Chapter 17 - Dihybrid and sex-linked crosses Flashcards Preview

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Flashcards in Chapter 17 - Dihybrid and sex-linked crosses Deck (60)
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1

Define Dihybrid Cross.

A dihybrid cross involves the inheritance of two characteristics.

2

What is the Law of Independant Assortment?

The Law of independant assortment states that when gametes are formed, either of a pair of alleles is equally likely to combine with either or another pair of alleles.

3

Is the Law of Independant Assortment Gregor Mendal's first or second law?

Second law.

4

What form of cell division causes the law of independant assortment?

Meiosis

5

What is Sex determined by?

Sex is determined by a pair of sex chromosomes (the X and Y chromosomes ). Females are XX and Males are XY.

6

What are linked genes

Linked genes are genes that are located on the same chromosome and tend to be transmitted together into the gamete.

7

How many pairs of chromosomes do humans have?

23 pairs.

8

What are 22 pairs of human chromosomes known as?

22 pairs of human chromosomes are known as autosomes

9

One pair of human chromosomes is known as what?

One pair of human chromosomes is known as sex chromosomes.

10

Name the sex chromosomes

X and Y

11

What do sex chromosomes determine?

The sex chromosomes determine the sex of the individual.

12

What 2 chromosomes do females have

Females have two X chromosomes.

13

What 2 chromosomes do males have

Males have an X and Y chromosome.

14

Define Sex chromosome

Sex chromosome is a chromosome that determines the sex of an organism

15

Which chromosome is smaller than the other?

The Y chromosome is much smaller than the X chromosme.

16

Does the Y chromosome have the same amount of information on it as the X chromosome?

The Y chromosome does not have the same amount of information on it as the X chromosome.

17

Why are males responsible for sex determination of their offspring?

Males are responsible for sex determination of their offspring as males contain two different chromosomes, X and Y.

18

When meiosis occurs, females produce gametes that all contain what chromosome?

When meiosis occurs, females produce gametes that all contain the X chromosome.

19

When meiosis occurs, half of the male's gametes carry what?

When meiosis occurs, half of the males gametes contain the X chromosome and half carry the Y chromosome.

20

On fertilisation, the egg cell contributes what?

On fertilisation, the egg cell contributes an X chromosome.

21

What does the male sperm determine?

The male sperm determines the sex of the offspring.

22

If an X sperm cell fertilises the egg, what will the offspring be?

If an X sperm cell fertilises the egg, the offspring will be female (XX)

23

If a Y sperm cell fertilises the egg, what will the offsprig be?

If a Y sperm cell fertilises the egg, the offspring will be male. (XY)

24

Every time a male and female are mated, what are the chances that the offspring will be male or female?

Every time a male and female are mated, there is a 50% chance that the offspring will be female and a 50% chance that the offspring will be male.

25

In the dairy industry, why does the 50% probability of male or female have particular consequences?

In the dairy industry, the 50% probability of male or female has particular consequences as female calves are often preferred over male calves.

26

Scientists involved in cattle breeding have done what for the reason of particular consequences of 50% male or female in dairy industry?

Scientists involved in cattle breeding have determined a way of separating sperm carrying X chromosomes from sperm carrying Y chromosomes in order to produce semen samples that have been sexed.

27

In mammals, what sex determines the sex of the offspring?

In mammals, the male determines the sex of the offspring.

28

In birds, what sex determines the sex of the offsprig?

In birds, the female determines the sex of the offspring.

29

In birds, what are the 2 chromosomes called?

In birds, the 2 chromosomes are called Z and W.

30

In birds, which chromosome is larger and has more genes?

In birds, the Z chromosome is larger and has more genes than the W chromosome.