3c: Sex determination

Question 1

in mammals, what determines development of male characteristics

Answer 1

SRY gene on the Y chromosome

Question 2

X chromosome inactivation definition

Answer 2

is a process by which most of one X chromosome is inactivated.

As the X chromosome inactivated in each cell is random, half of the cells in any tissue will have a working copy of the gene in question

Question 3

Hermaphrodites Definition

Answer 3

are species that have functioning male and female reproductive organs in each individual

They produce both male and female gametes and usually have a partner with which to exchange gametes

Question 4

benefit hermaphrodites

Answer 4

The benefit to the individual organism is that if the chance of encountering a partner is an uncommon event, there is no requirement for that partner to be of the opposite sex

Question 5

Environmental sex determination in reptiles is controlled by

Answer 5

environmental temperature of egg incubation.

Question 6

Sex can change within individuals of some species as a result of

Answer 6

• size
• competition
• parasitic infection
• temperature

Question 7

In some species the sex ratio of offspring can be adjusted in response to

Answer 7

Resource availability