4154268
Description
Flashcards by gfhgfhg gfhgfhg, updated more than 1 year ago
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Created by gfhgfhg gfhgfhg
almost 9 years ago
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| Question | Answer |
| what are the male and female gametes called and where are the produced ? | male = sperm ( testes) female = egg (ovaries) |
| how are identical twins formed ? | a fertilised egg spits in 2 |
| how are non - identical twins formed? | 2 separate eggs are fertilised by 2 separate sperm |
| Give 2 examples of genetic variation | attached or unattached earlobes eye colour |
| give an examples of environmental variation | scars |
| What is the hereditary material and where is it found ? | DNA , found in the nucleus of the cell |
| What are chromosomes ? | a chromosomes is a bundle of DNA |
| How many chromosomes are found in a human body cell | 46 or 23 pairs |
| What is a gene? | a gene is a section of DNA that codes for a particular characteristic |
| How are chromosomes arranged ? | they are arranged in homologous pairs |
| What is an allele ? | An allele is an alternate version of a gene, eg you inherit 2 alleles for eye colour one from each parent |
| Which allele is always expressed and which do you need 2 copies of to be expressed ? | the dominant allele is always expressed but you need 2 copies of the recessive allele for it to be expressed |
| What sex chromosomes are carried by the male and female | males carry Xy chromosomes females carry XX chromosomes |
| who determines the sex of the baby | the male |
| Are most genetic disorders found on recessive alleles or dominant ones | recessive |
| If B is the allele for Brown eyes and b is the allele for blue eyes , which combination of alleles would be needed for a person to have blue eyes | bb |
| what is a persons genotype? | the genes they carry |
| what is a persons phenotype? | the characteristics that a person shows |
| what is cystic fibrosis and is it recessive or dominant? | recessive - caused by a defective gene that means the person produces too much mucus that can lead to chest infections |
| What is Huntingtons and is it dominant or recessive ? | it is a dominant condition that causes nerve damage |
| what is sickel cell anaemia and is it dominant or recessive? | it is a recessive condition that causes red blood cells to be the wrong shape -they then block capillaries stopping oxygen getting to cells |
| Draw a genetic diagram to the genetic make up of the offpring of a male parent with the genotype Cc and female with genotype Cc | |
| Draw a genetic diagram to show that the percentage chance of 2 parents producing male or female offspring is 50% |
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