High in protein, and have no cholesterol

Photosynthetic membranes inside the chloroplasts

Pigments, electron transport protein and the ATP synthetase are all on or in this

double membrane

they are not photosynthetic membranes

In Mitochondria..

F₁ faces the..

High H+ faces

F₁ faces the matrix

High H+ faces the outside of the inner membrane

Chloroplast...

CF₁ faces the..

High H+ faces the

CF₁ faces the stroma

High H+ faces the inside of the thylakoid membrane

In mitochondria and chloroplasts H+ flux is..

H₂O oxidized to O₂

Energy required (light)

Makes sugars from CO₂

H+ high inside thylakoids

CF₁  faces out

H+ efflux during ATP synthesis

O₂ reduced to H₂O

Energy produced (ATP)

Makes CO₂ from sugars

H+ high outside inner membrane

F₁ faces in

H+ influx during ATP synthesis

light

CO₂ + H₂O --> (CH₂O)_n + O₂

carbohydrates              

CO₂ is reduced to make carbs by reductive biosynthesis in the dark reaction

requires ATP and NADPH from the light reactions

PQ

(plastoquinone)

PC

(plastocyanin)

1.  Photolysis

2.  Pass e- from PSII to PSI

3.  Pass e- from PSI to NADP+

PSII uses light energy to spolit water in the lumen.  This produces three inportant products:

H₂O--> 2H+ + ¹/₂O₂ + 2e-

Manufactoring and Distribution

Make proteins and lipids and ship then to their appropriate desttinations by vesicular trafficking.  Also some recycling done to save energy

Rough endoplasmic reticulum (not smooth)

Golgi

Transition vesicles

lysosomes

plasma membrane

Secreted continuously

Regulated release

Stay inside lumen of ER, golgi, or lysosomes

Membrane bound, integral protein on any membrane in this system

Soluble cargo, inside the vesicles
and

membrane bound cargo, both proteins and lipids, in the membranes

1. Soluble cargo, inside the vesicles

2.  Membrane bound cargo, both proteins and lipids in the membranes

Endoplasmic Reticulum

(ER)

Closed membrane system

inside this is called the lumen of the ER

Two Types:  Smooth endoplasmic reticulum

and rough endoplasmic reticulum

SER

Smooth Endoplasmic Reticulum

Steroid hormone synthesis

Detoxification, often converting bad hydrophobic (insoluble) compunds into hydrophilic (soluble) ones

Gluconeogenesis, making glucose from stored glycogen

Ca++ sequestration and regulated Ca++ release

Also has other functions

RER

Rough Endoplasmic Reticulum

Synthesis of integral membrane proteins

Synthesis of many suluble proteins, mainly secreted proteins and those destined to stay within the endomembrane system

Processing of newly synthesized proteins that were made by the RER

Membrane biogenesis by synthesis of membrane lipids and membrane proteins

Glycosylation of proteins and lipids

1. Free polysomes (polyribosomes) floating around freely in the cytoplasm

2. Bound to RER makiing proteins to travel in the endomembrane system

Protein in the process of being made but not complete

(not yet released from the ribosome)

1.  As soluble proteins in the cytoplasm on free polysomes

• Some can stay in the cytoplasm (tubulins, actin...)

Some can be targeted to go to organelles with and NLS, MLS, CLS. etc

2.  Contranslational  translocation on RER

• Integral membrane proteins
• Proteins destined to stay inside the endomembrane system as either biosynthetic or degredative enzymes
• secreted proteins

In the pulse chase expirement what does the chase do?

If a nascent protein has a signal sequeance, it binds to SRP

The SRP-signal sequence binds to the SRP receptor, movin the ribosome to the RER

Translation resumes with nascent protein in the translocon

Translation continues as the protein is translocated into the lumen of the RER

(First 3 same as that of endomembrane system)

If the nascent protein has a hydrophobic stop transfer sequence it will stop further translocation and make it an integral membrane protein.. if it does not has a stop sequence then it is a soluble protein instead of an integral membrane protein

Some translocation may continue until complete

The translocon opens leaving the integral membrane prote stuck in the membrane.  Two amino acid sequences are necessary for the sequence of an integral membrane protein

1-2. Start adding carbohydrates to the dolichol carrier on RER. Dolichol is a lipid

3-4. When the core carbohydrates is complete, flip it inside the RER

5. Inside the RER, transfer the core to a protein (or even a lipid)

6. Bud off a vesicle with the glycoprotein in it and send it to its destination

How do Complex Carbohydrates get on Glycoproteins so that they are facing the Outside of the Cell?

They travel through the Endomembrane System and end up on the outside when the transition vesicles turn inside-out

trans-Golgi Network

(TGN)

medial-Golgi

cis-Golgi Network

(CGN)

What does golgi do?

It sorts proteins to go into vesicles destined for other locations

*There are different compartments for different glcosylations

1. Help to form vesicles by causing membrane curvature and budding

2.  Help provide a mechanism for selecting proteins to go into vesicles

3.  Help provide a mechanism for vesicle identification so they can go to the right place

Trafficking of soluble proteins in vesicles from RER

1.  A transmembrane cargo receptor, facing the lumen of RER, binds specific cargo only inside the RER

2. The other end of the receptor protein, the part facing the cytoplasm, binds a specific coat protein. This labels the outside of the vesicle to tell anything in the cytoplasm what is inside

3.  The coat protein can help the membrane to bud off and may help to traffic the vesicle to its appropriate destination

How to sort and retain proteins from Golgi into COPII coated vesicles

1. Soluble proteins (cargo) ni the lumen bind to specific transmembrane cargo receptors which face the lumen.  This targets them to go into the vesicles

2.  COPII proteins bind to the cytoplasmic part of the cargo receptor

3.  The exterior COPII taregets the vesicle to move in an anterior direction

Retrieval of RER enzymes that get into Golgi

RER proteins that contain the amino acid sequence KDEL (lys, asp,glu,leu) should stay in RER

Some RER enzymes accidentally “escape” to Golgi in COPII vesicles

These enzymes can be retrieved by KDEL receptors in COPI vesicles and returned to RER

tight Junctions

adheres junctions

desmosomes

gap junctions

hemidesmosomes

cellular scaffolding or skeleton contained wihin the cytoplasm that is made out of protein

Is present in all cells

A dynamic structure that maintains cell shape, protects the cell, enables cellular motion and plays important roles in both intracellular transport and cellular division

1. Assembled from a pool of protein subunits

monomer --> polymer (polymerization)

polymer --> monomer (depolymerization)

2. The polymers (filaments) are often dynamic, always changing by assembly and disassembly

1. Microtubules

2. Microfilaments

3. Intermediate filaments

• Each filament is formed from a different protein subunit
• Subunits are connected to one another by weak noncovalent bonds
• Permits assembly and disassembly
• Each filament has distinct mechanical properties

nuclear lamina

others extend across cytoplasm

gives mechanical strength

together make a tubulin hetrodimer

they polymerize to make microtubules

can vary greatly

50-110 kDa

Tubulin Dimer

Subunit for the protofilament polymer

they polymeriz end to end to form protofilaments

This is a linear polymer of tubulin dimers

they then bundle into a hollow cylindrical filaments

alpha is the minus end

beta is the plus end

It is an important feature

one end will be exposer to the ɑ [-](alpha) end and the other end will have the β[+] (beta) end exposed

Cytoplasmic

Axonemal

Centriolar

They are found in the cytoplasm and are singlet (13 protofilaments).

They are scaffolded or in tracks for intracellular transport, cell shape, and cell division