Ch 12 Flashcards
cell division
reproduction of cells
cell cycle
life of a cell from formation to division
What is the term for the cells resulting from cell division?
daughter cells
genome
a cell’s endowment of DNA; all of the genes
Eukaryotic DNA
multiple strands of long, linear molecules
How is DNA packaged for cell division
coil into chromosomes
Each eukaryotic chromosome consists of:
one long, linear DNA molecule and many proteins
Chromatin
complex of DNA and proteins
somatic cells
all body cells except reproductive cells
gametes
reproductive cells
Number of chromosomes in humans
46
sister chromatids
joined copies of the original chromosome
centromere
where chromatid is attached most closely to its sister chromatid
Mitosis
the division of genetic material in the nucleus, results in 2 identical cells
cytokinesis
division of the cytoplasm
What type of proteins are in chromosomes?
histone proteins
Why is genetic material organized into chromosomes?
to ensure the equal distribution of DNA in cell division
Meiosis converts from _____ to ______.
diploid to haploid
Fertilization converts from _____ to ______.
haploid to diploid
Diploid
2n = 46
Haploid
n = 23
telomere
cap at each end of chromosome, protects
What would happen if a cell underwent mitosis but not cytokinesis
it would have two nuclei
Centromere separates the chromosome into two…
arms
The shorter arm of the chromosome is…
p-arm
The longer arm of the chromosome is…
q-arm
What makes up M phase?
mitotic phase: mitosis and cytokinesis
Interphase
preparation for cell division
order of phases
G1, S, G2, M
G1
first gap, growth and differentiation
S
synthesis, DNA replication
G2
second gap, more growth and completes preparation for division
Shortest phase of cell cycle
M phase
Stages of mitosis
prophase
metaphase
anaphase
telophase
Significance of G0
cell never leaves the G1 growth stage, non dividing state
centrosome
microtubule center in animals cells to form mitotic spindle
Where does the chromosome attach to the mitotic spindle
centromere/ kinetochores
Where do chromosomes line up in metaphase?
metaphase plate (imaginary)
Cytokinesis in animals
cleavage, causes cleavage furrow, pinching in two
Cytokinesis in plants
cell plate where cell wall materials collect
order of chromosomes in relation to size
1-22, largest to smallest plus big x and small y
centromere in center
metacentric
centromere a little off center
submetacentric
centromere more towards one end
acrocentric
centromere on end
telocentric
cancer and types
uncontrolled cell division
benign: doesn’t spread
malignant: spreads through cardiovascular or lymphatic systems
How do bacteria divide?
binary fission: cell grows to double its size then divides
How is the genetic material in bacteria organized?
singular circular DNA molecule with associated proteins
origin of replication
place on bacterial chromosome where replication starts
What is the cyclically operating set of molecules that coordinates key events in the cell cycle?
cell cycle control system
checkpoint
control point where stop and go signals can regulate the cycle
major checkpoints
after the G1, G2, and M phases
G1 checkpoint
restriction point, most important, sends cell to rest of cycle or remains in G0
types of regulatory molecules
protein kinases and cyclins
protein kinases
enzymes that phosphorylate: put phosphate groups on things
Cdks
cyclin dependent kinases, kinase myst be attached to a cyclin to be active
Cyclin concentration
cyclically fluctuating, peaks during S and G2
How is the cell regulated by cyclins and CDKs?
activity of CDK rises with cyclin concentration, kinases ad MPF cause phosphorylation that contributes to molecular events, like fragmentation of nuclear envelope or initiation of mitosis.
growth factor
protein released to stimulate other cells to divide
density dependent inhibition
crowded cells stop dividing
anchorage dependent inhibition
must be attached to a substratum/surface to divide
Why is inhibition important?
checks growth of cells at optimal density and location
transformation
process that converts a normal cell to a cancer cell
metastasis
spread of cancer cells to locations distant from original site.
