B5 genes
- Created by: sofia84
- Created on: 09-10-18 18:24
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- B5- genes
- genes and chromosomes
- Chromosomes are made of DNA and are found inside the nucleus
- Each chromosome contains a number of genes
- A gene is a section of DNA that codes for a protein
- A genome is an organism's complete set of genes
- Genotype and Phenotype
- Genes are responsible for our characteristics
- we have two copies of every chromosome in our cells, therefore we have two copies of each gene
- Th different forms of each gene are called alleles
- We use capital or lowercase to show if the alleles are dominant or recessive
- eg, if there are two dominant alleles for brown eyes this would be shown as BB
- If two recessive alles are present for blue eyes this would be bb
- If one of each allele is present eg Bb then the dominant characteristic is seen so the eyes are brown
- If two recessive alles are present for blue eyes this would be bb
- The phenotype is the characteristic seen
- The genotype is the genes that are present
- A heterozygous person has two different alleles eg Bb
- A homozygous person has both alleles the same eg bb
- Inherited variation is cause by the genes inherited from the parents
- Environmental variation is caused by environmental factors
- skin colour
- even if someone has tall genes they may still be short due to mall nourishment
- weight
- intelligence
- eyecolour
- blood group
- inherited diseases
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- Environmental variation is caused by environmental factors
- genes and chromosomes
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