Biology paper 2

• What is sexual reproduction

  Sexual reproduction involves the fusion of both female and male gametes these gametes are produced by maiosis. Each gametes contain 23 chromosmose however when they go through fertilization they produce one normal cell with 46 chromosomes.
• explain why the offspring will not be identical ?

  the offspring will receives a mixture of genes so the this leads to variation in the offspring
• What is asexual reproduction

  asexual reproduction doesnt involves the fusion of gametes and so therefore no gametes are required. There’s No variation in the offspring and they are identical they are also called clones.
• how many pairs of chromsomes does human body cell have ?

  23 pairs of chromsome.
• how many pairs of chromosomes determine characteristics ?

  22 Paris
• what does the 23rd pair of chromosome determine?


  if the offspring will be male or female
• what chromosomes do males have

  x and y
• what chromosomes do females have ?

  X and X
• What is genetic diagram ?


  A diagram that shows the chance of having a boy or a girl
• what do you call an organism that have the same type of allele?

  homozygous
• What do you call an organism that has different type of allele

  Heterozygous
• what are the two types of allele ?

  dominant and recessive
• Capital letters are used to show what type of allele

  Dominant allele
• small letters are used to show what type of allele ?

  recessive
• What is genotype 


  The mix alleles
• What allele causes cystic fibrosis ?

  Recessive allele
• Explain cystic fibrosis

  is an inherited disorder of cell membrane both parents must be carriers or carry the disorder for the child to have it.
• Which allele causes polydactyly

  Dominant allele
• explain polydactyly

  It is caused by dominant allele which means only one parent needs to carry that allele that leads to this disorder for the child to have it.
• What do family trees also show ?

  Family trees shows inheritance alleles
• Embryo screening 


  They can be inherited for disorder.
• Explain embryo screening

  During the IVF fertilization scientist get too look at the embryo before putting it in the mother’s womb. Scientist will be able to remove cell from each embryo and looks at it genes, many inherited disorders can be picked up this way. dna can also be taking from the womb to test for the inherited disorder.
• What are the disadvantage of embryo screening 


  It Suggest that people with genetic disorders are not wanted. This could lead them to being treated unfairly

  screening is expensive
• what are the disadvantage for embryo screening 


  it will help to stop people suffering

  treating disorders costs a lot of money
• Bacteria resistant

  A mutation leads to a bacteria becoming resistant, to antibiotic this means that the the antibiotic will not be able to kill the bacteria.
• when bacteira become resistant to antibiotics, they are called antibiotic-resistant bacteria.
• A bacteria becoming resistant this is an advantage beca use it means that the bacteria will not be killed and it will be able to produce.
• antibiotic-resistant bacteria are dangerous becuare there are no effected treatment

  and our body is not immune to it
• The reason why antibiotic-resistart bacteria develops is becuase the overuse of antibiotic.