mitosis

Question 1

mitosis happens

Answer 1

after fertilization
during growth and developments
to replace dead or damaged cells

Question 2

meiosis happens

Answer 2

only in gonads in animals and in structured cells in plants

Question 3

mitosis vs meiosis

Answer 3

mitosis: 2 dauther cells, same number pf chromosomes as parent cell
meiosis: 4 daughter cells, half number of chormosomes as parent cell

Question 4

autosomes/sex chromosomes

Answer 4

autosomes are 22, body chromosomes,
sex chromosome: 23rd, X or Y

Question 5

karyotype

Answer 5

profile of a persons chromosomes

Question 6

gamets number of sets of chromosomes

Answer 6

1 set (haploid)

Question 7

diploid

Answer 7

2 sets, autosomes in humains are diploid

Question 8

homologous pairs

Answer 8

chromosomes come in homologous pairs (one from each parent, same lenght, shape and genetic information, talk about same things)

Question 9

alleles

Answer 9

alternate versuons of same genes on chromosoe, genes at same locus. can code for same or different thing

2 alleles: blood A type and Blood B type ex

for women, sex chromosomes (XX) contain 2 copy of genetic material, if one is mutated the second one can come to rescue. For men (XY) only one copy of what is on the X specific region, and 1 copy of whats on the y specific region

homologous reagion for both (tiny bottom, copies on XY too)

Question 10

stem cells

Answer 10

in gonads: stem cels maintain the stem cell population by mitosis
in response to hormones, stem cells will go through meiosos and become gametes (haploid). they have left the cell cycle

in rest of body: stem cels maintain the stem cell population by mitosis
in response to chemical signal, stem cells will get differentiated to replace other cells for ex they have left the cell cycle

Question 11

cells in cell cycle

Answer 11

interphase : G1, S, G2
cell division (mitosis)
cytokinesis (division of cytoplasm)
back to interphase

Question 12

cells outside of cell cycle

Answer 12

Cells are in G0
performing their job as a neuron for example
making new organelle as needed

Question 13

mitosis phase

Answer 13

(nuclear replication)

prophase: chromosomes condense to facilitate movement and keep safe. Mitotic spindle/ spindle fibers are just being assembled, nuclear envelop still intact.
Prometaphase: nuclear envelope breaks down, mitotic spindle complete and attaching to all condensed replicated chromosomes
metaphase: chromosomes area aligned at the metaphase plate by the spindle fibers.
anaphase: early: sister chromatids seperated by mitotic spindle fibers and are now called unreplicated chromosomes. Later: chromosomes being moved towards centrioles (at pole) by spindle fibers
telophase: chromosomes at pole, cleavage furrow present

Once nuclear enevlope reforms, chromosomes decondense mitosis is complete !! cell is in late cytokinesis

meiosis same only with meiosis 1 (1 all phases), cytokinesis, meiosis 2 (2 all phases), cytokinesis

Question 14

interphase

Answer 14

takes the longuest

G1 (gap 1): most organelles are replicated
S phase: copy all the chromosomes, sythesize DNA and associated proteins. now 2 identical sister chromatids, connected at their centromeres
G2: centrioles druplicated and make other proteins that will be needed

Question 15

cytokinesis

Answer 15

division of cytoplasm, begins in telophase but not part of mitosis

ring of protein filaments encircles the cell (cleavage furrow) and contracts to split into 2 daughter cells

cytokinesis is complete when 2 daughter cells are formed, mitosis is complete when nuclear enveloppe formes (can be 1 parent cell with 2 nuclei)

Question 16

mitosis in plants

Answer 16

same but no centrioles
cytokinesis is different: golgi formes a line of vesicles that fuses to become plasma membrame and cell plate

Question 17

mitosis in haploid cells

Answer 17

same but no homologous chromosomes

Question 18

cell cylce in bacteria

Answer 18

reproduce by binary fission, not mitosis, prokaryotes never do mitosis,
cytokinesis : cleavage furrow and spetum (new dividing wall) forms in the middle of the cell, 2 cells released and continue their lives as 2 bacteria

Question 19

checkpoint

Answer 19

critical control point to regulate cycle, stop or go ahead

G1 checkpoint: cell size
nutrients
growth factors
DNA damage

G2 checkpoint: cell size
DNA replication

Spindle assembly checkpoint: chromosomes attachment to spindle

if not the resting state G0

Gene mutation can lead to loss of cell cycle regulation, can lead to tumor