AP Bio- cells mitosis

mitosis

results in genetically identical daughter cells

genome

set of genetic information

chromosomes

structures that contain most of the organism's dna - condensed chromatin

chromatin

what makes up chromosomes

G1, S, G2

stages in interphase (in order)

grows, duplicates dna, grows some more

what happens during G1? S? G2?

eukaryotes

mitosis is unique to ____

chromatin fibers become more tightly coiled, and chromosomes can be seen. nucleoli disappear, mitotic spindle begins to form

prophase

nuclear envelope breaks and disappears. microtubules now reach the chromosomes, and some attach to the kinetochores. motor proteins move chromosomes towards the center

prometaphase

mitotic spindle is fully formed, with poles at opposite ends of the cell. chromosomes and centromeres are lined up on metaphase plate. for each chromosome, kinetochores of the 2 sister chromatids face opposite poles

metaphase

centromeres of chromosomes come apart, separating them. motor proteins of the kinetochores walk the daughter chromosomes to the pole of the cell. spindle microtubules attached to chromosome shorten, those not attached lengthen

anaphase

equivalent and complete collections of chromosomes have reached the poles

when does anaphase end?

reverse of prophase. nuclear envelopes form around chromosomes, nucleoli reappear. cell elongates. at the end, mitotic spindle disappears

telophase

prophase, prometaphase, metaphase, anaphase, telophase

stages of mitosis in order

cleavage furrow, cell plate

animal cytokinesis involves ____; plant cytokinesis involves ____

density-dependent inhibition - once crowded, they stop dividing. anchorage dependence - must be in contact with a solid surface to divide. density is more common

2 things that affect cell division. explain them

cell cycle control system

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

g1, g2, m

location of 3 checkpoints in cell cycle

when the cell doesnt pass the g1 checkpoint. for instance, nondividing nerve cells and muscle cells

g0 phase

receptor, signal transduction pathway

growth factors bond to ____ sites on plasma membrane and trigger a ____ that overrides checkpoints, allowing division to occur

abnormally growing mass of body cells

tumor

tumor is in original spot; can be removed

benign tumor

spreads into other parts of the body

malignant tumor

cancers that originate in the coverings of the body, like skin or lining of the intestine

carcinomas

cancers that arise in bone and muscle; tissues that support the body

sarcomas

cancer of the blood or bone marrow

leukemia

cancer of the lymph nodes

lymphomas

no density-dependent inhibition; defective cell control system ("immortal" can divide infinitely), override checkpoints anyway; synthesize their own growth factors

features of cancer cells (3)

When cancer cells move from their original location - loss of cellular adhesion

Metastasis

MTOC

Microtubule-organizing center involved in cell division.

kinetochore

A protein structure on chromatids where spindle fibers attach during cell division.

centromere

The region of a chromosome where two sister chromatids are joined and where the kinetochore forms during cell division.

non-kinetochore fibers

Microtubules that do not attach to kinetochores but help in the elongation of the cell during anaphase.

proto-oncogenes(Ras)

Normal genes that promote cell growth and division; when mutated (constant division), they can lead to cancer.

tumor suppressor genes (p53, p21)

Genes that regulate cell division and prevent uncontrolled cell growth; mutations can lead to cancer.

p53

Also known as the 'guardian of the genome' for its role in regulating the cell cycle and preventing tumor formation.

ras protein

A protein that, when mutated, can lead to uncontrolled cell division and is involved in many cancers.

density dependent inhibition

A regulatory mechanism that stops cell division when cells become too crowded.

anchorage dependence

The requirement for cells to be attached to a solid surface to divide.