Topic 3 Genetics

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What is Meiosis?
A form of cell division in which one parent cell produces four haploid daughter cells.
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Explain the role of meiotic cell division?
Meiosis creates gametes.Has two sets of chromosomes and is diploid.Each chromosome replicates.The two copies remain attatched-make x shape. Cell divides into two and two again.Each of 4 daughter cells has copy of 1 chromosome from each pair- Haploid
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What is DNA?
DNA is a polymer made up of two strands joined up by pairs of substances called bases to form a double helix. 4 base pairs-Adenine,Thymine,Cytosine and Guanine. A and T , C and G. Matching bases are complementary base pairs joined-weak hydrogen bonds
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What is a genome?
A genome is the entire DNA of an organism and a gene as a section of DNA molecule that codes for a specific protein.
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Explain why there are differences in the inherited characteristics as a result of alleles
Genes for the same characteristics can contain slightly different instructions that create variations. Different forms of the same gene are called alleles. Different combinations of alleles in each person gives us slightly different characteristics.
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What is a Chromosome?
Structure found in nuclei of cells. Each chromosome contains one enormously long DNA molecule packed with protein
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What is a Gene?
A unit of heredity which is transferred from a parent to offspring and is held to determine some characteristic of the offspring.
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What is an Allele?
Genes that come in different versions.
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What is Dominant?
An allele that will always affect a phenotype (characteristics produced by a certain set of alleles) as opposed to a recessive allele , whose effect will not be seen if a dominant allele is present.
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What is Recessive?
An allele that will only affect the phenotype if the other allele is also recessive. It has no affect if the other allele is dominant.
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What is Homozygous?
When both the alleles for a gene are the same in a orgainsm
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What is Heterozygous?
When both alleles are different in a organism
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What is a Genotype?
The alleles for a certain characteristics that are found in an organism
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What is a Phenotype?
The characteristics produced by a certain set of alleles
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What is a Gamete?
A Gamete is a haploid cell produced by meiosis used for asexual reproduction
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What is a Zygote?
A fertilised egg cell
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Explain Mono-hybrid inheritance
The study of how the alleles of just one gene are passed from parents to offspring
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Punnet Square (How offspring is determined at Fertilisation)
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Describe the causes of variation that influence phenotype
Genetic Variation-different characteristics as a result of mutation and asexual reproduction. Environmental Variation-different characteristics caused by an organisms environment.
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Outcomes of Human Genome project
Shown there is variation between people but over 99% of DNA bases in different people-same. Medicine-mapping a persons genome can indicate their risk of developing diseases that are caused by different alleles of genes. Can identify which medicine w
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Outcomes of Human Genome project and medicine
Medicine-mapping a persons genome can indicate their risk of developing diseases - caused by different alleles of genes. Can identify which medicine works best to treat persons illness because the alleles can affect how medicine works in the body
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There is usually extensive gentic variation within a population of a species and that they arise through mutations
That most genetic mutations have no effect on the phenotype for some mutations , some mutations have small effect on phenotype and rarely, a single mutation will significantly affect the phenotype.
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Card 2

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Explain the role of meiotic cell division?

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Meiosis creates gametes.Has two sets of chromosomes and is diploid.Each chromosome replicates.The two copies remain attatched-make x shape. Cell divides into two and two again.Each of 4 daughter cells has copy of 1 chromosome from each pair- Haploid

Card 3

Front

What is DNA?

Back

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Card 4

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What is a genome?

Back

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Card 5

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Explain why there are differences in the inherited characteristics as a result of alleles

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