Cell Bio test #3

Pray for me its getting worser and worserp

What are some of the primary function of cells

A. to move- they have skeletal and mollecular nanoscale motors

B. generate and consume energy

C. reproduce and use genome

D. synthesise traffic

What are some of the functions and locations of organellses in the cell (their structure i mean) (nucleolus, mitochondria, cjloroplast, ribosomes, lysosomes and peroxisomes, vacuoles endoplasmic reticulum

1. Nucleolus

   1. Structure and location: 

      1. largest organelle

      2. Has a double layered membrane

      3. Nucleolus are inside (produces the ribosomal DNA

   2. Function:

      1. Control center of the cell. Contains the DNA (builds ribosomes)

   3. Q? How is the nucleus organized

      1. Into nuclear bodies (areas with specific functions)

2. Mitochondria

   1. STructure and location

      1. Has two membranes. (inner membrane = cristae = increase surface area

   2. Function: powerhouse of the cell (produces ATP

3. Chloroplasts

   1. Structure and location: found in plant cells

   2. Contains Thalakoids

   3. Stroma surrounds the Thylakoids that carry their own DNA

   4. Function

      1. Photosynthesis

4. Riboomes

   1. STructure

      1. Small comple of ribosomal RNA and proteins

   2. Functions

      1. Covnerts mRNA into proteins 

5. *** Lysosomes and perodiomes

   1. Structure and locations

      1. Samll membrane bound sacs filled with enzymes

         1. Lysosomes: (works in acidic conditions = contains hydraulic enzymes)

            1. Function: Breaks down old cellular components, pathogens, or large unneeded molecules

            2. Uses a protein pump to keep high H+ conditions (if bursting will not activate the basic cell)

         2. Peroxiomes: Iholds oxidative enzymes that contains catalysts

            1. Function: helps detoxify harmful sbustances and metabolize fatty acids

6. Vacuoles

   1. Structure and location:

      1. Animals have many small ones, plants have one large one in each cell

   2. Function:

      1. Stores water and nutrients for the cell

1. Endoplasmic reticulum: series of interconnected membranes.. Sacs and tubules that modifies proteins and synthesises lipids

   1. Smooth ER:

      1. Structure- does not have surface ribosomes

      2. Purpose

         1. Synth

            

            esis lipids

         2. Detoxifies drugs and poisons

         3. Stores caclium

What are the different structure sin the Endoplasmic reticulum and waht is it?

1. Endoplasmic reticulum: series of interconnected membranes.. Sacs and tubules that modifies proteins and synthesises lipids

   1. Smooth ER:

      1. Structure- does not have surface ribosomes

      2. Purpose

         1. Synthesis lipids

         2. Detoxifies drugs and poisons

         3. Stores caclium

   2. Rough ER

      1. Strucutre-

         1. Network of membrane- bound sacks/tubles with ribosomes = looks rough

      2. Purposes:

         1. Syntesises proteins especially ones for secretion into membranes

         2. Begins post-translational modification of proteins

            

What is the function of the golgi apparatus and what is its structure

1. Structure:

   1. Stacks of flattened membrane bound stacs

   2. Cis faced (receiving)- Closer to teh ER

   3. , Trans face(shipping) - farther from the ER

2. Function:

   1. Modifies, sorts, and packages proteins and lipid

   2. Dispatch Products via vesicles for secretin within the cell

      

What ar esome of the cytoskeletal elements and what do they do?

1. Actin filaments

   1. Consist of two coiled strand made of actin. They are found just beineth the plasma membrane= 

   2. Function: to stiffen the membrane and used for cell movements

2. Intermediate filaments

   1. Structure: made up of a wide range of proteins (long string like)

   2. Function: structural support. Found just inside the nuclear envelope to stiffen up its structure and provide attachemtn sites for chromosomes

3. Microtubles

   1. Logn hollow calendars

   2. Made up of protein combinations of alpha and beta tubulin

   3. Functinon: helps transport cell cargo

Descrie trends in nuclear organization? how do heterochromatin and euchromatin play into it?

