Biology - Cell Cycle & Mitosis

karyokinesis

Another name for mitosis. Means nucleus dividing.

somatic cells

Body cells.

interphase (events)

Cell is forming and carries on with its normal metabolic functions. Cell obtains nutrients, duplicates its chromatids.

mitosis (events)

Cell is replicating itself.

centromere

Connects the doubled chromosomes together.

cell cycle

Events that take place in eukaryotic cell between its formation and the moment it replicates itself.

G1/Growth 1 Phase

First stage of interphase - cell creates organelles and begins metabolism. Occurs after cytokinesis. The major period of cell growth.

prophase (events)

First stage of mitosis. DNA molecules are shortened and condensed by coiling to form visible chromosomes. Enzymes break down nuclear membrane and nucleolus. Spindle fibers form.

spindle fibers

Form during prophase. Later attach to and move chromosomes.

telophase (events)

Fourth stage of mitosis. Chromosome pairs (chromatids are pulled to opposite poles of cell). Nuclear envelope and nucleolus reform. Chromosomes uncoil. Spindle fibers disintegrate.

3 Parts of Interphase

G1 (growth 1), S phase (synthesis), G2 (growth 2)

chromatin

Genetic material during interphase. NOT clearly seen because it isn't tightly coiled.

chromatid

Genetic material located in the nucleus of the cell. Made of DNA (one coiled DNA double helix molecule). Have a long arm and a short arm.

chromosomes

Genetic material that CAN be seen once prophase begins because they are shortened and condensed by coiling.

3 Things That Form During Cell Cycle

Hair, skin, blood cells

Examples of Cells in G0 Phase

Heart muscle, eyes and brain cells.

cleavage furrow

How animal cells divide the cytoplasm. Cell membrane is constricted in the middle, then cytokinesis occurs.

cell plate

How plant cells divide the cytoplasm. Cell plate is formed in the center to divide the cytoplasm.

2 Main Phases of Cell Cycle

Interphase and Mitotic phase (M mitosis).

equator

Middle of the cell. Chromosomes line up here during metaphase.

2 Main Stages of Cell Division

Mitosis (division of nucleus) and cytokinesis (division of cytoplasm).

cell division

Mitotic (M) phase and cytokinesis (C phase) together - division of the parent (original) cell into 2 daughter (new) cells, each with the same (identical) genetic information as the parent cell.

Does mitosis occur in prokaryotic cells?

NO. If there is no nucleus, there is no mitosis.

daughter cells

Name given to the two identical cells that are created after mitosis and cytokinesis.

G0 Phase

Phase that cells enter when they exit the cell cycle (usually from G1 phase). Cells are alive and metabolically active, BUT DO NOT DIVIDE, DO NOT COPY DNA AND DO NOT PREPARE FOR CELL DIVISION. These cells cannot be replaced if they are damaged.

interphase (definition)

Phase that occurs between the times when a cell is dividing (absence of cell division). Longest phase of the cell cycle. Where most cells spend majority of lifetime.

mitosis

Process in which a eukaryotic cell separates its already duplicated chromosomes into 2 sets of chromosomes so there will be 2 identical nuclei. Occurs after the G2 phase. NUCLEUS AND NUCLEAR MATERIAL DIVIDE DURING THIS PHASE. Cytokinesis (cytoplasm division) follows.

binary fission

Process used by bacteria to divide and reproduce (no nucleus).

cytokinesis

Process whereby a single cell is divided into two identical daughter cells whenever the CYTOPLASM and cell membrane are divided.

4 Stages of Mitosis

Prophase, metaphase, anaphase, telophase.

germ cells

Reproductive cells.

S Phase/Synthesis Phase

Second stage of interphase - DNA synthesis or replication occurs - the chromosomes of the cell are copied. (Creates 2 sister chromatids). The centromere is also copied.

metaphase (events)

Second stage of mitosis. Spindle fibers attach to centromeres of chromosomes. Chromosomes align at cell's equator (middle).

G2/Growth 2 Phase

Third and final stage of interphase - Shortest phase. Cell grows in preparation for cell division (rapid growth).

anaphase (events)

Third stage of mitosis. Spindle fibers shorten and centromere splits, separating two sister chromatids.

enzymes

Used to break down nuclear membrane during prophase.

mature organism

What a fertilized cell develops into during the cell cycle.