Cell Cycle

Why must Multi-cellular organisms regulate mitotic cell division?

To function like producing new blood cells

Does your body instruct its adult stem cells to divide when it needs a new supply of cells?

Yes to divide and indicate a need for new cells to maintain or repair

Why does your body frequently require a supply of new cells?

Growth, repair, replacement

What is the cell cycle?

The life cycle of the cell in specific biochemical events in each cell phase

What are its phases?

G1, G1/S checkpoint, S,G2, G2/M checkpoint, Spindle checkpoint, Mitosis

What is interphase

Cell prepares to reproduce (G1, S, G2)

What are the three parts of interphase?

G1- growing

S - Synthesis of DNA and Proteins (Replication of mom and dad chromosomes)

G2 - still growing about to divide (double in size)

What is M phase?

Cells divide

what is G0

The “resting phase” when the cell is dorment before needing to be replicated.

Can some cells in the G0 phase re-enter the cell cycle when the body requires new cells?

Yes, G0 is a dorment stage when cells rest when the body needs new cells

During which cell cycle phase does the adult stem cell make commitment to divide?

G1 because it is growing

During which cell cycle phase does the adult stem cell Replicate DNA?

S phase - DNA Polymerase replicates all 46 DNA molecules in the nucleus for each daughter cell to inherit 46 DNA molecules

Which cell cycle phase does the adult stem cell synthesize Nucleotides?

G1 - synthesizes Deoxyribonucleotides & Histone proteins that enable DNA sythesis in the next phase (S)

Which cell cycle phase does the adult stem cells duplicate its organelles?

G1 and G2 both are growth G1 makes molecular building blocks and G2 furthers growth and manufacture proteins and organelles for mitosis

Which cell cycle phase does the adult stem cell make its final preparations before dividing?

G2 - cells focus on growth of nesscary proteins and organelles before division

Which cell cycle phase does the adult stem cell finishing doubling in size

G2 - prepares for division

Which cell cyle phase does the adult stem cells divide by mitotic cell divison?

M phase -

What is the purpose of Mitosis?

Ensures the cell has two nuclei with 46 DNA molecules

What is the purpose of Cytokinesis?

separates the cell to form two daughter cells

What is the funcation of cell cycle checkpoint?

Search for detect and repair biochemical errors (quality control)

Do some mutations inactivate cp?

Yes, loss of funcation mutations

Do cancer cells ignore one or more checkpoints?

No, cell can not be repaired and self destructs

Can cancer result from one or more defective cp?

Yes, when cp fail the cells divide with DNA damage or chromosomal abnormalities.

Which biochemical errors activate the G2/M Phase CP?

incomplete replication

What biochemical errors activate M phase CP?

improperly attached spindles to chromosomes

A CP is activated due to a biochemical error

A pause in the cell cycle

Will the adult stem cell enter the next phase after repair?

Yes CDK enables the cells to advance

CDK

Regulatory molecules that control cell cycle progression

Will the cell self destruct by apoptosis if the error can’t be repaired?

yes, and then starts the cycle again

What is apoptosis?

programmed cell death

Can mutations prevent apoptosis in cancer cells?

Yes the mutation can disrupt pathways by inactivating tumor supressors

What are cyclin?

regulatory proteins that control cell divison by binding to CDKs

What are CDKs?

enzymes that are dependent on cycles to control the cell cycle through phosphorylation

What activates CDKs?

Cyclins binding to CDKs

What is the funcation of proteasomes?

Marks proteins for distruction to regulate the cell processes

What are some applications of Go-singals?

triggers cells to exist resting phase and reenter the active cell cycle

Adult stem cells in the G1 phase must recognize a go signal to pass—

G1 CP

The spindle Microtubles did not attach to some of the chromomes. Which cell cycle checkpoint will be activated?

M phase

Which dynamic structure coordinates the movement of chromosomes during mitosis?

Spindle

The G2/M cell cycle checkpoint is activated by?

Mutation in DNA

The G2/M phase checkpoint verififies the absence of DNA mutations. The Adult stem cell will respond by?

Advancing to the next cell cycle phase (M)

If an adult stem cell in the G1 phase does not recognize the required go signal the adult stem cell will—

Exit the cell cycle & enter the G0 phase (Resting phase)

Which regulatory molecules are required to induce mitotic cell division in these adult stem cells?

Go-signal

Cancer can result from the inactivation of one or more

Cell cycle checkpoints

An activated cell cycle checkpoint cannot coordinate the repair of a critical biochemical errors. This defective adult stem cell will—

Self destruct by apoptosis

An activated checkpoint repaired a critical biochemical errors. After repair, the activated checkpoint released a signal that instructed this adult stem cell to—

Advance to next phase of cell cycle

The accuracy & Reliability of the cell cycle control system are essential to ensure

The cell cycle control system regulates the cell cycle & the mitotic division of adult stem cells. This quality control system consists of—

During M phase, the adult stem cell physically separate into two identical daughter cells during

Cytokinesis

Each event Occurs during the G2 phase exept for

Making the commitment to reproduce (Divide)