1. THE NUCLEUS IS ORGANIZED INTO NUCLEAR BODIES WITH SPECIFIC FUNCTIONS

2. Ribosomes are assembled in the nucleolus

3. Transcriptionally active genes are localized to the interior of the nucleus

4. What are the different localizations of euchromatin and heterochromatin in the cell

   1. Transcriptionally active genes are localized into the interior of the nucleus

      1. Heterochromatin = associated with the nuclear envelope, periphery of the nucleolus (more transcriptionally active)

Q?What is the nuclear laminar 

Made up of lamin protiins (blue windy structures in between the nuclear envelope and

membrane)- pushed against nuclear proteins

Q? What is the purposes of Heterochromatin protein 1 (HP1)

1. Binds to inactive chromatin- binds to Lamin B receptor (LBR), linking the heterochomatin to the nuclear envelope

What do you think might be somedisruptions/mutations that would affect nuclearorganization? What would the consequence be?

HP1, LBR could be mutated in ways that they are nonfunctional,

can’t bind to chromatin

•

LBR no longer inserts into nuclear membrane

•

This could affect location of chromatin in the nucleus, and

possibly disrupt levels of transcription

What is the endomembrane system and what is it used for? What is found in the system and discribe what they are

it is a grouop of organelles that helps modify, packag,e and transport lipids in the proteins?

1. nuclar envelope

2. lysosomes

3. vesicles

4. plasma membrane

What are teh differnt types of endosomes and lysosomes and what do they do

1. Endosomes- used for sorting

2. endocytosis; when you take up molecule from otuside the cell in endocytic vesicle

3. Sorting endosome: sorts componnets to be recycled or degraded

4. Recycling endosome: brings membrane receptors back to the membrane

5. Late endosomes: fuse with vesicels carrying acid hydrolases

   1. creates a lysosome

1. lysosomes- used to degrade intracellular materials

   1. Can break down bological polymers

   2. works at very high acidic conditions to ensure saftey just incase the structure bursts

   3. uses proton pumps to keep concentrations high

Describe the puls chase experiement and its effectiveness

1. When pancreatic cells make digestive enzymes into the small intestine

   1. “Pulse” = short exposure to radioactive amino acids

      1. Newly synthesized proteins were detectable since they were radioactive

   2. Chase = incubated cells  for various amounts o

      f time then images (only lasts a short amount of time0

      1. At around 120 minutes they leave the cell

How are proteins and lipids transported from the ER? descrube anteriograde and retro grade transport sequences and what receptors they use

1. Anterograde transport

   1. Proteins and lipids transported out of the ER through (ER exit sites (ERES)

2. Retrograde transport

   1. Uses the KDEL sequence

      1. Receptors recognises the sequences and transports back to ER

      2. Usually stuff that is important to keep in the ER

what wold be the results of the pulse chase expeiremnt look like if you 1. label a protein with a KDEL sequence and 2. lbe a protein that gets secreted from the cell

1a. you would go from the ER to golgi but back to the ER

2a. you would go from the er to secratory vesicles to be released ro the cell

how would you run a neceesary vs suffiencent expeirement for the sequence

deletions… just think about it

What are some of the mechanisms of protein transport? What are the 3 families of vesical coated proteins

COPI-coated vesicles

1. Bud form the ERGIC or golgi and returs proteisn to ealerer compartments (retrograde transport)

   COPII- coated vesicels

   1. carries proteins from the ERGIC to the golgi (cis fac

Clatherin-coated vesicles

1. transports in both directions (beteen the trans golig, endosomes, lyssomes, and plasma membrane) (works aroudn the cell

What are the GTP binding proteins and their functions

They help regulate the formation of coated vesicles

A. How>

1. gtp-proteins recruit adaptor proteins = interacts with the receptors bound to cargo proteins

   1. the adaptor proteins bind = recruits the coat proteins

Describe the LDL example of protein transport

1. LDL receptor on cell membrane binds to LDL

2. Endocytose the LDL (brings it into the cell)

3. LDL is released in the EArly endosomes

4. The receptor is recycled

5. Lysosomes break down the LDL and releases its components

   

 Where can you find mutations in the LDL receptors

1. Cyytoplasmic tails = used to associate with coat proteins. Mutations are tytpically found here

How does protein sorting work? (describe it and what can be found through it)? how does a protein/ibosome know if it should go to the ER or stay in the cytosol

