What is the sequence of DNA copying and cell divisions in meiosis?
DNA is copied once before the cell divides twice, with no further copying between divisions.
AQA GCSE Combined Science: Trilogy (8464) — Biology — Higher · 4.6.1.2
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What is the sequence of DNA copying and cell divisions in meiosis?
DNA is copied once before the cell divides twice, with no further copying between divisions.
How many gametes are formed by meiosis?
Four.
How many chromosome sets does each meiotic gamete have compared with the original cell?
Each gamete has one set; the original cell has two sets.
How are chromosomes from each homologous pair distributed to meiotic gametes?
Each gamete receives one chromosome from each homologous pair.
How do the gametes produced by meiosis compare genetically with one another?
They are genetically different from one another.
How many sets of chromosomes does a gamete nucleus contain?
One set; the nucleus is haploid.
What chromosome sets does a zygote nucleus contain after two gamete nuclei fuse?
Two sets, one from each gamete; the nucleus is diploid.
What is the significance of the change from haploid gametes to a diploid zygote?
It maintains the species’ chromosome number across generations.
What is mitosis?
Nuclear division that gives rise to genetically identical daughter cells.
What happens to chromosomes before mitosis?
They are replicated exactly.
How does mitosis distribute replicated chromosomes between daughter cells?
Chromosome copies separate, so each daughter cell receives the same genetic information and chromosome number is maintained.
What four processes does mitosis enable?
Growth, repair of damaged tissues, replacement of cells, and asexual reproduction.