X and Y chromosomes

Question 1

How many matched pairs are there in a chromosome?

Answer 1

22 (the 23rd pair can either be XY or XX)

Question 2

what does the 23rd chromosome pair determine?

Answer 2

whether the offspring are male or female

Question 3

what chromosomes would a male have?

Answer 3

-an X and Y chromosome (XY)
-the Y chromosome causes male characteristics

Question 4

what chromosomes would a female have?

Answer 4

-an XX chromosome (XX)
-this combination allows female characteristics to develop

Question 5

what percent chance is there that each sperm cell gets an X chromosome?

Answer 5

50%

Question 6

what percent chance is there that each sperm cell gets a Y chromosome?

Answer 6

50%

Question 7

what is a genetic diagram?

Answer 7

models that are used to show all the possible outcomes when you cross together different genes or chromosomes

Question 8

how would you draw a punnett square (a type of genetic diagarm) to show the outcome of the fusion of male and female gametes?

Answer 8

1)Put the possible gametes
from one parent down the side, and those from the other parent along the top.
2)Then in each middle square you fill in the letters from the top and side that line up with that square. The pairs of letters in the middle are the possible combinations of the gametes.

Question 9

what would a web like genetic diagram for the fusion of male and female gametes look like?

Answer 9

1) At the top are the parents.
2)The middle circles show the possible gametes that are formed. One gamete from the female combines with one gamete from the male (during fertilisation).
3)The criss-cross lines show all the possible ways the X and Y chromosomes could combine. The possible combinations of the offspring are shown in the bottom circles.