AP Bio cells transduction and Meiosis

genome

genetic material of an organism or virus, the complete complement of an organism or virus’s genes along with its noncoding nuclei acid sequence

DNA molecules in prokaryotic vs eukarya genomes

prokarya genomes have a single dna molecule

eukaryotic genomes have numerous dna molecules

chromosomes

a cellular structure consisting of one dna molecule and a associated protein molecule

associated protein molecule

associated proteins help keep structure

eukaryotic chromosomes

multiple, long linear chromosomes in nucleus 

prokaryotic chromosomes

a singl circular chromosome in nucleoid

chromattin

entire complex of dna and proteins that makes up the eukaryotic chromosomes

somatic cells

all cells except sperm and egg, the nuclei has 46 chromosomes (in human)

gametes

reproductive cells, egg/sperm (only have 23 chromosomes in humans)

chromatin fibers start in the form of long thin fibers, but after cell division they become______

densley coiled and folded, making the chromosomes short and thick

sister chromatids

2 copies of duplicated chromosome joined together, each one contains and identical dna molecule and are attatched by cohesins (protein complexes)

each duplicated chromosome is made of _____ sister chromatids

2 sister chromatids

centromere

region made up of repetitive sequences in chromosomal dna where the chromatid is attatched most closely to the sister chromatid (each sister chromatid has one)

mitosis

division of the genetic material in the nucleus (distribution of chromosomes into 2 daughter cells)

cytokenesis

division of the cytoplasm, producing 2 daughter cells

-in animal cells a cleavage furrow is formed until it is pinched into 2 cells

meiosis

produces gametes, yields daughter cells with only one set of chromosomes

fertilization

fuses 2 gametes together and returns chromosome number to 46

mitotic (M) phase

includes mitosis and cytokenises and is usually the shortest part of the cell cycle (1hr)

interphase

period where cell is not dividing, high cellular metabolic activities, where chromosomes and organelles are duplicated

-made of: G1, s, G2

G1 phase

first growth phase, consisting of portion of interphase before dna synthesis starts

s phase

synthesis phase, dna replicated here

g2 phase

2nd growth phase, portion of interphase after dna synthesis occurs

-2 centrosomes have formed by duplication of a single centrosome

prophase

-the chromatin fibers coil tighter condensing into chromosomes and nucleoli disappear 

-each duplicated chromosome appears as 2 identical sister chromatids joined at the centromere

-mitotic spindle begins to form /aster forms

-centrosomes move away from eachoter propelled by lengthening microtubules

prometaphase

-nuclear envelope fragments and microtubules can invade nuclear area

-kinetichore: specialized protein structure, has formed at centromere of each chromatid

-kinetichore microtubules: jerk chromosomes back and forth, nonkinetichore microtubules lengthen cell by interacting w those from opposite side

-chromosomes are even more condensed

metaphase

-centrosomes are at opposite poles of cell

-chromosomes all arrive at metaphase plate (middle)

-kinetichore of the sister chromatids are attatched to kinetichore microtubules coming from opposite poles

anaphase

-cohesion proteins are cleaved usins sparse causing sis chromatids to part and the 2 new daughter chromosomes move towards opposite ends of cell (each have complete collections of chromosomes)

-cell elongates even more as nonkinetichore microtubules lengthen

telophase

-2 daughter nuclei form in cell and nucleoli reappear

-chromosomes become less condensed and remaining spindles are depolymerized, completing mitosis

microtubule polymerizxation

microtubules lengthen by adding tubulin protein spindle

microtubule depolymerization

microtubules shorten by taking out tubulin subunits

aster

short microtubules extending from centrosomes

plant cell telophase

vesicles from golgi move along m,icrotubules to middle of the cell where they collapse producing cell plate which grows until it fuses w plasma membrane and formed cell wall to split

binary fission

prokaryotes undergo: asexual reproduction in single celled organisms where cell doubles in size then divides

dinoflagallete

unicellular eukaryote, the nuclear envelope remains intact during cell division

diatoms

envelope stays, microtubules form spindle in nucleus

cell cycle control system

cyclycally operating set of molecules in the eukaryotic cell that triggers and coordinates key events in the cell cycle

checkpoints

control points where stop and go signals regulate the cycle

-3 important ones: g1, g2, m

g1 chekcpoint

most important, if it doesn’t pass it goes to G0 phase ( nondividing state) but can be called back by external cues

g2 checkpoint

makes sure all chromosomes are attatched to spindle fibers from both poles allowing it to advance to anaphase

m checkpoint

cell in mitosis receives stop if any chromosomes are not attatched 

s phase checkpoint

stop cells w dna damage from proceeding

growth factor

protein released by certain cell stimulating other cells to divide

platelet derived growth factor

pdgf triggers signal transduction allowing cells to pass G1 checkpoint

density dependent inhibition

crowded cells stop dividing, but some cells being removed allows dividing to continue until filled again

anchorage dependence

cell must be attatched to a substratum to divide (in most animal cells)

cancer cells

-make own required growth factor

-stop dividing at random points, not set checkpoints or divide forever 

-undergo transformation: when cells gain ability to divide forever

benign tumor

mass of abnormal cells w specific genetic andcellular changes so cells aren’t capable of surviving at new site

malignant tujmor

cancerous tumor containing cells w huge genetic and cellular changes capable of spreading to neighbor tissues

-metastasis: spread of cancer to locations distant from of site

quorum sensing

when bacterial cells snes the concentration of signaling molecules allowing bacteria to monitor their own local density

formation of biofilm

aggregation of bacterial cells attatched to a surface by molecules secreted by cells a uses biofilm to protect the cells in it and often take nutrition from the surface they’re on 

