10.1-Cell Growth

why do cells divide?

growth, repair, reproduction

mitosis

when cell "clones" itself (making regular body cells)

cytokinesis

division of cytoplasm

what happens during cytokinesis

cell membrane "pinches off" to split cytoplasm and daughter cells

how many PAIRS of HOMOLOGOUS chromosomes do humans have?

23 pairs

how many individual chromosomes do humans have?

46

a chromosome always has a...

centromere

what is a centromere

where spindle fiber attaches onto chromosome during cell division

longest phase of cell cycle

interphase

first step of interphase

G1 cycle

second step of interphase

S phase

third step of interphase

G2 phase

what happens in G1 phase

cell grows, "building blocks" needed for S phase (DNA copying) is made

what happens in S phase

DNA is copied

what happens in G2 phase

cell organelles are duplicated, mitosis preparation begins

what phase is cell cycle exit

G0

what can cause cell to exit G0 phase?

when repairing damage or chemicals that trigger reentrance to cell cycle is emitted

first phase of mitosis

prophase

second phase of mitosis

metaphase

third phase of mitosis

anaphase

fourth phase of mitosis

telophase

PMAT

prophase, metaphase, anaphase, telophase

longest phase of mitosis

prophase

what happens in prophase

nuclear membrane slowly dissolves, centrioles are arranged on opposite side of nucleus

chromatin

fibrous DNA material, when cell not replicating

chromosomes

condensed chromatin WITH A CENTROMERE

homologous chromosomes

chromosomes with the same genes in the same order

sister chromatids

two same chromosomes attached to one centromere, found during cell replication

human cell typical division time

24 hours

what happens in metaphase

chromosomes line up at middle of cell, connected to spindle fiber and centrioles

anaphase

sister chromatids are separated

telophase

nuclear membrane begins reforming around separated sister chromatids

cytokinesis in PLANTS

cell plate forms

what does cell plate turn into

new cell wall

gamete

sperm cell

zygote

result of egg + sperm