Chapter 16: Cell Cycle Mitosis And Meiosis Flashcards
requirements for cell growth
growth and metabolism- cell mass must increase
DNA replication- DNA is duplicated so there are 2 exact copies of each chromosome
mitosis and cytokinesis- contents of cell are divided so each cell gets identical amount of genetic material
mitosis is ___ division
cytokinesis is ___ division
nuclear
cell/cytoplasm
phases of the cell cycle
G1- gap between M and S, start
S - DNA replication, centrosome is replicated
G2 - gap between S and M
M- mitosis and cytokinesis
phases in interphase
G1, S, G2
cytokinesis
division of the cytoplasm (there are 2 cells now)
Mitosis
division of the nucleus
what happens when cells pass a point in G1 called start or ____?
restriction point
they are committed to going through the rest of the cell cycle
what happens to cells that don’t pass through start?
may enter G0, a resting phase, until conditions change
cells spend a lot of time in which phase?
G1
chromatid number
G1: each chromosome has ___ chromatid
G2: each chromosome has ___ chromatid
1
2
key transition points in the cell cycle are
most important?
G1 checkpoint: restriction point (start)- most important
G2 Checkpoint
Metaphase Checkpoint
G1 checkpoint
regulates passage beyond start and entry into S
main regulatory checkpoint. Once a cell passes start if is committed to dividing
G1 checkpoint is influenced by
growth factors- like hormone, promotes growth
nutrients- have enough nutrients to support 2 cells
cell size- is it big enough to split into 2?
DNA damage- don’t want to replicate cells with damage
G2 checkpoint
regulates entry into M
G2 checkpoint influenced by
cell size
DNA damage
DNA replication- is replication complete?
Metaphase checkpoint
cells checks to make sure chromatids are attached to spindle. Mitosis is delayed until all chromatids can be properly attached
past the metaphase checkpoints, cells are
committed to dividing the chromosomes up between 2 daughter cells
Metaphase Checkpoint is influenced by
chromosome attachments to spindle
function of mitosis
to produce a duplicate of the parent cell
all growing cells carry out
2n cells->
1n cells->
mitosis
2 new 2n cells (diploid)
2 new 1n cells (plants and fungi, not humans) (haploid)
when does Mitosis occur
M phase
diploid organisms have _ of each chromosome, ___ from each parent
2
1
sister chromatid
Same genes and exactly the same alleles
homologous chromosomes
same genes, may have different alleles
nonsister chromatids
same genes, may have different alleles
function is to produce 2 identical cells
each cell is ___ to the parent cell
each cell has ____ dna
mitosis
identical
exactly the same
chromatin
complex of DNA and proteins
DNA is double stranded and made of nucleotides
50% is protein (histones and nonhistones)
extended losses lacked uncondensed for of DNA
form
found where
chromatin
beads on a string
interphase (actively growing)
form of DNA accessible to enzymes
chromatin
most tightly packed condensed form of DNA
shape
visible
chromosome
X shaped chromosome
only mitosis and meiosis
chromosome need __ types of sequences and they are
3
ORI- original of replication
Centromere- connect to the spindle fibers and sister chromatids
telomere- ends of chromosomes
kinetochore
protein disc
one end attaches to centromere of chromosome
one end attaches to kinetochore microtubules- spindle
homologous chromosomes
same genes in same order
one from each parent
same six and shape
may have different alleles
heterologous chromosomes
different chromosomes
contains different genes
each chromatid is ___ of DNA
one molecule
one half of the x - the other half is identical
haploid
1N
1 of each chromosome
human gametes
diploid
2N
2 of each kind of chromosome
human somatic cells
one complete set came from mom and dad
N=
of heterologous chromosomes
gene
region of DNA that codes for an RNA or protein (trait)
allele
different form of a gene/ trait
a vs A
you can have more than two forms of alleles