1.6 Cell Division

True of False?

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

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)