Cell Division Flashcards
what is the cell cycle for when mitosis happens
The cell grows - everything in it duplicates - the cytoplasm, the organelles, chromosomes
Mitosis
Prophase
Metaphase
Anaphase
Telophase remember like PMAT
what happens in prophase
In prophase, the nuclear membrane dissolves. Chromatin coils around histones and condenses into chromosomes. Spindle fibres form at the poles and attach to the centromeres of each chromosome.
what happens in anaphase
In anaphase, the spindle fibres contract, pulling apart the sister chromatids and pull them in to the poles of the cell
what happens in metaphase
In metaphase, the spindle fibres arrange the chromosomes at the equator of the nucleus
what is cytokinesis
the movement of the cytoplasm, the final part of the cell splitting
what happens in telophase
In telophase, the nuclear membrane forms and the cell membrane starts to cleave
what happens before mitosis
Before mitosis starts, the cell grows and duplicates everything in it - all the organelles (including the cytoplasm)
Chromosomes also replicate
what does each daughter cell recieve in mitosis(genes wise)
Each daughter receives one copy each of every single chromosome
what cell in our body has not been produced by mitosis
Apart from gametes every single cell in our body has been produced by mitosis, originating from the single zygote
what happens as we get older, mitosis wise
Mitosis slows down as we get older, but even as adults, some cells in the body undergo a lot of mitosis
what are some examples of mitosis (4)
Some examples:
1. A million skin cells come off even when you touch things, so a million skin cells need to be replaced constantly - this is done via mitosis
2. As food moves through the gut, it scrapes some cells away from the lining of our intestines - these cells are replaced via mitosis
3. In our spleen, a lot of red blood cells are destroyed regularly - these are replaced via mitosis with cells in our bone marrow
4. Cells in cancer also divide by mitosis, and let the cancer grow
Meiosis is used to create haploid gametes
how many stages does meisis have
Unlike mitosis, meiosis has two stages, results in four new cells, and each of those cells are genetically DIFFERENT to each other and the parent cells
descibe the flowchart for meiosis stage 1
Meiosis:
Chromosomes pair up in homologous pairs
Members of each homologous pair separate
Nucleus/cell cleaves to form two daughter cells, each has half the original number of chromosomes (at this stage, the chromosomes are still made up of sister chromatids)
descibe the flowchart for meiosis stage 2
Meiosis Stage 2 (similar to mitosis)
Each sister chromatid separates and moves to the opposite poles of the nucleus, and two new cells are formed from each cell once more.
This results in four haploid gametes
The haploid gametes have genetic variation as they don’t have the same combinations of alleles
what are the differences between mitosis and meiosis (4)
mitosis produces genetically indentical daughter cells whereas meiosis produced genetically variated daughter cells
mitosis produces 2 daughters whereas meiosis produces 4 daugters
Mitosis produces diploid cells, meiosis produces haploid cells
In mitosis there is only one cell division but in meiosis there is two
