1.6 Cell Division

True of False?

Depending in the cell, it will have a different life span?

TRUE

What are the two types of cell classification?

* Apoptosis
* Necrosis

Characteristics of Apoptosis

* The process of a programmed cell death
* Requires ATP
* Shrinks
* Active process
* Nuclear condensation

Characteristics of Necrosis

* An unprogrammmed form of cell death
* Caused by something
* Passive process
* Passive process
* Cell swells
* No ATP required

What is the Cell Cycle?

A cell cycle is a series of events that takes place in a cell as it grows and divides.

Parts of the cell cycle

* Mitosis (10%)
* Prophase
* Metaphase
* Anaphase
* Telophase
* Interphase (90%)
* G1 Phase (Cell Growth)
* S Phase (DNA Replication)
* G2 Phase (Preparation for mitosis)
* G0 Phase
* Phase where the cell is resting

What is Mitosis?

Mitosis is the process by which a cell replicates its chromosomes and then segregates them, producing two identical nuclei in preparation for cell division.

What type of cell is used in Mitosis?

DIPLOID CELL

* Contains all the generic material
* 46 chromosomes

STAGE 1 OF MITOSIS

* Prophase

* First phase of mitosis
* Chromosomes become visible as tightly coiled threadlike structures
* Mitotic spindle forms

STAGE 2 OF MITOSIS

* Metaphase

* The chromosomes line up in the middle
* The nucleus is no longer visible
* Spindle fiber hold the chromosone right in the middle (CENTROMERE)

STAGE 3 OF MITOSIS

* Anaphase

* The chromosomes separate → creating duplicated material on each side
* Chromosomes are now found in the polar of the new daughter cells
* Centrioles holds the spinde fibers

STAGE 4 OF MITOSIS

* Telophase

* A nuclear membrane forms around the new chromosomes
* Spindle fibers are gones
* Chromosomes have finished moving to the opposite sides of the cell
* Daughter nuclei forms

Cytokinesis

* “STAGE 5”

* The final split-up between the two cells
* Division between the two daughter cells
* Physically divides into two new cells

Whart are the cell cycle phases?

* G1 phase
* S phase
* G2 phase
* G0 phase

CELL CYCLE

* G1 PHASE

* Growth of the cell
* Surface area is way to big
* Makes a new set of organelles and proteins

CELL CYCLE

* S PHASE

* Replicates DNA
* Copies genetic information
* Checking genetic material that both daughter cells will have

CELL CYCLE

* G2 PHASE

* Growth → organelle reproduction
* Preparation for cell division
* Synthesis of special protein preparation

CELL CYCLE

* G0 PHASE

* Phase where the cell is completely resting
* Right after cell division
* First or last stage
* The time when the cell is neither dividing nor preparing to divide

\

EXAMPLES:

* Heart and neuron cells stay at this phase

What are Cyclins?

Speacialized proteins that are responsible for the progression of the cell cycle

* Associated with the cycle of cell division
* Certain processes of mitosis

How many checkpoints are in the cell cycle?

* 3 checkpoints in:
* G1 phase
* G2 phase
* M phase (METAPHASE)

Characteristics about checkpoints

Cyclins presented: Cyclin Dependent Kinane (enzyme)

* Together CDK and Cyclins form the checkpoints
* Is one of these fail, cancer is presented

Checkponit 1: G1 PHASE

* Check for nutrients, growth factors, DNA damage

\
Cyclin D (CDK 6)

Cyclin D (CDK 4)

Checkpoint 2: G2 PHASE

* Determine the sate of pre-mitotic cells
* Identify any replication faults

\
Cyclin A (CDK 2)

Cyclin E (CDK 2) (Presented in the phase)

Checkpoint 3: Mitosis (Metaphase)

* Ensure proper spindle assembly and correct attachment to centromeres

\
Cyclin B (CDK 1)