Question: A plant trisomic for a chromosome carrying the A gene has the genotype A/a/a. Which of the follow…

A plant trisomic for a chromosome carrying the A gene has the
genotype A/a/a. Which of the following represents a gamete this
plant could NOT produce?
      
a. A/a
      
b. A
      
c. a
      
d. A/A

In humans, males have only one X chromosome and females have two,
yet housekeeping X chromosome genes are expressed in roughly equal
amounts in males and females. How can this be explained?

      
a. The X chromosome is hyperactivated in males
      
b. Both X chromosomes are hypoactivated in females
      
c. One X chromosome in females is inactivated
  
d. The Y chromosome in males actually contains similar genes as the
X chromosome.

The following pedigree shows the inheritance of a rare X-linked
disease of the blood, affected individuals are indicated by shaded
symbols. The propositus (indicated by an arrow) has 45 chromosomes
and is sterile. From the choices below, choose one that can account
for both the sterility and the blood disease in this female.

a. The woman’s father was a carrier for the disease on his X
chromosome

      
b. The woman is likely demonstrating a case of Turner syndrome

      
c. The woman is likely demonstrating a case of Down syndrome

      
d. The woman’s mother’s eggs likely experienced a nondisjunction
event.