-ex: film on teeth

secretion of toxins by infectious bacteria

can resist antibiotics bec it evolves, to stop it need to interfere w signaling pathways from quorum sensing

stapohylocus aureas

common bacterial species found on the surface of healthy skin that can turn into a pathogen

scchromyces cerevisiae (YEAST CELLS)

use chemical signaling to identify sexual mates

-2 types o mating, alpha and beta and they only recept the opposit4e

pararcrins signaling

local signaling when a signaling cell acts on nearby target cells by secreting molecules of a local regulator

synaptic signaling

local signaling that occurs in animal nervous system, electrical signal along nerve cell triggers secretion of neurotransmitter molecules which act as chemical signals causing diffusion across synapse and trigger response in cell

endocrine signaling

long distance hormonal signaling, cells release hormones and travel thru body until reaching target cells

ethylene

plant hormone that regulates growht

ligand

molecule that specificallly binds to another molecule

-ligand binding causes proteins to change in shape

g protein coupled receptor

signal receptor protein in plasma membrane that responds to binding of signal molecule by activating g-protein

1signal ligand binds to receptor

2.) receptor binds to inactive g-protein causing gap to displace gdp causing the activation of the g-protein

3.)g-protein dissociates and binds to enzyme causing chaperone and func change

4.)GTP hydrolyzed and g-protein returns to inactive state

g -protein

protein that binds energy rich molecule to gap

Receptor tyrosine kinase

,e,brand receptors that attatched phosphate to tyrosine, membrane receptors that attach to activate 10+ transductionpathways

1.) ligand binds to sight causing dimerization

2.) tyrosine kinase regions are activated and an unphosphorylated dimer is formed

3.) uses 6atp to phosphorylation the tyrosine kinase regions making a phosphorylation dimer

4.) after fully active relay proteins inside cell recognize it and bind to phosphorylated tyrosine causing structural change which activates relay protein to trigger cell response  

dimerization

2 receptor monomers associate close together

protein kinase

enzyme that catalyzes the transfer of phosphate groups from atp to another protein

tyrosene kinsae

enzyme that catalyzes transfer of phosphate group from atp to amino acid tyrosine of substrate protein

ligand gated ion channel

membrane channel receptor containing a region that can act as a gate opening/closing channel when receptor changes shape

-allows/blocks flow of ions like Na or Ca

intracellular receptor proteins

found in cytoplasm or nucleus of target cells, hydrophobic signal molecules must be small enough to cross plasma membnrane

transcription factor

special protein controlling which genes are turned on 

signal transduction pathway

chain of molecules interactions that leads to a particular response in the cell

second messengers

small, no protein, water soluble molecule spread thru cell rapidly bc of diffusion easily

phosphorylation cascade

series of chemical racsions during cell signaling mediated by kinases, in which each kinase phosphorylates activating another

1.) activated relay molecule activates protein kinase 1

2.) protein kinase 1 phosphorylates protein kinase 2

3.) protein kinase 2 phosphorylates protein leading to cell response’

4.) protein phosphatases catalyze the removal of the phosphate groups from the protein making them inactive

protein phosphotases

rapidly does dephosphorylation and turns off signal transduction pathways

cyclic amp

second messenger, small molecule produced from atp, broadcastssignal to cytoplasm

-usually activates protein kinase a

phosphodiesterase

converts cAMP to AMP, deactivating cAMP and its signal sneding

adenylyl cyclase

converts ATP to cAMP

-activated by epinepherine

cAMP signaling pathway

1.) messenger binds to GPCR

2.) activated GPCR binds to g protein bound by GTP, displacing GDP

3.) active G-protein binds to ardently cyclase, activating it

4.) activated adenylyl converts ATP to cAMP

5.) cAMP activates PKa leading to cell response

6.) G-protein hydrolyzes bounmd GTP to bound GDP leading to inactivation

cholera toxin

enzyme chemically modifying g-protein

calcium ion

second messengers triggered by GPCR and RTK

-level of calcium ions in extracellular fluids or blood is 10x higher than in cytosol

Release of calcium from er pathway

1.) signal molecule binds to receptor causing activation of phospholipids C

2.) phospholipids C cleaves phospholipid PIP2 into DAG and IP3

3.) DAG fun as as second messengers triggered in other pathways

4.) IP3 diffuses thru cytosine and binds to IP3 gated calcium channel in ER opening it

5.) calcium ions flow out of ER leading to an increase in calcium ion level in cytosine

6.) calcium ions activate next protein in one of more signaling pathways

protein synthesis signaling pathway

1.) activated receptor triggers phosphorylation cascade

2.) activated kinase enters nucleus and activates transcription factor

3.) transcription factor causes the transcription of genes leading to mRNA

4.) mRNA directs synthesis of new protein

stimulation of glycogen

1.) epinepherine binds to GPCR

2.) activated G protein activates adenylyl cyclase causing ATP to convert to cAMP activating PKa

3.) PKa activated phosphorylase kinase which activated glycogen phosphorylase

4.) glycogen produced

signal amplification

at each catalytic step ion cascade number of activated prodycts can be much greater than in preceding step

scaffolding proteins

large relay proteins that have several other proteins attatched to it

-increases signal transduction due to enhancing signal

apoptosis

programmed cell death, during this cellular agents chop dna and fragment organelles and cytoplasmic components

lobed

cell shrinks after cells parts are packaged into vesicles then digested

ced 4, ced 3, ced 9

relay proteins capable of transducing apoptosis signal

relay proteins

integrate signals from several sources and can lead to apoptosis pathways

apoptosis alarm signals

-one from nucleus after dna sufferer irepperabnle damage

-second from er when excessive protein folding happens