meiosis

• what are gametes

  sex cells
• what are gametes needed for

  reproduction
• what do gametes include

  sperm and egg cells
• what do sperm and egg cells include

  they include genetic material
• why are sperm and egg cells haploid cells

  they only have half of the genetic material
• what are haploid cells

  cells that only contain half the genetic material; e.g. sperm cells and egg cells
• why do sperm and egg cells only have half the genetic material

  when they fuse together to create a zygote, that cell has half of the mother's genes and half of the father's genes - making up the child's genes
• what do gametes combine to form

  a normal cell
• what do you call it when gametes combine to form a normal cell

  a diploid cell
• how much genetic material does a normal cell have

  two sets; one from each parent
• how many chromosomes do human cells have

  human cells have 23 different types of chromosomes
• how many different copies are there of each chromosome

  one from the mother, one from the father
• how many different chromosomes are in each human cell in total

  46 total chromosomes
• how are the chromosomes assorted

  in pairs: one from each parent
• what is the first step in meiosis

  replicate all the cells in DNA - forms chromosomes with an X shape
• what does an the X-shaped chromosomes consist of

  the original chromosome and the copy
• what is the second step in meiosis

  when the chromosomes line up at the centre of the cell in pairs
• what is the third step in meiosis

  chromosome pairs are pulled apart: first division
• what is the result from the first division

  two new cells that are genetically unique
• what is the fourth step in meiosis

  chromosomes are aligned again but the arms (half of the Xs) are pulled apart
• what is the result of the fourth step

  cell divides again, resulting in four genetically unique cells: second division
• what is the final result

  the gametes will develop into sperm cells and egg cells
• how does the cycle start again

  when the sperm and egg cells fuse during fertilisation, they form a diploid cell and the cycle repeats
• what is the overall meaning of meiosis

  a type of cell division that results in four daughter cells each with half the number of chromosomes of the parent cell, as the production of gametes
• why are the maternal and paternal chromosomes random

  random arrangements lead to genetic diversity