Chapter 8 Mitosis Flashcards
3 Reasons to make new cells
1- Repair damaged cells
2- grow new cells
3- regeneration (ex: gecko tail grows back)
what is mitosis
division of somatic cells (non sex cells)
describe Eukaryote cells
- have more DNA
- linear (not circle)
- in compact chromosomes (2+)
2 types of cell division
Mitosis and Meiosis
Mitosis
Cell division in somatic cells (non-reproductive cells)
also known as autosomes
Vast majority fall under this category
Meiosis
Cell division in sexual reproductive cells
- Also known as germ cells= “early cells”
Binary Fission
Cell division of prokaryotes 2 steps 1- Cell replicates 2- Cell divides --pair is called daughter cell --makes identical clones of each other
4 Stages of Mitosis
Prophase
Metaphase
Anaphase
Telephase
Interphase
G1- growth stage (not really growing but a resting stage)
- most cells spend most of their life in this stage
S- DNA replication
G2- replication of organelles other important things in cell
Chromatin phase
diploid
full set of chromosomes to be an actual functioning cell
- another word for somatic cells
Prophase (4-steps)
1- DNA condensed into chromo. from loose chromatin condensed to tight coiled chromosomes
(2)sets of DNA
1 for old set pull apart to create 1 for new set
2- Centrioles go to opposite end of cells
3- Spindle fibers form
4- nuclear envelope disinegrates
somatic cells
any cell except sex cells ( sperm or egg)
Metaphase
- chromosomes line up in central equator
2. spindle fibers connect to centromeres
Anaphase
- centromeres separate causing chromosomes to become chromotids
Telophase
- spindle fibers disintegrate
- 2 nuclear envelopes form around each sister chromotids
- chromosomes reform to chromatin (uncoiled)
- cleavage furrow occurs (pinching off to make to cells)
Cytokinesis
cell division actually occurs to break cell into 2 cells
karyotype
an arrangement of chromosomes
- 46 chromosomes make up 23 pairs
of that
22 pairs are autosomes and 1 pair sex chromosomes
also a genetic test to check for abnormalities
autosomes
any cell in body not sex chromosomes
sex chromosomes (germ cells) half = haploid= gametes
1 pair of chromosomes is sex cell
females= XX
males= XY
What are 3 checkpoints, when do they occur, and what do they check for? if it does not pass what happens? if it does pass what happens?
G1, G2, M
G1- occurs at end of G1(resting phase)
- checks for damaged cells in DNA (carcinogens or mutagens that cause cancer) - if is does not pass: cell will repair if possible or told to die - if it passes: it will go to S-phase to replicate
What are 3 checkpoints, when do they occur, and what do they check for? if it does not pass what happens? if it does pass what happens?
G2
G2- occurs at end of G2
- checks for proper replication - if it does not pass it will repair - if it passes it will trigger mitosis in M-phase
What are 3 checkpoints, when do they occur, and what do they check for? if it does not pass what happens? if it does pass what happens?
M
M- checkpoint happens after mitosis in M-phase
- tells the cell to split to make 2 daughter cells - cell dies if it doesn't pass - cell will go to C- phase (cytokinesis) if passes