Reproduction Flashcards

1
Q

Define sexual reproduction

A

Is where a genetic information from two organisms (Mother&Father) is combined to produce offspring which are genetically different to either parent.

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2
Q

What do the mother and father produce in sexual reproduction?

A

Gametes by meiosis - Egg and sperm cells in animals

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3
Q

How many chromosomes in each gametes in humans contain?

A

23 chromosomes - half the no. of chromosomes in a normal cell

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4
Q

What do the egg and sperm cell do?

A

Fuse together by fertilisation to form a cell with the full number of chromosomes

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5
Q

What do offspring inherits from both parents?

A

Features - receives a mixture of chromosomes from its mum and dad

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6
Q

What does the mixture of genetic information produce?

A

Variation in the offspring

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7
Q

Give an example of an organism that can reproduce

A

Flowering plants

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8
Q

Explain how flowering plants can reproduce

A

They have egg cells, but their version of sperm is known as pollen

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9
Q

What is required in asexual reproduction?

A

One parent cell - so the offspring are genetically identical to the parent

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10
Q

What does asexual reproduction happen by?

A

Mitosis - an ordinary cell makes a new cell by dividing in to 2

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11
Q

Define the term clone

A

The new cell has exactly the same genetic information as the parent cell

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12
Q

Give examples of organism that reproduces asexually

A

Bacteria
Some plants
Some animals

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13
Q

What do gametes have?

A

One copy of each chromosomes

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14
Q

Why do gametes only have one copy of each chromosome?

A

When gamete fusion takes place you get the right amount of chromosomes again - two copies of each

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15
Q

How do you make gametes which only have half the original number of chromosomes?

A

Cells divide by meiosis

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16
Q

What does meiosis involve?

A

Two cell divisions

17
Q

Where does this occur in humans?

A

Only happens in the reproductive organs

18
Q

Give examples where they occur in humans

A

Ovaries - Females

Testes - Males

19
Q

Explain what happens in Meiosis

A

Duplicates DNA = two armed chromosomes
One arm of each chromosome = exact copy of other arm -Replicate
Arrange themselves into pairs

1st division - chromosome pairs line up in the centre of the cell, pairs pulled apart - new cell only has one copy of each chromosome

2nd division - chromosomes line up again in the centre of the cell. Arms of chromosomes pulled apart

= 4 gametes, single set of chromosomes
Each gamete is genetically diff. = shuffled up and at random each only gets half chromosomes

20
Q

How after two gametes have fused during fertilisation?

A

Resulting new cell divides by mitosis to make a copy of itself

21
Q

What does mitosis produce when it repeats its self many times?

A

Lots of new cells in an embryo

22
Q

What happens as the embryo develops?

A

These cells then start to differentiate into the different types of specialised cell that make up a whole organism

23
Q

What does the offspring from sexual reproduction have?

A

A mixture of two sets of chromosomes

24
Q

What does the organism inherit?

A

Genes and features from both parents, which produces variation in the offspring

25
Q

What does variation increases?

A

The chance of species surviving change in the environment

26
Q

Explain the change in the environment that could kill some individuals

A

It’s likely that variation will have led to some off the offspring being able to survive in the new environment = survival advantage

27
Q

Define natural selection

A

Individuals with characteristics that make them better adapted to the environment have a better chance of survival, they are more likely to breed successfully and pass the genes for the characteristics on.

28
Q

What cab we do with selective breeding?

A

To speed up natural selection which allows us to produce animals with desirable characteristics

29
Q

Define selective breeding

A

Is where individuals with a desirable characteristic are bred to produce offspring that have the desirable characteristic too.

30
Q

Explain how we can increase food production

A

By breeding animals that produce a lot of meat

31
Q

Give advantages of asexual reproduction

A

Needs to be one pair
Uses less energy - organisms don’t have to find a mate
Faster
Many identical offspring can be produced in favourable conditions