Meiosis and mitosis Flashcards
Where is DNA found?
Nucleus and mitochondria (maternal)
How is DNA arranged?
DNA coils round histones
Nucleosomes
Supercoils
Chromosomes
Define prokaryote?
No nuclear membrane
DNA arranged single chromosomes
Define Eukaryote?
DNA in nucleus- bound histones
What joins 2 chromatids?
Centromere
Explain mitosis?
Prophase- Nuclear membrane disintegrates
- Chromatin condenses into
chromosomes
- Centrosomes nucleate
microtubules- move opposite
poles and nucleus
Prometaphase- Nuclear membrane breaks
down
- Microtubules invade nuclear
space
- Chromatids attach to
microtubules
- Cell no longer had a nucleus
- Chromosomes attach to
spindle via centromere
Metaphase- Chromosomes line up
metaphase plate
Anaphase- Sister chromatids separate,
Spindle fibers contract to pull
opposite poles of cell
Telophase- Nuclear membrane reforms
- Chromosomes unfold- chromatin
- Cytokinesis begins
Cytokinesis- Cell organelles evenly distributed
around each nucleus
- Cell divides into two daughter
cells
What stage of mitosis?
Metaphase- Chromosomes line up
metaphase plate
What stage of mitosis?
Anaphase
What stage of mitosis?
Prometaphase
What stage of mitosis?
Telophase
Cytokinesis
Draw mitosis?
What stage of mitosis do chromosomes line up on equatorial plate?
Metaphase
Which phase are sister chromatids seperated?
Anaphase
Which phase does the nuclear membrane reform?
Telophase
Which stage does the cell divide?
Cytokinesis
Explain cell cycle
G1- Preparation of replication
- cellular contents excluding chromosomes
duplicated
S- DNA doubles through replication
- Histone proteins double protein synth
- 2x as much DNA
G2- Chromosomes condense- coil, visible
- Energy stores accumulate
- Mitochondria and centrioles double
G2 checkpoint- check if ok
Mitosis- (see above)
Cytokinesis
Cell division- 2 diploid cells prod
Draw mitosis
What causes genetic diversity in meiosis?
Prophase 1- Crossing over occurs between
non- sister chromatids
Metaphase 1- Random assortment on
metaphase plate
Explain meiosis?
What formed?
4 haploid daughter cells produced
What occurs in meiosis two?
Sister chromatids within the two daughter cells separate
Forming four new haploid gametes.
What is the difference between meiosis one and two?
Meiosis 1 starts one diploid parent cell and ends with two haploid daughter cells- halving number of chromosomes in each cell
Meiosis 2 starts with two haploid parent cells and ends with four haploid daughter cells
Meiosis 1- genetic diversity
Draw miosis 1 and two?
In cell cycle at one point does DNA double?
Synthesis
At what stage do chromosomes condense in cell cycle?
G2
State differences between meiosis and mitosis?
What produces genetically different gametes?
Meiosis
Mitosis- genetically identical to parent cell (t)
What process halve chromosome number?
Meiosis
Mitosis- retained
What produces diploid cells?
Mitosis
Meiosis- haploid gametes
What has two divisions?
Meiosis
