Bio - ch 12 cell cycle

Cell Cycle

ordered sequence of events that make up a cell’s life cycle. Starts with cell being formed from division of parent cell, ends with cell dividing into two daughter cells

Genome

Sum total of all genetic material an organism

Chromosome

A cellular structure consisting of one DNA molecule and associated protein molecules

Chromatin

The complex of DNA and proteins
that makes up eukaryotic chromosomes

Cell division

The reproduction of cells (one
step of cell cycle)

Mitosis

Cell division that occurs in somatic cells, and results in two identical, diploid cells

Somatic cell

Any cell in a multicellular organism
except a sperm or egg

Gamete

A haploid reproductive cell (e.g., egg or sperm

Sister chromatids

Two copies of a duplicated chromosome attached to
each other by proteins at the centromere

Centromere

The region on each sister chromatid where it is most
closely attached to its sister chromatid

G0 phase

exit from cell cycle - nondividing phase

Interphase

The period in the cell cycle when
the cell is not dividing (G1,S,G2 phases)

G1 phase

First growth phase of cell cycle before
DNA replication begins

S phase

Synthesis phase. Stage where DNA is
replicated

G2 phase

Second growth phase of cell cycle after DNA replication

Mitosis (mitotic phase)

Stage of cell cycle where cell division occurs, ONE parent cell divides into TWO daughter
cell

Prophase

• chromatin fibers coil into discrete, visible chromosomes, each made up of 2 sister chromatids

• the mitotic spindle begins to form (composed of centrosomes & microtubules)

• the centrosomes migrate away from each other, propelled in part by lengthening of microtubules

Prometaphase

• chromosomes become more condensed

• Nuclear envelope fragments

• Microtubules extending from each centrosome begin to
  invade nuclear area

• Some microtubules attach to chromosomes

Metaphase

• Centrosomes are now at opposite poles of the cell
• Chromosomes line up equidistant between the two poles
• For each chromosome, the sister chromatids are attached to different microtubules, attached to microtubules from the different poles

Anaphase

• Sister chromatids part from each other, each becoming an
  independent chromosome

• Newly formed daughter chromosomes move apart toward
  opposite ends of the cell as the microtubules they are
  attached to shorten

• Cell elongates, so by end of telophase each pole of the cell
  has full set of chromosomes

Telophase

• Two daughter nuclei form at opposite ends of the cell. Nuclear envelopes made of fragments of parent cell’s nuclear
  envelope and other parts of endomembrane system

• Chromosomes begin to unravel become less condensed.

• Microtubules of spindle apparatus break down

• Mitosis is now complete; cell can now complete cytokinesis to form two identical daughter cells

Cytokinesis

The division of the cytoplasm to form two
separate daughter cells immediately after cell division

Parent cell

One cell that divides into two daughter cells (holds the original genetic material)

Daughter cell

the two cells formed from the parent cell that contain an identical copy of the genetic material from the parent cell

Centrosome

Organelle in animal cells, which
contains 2 centrioles, and acts as a micro-tubule
organizing center during mitosis

Mitotic spindle

An assemblage of microtubules and associated proteins that is involved in the movement of chromosomes during mitosis

Cell cycle control system

A cyclically operating set of molecules in the eukaryotic cell that both triggers and coordinates key events in the cell cycle

Cyclins

cellular protein that that plays an
important role in regulating the cell cycle (act as checkpoints in the cell cycle)

Cancer

uncontrolled cell division

Tumor

A cluster of overly produced cells

Benign Tumor

Isolated and generally harmless tumors, and do not interfere with normal organ function (non-cancerous)

Malignant Tumor

Tumors that can survive in other parts of the body, and spread to new tissues, impairing organ function

Metastasis

The spread of cancer cells to locations distant from their original site