Cell Division Cycle

These flashcards cover the key concepts related to the cell division cycle, including phases, regulatory mechanisms, and processes specific to mitosis and cytokinesis.

What is the cell cycle?

A universal process of cellular reproduction involving a series of ordered events: duplication of cellular contents and division into two new 'daughter' cells.

What happens during the G1 phase of the cell cycle?

G1, or 'Growth 1', involves growth, synthesis of proteins and macromolecules, formation of organelles, and evaluation of progress towards 'maturity'.

What is the purpose of the G0 phase?

The G0 phase, or '0 growth', is an optional resting phase for cells.

What occurs during the S phase of the cell cycle?

The S phase is when the synthesis of new DNA occurs.

What are the key events that take place during the M phase?

The M phase involves mitosis, which is the segregation of replicated DNA, and cytokinesis, which is the division of the cytoplasm.

What is the role of checkpoints in the cell cycle?

Checkpoints monitor the processes of the cell cycle, stopping them if something goes wrong either within the cell or in the environment.

What is the function of cell-cycle kinases?

Cell-cycle kinases phosphorylate proteins involved in regulating the various processes of the cell cycle.

What are cyclins and their role in cell cycle control?

Cyclins are regulatory proteins that activate cyclin-dependent kinases (Cdks), essential for controlling the cell cycle.

Describe the Cdk-activating kinase (CAK) function.

CAK phosphorylates ATP-bound Cdks, activating them for cell cycle processes.

How do Cdk inhibiting proteins (CKIs) affect Cdk activity?

CKIs bind to Cdks, altering their structure and inactivating them by blocking their active sites.

What happens during the entry into mitosis?

M-Cdk becomes activated, leading to the removal of inhibitory phosphates by Cdc25 and inhibition of Wee1.

What role do cohesins play during mitosis?

Cohesins hold sister chromatids together until they are separated during anaphase.

How do astral motor proteins function during anaphase?

Astral motor proteins pull the poles apart, aiding in the separation of sister chromatids.

What is cytokinesis and how does it differ in animal and plant cells?

Cytokinesis is the splitting of the cytoplasm; in animal cells, it forms a contractile ring, while in plant cells, a cell plate is formed.

What is the function of the phragmoplast in plant cell division?

The phragmoplast helps construct a new cell wall between dividing cells, using vesicles that transport wall components.