Biology (Cell Cycle) Flashcards
study
- The series of events that occurs in a cell from one division to the next.
- Cell cycle helps our body to grow and induce healing.
CELL CYCLE
The cycle is divided into:
- Interphase (G1, S, and G2)
- Mitosis (Prophase, Metaphase, Anaphase, and Telophase)
The length of the cycle is approximately
20 to 24 hours
The interphase (preparation for mitosis) may last for about
18 to 20 hours
The mitosis (cell division) may last for
2 hours
(The cell prepares for the mitosis)
INTERPHASE
- Cell increase in size and organelles duplicate.
- Production of carbohydrates, lipids, proteins, and enzymes in preparation for the next phases.
G1 PHASE (Gap 1)
G1 Checkpoint Requirements
(1) Cell has enough nutrients like
protein, carbohydrates and lipids;
(2) Cell has adequate energy reserves; and
(3) Cell also checks for DNA damage.
a surveillance mechanism that monitors the order, integrity, and fidelity of the major events of the cell cycle.
Checkpoint
TRUE or FALSE: if some requirements are missing, the process will undergo cell cycle arrest or the cell cycle will stop; afterwards, the cell will activate programmed cell death or apoptosis.
TRUE
- DNA that will be passed on the daughter cells in Mitotic phase is replicated.
- DNA replication (DNA can’t be too much or too less)
S PHASE (Synthesis of DNA)
- Cell continues to increase in size and volume
- Replenishment of energy
- Microtubule assembles to form spindle fibers.
G2 PHASE (Gap 2)
G2 Checkpoint Requirements
(1) Ensures that all DNA are completely
and correctly replicated;
(2) Repairing damages DNA; and
(3) Check if there if size and nutrients are sufficient.
(This is the cell division proper)
THE MITOSIS (MITOTIC PHASE)
- DNA condenses into chromosomes (DNA is doubled so there’s not much space in nucleus so it condenses to chromosomes)
- Centrosomes start to move to the opposite poles. - Spindle fibers emerge from the centrioles.
- Nuclear membrane and nucleolus disappear.
PROPHASE (pro-before; phase-appearance)
- Centrioles have reached the opposite poles - Spindle is fully developed.
- Each chromosome (composed of 2 sister chromatids, attached by centromere, kinetochore is where spindle fibers attach to catch chromosomes) is attached to spindle fibers.
- Chromosomes align at the center.
METAPHASE (meta-middle; phase-appearance)
M Checkpoint Requirements
Ensures that all of the chromosomes are attached to the spindle fibers by their kinetochore.
TRUE OR FALSE: If there is an unattached chromosome, there will be abnormal cells.
TRUE
- Sister chromatids are pulled toward opposite directions.
- Cells become elongated.
ANAPHASE (ana-backward; phase-appearance)
- Chromosomes have reached their opposite poles.
- Formation of “cleavage furrow” (break between two cells)
- Nuclear membrane re-forms enclosing each set of chromosomes.
- Chromosomes start to decondense.
- The spindle fibers start to disappear.
- CYTOKINESIS (Cytoplasm divides into two new daughter cells and completely parts away)
TELOPHASE (telo-end; phase-appearance)
(break between two cells)
cleavage furrow
(Cytoplasm divides into two new daughter cells and completely parts away)
Cytokinesis
The cell will undergo a “resting stage” before starting another cell cycle.
G0 PHASE
- are condensed units of DNA
- sister chromatid (some have 1 or 2)
- connected by centromere (protein)
- kinetochore
Chromosomes
- is composed of two centrioles.
- Emerge spindle fibers
- Composed of cytoskeleton
- Spindle fibers emerge from the centrosome during cell division.
Centrosome