How does it work? ther are ribosomes on the rough ER and in the cytoplasm

1. free ribosomes: proteins go to the nucleisu, mitochondria, and chloroplast

2. membrane boudn: golgi, plasma membrane, endoo and lysosomes, nucelar membrane, secratory vesicles

knows wehre to go based on signals made on the proteins

how do proteins from the ribosome know where to go based on where they were made

1. Immunoglobulin light chain proteins

   1. Secreted from cells (found in the ER of membrane bound proteins)

   2. Larger proteins are unable to pass through the ER since tey are signal sequences that are used to direct it to the ER

   3. The signal is eventually cut out

      

How do you know the orientation of systolic free ribosomes

1. When translation first takes place, the fist proteins formed = (ER signal sequence- is recognized and bound to ER (HYDROPHOBIC) (N SEQUENCE)

How does protein sorting work>

---

Describe the steps for this mechanism

1. Signal is recognized By SRP receptor (FROM N TERMINUS FROM FIRST TRANSLATION)

   1. What is there

   2. Srp receptor is right next to the translocon

      1. Integral membrane proteins are on the membrane via alpha helices (the spindley part in the membrane)

      2. They are inserted into the membrane during the translational process ans the protein is being translate 

         1. Can have many different orientations

            

How do you remember the orientation of proteins during protien sorting

1. Steps and rules

   1. Step 1. Signal sequence is cleaved as poly peptide crosees the membrane N Terminus to the ER

      1. Rule 1: N-terminal signal sequence (first protein form) = N terminus in the lumen 

   2. Step 2: if there is a transmembrane sequence (yellow alpha helix with a bunch of hydrophobic amino acids

      1. Translocation halted when translocon recognizes trans membrane sequence

         1. Results… shifts  protein over and moves it to the plasma membrane (shifted to the right)

   3. Step 3. Continue translation off of the membrane and forms the C terminus outside in the cytosol

Q? What would you do with no N-Terminal Siganl sequence

1. Step 1: *uses internal trasnmembrane sequences)

   1. Step 1: SRP recognizes transmembrane sequence alpha helix

   2. Step 2: puts the alpha helix into the membrane

   3. Translocon will move the alpha helix outt (n terminus on the outside in the cytosol)

   4. Rest of the protein is made in the lumen 

   5. (can be oriented diffferenty with depending on the instructions of the alpha helix)

Q? What would you do with multi alpha helix proteins: (multi pass)

1. Steps 1: the same things happens again but restarts the sequence a bunch of times.

   1. Note: to pass through a membrane you need an alpha helix (it will direct it in the opposite direction… like threading a needle 

Protein sorting conceptual questions 1.

Consider a protein that is normally cytoplasmic. What

would happen if you fuse an N terminal signal sequence to it?

2. consider a transmembrane protein with the structure..

1. a: the protein would end up in the lumen of th ER

Consider a protein that is normally cytoplasmic What would happen if you fuse an N terminal signal sequence to it?

1. The protein would end up in the Lumen of the ER

   1. Why?

      1. Be careful of wording: if it is cytoplasmic it would be listed as such

. NOt transmembrane because it has no mention of an alpha helixIf it is cytoplasmic… (

HAS AN Er signal sequence complex

2. Consider a transmembrane protein with the structure. You fuse the ER signal sequence at the n terminus protein. Which diagram shows the position 

   1. Know that n terminus has to be in the ER lumen. Be careful with the transmembrane. Cannot cross membrane without the alpha helices

      1. Try to maintain the same number of alpha helix before and after.

      2. Keep on putting alpha helices from where the came from

What is the yeast UPR pathway? how would you diagram it? what triggers it?

