bio test: cell division

chromotin

chromotin

loosley coiled uncondensed DNA

chromosome

tightly coiled condensed DNA

sister chromotids

identical copies of a chromosome

centromere

holds sister chromatids together

homologous chromosomes

chromosomes that occur in pairs in sexually reproducing organisms

somatic cells

2 sets of chromosomes per cell; diploid; body cell

gametes

1 set of chromosomes per cell; haploid; sex cell

male

XY

female

XX

3 characteristics that distinguish chromosomes from one another

size, pattern, centromere location

interphase

inbetween division

G1 phase

growing phase

S phase

DNA replication

G2 phase

preperation for mitosis

Mitosis

Cell division

prophase

4 replicated chromosomes; the chromatin condenses into chromosomes, the centrioles seperate and spindle fibers form and attach to the centromeres. the nuclear envelope and nucleolus breaks down.

metaphase

the chromosomes line up across the center of the cell. each chromosomes are moved by the spindle fiber that is connected at its centromere.

anaphase

the sister chromatids seperate into individual chromosomes and move apart

telophase and begining cytokinesis

8 unreplicated chromosomes; 2 nuclear envelopes form; the spindle fibers break down and chromosomes uncoil back into chromotin, cytokinesis starts

Cytokinesis

the cytoplasm and organelles divide into two seperate cells

In mitotic cell divison, one diploid cell divides to form….

2 diploid cells

Order of phases

Interphase

Prophase

Metaphase

Anaphase

Telophase

Cytokinesis

cyclins

proteins that control the cell cycle

internal regulators

respond to events inside the cell

external regulators

respond to events outside the cell

if cell lose the ability to control of their growth

tumors will form

Benign

non-harmful tumor

malignant

harmful tumors

differentiation

stem cell “gets a job” becomes a specific working cell

stem cell

can be used for many differnt cell replacments

advantages of sexual reproduction

genetic variation

disadvantages of sexual reproduction

very slow; requires two organisms

advantages of asexual reproduction

fast

disadvantages of asexual reproduction

identical copies