Exam 3 Flashcards
Mitosis
produces somatic cells - one “parent” cell divides to become TWO genetically identical daughter cells (46 chromosomes each)
Meiosis
produces gametes - one “parent” cell divides and ultimately becomes FOUR genetically different daughter cells that each have half as much DNA as the parent cell (23 chromosomes each)
Where does mitosis take place?
all over the body
Where does meiosis take place?
reproductive organs
M (mitotic) phase
chromosomes are condensed
Interphase
chromosomes are uncoiled
cells are growing and carrying out their specialized functions
What are the three phases within interphase?
G1, S, G2
What two events take place in the M phase?
Mitosis and Cytokinesis
During Mitosis
the two sister chromatids separate to form independent daughter chromosomes
one copy of each chromosome goes to each daughter cell
What are the five subphases of mitosis?
Prophase, Prometaphase, Metaphase, Anaphase, Telophase and Cytokinesis
Prophase
chromosomes condense and coil upon themselves to produce thick stands of DNA
Prometaphase
the nuclear envelope breaks down
Metaphase
the chromosomes attach to microtubules, and then lineup in the middle of the cell
Anaphase
sister chromatids separate into daughter chromosomes (chromatids are split into two chromosomes and are then pulled to their respective sides of the cell)
Telophase and Cytokinesis
Nuclear envelope reforms after the chromosomes get on their respective sides and the chromosomes decondense. The cell will then undergo a cleavage (cytokinesis) creating two separate cells
A cell containing 92 chromatids at metaphase, would after mitosis, produce two nuclei containing how many chromosomes each?
46
What is MPF?
mitosis promoting factor that is composed of two subunits
- cyclin
- cyclin-dependent kinase (CDK)
Cyclin
a protein that is present in different concentrations throughout the cell cycle
CDK
a protein kinase enzyme that catalyzes the transfer of a phosphate group from ATP to a target protein
What are the G1 checkpoints?
- cell size is adequate
- nutrients are sufficient
- social signals are present
- DNA is undamaged
What are the M-phase checkpoints?
- chromosomes have attached to the spindle apparatus
- chromosomes have properly segregated and MPF is absent
What are the G2 checkpoints?
- chromosomes replicated successfully
- DNA is undamaged
- activated MPF is present
How many parts of meiosis are there?
Two
What are the subparts of Meiosis 1?
Interphase, PRophase 1, Metaphase 1, Anaphase 1, Telophase 1 & Cytokinesis
