Cell Cycle and Mitosis -9

Cell Division

Cell division is the process by which a cell reproduces.

Functions of Cell Division

Cell division allows growth, repair, and reproduction.

Genome

The genome is the complete set of genetic information in a cell.

Chromosomes

Chromosomes are DNA molecules packaged with proteins.

Somatic Cells

Somatic cells are body cells with two sets of chromosomes.

Gametes

Gametes are reproductive cells with one set of chromosomes.

Human Chromosome Number

Human somatic cells have 46 chromosomes.

Chromatin

Chromatin is the DNA-protein complex in non-dividing cells.

Sister Chromatids

Duplicated chromosomes consist of two identical sister chromatids.

Centromere

The centromere is the region where sister chromatids are attached.

Kinetochore

Kinetochore proteins attach chromosomes to spindle fibers.

Telomeres

Telomeres protect chromosome ends from degradation.

Cell Cycle

The cell cycle is the life cycle of a cell from one division to the next.

Interphase

Interphase is the non-dividing phase where the cell grows and prepares to divide.

G1 Phase

G1 is the first gap phase where the cell grows and produces proteins.

S Phase

S phase is when DNA replication occurs.

G2 Phase

G2 is the second gap phase where the cell prepares for mitosis.

G0 Phase

G0 is a resting phase where cells stop dividing.

Centrosome

Centrosomes organize microtubules and spindle fibers.

Mitotic Phase

The mitotic phase includes mitosis and cytokinesis.

Mitosis

Mitosis is the division of the nucleus.

Cytokinesis

Cytokinesis is the division of the cytoplasm.

Prophase

Chromatin condenses into visible chromosomes and the spindle begins to form.

Prometaphase

The nuclear envelope breaks down and spindle fibers attach to kinetochores.

Metaphase

Chromosomes line up at the metaphase plate.

Anaphase

Sister chromatids separate and move to opposite poles.

Telophase

New nuclear envelopes form and chromosomes decondense.

Cleavage Furrow

In animal cells, cytokinesis occurs via a cleavage furrow.

Contractile Ring

Actin and myosin form a ring that pinches the cell in two.

Cell Plate

In plant cells, vesicles form a cell plate during cytokinesis.

Mitotic Spindle

The mitotic spindle is made of microtubules that move chromosomes.

Microtubules

Microtubules are cytoskeletal fibers composed of tubulin.

Motor Proteins

Motor proteins move chromosomes along microtubules.

Binary Fission

Binary fission is the method of cell division in prokaryotes.

Evolution of Mitosis

Mitosis likely evolved from binary fission.

Cell Cycle Regulation

The cell cycle is regulated by internal and external signals.

Checkpoint

A checkpoint is a control point where the cell cycle can pause.

G1 Checkpoint

The G1 checkpoint determines whether a cell commits to division.

G2 Checkpoint

The G2 checkpoint ensures DNA replication is complete.

M Phase Checkpoint

The M checkpoint ensures chromosomes are properly attached.

Cyclins

Cyclins are proteins that regulate the cell cycle.

Cyclin-Dependent Kinases

CDKs are enzymes activated by cyclins.

MPF

Maturation-promoting factor triggers entry into mitosis.

Growth Factors

Growth factors are external signals that stimulate cell division.

Density-Dependent Inhibition

Crowded cells stop dividing due to limited space.

Anchorage Dependence

Cells must be attached to a surface to divide.

Cancer Cells

Cancer cells ignore normal cell cycle controls.

Transformation

Transformation is the conversion of a normal cell to a cancer cell.

Tumor

A tumor is a mass of abnormal cells.

Malignant Tumor

Malignant tumors invade other tissues.

Metastasis

Metastasis is the spread of cancer to new locations.

Cancer Treatment

Chemotherapy and radiation target rapidly dividing cells.

HeLa Cells

HeLa cells are immortal cancer cells used in research.