1. it is triggered by a large sum of unfolded proteins in the ER

2. E stress signaling is charachtersed in the Saccharomues cerevisaie

   1. goverened by the stress receptor (IRE1)

   2. downstream transcrption factor HAC1 used

      1. it helps upregulat ehte proteins to help deminish sthress to help proteins fold correctly

How does the UPR pathway play into necessary and sufficient shit

1. Do you think IRE1p is necessary 

   1. Yes? Why? It is the censor.. Without it you cant sense anythign

2. Do you think HAC1 is necessary

   1. Yes. It would be necessary because it is a straight pathway

3. How would you design an experiment

   1. You could create an experiment to get rid of those transcription factors. (deltion) 

4. What about sufficiency in these components? Would you be able to test that  

   1. Would not be able to test since they are all necessary

What are teh steps to vertebrate UPR pathways

1. Unfolded proteins vind to the receptors (receptors bind to unfoled proteins)

2. pathways activated= transcription factors that increase the UPR target genes

   1. first wave (very quick) second wave(activates tehe transcription factors)

   

What happens during the first wave of vertibrate UPR pathways

1. Activation of PERK

   1. Inhibits protein translation through the phosphorylation of eIF2a (be able to read off figure)

      1. Alpha components gets phosphoylated and transcription is blocked

         1. (PERK –> eIf2a)

2. Selective degradation of MRNA

   1. Is initiated through regulated IRE-1 dependant decay (RIDD)

      1. Q? What does this mean and where is it shown on the figure

         1. ER-located proteins = proteins that are made into the er

         2. mRNA deredation (RIDD)

         3. IRE1a - triggers the rIDD process

            

What nhappens during the second wave of resposnes during the UPR pathway? what are the 3 pathways to the second wave of UPR

1. All components of the first wave of responses go into the second wave = UPR target genes (proteins- helps decrease the number of unfolded proteins)

   1. Q? What are the 3 pathways to the second wave of UPR (figures will be shown. Know how to interpret)

      1. IRE1a

         1. Ire1A (receptor). Dimerizes (brings two receptors together) and autotransphosphorliate to activate 

         2. Processes the mRNA for XBP1 allowing it to be translated into protein

         3. Protein is a transcription factor- goes to the nucleus to upregulate UPR genes

      2. PERK (protein kinase RNA-like ER Kinase)

         1. Perkk Phsophorylates the eiF2a activated

         2. Allows for selective translation of ATF4 ( eIF2a is an initiation factor involved in translation)

         3. ATF4 is a transcription factor- increases expression of UPR tearet genes

      3. ATF6

         1. ATF6 translocates to the golig after detecting unfolded proteins

         2. Processed by proteases (break down proteins), = releases ATF6f

         3. ATF6f= transcription factor= upregualtes UPR target genes

What would be expected outcome if a mutation prevented the phosphrylation of eIF2a in a vertebrate cell

• reduced ability to regulate protein load in the ER, leading ot increased sress

What is and what are teh components of the nucelar envelope? what are the components and discription of the nuclear pore complexes

1. Nuclear envelope consists of 

   1. 2 nuclear membranes (inner and outer)

   2. Is continuous with the ER

   3. Underlying nuclear lamina (mesh network on the edge of the inner membrane)

      1. Provides structural support

      2. Made up of proteins called lamins (associate with eachother 

1. Nuclear pore complexes (description and componnetns)

   1. Made up of many nucleoporins (proteins

   2. Spans both the inner and outer membrane (nucleus to cytoplasm)

   3. Rings on the cytoplasmic and nuclear sides

   4. Protein filaments extend from either side

   5. Central channel lined by proteins 

   6. Varrier to permeability, regulate transport

How are proteins targeted to the nucleus called and singled?

