2. Evolution Pt3

Question 1

What are chromosomes Made of?

Answer 1

DNA, contains all the genetic material.

Question 2

Where are chromosomes found?

Answer 2

Nucleus

Question 3

How many copies of one chromosomes do we have in a cell?

Answer 3

2 copies of every chromosomes, one pair, 2 copies of every genetic instruction

Question 4

Where do our pair of chromosomes come from?

Answer 4

1 from the mother

1 from the dad

Question 5

How many copies of a chromosomes do humans have in a cell?

Answer 5

46 copies, 23 pairs

Question 6

What do you call a complete set of chromosomes (all 46)?

Answer 6

Karayotype

Question 7

What must new cells contain that was the same as the old ones?

Answer 7

The same genetic information

Question 8

What are genetically identical organisms called?

Answer 8

Clones

Question 9

What happens in sexual reproduction?

Answer 9

The genetic material of 2 organisms is combined to create an offspring

Question 10

What are specialised sex cells called?

Answer 10

Gametes

Question 11

Where do you find the gametes in an animal?

Answer 11

The eggs and sperm

Question 12

Where do you find the gametes in a plant?

Answer 12

The pollen and egg

Question 13

Where are the gametes produced and what type of cell division do they carry out?

Answer 13

Gametes are produced in the testes and ovaries, they carry out meiosis

Question 14

Define meiosis

Answer 14

Meiosis:produces 4 cells each with half the normal number of chromosomes, because only 1 chromosome from the pair remains

Question 15

How many chromosomes do sperm or eggs have?

Answer 15

23

Question 16

What happens when an egg and a sperm fuse together?

Answer 16

It’s called fertilisation the sperm has 23 chromosomes add the 23 from the eggs equals 46

Question 17

Why is meiosis important?

Answer 17

It creates genetic variation, each sperm and egg has a different combination of chromosomes. Offsprings have different characteristics increasing the survival chances of the species

Question 18

Does meiosis always create a genetically unique embryo?

Answer 18

No, the embryo can split and crest identical twins/triplet

Question 19

Explain the process of meiosis

Answer 19

-the chromosomes double (DNA replication)
-the pair of chromosomes join up then spread, one going into one new cell and the other moving into the other cell
-then the chromosome splits forming 4 cells with 1 chromosome from each original pair
Meiosis is a cell division which produces 4 genetically unique daughter cells

Question 20

How many chromosomes does meiosis produce?

Answer 20

Half the usual amount of chromosomes

Question 21

Cells are genetically ……….. In meiosis

Answer 21

Different

Question 22

How many cells are produced per cell division in meiosis?

Answer 22

4

Question 23

What is the point of meiosis?

Answer 23

Used to produce gametes only

Question 24

What cells perform meiosis?

Answer 24

The reproductive organs (testes and ovaries)

Question 25

4 advantages of asexual reproduction

Answer 25

• more time & energy efficient
• only requires 1 parent
• many identical offsprings can be produced when conditions are favourable
• faster then sexual reproduction

Question 26

2 disadvantages of asexual reproduction

Answer 26

• No genetic variation

- no evolution by natural selection, so if conditions change the whole species could go extinct

Question 27

2 advantages of sexual reproduction

Answer 27

• produces genetic variation in offspring
• if the environment changes variation gives a survival advantage by natural selection
• natural selection can be speeded up by humans in selective breeding to increase food production

Question 28

1 disadvantage of sexual reproduction

Answer 28

-requires 2 organisms to combine genetic material