(Physiology)- Transport (Lec.3)

Question 1

Mediated facilitated diffusion
what molecules

Carrier Mediated facilitated diffusion
- what molecules

Answer 1

trans-membrane proteins, the protein just creates the tunnel. Can be open of closed. Na+ or K- move into the cell with concentration gradient

moves along concentration gradient doesn’t need ATP but needs active participation by carrier protein.
- Big glucose or amino acids can’t fit through other ones so they bind to carrier and go into the cytoplasm

Carrier protein is active

Question 2

Active Transport

Answer 2

moves against the concentration gradient to create a voltage and uses a carrier protein
ATP donates a P and helps ions bind to a carrier protein and flips it

Question 3

Primary active transport

Answer 3

against gradient
uses ATP, like a sodium-potassium pump. create a gradient for Na+ to want to come in and K+ out

3 sodium bind to inside and are expelled. using ATP we flip the molecule. Then 2 potassium bind and are imported

Question 4

SEcondary active transport

Answer 4

CO-TRANSPORT/ SYMPORTER
powered by concentration gradient of one solute. moves 2nd solute against the gradient

both ions move in the same direction
SYMPORTER

Lots of sodium outside, so wants to come in, with concentration gradient. Sodium powers it.

glucose or amino acids are pulled in for free with sodium

but glucose and amino acids are moving against their gradients

Question 5

Counter trasnport

Answer 5

ANTI-PORTER
similar to co-transport, but each molecule moves in different directions

powered by one going with its gradient and one going against

sodium coming into cell with gradient, but is moving calcium out against its gradient

Question 6

Vesicle Transport

examples

Answer 6

Endo and exocytosis, require energy

Ligand-mediated Endocytosis
Phagocytosis
Pinocytosis

Question 7

Receptor-mediated endocytosis

Eg.

Answer 7

Receptor sites are where molecules can bind to come inside the cell

molecules bind to the outside of the cell, and endocytosis takes in molecules as a vesicle

transport of lipids into the cell
LDL’s fat soluble vitamins, too big to difuse so have to be engulfed

Question 8

Phagocytosis

Answer 8

Immune cells do
engulf an entire pathogen
take it into the cell
use digestive enzymes to break down the pathogen
expel it using exocytosis

Question 9

Pinocytosis

Answer 9

bulk flow of water in and out of the cell

Question 10

Epithelial transport

Answer 10

MOVE SODIUM ACROSS 3 MEMBRANES FOR THE PRICE OF ONE
Combines both diffusion and active
transport for movement
Eg. Gut, Kidney

active Transport creates a high sodium concentration on the blood side of the cell
low sodium inside the cell
then the sodium channel allows sodium that wants to come into the epitheleal cells

Question 11

cell communication

what are the 3 types of receptors that can bind ligands

Answer 11

important for controlling growth, reproduction and other cellulat processes

Most use ligands (molecules that bind to cell or macromolecules)
* E.g hormones, neurotransmitters

3 types of receptors that bind ligands:
C.E.G receptors
* Channel-linked receptors
* Enzymatic receptors
* G protein-coupled receptors

Question 12

Channel linked receptors

Answer 12

Allow ions to move into or out of cells
* Occurs in response to neurotransmitter binding
* Help initiate electrical changes in muscle and nerve cells

change in electrical impulse
that is the neural message

Question 13

Enzymatic Receptors

Answer 13

we receive an external message, turn on protein kinases, turn on an enzyme that triggers a response
eg. protein synthesis

Protein kinase enzymes

KINASES TURNS ON A PROTEIN

put on a phosphate onto enzymes
or take off

turn on function or turn off

LIGAND BINDS, ACTIVATE PROTEIN KINASES ENZYMES, TURN ON ANOTHER ENZYME

phosphorylate and trigger another

change activites and processes within cell

• Phosphorylate other enzymes within the cell
• Turns on function
• Provides a mechanism for altering enzymatic activity

Question 14

G protein-coupled receptors

Answer 14

bind neurotransmitter, activates g protein, come over and open an ion channel or trigger a new enzyme

either way, turn on an enzyme that will turn on a function

OR, TURN ON A PROTEIN KINASE WITH A G PROTEIN

G PROTEIN CAN TRIGGER ANOTHER PROTEIN

AN EXTRA STEP

Question 15

second messenger

Answer 15

first is the hormone or neurotransmitter
bind to cell, specific binding site, triggers response inside the cell

cAMP, is the second

turn on protein kinases, which turn on proteins and enzymes

protein kinases turn on the cell response

take a phosphate put onto protein which triggers cell response

cell response to the hormone

Question 16

advantage to cAMP

when do we use it

Answer 16

lots of it is produced, which turns on a lots of kinases, turns on a lots of enzymes
which phosphorylates a lot of enzymes
activate a large response

QUICK AND FAST RESPONSE

a protein kinase can turn on many different responses

protein kinase, activates an enzyme that is triggerend by cAMP
cAMP dependent protein kinase

Question 17

other messengers

Answer 17

Calcium:
first messenger arrives
may trigger Ca from SER, can trigger kinase like cAMP too, give a cell response
works through DAG and IP3 proteins

Calmodulin:
another 2nd messenger, fast response
first messenger
calcium turns on calmodulin
calmodulin turns on kinases
kinases in an enzyme that puts a phosphate onto another enzyme or protein which adds energy and faciliates cell response

Question 18

3 second messengers

Answer 18

CCC
calcium
cAMP
calmodulin

activated once a primary messenger binds to outside

turn on enzymes by triggering protein kinases

which make cell responses