Signal transduction, ECM, mitochondria

Question 1

Membrane proteins

Answer 1

Play a major role in signal transduction by converting an extracellular signal into intracellular signals

Question 2

Signal transduction allows cells to

Answer 2

• Grow
• Divide
  -Survive (or not)
• Move
  -Differentiate (ie time to change)
• Up - or down regulate metabolic activity

Question 3

Ligand

Answer 3

-Small molecule that binds to a receptor

-Does not enter the cell

• Cytosolic side of the receptor is affected by the conformation change

-These conformational changes cause other proteins (in the cytosol or membrane bound) to become activated

Question 4

Ligand binding

Answer 4

Changes the conformation of the receptor protein

Question 5

Stages of signal transduction

Answer 5

1. Binding to the ligand to receptor
2. Signal transduction via second second messagers (like cAMP, cacium or G-protein
3. Cellular response (cellular growth, Cell division, Store glucose as glycogen)

Question 6

Glycogenesis

Answer 6

• How epinephrine (adrenaline) activates conversion of glycogen stored in the liver

(example of signal transduction

-At the core you have a glycogenin protein surrounded by branches of glucose units

Question 7

Glycogen

Answer 7

-A molecule assembled from glucose units

Question 8

Glycogenin

Answer 8

-Enzyme that acts as a primer to polymerize the first glucose molecules then other enzymes to take over

Question 9

Communities of cells

Answer 9

Cells that work together to preform a function

Question 10

Anchor membrane proteins

Answer 10

-Play and important role by interacting with components of the ECM

Question 11

ECM

Answer 11

• An organized network of material produced and secreted by cells
• Is abundant in connective tissue of animals
  (Tendons, ligaments, dermis)

Question 12

Functions of the ECM

Answer 12

1. Cell adherence
2. Communication between cells
3. Cell shapes, mechanical support
4. Serves as barrier, filters our some particles

Question 13

ECM and aging

Answer 13

-Development of facial wrinkles is a kind of fibrosis (thinking and scarring) of connective tissues of the skin

Question 14

Mis repair - accumulation aging theory

Answer 14

• Wrinkles develop from incorrect repair of injured elastin (elastic) fibers and collagen fibers
• During the repairing process some of the broken elastic fibers and collagen fibers are not regenerated and restored by altered fibers

Question 15

ECM components

Answer 15

-Made produced by cells and assembled in a network

• Major components are proteins like collagen and glycoproteins

-Proteoglycans = Proteins with chains of polysaccharides

Question 16

Non-animal cells

Answer 16

-Cells of bacteria plants and fungi have walls

-Plant cell walls = ECM

• Composed of cellulose, hemicellulose, pectin and proteins
  -Provides structural support to cell and to whole organisms (equivalent to skeleton)
• Protect cell from mechanical damage and pathogen attack

Question 17

Secondary wall

Answer 17

-Contains plasma membrane

-Contains cellulose + lignin

-Provides strength in these cells which provide mechanical support to the plant body

• Can function as a conduit for transporting water

Question 18

Middle Lamella

Answer 18

Where two (plant) cells