Cell division - Meiosis Flashcards
What does sexual reproduction involve?
Meiosis
In sexual reproduction, what are the offspring genetically different from and what does this result in?
Their parents and each other, producing variation in a population
What does each parent produce and what does it contain?
Sex cells (gametes) containing just one set of genetic material
What does each parent producing gametes involve and what are the gametes described as?
A special kind of cell division called meiosis and the gametes are described as being haploid
What happens during fertilisation to the nuclei of the gametes?
The nuclei of the gametes join together to form a zygote
What does the zygote has 2 complete sets of and is said to be what?
The zygote has 2 sets of genetic material and is said to be a diploid
How does the zygote grow and to form what?
By simple cell division (mitosis) to form the embryo
In meiosis what does the DNA do?
It copies itself and then the cell divides twice
What are the only cells in the human body that divide by meiosis?
What do these cells divide to produce?
Special cells in the testes and ovaries
Gametes (sperm and eggs)
The DNA replicates so what happens to each of the 46 chromosomes?
Each of the 46 chromosomes become 2 chromatids joined by a centromere
What do the 46 chromosomes sort themselves into and then what happens?
They sort themselves out into 23 homologous pairs and then the pairs separate, with one of each pair going to 1 side of the cell and 1 going to the other side
What does the cytoplasm do?
What does each of the new cells contain?
It divides
23 chromosomes(consisting of 2 chromatids joined by a centromere)
What happens to the chromatids in both of the new cells and what does the cytoplasm do?
They separate and the cytoplasm divides to form 2 cells
What happens at the end of meiosis?
4 haploid cells have been produced from every original diploid cell
