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108 Cards in this Set

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  • Back
Why do cells divide?
1. Grow-from one cell to trillions
2. Repair damage-boo-boo's need to heal; how somatic cells are replaced
3. Reproduce-if you're a one celled creature
What is bacteria reproduction called?
What do they not do?
Binary fission or Prokaryote Fission
Do NOT do mitosis
Steps for bacteria reproduction. (Long)
1. Ring of DNA attached to cell membrane
2. Cell reaches adult size, triggers ring of DNA to replicate
3. Phospholipids and peptidoglycans add to cell membrane between 2 DNA attachment points, pushes them apart.
4. cell membrane and cell wall pinch in, form 2 new identical daughter cells
5. Daughter cells grow into adult size...repeats.
Define cytokinesis
cells moving, cell and cytoplasm splitting in 2
how long does it take for bacteria to reproduce?
20 minutes
What positive effect does a fast reproduction cycle have for bacteria?

negative effect?
mutations to catch hold quickly in a population if beneficial

mutations in bacteria are usually bad
Define Mitosis
nuclear division
Why is it not mitosis when bacteria reproduce?
bacteria have no nucleus to divide.
who made the word mitosis?
Greek word for "mitos" means?
What does mitosis maintain from one generation to the next?
the chromosome number in cells
When is DNA visible in light microscopes?
When DNA wraps around histone spools
What does a chromosome consist of?
One DNA molecule + histone proteins wound up together
What is the mitosis game plan?
wants 2 daughter cells, identical to parent cells
what are the "recipes" needed to create a person called?
how many genes on a chromosome?
More than one
What are the bases?
T, A, C, G
how many genes are needed to make proteins?
What writes recipes for proteins?
Genes make proteins, proteins make...?
what you look like and how you work
Beadle and Tatum's definition of a gene.
"One gene codes for one polypeptide chain"
Mendelian definition of gene.
"A unit of heritable information"
Polypeptide chains have to do with...?
building proteins
What is the "waist line" in the chromosome called?
During most of a cell's life cycle, chromosomes are in the what state?
unduplicated state-when cell hasn't copied itself yet
What is the belt that holds the chromosomes together until needed to separate in mitosis called?
What is the kinetochore made of?
What does the kinetochore hold together?
2 identical chromosomes; sister chromatids, EXACTLY IDENTICAL
What are sister chromatids that are still attached with kinetochore still considered?
One chromosome in duplicated state
Define Sister chromatid
identical to each other-no way of telling which was the original
How complex an organism is, is somewhat relative to what?
quantity of DNA *how long it is*
Chromosome numbers are the same within?
the same species, species specific
Humans have 46 chromosomes in what cells? exceptions?
somatic cells
liver and red blood cells are exceptions
What are red blood cells missing?
nucleus and chromosomes
Why do red blood cells have no nucleus?
created in bone marrow, leaves nuclei in marrow.
How long do red blood cells live?
120 days
Define diploid
2 sets of instructions in each somatic cell (2N)
What is each pair of instructions called?
homologous pair of chromosomes
Centromere separates arms:
What is the shorter arm called?
What is the longer arm called?
short arm=p arm
long arm=q arm
define homologues
2 separate chromosomes
define locus
Think of it as address, location
Define allele
different form of traits, "flavors"
genes w/ different flavors
Define karyotype
test of chromosomes pictures
photographic testing of chromosomes, matching, cut and past to find abnormalities
What is the criteria for matching chromosomes?
-find length
-bands pattern
-position of the centromere
What are cells with only one set of instructions called?
haplid (N)
what stage is the picture taken for a karyotype test?
what is the fastest part of mitosis called?
when is it?
first 3 days
what is it called when a cell commits suicide?
how long (percent) is a cell in interphase?
what stains darker inside the nucleus?
No mitosis can occur if what are removed?
What do plants have in the centrosome?
On what do chromosomes travel during mitosis?
spindle fibers
What is the job of the nucleolus?
directs the making of ribosomes
What is the constricting at the equator of an animal cell called?
cleavage furrow
In animal cells, what is it called when microtubules begin constricting cell, creating a cleavage furrow?
Define Cell Plate Formation
