Sexual Reproduction And Meiosis Flashcards
What are somatic cells?
Diploid cells
Multicellular organisms produced by rounds of mitosis from a single cell
What are sex chromosomes ?
Pair of chromosomes that participate in sex determination at birth
What are gametes?
Redproductive cells of the organisms involved in sexual reproduction
Haploid cells
What are the stages of sexual reproduction?
1) spermatozoa and egg are produced by meiosis from diploid germ-line cells (2n)
2) fertilisation of gametes regeneration of the diploid structure of the somatic cells
3) the zygote develops into a new individual
What does meiosis do?
Produces 4 non-identical daughter cells
What are the phases in meiosis 1?
Prophase 1
Metaphase 1
Anaphase 1
Telophase 1
Cytokinesis 1
What are the phases in meiosis 2?
Prophase 2
Metaphase 2
Anaphase 2
Telophase 2
What happens during prophase 1?
Duplicated chromosomes homologous condense and brought together during a process called pairing
Cross over
What happens during metaphase 1?
The spindle microtubules from both poles capture each tetrad and move them towards the centre of the mitotic plate
What happens during anaphase 1?
Homologous chromosomes are separated from each other
What happens during telophase 1?
Two nuclear envelopes are formed around one set of duplicated chromosomes
What happens during cytokinesis 1?
Daughter cells that have one set of chromosomes are separated but duplicated
What happens during prophase 2?
A new spindle forms around the chromosomes
What happens during metaphase 2?
Chromosomes line up at the equator
What happen during anaphase 2?
Centrosomes divide
Chromatids move to the opposite poles of the cells
