Cell Division and Sex Determination Flashcards
What happens during interphase?
cell grows
chromosomes in nucleus replicated
cell respires to provide energy for mitosis
What happens during mitosis?
nucleus breaks down
DNA from the nucleus is split into 2 new identical nuclei
What happens in Cytokinesis?
cell splits into 2 new daughter cells
What is the role of mitosis?
allows organisms to grow in size - increasing no. of cells
allows dead or worn out tissues to be repaired/replaced
allows some species to reproduce by asexual reproduction
How does cancer form?
As a result of changes in a cell (eg:mutation) that leads to uncontrollable cell growth and division
How many daughter cells are produced in a diploid(full 2 sets of chromosomes) species?
four daughter cells each with a single set of chromosomes called haploid cells
Why is it important that chromosome no. found in each gamete is reduced to half normally found in an organism’s body.
prevents chromosome number doubling when fertilisation takes place
Why is genetic variation important in offsprings?
essential for natural selection - helps adapt to environment
and successful continuation of species over time
Compare chromosomes X and Y?
Y is much smaller and contains fewer genes
Y contains genes to initiate male sexual development - the last chromosome determines the gender
What is the probability and ration of a child being male or female?
50%
1:1
what is the end product of mitosis?
2 identical daughter cells clone to parent cell
23 pairs of chromosomes one from each parent
stages of meiosis?
fertilisation - male and female fuse to from zygote with a diploid number
2 rounds of cell division to reduce to haploid number
stages of meiosis?
fertilisation - male and female fuse to from zygote with a diploid number
2 rounds of cell division to reduce to haploid number
