Biology - Genetic Variation

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  • Created by: tps-josh
  • Created on: 07-11-16 21:44
Why does sexual reproduction lead to variation?
Sexual reproduction gives rise to variation because, when gametes fuse, one of each pair of alleles comes from each parent.
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How many pairs of chromosomes are there in human body cells? What are the female sex chromosomes? What are the male sex chromosomes?
In human body cells, one of the 23 pairs of chromosomes carries the genes that determine sex. In females the sex chromosomes are the same (**). In males the sex chromosomes are different (XY).
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How many genes control the ability to roll your tongue? What is an allele?
Some characteristics are controlled by a single gene. Each gene may have different forms called alleles.
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What is a dominant allele?
An allele that controls the development of a characteristic when it is present on only one of the chromosomes is a dominant allele.
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What is a recessive allele?
An allele that controls the development of characteristics only if the dominant allele is not present is a recessive allele.
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What does DNA stand for? What is the structure of DNA called?
Chromosomes are made up of large molecules of DNA (deoxyribonucleic acid) which has a double helix structure.
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What is a gene?
A gene is a small section of DNA.
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What do genes code for?
Each gene codes for a particular combination of amino acids which make a specific protein.
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Each person (apart from _________) has unique DNA. This can be used to identify individuals in a process known as DNA __________.
Each person (apart from identical twins) has unique DNA. This can be used to identify individuals in a process known as DNA fingerprinting.
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Card 2

Front

How many pairs of chromosomes are there in human body cells? What are the female sex chromosomes? What are the male sex chromosomes?

Back

In human body cells, one of the 23 pairs of chromosomes carries the genes that determine sex. In females the sex chromosomes are the same (**). In males the sex chromosomes are different (XY).

Card 3

Front

How many genes control the ability to roll your tongue? What is an allele?

Back

Preview of the front of card 3

Card 4

Front

What is a dominant allele?

Back

Preview of the front of card 4

Card 5

Front

What is a recessive allele?

Back

Preview of the front of card 5
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