OCR 21st Century B1 You and Your Genes Flashcards

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  • Created on: 17-03-16 18:53
where are the instructions to control how an organism develops and functions found in cells and what are they called?
Genes are found in the nucleus
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What is the genes definition?
genes are instructions for a cell that describe how to make proteins
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What are the two types of proteins and an example for each?
proteins may be structural (e.g. collagen) or functional (e.g. enzymes such as amylase)
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Put in order of size DNA, nucleus, chromosomes and genes
Genes, DNA, chromosomes and nucleus
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What are our characteristics determined by and state an example for each
Some characteristics are determined by genes (e.g. dimples), some are determined by environmental factors (e.g. scars), and some are determined by a combination of genes and the environment (e.g. weight)
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Many characteristics are determined by how many genes working together?
Many characteristics are determined by several genes working together (e.g. eye colour).
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What is the difference between sex and body cells
Body cells contain pairs of chromosomes and that sex cells contain only one chromosome from each pair
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Chromosomes in a ______ carry the same _______ in the _______ place
Chromosomes in a pair carry the same genes in the same place
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What is the definition of alleles?
Different versions of genes called alleles
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How many alleles does an individual have for each gene?
An individual usually has two alleles for each gene
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What are the definitions for homozygous and heterozygous?
The two alleles of each gene can be the same (homozygous) or different (heterozygous)
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How does variation arise from sexual reproduction?
During sexual reproduction, genes from both parents come together and produce variation in the offspring
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Why do offspring have some similarities to their parents?
Offspring have some similarities to their parents because of the combination of maternal and paternal alleles in the fertilised egg
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Why do different offspring from the same parents differ from each other?
Different offspring from the same parents can differ from each other because they inherit a different combination of maternal and paternal alleles
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What are the definitions of dominant and recessive?
Dominant allele always show an effect in the organism whereas recessive is when an allele only shows an effect if both alleles of the pair are the same
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What sex chromosomes do males and females have?
Human males have XY sex chromosomes and females have XX sex chromosomes
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How do testes and ovaries develop?
The sex-determining gene on the Y chromosome triggers the development of testes, and that in the absence of a Y chromosome ovaries develop
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What is the probability of human offspring being male or female?
Male 50% Female 50%
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What are the definitions for the terms phenotype and genotype?
The term genotype describes the genetic make-up of an organism (the combination of alleles), and the term phenotype describes the observable characteristics that the organism has.
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Other cards in this set

Card 2

Front

What is the genes definition?

Back

genes are instructions for a cell that describe how to make proteins

Card 3

Front

What are the two types of proteins and an example for each?

Back

Preview of the front of card 3

Card 4

Front

Put in order of size DNA, nucleus, chromosomes and genes

Back

Preview of the front of card 4

Card 5

Front

What are our characteristics determined by and state an example for each

Back

Preview of the front of card 5
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