Cell division Flashcards
Why do cells divide?
- Reproduction
- Growth of an organism
- Repair or replace lost cells
What does a genome contain?
Chromosomes
Chromatin (DNA moleucle + proteins)
Euchromatin (actively expressed part of the chromosome)
A cell’s genetic information is called its ____?
Genome
How many somatic cells do humans have?
46
Mitosis
Separates the sister chromatids into 2 chromosomes and distributes one to each daughter cell
Cytokinesis
Separates the cytoplasm
Mitotic spindle is in?
The cytoplasm
What is the longest part of the cell cycle?
Interphase (90%)
The cell cycle consists of which 2 phases?
M phase:
- Mitosis
-Cytokinesis
Interphase:
-G1
-S
-G2
What do we start with and end with?
Start: One cell with one nucleus and two copies of each chromosome
End: Two nuclei, each with one copy of each chromosome
Chromosomes are in?
The nucleus
Centrosomes are in?
The cytoplasm
What is in the way?
The nuclear envelope
Before mitosis:
Centrosomes are ________
Chromosomes are ______ but not_____
Nuclear envelope separates ______ from ________
In the cytoplasm
Already duplicated/condensed
The cytosol/the nucleus
5 stages of mitosis?
- Prophase
- Prometaphase
- Metaphase
- Anaphase
- Telophase
Prometaphase:
The centrosomes are now _________
The nuclear envelope _________
The mitotic spindle microtubules attach to the condensed sister chromatids at the _______
At opposite ends of the cells
Fragments
Kinetochore
Telophase and cytokinesis:
The chromosomes start to _______
Nuclear envelope _______
Nucleolus________
Formation of ________ to split the cells in 2
Become less condensed
Reforms around each new nucleus
Re-condenses
Cleavage furrow/cell plate
Prophase:
Centrosomes migrate to ______
Mitotic spindle ______
Chromosomes _______
Nucleoli________
Opposite sides of the cell
Starts to assemble
Condense
Disappears
Metaphase:
Sister chromatids align at _______
Each sister chromatid is attached to a _____ and the other end of the microtubule is attached to a _______
The metaphase plate
Microtubule
Centrosome
Anaphase:
The microtubules shorten moving the daughter chromosomes to ________
The poles of the cell
Binary fission in prokaryotes is a ______, is carried out on a single _______, and begins replicating DNA from _________.
Form of asexual reproduction
Chromosome
The origin of replication (in the circular DNA)
Cell plate forms in ____ using _____?
Plant cells
Cellulose
A cleavage furrow forms in _____ using ____?
Animal cells
Actin microfilaments and myosin
What are the three main checkpoints?
G1, G2, M
Fusing a ______ with a cell in _____ or ______ suggests that molecules in the cytoplasm during those phases control the progression into those phases
G1 cell
S or M
The G1 checkpoint occurs before ______
S phase
The cell cycle is regulated by _____?
Checkpoints
Does having less nuclei express lots of genes fast?
No. Having more does.
The control system is regulated by _______ and _________.
Cyclins
Cyclin-dependent kinases
After the ________ checkpoint, the cell proceeds into mitosis through a specific cyclin and cdk forming the _______.
G2
Maturation promotion factor
What does the G1 checkpoint “ask”?
If the cell is large enough
Has enough nutrience
Undamaged DNA
What does the G2 checkpoint “ask”?
If DNA was successfully replicated
If DNA is undamaged
M phase occurs during _______
Metaphase
What does M phase “ask”?
Are the chromosomes aligned at the metaphase plate?
Are kinetechores attached the spindle fibres?
Ensures the daughter cells are not missing chromosomes or have extra chromosomes
What is cancer?
A collection of diseases caused by a group of cells that divide uncontrolled
Cancer cells make their own ______ to promote dividing
Growth factors
