sexual reproduction

• In sexual reproduction are offspring genetically different or identical to parents?

  genetically different
• What type of cell division is used in sexual reproduction?

  meiosis
• sperm and egg cells are what type of cells?

  gametes
• In humans, how many chromosomes does a single gamete contain?

  23
• In fertilisation in sexual reproduction, the gametes fuse together to form a cell with a full number of chromosomes
• How many chromosomes in a normal cell?

  46
• In sexual reproduction, because there are two parents the offspring will contain a mixture of the parents genes
• Give some advantages of sexual reproduction

  variation produced which increases surviving environmental changes

  more likely to breed successfully
• Selective breeding can be used to speed up what?

  natural selection
• What is natural selection?

  Natural selection is the process by which certain traits become more or less common in a population over time based on their ability to survive and reproduce.
• Gametes only have one copy of each what?

  chromosome
• When gamete fusion takes place, the right amount of chromosomes is in the cell.
• To make gametes cells go through what?

  meiosis
• How many cell divisions are there in meiosis?

  2
• Meiosis only happens in what kind of organs?

  Reproductive organs.
• Describe meiosis


  chromosomes make identical copies of themselves

  similar chromosomes pair up

  sections of DNA get swapped

  first cell division - chromosome pairs separate

  second cell division
• a diploid cell is a cell that contains..

  two sets of chromosomes
• a haploid cell is a cell that contains..

  one set of chromosomes (a gamete or sex cell)
• After two gametes have fused during fertilisation, the new cell divides using what to make a copy of itself?

  mitosis
• mitosis repeats many times to produce lots of new cells in an..


  embryo
• As an embryo develops, the cells inside start to..

  differentiate