B1.7 Genetic variation and its control Flashcards

1
Q

What is variation within a species?

A

Differences in characteristics in organisms in the same species

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2
Q

What can differences in characteristics be due to?

A

The genes they have inherited (genetic causes), the conditions in which they have developed (environmental causes)

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3
Q

What does the nucleus of a cell contain?

A

Chromosomes

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4
Q

What do chromosomes carry?

A

Genes

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5
Q

What do genes control?

A

The characteristics of the body

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6
Q

What do different genes control?

A

The development of different characteristics of an organism

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7
Q

Why do plants and animals have similar characteristics to their parents?

A

Characteristics are determined by genes inherited from their parents

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8
Q

What does the combination of genes from both parent cause?

A

Genetic variation

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9
Q

What is environmental variation?

A

Any difference that has been causes by the conditions something lives in

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10
Q

What are some example of a mixture of genetic and environmental variation?

A

Body weight, height, skin colour, condition of teeth, academic or athletic prowess

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11
Q

How many chromosomes does the nucleus contain?

A

23 pairs

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12
Q

What does DNA from?

A

Chromosomes

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13
Q

What is the name of different forms of the same gene?

A

Alleles

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14
Q

What are the two types of reproduction?

A

Sexual and Asexual

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15
Q

What does sexual reproduction involve?

A

Two parents

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16
Q

How many chromosomes does a gamete contain?

A

23 (half the number of a normal cell)

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17
Q

What is sexual reproduction?

A

The joining (fusion) of male and female gametes

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18
Q

What does sexual production lead to?

A

The mixture of genetic information from two parents resulting in variety in the offspring

19
Q

How many parents are there in asexual reproduction?

20
Q

Is there any mixing of genetic information in asexual reproduction?

21
Q

What are the individuals produced by asexual reproduction?

A

Genetically identical to the parent (clones)

22
Q

What are the two ways of cloning plants?

A

Plant cuttings and tissue culture

23
Q

How can plants be produced quickly and cheaply?

A

Taking cuttings

24
Q

What do gardeners take cuttings from?

A

Good plants so that the plants produced will be genetically identical to a good plant

25
What is tissue culture?
Where a few plant cells are put into a growth medium with hormones and they grow into new plants, clones of the parent plant
26
How can tissue culture be made?
Very quickly in very little space and grown all year
27
What are embryo transplants?
The production of cloned offspring using embryo transplants
28
What are the processes of embryo transplants?
Sperm cells are taken from the desired male and egg cells from the desired female. The two are then fertilised. The embryo that develops is then split many times (to form clones) before any cells become developed. These embryos can then be implanted into lots of other cows, each developing into genetically identical organisms
29
What does adult cell cloning involve?
The taking of an unfertilised egg cell and removing of its genetic material. A complete set of chromosomes from an adult body cell is then inserted into the empty egg cell. The egg cell is then stimulated by an electric shock, this makes it divide. When the embryo is a ball of cells its implanted into a adult female to grow a genetically identical copy
30
In genetic engineering, how can genes from the chromosomes of humans and other organisms be removed?
They can be 'cut out' by enzymes
31
What is an issue with cloning?
It results in a reduced gene pool
32
What is the problem with a reduced gene pool?
If the population are closely related and a new disease appears, they could all be wiped out as none of the population will have resistance to the disease
33
What do some believe the cloning of animals will result in?
The cloning of humans
34
When do scientists use the method of using enzymes to cut out useful genes?
The insertion of the insulin gene
35
Where else can useful genes be transferred to?
Animals and plants
36
When are useful genes transferred to animals and plants?
At the very early stages of development
37
Why do GM crops have their genes modified?
To make them resistant to viruses, insects and herbicides
38
What are the name of crops which have been modified?
Genetically Modified Crops
39
What is an example of a GM crop?
Crops which are resistant to insect attack or herbicides
40
What do GM crops generally show?
Increased yields
41
What are people concerned the GM crops will effect?
The population of wildflowers and insects and human health
42
What do some people think will happen due to changes in the numbers of weeds and flowers as a result of GM crops?
Decrease in farmland biodiversity
43
Why do some think GM crops are not safe?
They are worried people will develop allergies to the food
44
What do some people think will happen as a result of potential herbicide resistance?
A new 'superweed' variety