Exam 3 Flashcards
Mitosis and binary fission generate
2 genetically identical copies from one cell
lifespan of cell
varying life span is required for growth, repair, and development, as well as reproduction. Lifespan varies from days to years.
meiosis
generates genetically unique cells from parent cells, occurs in just reproductive tissues, 1 cell to 4 cells
apoptosis
programmed cell death, triggered by caspases, enzymes that trigger apoptosis
cell cycle stages
interphase - preparation for division, long time
- G1 growth
- S Synthesis
- G2 growth 2
Mitosis - active division, less time
interphase
involves G1, G0, S, G2, longest part of a cells life, cell performs normal functions and prepares for mitosis
G0
cell functions normally but is not preparing for division, is at rest
ex) nerve cells
G1
cell grows, produces new organelles, and materials to make DNA, communication also occurs between cells
S
synthesis - all cells must replicate DNA before dividing
G2
protein production required for cell division involves, centrioles and centrosomes
mitosis
divides two eukaryotic copies of DNA are separated into two cells, occurs in all cells, 1 to 2 cells
cytokinesis
actual physical splitting of a single cell into two daughter cells
control of cell cycle factors
signal: an agent that influences the activities of the cell
growth factor: signaling proteins received at the plasma membrane secreted by one cell that INHIBITS or PROMOTES growth of another cell
G1 checkpoint
- main checkpoint
- evaluates growth signals and size
- determines nutrient availability
–> CDK needs to be present to release E2F so it can bind to DNA - assesses DNA integrity
–> p53 proteins check quality control, if DNA is damaged, p53 phosphorylates and repairs DNA, or p53 is broken down
G2 checkpoint
determines if S phase created undamaged copy of DNA
M checkpoint
occurs near end of metaphase in mitosis
checks that 2 copies of DNA are lined up properly
make sure to know spindle fibers are attached to sister chromatids
when is cell division prevented?
when cells are old, diseased, have a virus, metamorphosizing, or arresting at G0
cancer
uncontrollable cell division
benign
abnormal growth, noncancerous
malignant
abnormal growth, is cancerous, and threatens life
metastasis
spread of cancer from the place of origin throughout the body, invades tissue
contact inhibition
the sense that normal cells have to stop replicating when in contact with one another
angiogenesis
formation of new blood vessels to invade adjacent tissues
cancer vs normal cells
cancer
- non differentiated
- abnormal nuclei
- do not undergo apoptosis
- no contact inhibition
- disorganized
- undergo metastasis
normal
- differentiated (specialized)
- normal nuclei
- contact inhibition
- one organized layer
- remain in original tissue
proto-oncogenes
- code for proteins that promote cell cycle and prevent apoptosis
- can become an oncogene if mutated, and will not be able to stop the cell cycle (continuing to press the gas pedal)
- M (dominant) - gain of function, only need one mutation to lead to complete loss of control of cell cycle
tumor suppressor genes
- code for proteins that inhibit the cell cycle and promote apoptosis (Rb, p53)
- can become mutated, preventing necessary checkpoint needed to regulate errors in DNA (brake failure - not being able to stop)
- m (recessive) - gain of function, need both mutations to lead to complete loss of control of cell cycle
causes of mutation
- hereditary
- environmental
- pesticides
- chemicals / toxins
- radiation
genome
all the cells genetic material
chromosome
individual molecules of DNA
how many chromosomes to humans have?
46, 23 pairs, 22 autosomal pairs, 1 sex pair
diploid
represented by 2n
2 copies of each type of chromosome are present
How is DNA organized in interphase?
loosely packed to make genetic information easily accessible for protein generation
How is DNA organized once replicated?
sphase
DNA is condensed into manageable packages to be transported into daughter cells
histones
proteins that wind DNA up into chromosome structure from double helix structure
nucleosome
a stretch of DNA coiled around 8 histone proteins
chromatin
DNA and proteins combined together, there are 2 types
euchromatin
loosely coiled, site of active gene transcription
heterochromatin
densely packed, inactive gene transcription
centromere
where sister chromatids are attached
asexual cell division
genetically identical offspring, requires only one parent
sexual cell division
genetically different offspring, requires 2 parents
generation time
time it takes for a bacterial population to double
binary fission
divides prokaryotic cell into two identical cells over and over again
prokaryotic cell division types
asexual or sexual