1. They are called nuclear localization signals (NLS) targeted by specific amino acid sequences)

What are the steps to nucelar import and export

1. Nuclear Import (part 1: to the left)

   1. Need to get cargo protein into the nucleus

   2. Cargo protein has (NLS)

   3. NLS on protein recognized by importin

   4. Cargo protein/importin complex bind to and pass through nuclear pore complexes

   5. Ran-GTP binds to importan, relases protien in the nuclius 

2. NI part 2- Importan back to cytop

   1. Need to get important back to the cytoplasm

      1. Importin/Ran-GTP complex binds and passes through nuclear pore complex

      2. RAN GAP (attached to the nuclear pore complex) (GTPphase-activating protein)- hydrolyzes GTP to GDP

         1. Importin is released into the cytoplasm

      3. Now we have to bring the ran into the nucleus (start of nuclear import)

3. Nuclear Import (part 3)- RAN-GTP back to the nucleus

   1. Ran-GDP binds to NTF2 (import receptor)

   2. Need to make it RAN GTP 

      1. RAN-GEF (bound to chromatin) exchanges GDP to GTP

4. Nuclear export (uses NES- nuclear export singnal)

   1. Ran-GTP, exportin, and cargo protein forms a complex

   2. Bind and pass through the nuclear pore complexes

   3. Ran GAP hydrolyzes GTP into GDP and causes release of the cargo (outside in the cytoplasm)

   4. RAN GDP and exportin returned to the nucleus 

   5. ame as ran GDP for nuclear import (look at part 3 of nuclar import)

   6. Exportin passes through on its own 

   7. RAN GEF exchagnges GDP for GTP

5. 

HOw does the transport of MRNAs work

1. mRNAs are transported by RAN-independent mechanism (no ram)

   1. Associated wit about 20 proteins in the nucleus

   2. Some of the proteins are part of an exporter complex, which exports the RNA out of the nucleus

   3. Helicases on the cytoplasmic side remodels mRNA and removes exporter proteins

What are redox reactions and what are tehir trends

A. Reduxion is gaining. Transfer of electrons in association with the transfer of hydrogen ions

1. Oxidation is losing the electrons 

   1. You can always follow the path of the hydrogens

2. NAD+ to NADH

   1. Oxidation= NAD+ to NADH

   2. Reduction= NADH to NAD+ 

ATP and phosphrylation. What happens to the reaction energy when you phosphrylate a reactant

a. there is an increase in the free enrergy of the reaction

• endergonic to exergonic

• non-spontaneous to spontaneous (from needeing an addition of energy to not needing an addition to energY0

• chasnges the conformation to make it more energetically favorable

What are all the componenets of the erngy cicycle/cellular respiration in the cell

• Aerobic cellular respiration

  • glycolisis

  • citric acid/krebs cycle

  • oxidative phoshprilation

1. Aerioic cellular respiration

   1. Glycolysis - Glucose (6c) → pyruvate (3c) - produces 2 net ATP (cytosol), NADH

      1. pyruvate processing after

   2. Goes into the cytric acid cycle in the mitochondria - creates 6CO2 and 2 atp, NADH and FADH2

   3. NADH an dFADH2 go to oxidative phsopohrilation to create 34 atp (and h20)

What are the components of glycolysis

A. one glucose creates 2 pyruvate

B. 2 total atp is created (for created -2 that is consumed)

phorporilation of the glucose makes things more energyetically favorable Aerioic cellular respiration

1. Glycolysis - Glucose (6c) → pyruvate (3c) - produces 2 net ATP (cytosol), NADH

2. Goes into the cytric acid cycle in the mitochondria - creates 6CO2 and 2 atp, NADH and FADH2

3. NADH an dFADH2 go to oxidative phsopohrilation to create 34 atp (and h20)

What are the components of glycolyisi

1. One glucose creates 2 pyruvate

2. Two total atp is created (2atp in 4 atp out)

3. Phosphorylation making things energetically favorable 

What is pyruvate processing + the citirc acid (krebs cycle) and what do they do

1. Pyruvate is oxidised and CO2 is formed 

2. Acytl COa is created 

3. Rest of the oxiation of carbon molecules 

4. 3nadh and 1 fadh formed

5. adp is turned into atp

Describe the steps and fuction of oxidative phosphorilation

1. Electron carriers will give up their electrons (NADH and FADH2). (oxidised)

2. Electrons will go through structure sin the proteins

3. Hydrogen pumps from the mitochondrial matrix to the intermembrane space

   1. Matrex = low hydrogen

   2. Intermembrane spacehas high concentration

4. ATP formation

   1. Hdyrogens from the outer membrane goes through ATP syntahse and ADP is phoshorilated

   2. 

