mitosis
process by which a cell divides to create 2 identical daughter cells, includes the phases prophase, metaphase, anaphase, and telophase
interphase
cell grows and develops, replicates DNA, contains phases G1, S, G2, and M
prophase (including prophase 2)
first and longest phase of mitosis in which chromosomes condense and the nuclear membrane disappears, spindle fibers begin to form
metaphase (including metaphase 2)
chromosomes line up on the middle of the cell, single file
anaphase (including anaphase 2)
spindle fibers pull sister chromatids to opposite poles of the cell
telophase (including telophase 2)
final stage of mitosis, nuclear membrane begins to form, cells begin to separate, DNA uncoils
meiosis 1
separates homologous chromosomes, forms 2 cells
meiosis 2
separates sister chromatids, forms 4 cells
daughter cells
cells produced by cell division
what produces four different daughter cells?
meiosis
what produces two identical daughter cells?
mitosis
somatic cells
body cells, diploid
diploid cells
cells that contain two sets of chromosomes (2n)
haploid cells
cells that contain only one set of chromosomes (n)
cell cycle
process in which cells reproduce
cdk
cyclin dependent kinase, what is activated by cyclin
cyclin
broken down by cdk, found in the reproductive process of eukaryotic cells
MPF
maturation promoting factor, promotes the m stage in the cell cycle
when are levels of cyclin the highest?
increases the most in the G2 phase, breaks down in the m phase
when are levels of cdk the highest?
they remain the same throughout the cellular process
when are levels of MPF the highest?
when the cell is approaching the m phase
cancer
disorder in which some of the body's cells lose the ability to control growth
how does cancer occur?
a mutation causes the cell to bypass regular checkpoints decreasing the span of the cell cycle, the cells reproduce more quickly, lack density and anchorage dependence
density dependence
cells will stop dividing when they run out of room to reproduce
anchorage dependence
cells can reproduce when they are attached to other cells or some sort of tissue
prophase 1
chromosomes become visible, nuclear envelope breaks down, tetrads form, crossing over occurs
metaphase 1
homologous chromosomes line up side by side in the middle of the cell
anaphase 1
homologous chromosomes are seperated by spindle fibers, pulled to opposite poles of the cell
telophase 1
2 daughter cells are formed, each daughter cell contains only one chromosome of the homologous pair, is haploid
spindle fibers
made of microtubules, assist in cell division by pulling chromosomes to opposite sides of cells
centrosomes
organelles that produce microtubules (spindle fibers), where they root from
centromeres
areas where the chromatids of chromosomes attach
chromatids
"sister" parts of a chromosome
homologous chromosomes
chromosomes that are relatively the same size and share the same spot for the same gene
G1 phase
phase when the cell grows and organelles are copied
G0 phase
cell is not dividing and is not preparing to divide
G2 phase
phase of the cell cycle in which the cell grows again
S phase
DNA is replicated
genetic variation
differences between genes in an individual in comparison to the population
mutation
random change in genes
crossing over
homologous chromosomes in tetrads exchange portions of chromatids
independent assortment
random distribution of pairs of genes to different chromosomes to gamete cells
random fertilization
genetic variation caused by the fact that any sperm can fertilize any egg
histones
protein molecules around which DNA is tightly coiled in chromatin
synapsis
pairing of homologous chromosomes (tetrads), allows possible crossing over
tetrads
paired set of homologous chromosomes
chromatin
unwound DNA
G1 checkpoint
checks for cell size and proper replication of organelles
S checkpoint
checks for DNA damage, can potentially repair damaged DNA
M checkpoint
checks that chromosomes are correctly attached to spindle fibers
apoptosis
programmed cell death
amplification cascade
Advantage of second messenger signal transduction pathways is the possibility of amplified response
phosphorylation cascade
A series of enzyme-catalyzed phosphorylation reactions commonly used in signal transduction pathways to amplify and convey a signal inward from the plasma membrane.