) will produce 400 offspring. How many of the offspring will be short?

200

A heterozygous tall plant with purple flower (TtPp) is allowed to cross with a true breeding short plant with white flower (ttpp), which will produce 1000 offspring. Based on law of independent assortment, how many offspring will be short with purple flower? (T-tall, dominant; t-short, recessive; P-purple, dominant; p-white, recessive)

250

A heterozygous pea plant that is tall with purple flower, TtPp, is allowed to self-fertilize. Tall (T) is dominant over dwarf (t), Purple (P) is dominant over white (p). In the offspring, the probability of plants that are short with purple flowers will be?

3/16

Albinism is a recessive human trait controlled by a single gene in autosome, if a phenotypically normal couple produced an albino child, what is the probability that their first child is normal but the second and third child are albino?

3/64

The following pedigree documented a genetic disorder Tay-Sachs disease in a family. Tay-Sachs disease is a rare, inherited disorder that destroys nerve cells in the brain and spinal cord. Tay-Sachs disease is typically found in people with certain ancestry, such as Eastern European Jews. A fatty substance in the brain destroys nerve cells. Symptoms of slowed development usually appear around six months of age. Symptoms progress until they lead to death, often around age four. There is no cure for Tay-Sachs disease. What is the inheritance pattern of Tay-Sachs disease?

Autosomal recessive

You cross a pea plants with purple flower with a pea plant with white flower (recessive, pp). All the offspring have purple flower. Based this result, you conclude that the genotype of purple flower pea plant tested is

PP

All possible gametes produced by a pea plant with a genotype ttYyrr will be

tYr, tyr