phospholipid wall between new cells, cellulose becomes deposited in phospholipid and becomes new cell wall.
Who does Cell Plate Formation? Why?
-Plant cells/fungi cells
-cell wall won't let cleavage furrow form-too ridgid
What is special about your skeletal muscles?
Have had the same ones since you were born; gotten bigger bu no new ones
What are skeletal muscles made out of?
1 long big fiber with a lot of nuclei but no cell membrane
We can find the cure for cancer if we can figure out what?
the regulation of mitosis
What state are most cells in the body in?
What does a cell do while in G0?
not doing mitosis, doing other jobs
What cells do the most mitosis?
hair and skin cells
In the experiment where 2 cells, in different stages, were fused. What did this prove?
Chemical signals regulate mitosis, chemically driven process
What are the 2 main types of regulationg proteins?
CDK's and Cyclins
Define Kinases
category of enzymes, puts phosphate gropus on and off things
Define phosphoralate
stick phosphorate on something
What protein remains constant throught the cell cycle?
Unless attached to Cyclin, what is CDK considered?
Define Cyclin
protein whose concentration fluctuates throughout cell cycle.
Cyclin + CDK = ?
What do MPF's do?
a few MPF's get phosphoralted which triggers more phosphorylation of MPF's and the cell passes the G2 check poing and mitosis begins
What do activated MPF's do? (2 things)
1. cause cyclin production to cut down
2. increase proteases that "eat" the cyclin part of the MPF
Mitosis is complete when what levels are down?
MPF levels
What is cancer?
unregulated mitosis
What is G1 probably restricted by?
mostly P53's
What does P53 do?
tells cell to repair itself, if it cant be fixed, apotosis
How can cells in G0 be triggered into S?
by an injury
Define Density-Dependent Inhibition
-cells next to injury site begin to divide, fill in and then stop dividing
-when cells are touching on one single layer, mitosis stops
Define Anchorage dependence
Cells must be "ON" some surface to grow.
Define Metastisizing
spreading of cells, no following anchorage dependence
How does your body know when you're injured?
red blood cells destroyed by injury=pieces of blood cells (platelets)=release PDGF which is a growth factor
Define Growth Factor
proteins that stimulate mitosis
What do these stand for and what do they stimulate?
1. EGF
3. IGF
4. NGF
1. Epidermal growth factor, stimulates skin
2. platelet derived growth factor, stimulates cyclin
3. insulin-like growth factor, stimulates fat
4. nerve growth factor, stimulates nerves
Define protooncogene
genes that are activated by growth factors
Define oncogene
mutated protooncogenes that over express resultes
How many prootoncogenes known?
Over 30
well known protooncogenes?
ras, mol, myc, fos, jun
Define tumor-suppressor genes
genes that produces proteins that block oncogenes, keep protooncogenes in check
what is the #1 suppressor gene?
what % of breast cancer are related to BRCA1 or BRCA2?
What does Rb do?
prevents Retino blastoma
what are 2 shapes that amino acids take?
beta-pleated sheets
alpha helixes
important stuff on P53 (5 things)
-doesnt do anything in normal healthy cells
-will stop cell in G1 until DNA can be repaired
-triggers apoptosis
-can override most all other mutations
-works even if only one copy is correct
how many codons does a P53 gene have?
what does BRCA1 and BRCA2 cause?
most forms of heritable breast cancers
Define Redundancy
takes more than one mutation to screw up. System for safeguarding
What are the 5 steps to redundancy?
1. mutation in one of the two APC genes
2. mutation in second APC gene
3. Becomes an oncogene
4. loss of the tumor-suppressor gene
5. mutation of P53
Define telomeres
at end of each chromosome-long tandem repeats
TTAGGG in humans
Define Hayflick Limit
about 50ish rounds of mitosis, the cells just stop doing mitosis, hits old age, not a death sentence
Every time a cell goes through mitosis what happens?
lagging strand gets a little shorter, telomeres get cut off
define senescense
old age
What are some examples of cells hitting the hayflick limit?
dermal fibroblasts-lose elasticity, wrinkle, become thin
-lining of blood vessels-link sugars and be come atherosclerotic
Define telomerase.
what's it made of?
What does it act like?
-enzyme that puts TTAGGG back on the end
-mix of RNA and protein
-reverse transcriptase
what cells is telomerase found?
reproductive and skin cells
What did Cech discover?
all enzymes are not proteins, a couple RNA's can autoenzyme themselves and each other
-called these ribosomes
What is found in high levels of virtually all cancer cells?
what does this do?
Telomerase, makes cells immortal