What part. ofthe mitochondira is used for cellular repsiration

1. There is the outer membrane and the inner membrane. 

   1. Inner Membrane: where electron transport proteins go. Electron carrieres are attached ehr

Describe ATP synthase and how it forms ATP? What is it? What is the F1 complex? The F0 complex

1. ATP synthase = molecular machine in the inner mitochondrial membrane

2. F0 complex (membrane bound)

   1. Works like proton channel = allows H+ ions to flow back into the mitochondrial matrix down their concentration gradient

   2. Movement drives rotation of the enzyme

3. F1 complex (catalytic portion in the matrix)

   1. Rotational movement in F0 is transmitted to conformational changes in F1 = atp production

   2. Enzyme works in 3 steps (driven by mechanical movement)

      1. Binding of ADP and Pi

      2. Catalyzing the reaction to form ATP

      3. Releasing ATP 

Major difference between mitochondrial and chloro plast structures

• ery sisilar but chloroplasts have thylakoids

Write out and describe the pathway of a protein designed for the mitochondrial matrix or the inner mitochondrial membrane

1. Proteins are fully made in the cytosol

2. Positive presequence recognized and brought to: the tom complex.

3.  Repelled quickly through intermembreane space (lots of positive charges reel the presequence)

   1. WHY? - because its positively charged and is repelled from the intermembran space 

4. Through TIM complex

5. Into the matrix or inner membrane

   1. If destined for the matrix = goes through instantly

   2. Destined for the inner membrane: translocase recognizses if it is supposed to be in the inner membrane

6. MPP cleaves the presequence

   1. Cuts the sequence (not fully formed protein met)

Write out the pathway of a protein Write out the pathway of a protein made from the mitochondrial genome and destined for the inner mitochondrial membraneand destined for the inner mitochondrial membrane

1. These are mainly made from the mitochondrial dna

2. Protein made in the matrix

3. Inserted into the membrane through Oxa 1 translocase (no positive charges0

   1. Helper proteins help carry it through yellow

   2. 

Write out the pathway of a protein destined for the outer membrane that has alpha helix or beta barrels

1. Peorwina with alpha helix go throug MIm1

2. Proteins with beta barrel first come through tom complex then through sam complex 

Note” proteins that are made for  outer mitochondrial membrane are made up of nuclear genome*

Write out the pathway for a protein destined for chloroplast stroma (chloroplast protein import)

more simple pathway to be completed

1. N-terminal signal sequence

2. Go through TOC complex

3. Then through TIC complex (requires energy from atp)

4. Sequence signal cleaved by spp

HSP are chaperones (do not go through the complexes)

How does mitochondrial import protieins in parkisons diease

1. Know how to look at the graph

   1. Tim and tom complex proteins levels are decreased in PD

   2. Leads to cell dysfunction and cell death

2. Overexpresison of TOM in PD patient cells

   1. As ros levels indicate cell stress increased ROS with increased cell stress)

   2. Researchers overexpressed TOm in pd cells (in vitro)

   3. REsult?

      1. Decreased cell stress

      2. Possible target for further research on PD

Q? what would happen if there is no proton gradeient

1. protiens would get stuck in the intermembrane space- no drive to go through the Tim complex

Where would proteins be if their presequence was cleaved off prematurely

the cytosol

What are some similarietes and differences between mitochodnrial and chloroplast transport

What are the components of the mitochondria (plymer and monomer forms) (tructure and use)

1. Actin

   1. “Monomer” form

      1. G-actin (globular)

      2. Single protein

      3. Attached to ATP (or ADP)

   2. “Polymer” form

      1. Polarity 

      2. F-actin (filament)

      3. Monomers attach together

      4. Has polarity (ends are different )(plus and minus end)

   3. Function(s)

      1. Cell movement, cell structure microvilli

2. Microtubules

   1. Monomer” form

      1. Tubulin dimer: alpha and beta subunits

      2. Attached to GTP (or GDP)

   2. “Polymer” form

      1. Cylender shape, dimers strung togehter

   3. Function(s)

      1. Mitotic/meiotic spindle, Cell shape, movement, organelle transportli

3. Intermediate filaments 

   1. Monomer form

      1. Two polypetiedes come together in a coiled-coil structure

   2. Polymer form

      1. A tetramer forms. Tetramers come together as protofilaments. Multiple protofilaments come to form a filament

   3. Function

      1. Keeps cells together, especially as we think about tissues

How does the actin polymer form

A. g actin globulars have different ends( they have polarity due to differences in natural shape)

actin molecules are able to attach to become a polymer

Describe the tubulin structure

1. tubulin structures have alpha tubulin and beta tubulin. Has a plus and minus end for polarity.

