Bio Unit 6

IPMAT

stages of cell cycle

90%

% of cell life spent in interphase

10%

% of cell life spent in mitosis and cytokinesis

G1, S, G2

stages of interphase

G1

stage of interphase where most time is spent, growth, metabollic activity, produces protein + organelles

S

DNA synthesis phase, copies chromosomes

G2

organelle duplication phase, also growing, activity1

nuclear division

PMAT, not cytokinesis

cytokinesis

division of cytoplasm

functions of cell division

asexual reproduction, growth + development, tissue renewal

chromatin fibers

state of DNA when a cell is not dividing/preparing for cell division

DNA condensation

after replication, each chromosome fiber becomes densely coiled and folded, shorter and thicker

unduplicated chromosome

single w/ one centromere, not attached to anything else

duplicated chromosome

sister chromatids attached at centromere

ovaries/testes

meiosis location

1 division per 24 hrs

length of cycle

1 hr

M phase length

10-12 hrs

S phase length

4-6 hrs

G2 phase length

5-6 hrs

G1 phase length

animal cytokinesis

cleavage furrow, pinches cell in two

plant cytokinesis

cell plate which divides cell into two and creates a new cell wall

3 checkpoints

in the G1, G2, M phases

G2 Checkpoint

cyclin produced, combines with CDK to form MPF, passes checkpoint and begins mitosis

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MPF

promotes mitosis by phosphorylating various proteins

activity of MPF

peaks during metaphase

cyclin component of MPF

degraded during anaphase, terminates the M phase, cell enters G1 phase

Cyclin degradation

continues during G1

CDK

recycled during G1

concentration of cyclin

increases starting at S phase of interphase, starts to decrease during M phase

during mitosis

when is MPF active

G1 w/o go-ahead

cell exits the cycle and enters G0 (non-dividing state)

G0

cell’s non-dividing state

G1 w/ go ahead signal

cell continues on in the cell cycle

M Checkpoint stop

prometaphase, a cell receives stop signal when any chromosomes aren’t attached to spindle fibers

M Checkpoint pass

metaphase to anaphase, when all chromosomes are attached to spindle fibers from both poles, go-ahead signal allows cel to go to anaphase

development from a fertlized cell, growth, repair

multicellular eukaryotes depend on cell division for

chromatid

each half of the chromosome

centromere

point where chromatids attach

chromatin

thin, uncoiled strands of DNA and protein, interphase

genome

all DNA

somatic cell

body cells

gamete

sex cell (sperm/egg), haploid (n, 23 chromosomes)

histones

protein that condenses DNA

DNA→ chromatin → chromsome

order of DNA condensation

chromsomes

can’t see them in interphase

23 pairs, 46 total

number of chromosomes in somatic cells

prophase

early mitotic spindle, start to see condensed chromosomes, nuclear envelope starts to disapear

prometaphase

centrioles start to separate chromosomes, fragments of nuclear envelope, spindle fibers attach

metaphase

chromsomes attached to spindle fibers, align along metaphase plate (equator), centrosome at one spindle pole,

anaphase

chromosomes pulled apart (into daughter chromosomes), pulled and pushed by spindle fibers

telophase

chromosomes at opposite ends, nuclear envelope reappearing, nucleolus forming

cytokinesis

cytoplasm splits into 2, cleavage furrow pinching

mitotic spindle

structure made of microtubules that controls chromosome movement during mitosis

centrosome

where assembly of spindle microtubules begins in animal cells, the microtubule organizing center, replicates during interphase

kinetochore

kinetochore

s

a protein structure that forms on a chromatid during cell division, serves as a point of attachment for spindle fibers, which are responsible for separating the chromatids during mitosis or meiosis.

cell plate

way of creating new cell wall for cytokinesis in plant cells

binary fission

reproduction for prokaryotes, chromsome replicates (begining at origin of replication), 2 daughter chromosomes move apart, plasma membrane pinches inward

yes

is the nuclear envelope present in G2 of interphase

yes

is the nuclear envelope present in prophase

yes

are the nucleoli visibile in G2

yes

are the chromsomes duplicated in G2

no

are the chromsomes visible and condensed in G2

no

are nuceloli visible in prophase

yes

are chromsomes condensed, visible, and duplicated in prophase

no, fragments

is the nuclear envelope present in prometaphase

yes

are chromsomes duplicated and condensed in prometaphase

no

is the nuclear envelope present in metaphase

yes

are chromosomes duplicated and condensed in metaphase

opposite poles

where are centrosomes located in metaphase

no

is the nuclear envelope present in anaphase

no

are the nucleoli visible in anaphase

no

are the chromosomes duplicated in anaphase

no

are the chromsomes condensed and visible in anaphase

yes, forming

is the nuclear envelope present in telophase/cytokinesis

yes

are the nucleoli visible in telophase/cytokinesis

no

are the chromosomes duplicated in telophase/cytokinesis

less

are the chromosomes condensed in telophase/cytokinesis

depolymerized

what happens to the spindle fibers in telophase

meosis

form of cell division by which gametes with half the number of chromosomes are produced, sexual reproduction, two division

mitosis

will never be haploid in number

diploid

2n, 46 chromosomes

haploid

n, 23 chromosomes

gamete

sex cell, always haploid

fertilization

fusion of a sperm and egg to form a zygote

zygote

fertilized egg, diploid

gonads (testes/ovaries)

only location of meiosis

spermatogenesis

male meiosis

oogenesis

female meiosis

Interphase 1

meiosis, not important because there is no function, duplicating chromosomes

homologous chromosomes

pair of chromosomes similar in shape and size, maternal and paternal, carry the genes

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tetrads

homologous pairs

locus

position of a gene

22 pairs

human pairs of autosomes1

1 pair

human pairs of sex chromosomes

DNA → protein → trait

order for DNA coding for genes

karyotpyes

method of organizing the chromosomes of a cell in relation to number, size, and type

Down’s Syndrome

didn’t divide chromosomes equally, extra chromosome

goals of meiosis

reduce chromosomes, create genetic variation

90%

% of meoisis spent in Prophase I