Biology: The Cell Cycle

Cell Cycle

An ordered sequence of events in the life of a cell

Mitosis

A process of nuclear division in eukaryotic cells conventionally divided into five stages: prophase, prometaphase, metaphase, anaphase, and telophase. Mitosis conserves chromosome number by allocating replicated chromosomes equally to each of the daughter nuclei.

What are the four stages of mitosis?

Prophase

Metaphase

Anaphase

Telophase

Prophase

The first stage of mitosis, in which the chromatin condenses into discrete chromosomes visible with a light microscope, the mitotic spindle begins to form, and the nucleolus disappears but the nucleus remains intact.

Metaphase

The third stage of mitosis, in which the spindle is complete and the chromosomes, attached to microtubules at their kinetochores, are all aligned at the metaphase plate.

Anaphase

The fourth stage of mitosis, in which the chromatids of each chromosome have separated and the daughter chromosomes are moving to the poles of the cell.

Telophase

The fifth and final stage of mitosis, in which daughter nuclei are forming and cytokinesis has typically begun.

Cytokinesis

The division of the cytoplasm to form two separate daughter cells immediately after mitosis, meiosis I, or meiosis II.

Cell Division

The reproduction of cells

Chromosomes

A cellular structure carrying genetic material, found in the nucleus of eukaryotic cells. Each chromosome consists of one very long DNA molecule and associated proteins

Chromatin

The complex of DNA and proteins that makes up eukaryotic chromosomes. When the cell is not dividing, chromatin exists in its dispersed form, as a mass of very long, thin fibers that are not visible with a light microscope

Sister Chromatids

Two copies of a duplicated chromosome attached to each other by proteis at the centromere and sometimes, along the arms. While joined, two sister chromatids make up one chromosome. Chromatids are eventually separated during mitosis or meiosis II

interphase

The period in the cell cycle when the cell is not dividing. During interphase, cellular metabolic activity is high, chromosomes and organelles are duplicated, and cell size may increase. Interphase often accounts for about 90% of the cell cycle.

G1 Phase

The first gap, or growth phase, of the cell cycle, consisting of the portion of interphase before DNA synthesis begins.

S Phase

The synthesis phase of the cell cycle; the portion of interphase during which DNA is replicated.

G2 Phase

The second gap, or growth phase, of the cell cycle, consisting of the portion of interphase after DNA synthesis occurs.

Cleavage Furrow

The first sign of cleavage in an animal cell; a shallow groove around the cell in the cell surface near the old metaphase plate.

Cell Plate

A membrane-bounded, flattened sac located at the midline of a dividing plant cell, inside which the new cell wall forms during cytokinesis.

Checkpoint

A control point in the cell cycle where stop and go-ahead signals can regulate the cycle.

G0 Phase

A nondividing state occupied by cells that have left the cell cycle, sometimes reversibly.

Do prokaryotic cells do mitosis?

no, but eukaryotic cells do.

Another name for mitosis

karyokinesis, cellular nucleus division, asexual reproduction

Three parts of Cell cycle?

Interphase, Mitosis, Cytokinesis

How do prokaryotic cells divid?

Binary fission

Why do prokaryotic cells not do mitosis?

They are a single called, no internal membrane system for molecular transport and movements of materials within the cell.

Somatic cells

Any cells in the body other than reproductive cells

Germ cells

Reproductive cells that give rise to sperm & ovum

What type of division do somatic cells use?

mitosis

What type of division do germ cells use?

Interphase I: G1, S & G2

Nuclear membrane

A highly-porous membrane that separates the nucleus from the cytoplasm

Prophase, metaphase, anaphase, and telophase go with what part of cell cycle?

four phases of mitosis

animal cells in cytokinesis

the cell spits into two daughter cells

Plant cells in cytokinesis

begins when vesicles filled with wall building materials fused to form a cell plate at the equator of the cell. The cell plate will keep growing longer and longer out towards the sides and splits the cell

Why do cells have to divid?

if the cell gets too big it wont be able to function