Do intermediate fillaments have polarity???

No lol

What is treadilling? Which filamments undergo this mechanisms? how is it similar between those molecules? what would happen if you cut in between the fillaments

Treadmilling

• Microtubule and actin

• “ monomers” with ATP/GTP attached are added to the plus end (growing end) of the filament

  1. ATP for actin, GTP for tubulin of microtubules

• ATP/GTP hydrolyzed at some point after addition

• Monomers with ADP/GDP attached are not as tightly bound and are lost off the minus end of the filament 

  1. Disassembly of the filaments

How do cells move and what is used in the fuction (which proteins and components

1. RHO

   1. Receives the signal to migrate. Activates RHO on actin

2. Proflin

   1. Exchange the Adp to atp on the monerm (forms ATP-actin)

3. Formin 

   1. Forms. Forms actin filaments in the forward direction

4. ArP2/3

   1. Building the actin branches off of the actin filament

How are microtubles oriented in the cell?

1. Minus end at the centrosome in the center of the cell

2. Positive ends on the microtubles 

   1. Closer to the outside of the cell (cell membrane)

What happens when the cell is dividing

1. The minus sides remain cetered at the centrisomes

2. Pluss signs overlap and attach to the chromosomes themselves

What ar ethe different types of microtubules and what are their funcitons

1. Kinetochore microtubles

   1. proteins are in the chromoses

   2. they try to bring the chromosome to one sid eof the cell

   3. Kenisins (attach to the chromosome ) (microtuble dissasebly

   4. Kensin will walk to the minus end of the microtubule

      1. the microtuble is activley dissasembled

2. Interpollar microtubules

   1. motor protiens (kinesin) walks to the plus end an dpushes the microtubles apart

   2. Slides apart to pull the chromosomes to opposite ends

3. Astral microtubles

   1. motor proteisn dynein walsk to inus end and pulls apart the microtubles to edges

      

What gies the ecm these charachteristics :STrong network, gel like consistancy, connection of ECM to cell

What would happen if interins are over or underactive

1. Integrins link cell to extracellular matrix

2. Focal adhesion?

   1. Cell is grabbing onto the floor for cell movement (floor is ecm) (helps move forward)

   2. Sends signal to move cell forward 

What are the cell juncions

!. Adherins junctions and Desmosomes

1. Cadherins mediate adheision between fillaments

2. Adherein junctions link actin fillaments of adjacesnt cells

3. Desmosomes use desmosomal cadherins to connect intermeiate fillamets, provding structural support

2. Tight junctions

   1. forms barriers between compartemnts and regulate molecular passage

   2. prevents diffusion of membrane proteins

   3. not linked to cytoskelital elements

3. Gap junctions

   1. allwos direct cytoplasmic communication between adjacent cells through connections

   2. enables the passage of ions and small molecules for cooridnated resposes (ex heart muscel)

What are some of the key components of the EC

• Collagin:

  • most abundant ECM protein, composed of three polypetide chains wound tighly togehter. Glycine occurs at every third amino acid (helps keep in close packing of the chains)

• Matrix polysacharides

  • Proteglycans: proteins with carbohydrait chains attached, on the outside of the cell

    • Glycosaminoglans (GAGS): long branched polycaccharides tha attach to proteins to form proteglycans

    • provide a gel- like consisency to the ECM by attracting water molecules due to negatively charged sulfate groups

• Adhesion proteins

  • Fibronectin: connects collagin and proteglycanc to cell surfaces via integrins

  • Laminin: binds to eachother, integrins, and proteglycans promoting cell adhesion and communication.

describe some of the Cell-ecm interactions

• cells can interact with the ECM through adhesion proteins (intigrins)

  • intigrins: transmembrane proteins that link the ECM to the cytoskeletin

Which of the following would happen if clathrin-mediated vesicle formation is inhibited?

• Endocytosis from the plasma membrane would be disrupted

Proteins destined to be secreted from the cell will be made by what

the rough er!!!