cell division + cycle Flashcards
why did cells undergo cellular division
- to REPLACE dead/dying cells
- to produce more cells during organism GROWTH and DEVELOPMENT
- to REPRODUCE
- maintain SURFACE AREA fo VOLUME RATIO so cells nutritional, respiratory, excretory requirements are met
when a cell gets too large, chemicals such as carbon dioxide or oxygen, nutrients, waste, water:
move into or out of the cell fast enough
sexual reproduction requires
2 parents
make gamete: sperm
female gamete: egg
gamete:
reproductive cell, only have HALF THE CHROMOSOMES
fertilization= two gamete unite to form
zygote
sexual reproduction: the offers print resembles the patents due to:
receiving 23 chromosomes from each parent
= 46 total chromosomes
sexual reproduction occurs mostly in:
multicellular organisms
asexual reproduction requires: (think hera having hephaestus)
1 parent
parent cell divides into two identical daughter cells
genetic info duplicated before division
asexual reproduction occurs in:
both unicelllular and multicellular organisms
somatic cell:
any biological cell forming in body of multi cellular organism
each somatic cell in your body contains:
23 PAIRS of chromosomes, total 46
karyotype:
graphic representation of organisms chromosomes
two stages of cell division (eukaryotes)
mitosis (division of nucleus)
cytokinesis (division of everything else)
longest stage of the cell cycle
interphase
where do cells spend the majority of their life
interphase
three main parts of interphase
G1, S, G2
G1 phase (INTERPHASE):
cell spends most of functional life
perform specialized tasks (respiring, making new organelles, producing mitosis proteins)
S phase:
DNA molecules are replicated
go from single stranded DNA (G1) to double stranded
only ___ cells should enter mitosis
HEALTHY
during the ____ phase, the cell continues to increase in size and prepare for cell division
G2
what occurs during the G2 phase (interphase)
- centrioles and other organelles continue to replicate
- more proteins and enzymes are synthesized
mitosis EXACTLY duplicates the parent nucleus and produces:
2 daughter nuclei (same number of chromosomes as parents, same genetic info on those chromosomes as each other and parent)
mitosis is composed of four phases: PMAT
Prophase, Metaphase, Anaphase, Telophase
prophase: first phase of actual cell division
- chromatin condense
- centrioles separate and migrate to poles
- spindle divers extend toward centromeres
- nuclear membrane disintegrates, nucleolus disappears
double chromosomes:
when chromatin condense and shorten in PROPHASE (phase 1 of cell division)
Metaphase (2nd phase of cell division):
- chromosomes line up in pairs at equatorial plate
centromere of each chromosome is attached to a separate spindle fiber
equatorial plate:
center of cell
Anaphase (3rd phase of cell division):
- spindle fibers shorten, chromatids pull apart at centromere
- after sister chromatids separate, they become daughter chromosomes
- chromosomes pull toward opposite piles and spindle fibers shorten
Telophase (4th phase of cell division):
- cleavage furrow forms between two cells and spindle fibers disappear
- nuclear membrane forms, plus two new nuclei
- chromosomes stretch out and aren’t visible
- nucleolus forks within nuclei
final step in cell division:
division of the nucleus
steps of cytokinesis:
daughter cells formed are now in interphase, total of 46 chromosomes
occurs after mitosis
tumours are basically uncontrolled ___
mitosis
chromatin vs chromosome vs chromatid
tin: chain of DNA, forms a chromosome
some: rolled up DNA going thru cell division
(sister) tid: branches of same
prophase (key point)
parent cell chromosomes condense
metaphase (key point)
chromosomes line up
anaphase (key point)
paired chromosomes separate and move to opposite ends of cell
telophase (key point)
cleavage furrow splits the cytoplasm
paired chromosomes are also known as
daughter chromatids
if the cells in a cell cycle diagram are round, they are:
animal cells
what would happen if a cell had faulty spindle fibers
they wouldn’t attach to centromere and pull sister chromatids apart.
what would happen if cytokinesis was skipped
each cell would have two nuclei.
