chp 6

Question 1

extracellular matrix contains ____

Answer 1

integrins

Question 2

what are integrins?

Answer 2

class of glycoproteins, that extend from the cytoskeleton within a cell through plasma membrane, into the cellular matrix

Question 3

What do integrins do?

Answer 3

serve as adhesion molecules between cells and extracellular matrix. They act as relay signals between the intracellular and extracellular components

Question 4

functions of integrins are?

Answer 4

impart a polarity onto the cell
affect ability of cell motility
affect ability of cells to proliferate in tissues
affect cell adhesion in their tissues

Question 5

what are the two types of carrier-mediated transport?

Answer 5

facilitated diffusion and active transport

Question 6

Three types of non-carrier mediated transport

Answer 6

simple diffusion of lipids, simple diffusion of ions, osmosis

Question 7

simple diffusion of lipids are:

Answer 7

molecules through phospholipid bilayers of plasma membrane

Question 8

simple diffusion of ions ?

Answer 8

across plasma membrane through channel proteins

Question 9

osmosis is?

Answer 9

diffusion of water molecules through aquaporin channels in plasma membrane

Question 10

passive transport

Answer 10

-is the net movement of molecules/ions from HIGH to LOW concentration.
-no ATP or energy required
-all types of non-carrier mediated transport fall under passive transport

Question 11

Active transport is what type of transport?

Answer 11

carried-mediated transport

Question 12

net movement of molecules/ions from LOW to HIGH concentration against a concentration gradient
-atp/energy is required

Answer 12

active transport

Question 13

what type of transport is facilitated diffusion?

Answer 13

carried-mediated transport

Question 14

-Glucose or organic molecule binds to site on specific carrier protein.
-Carrier protein undergoes conformational change to release molecule on other side of membrane
-if the organic molecule in questions concentration INCREASED outside if the cell, this would INCREASE of facilitated diffusion

Answer 14

facilitated diffusion

Question 15

Net diffusion is?

Answer 15

to have a concentration difference , the aim is to equalize the concentration of both regions

Question 16

Diffusion through the PM

Answer 16

-concentrations from HIGH to LOW
-nonpolar molecules and small but uncharged molecules with polar covalent bonds can diffuse across plasma membrane
-oxygen concentration is high in extracellular fluid
-gas exchange by diffusion occurs in the lungs
-concentration gradient for O: high (air) to low (blood)
-concentration gradient for CO2: high (blood)to low (air)

Question 17

ion channels

Answer 17

these proteins allow charged ions to be transported but are selective in which ones they allow

Question 18

ion channels can always be ______

Answer 18

gated so require a certain stimulus to open an closed channel.

Question 19

rate of diffusion depends on:

Answer 19

1. Magnitude of concentration difference across membrane
2. Permeability of membrane to diffusing substances
3. Temperature of solution
4. Surface area of membrane through which substances are diffusing

Question 20

osmosis has 2 requirements to occur:

Answer 20

1. membrane must be selectively permeable to solute
2. difference in solute concentration on two sides of the membrane

Question 21

what is osmotic pressure?

Answer 21

pressure needed to stop osmosis from occurring. The greater the solute concentration of a solution, the greater its osmotic pressure

Question 22

measuring osmolality

Answer 22

measure of total concentration of a solution

Question 23

tonicity is ?

Answer 23

describes the effect of solution on osmotic movement of water

Question 24

isosmotic?

Answer 24

having the same osmolality

Question 25

hypotonic is?

Answer 25

cells enlarge/burst water goes in volume increases

Question 26

hypertonic is?

Answer 26

cells shrink bc water leaves

Question 27

common characteristics between enzymes and carrier proteins:

Answer 27

specificity, competition, satuaration

Question 28

transport maximum?

Answer 28

Maximum rate at which a substance can be transported by carrier protein across a plasma membrane. Transport maximum is related to saturation

Question 29

occurs when hydrolysis of ATP is directly responsible for the function of the carriers.

Answer 29

primary active transport

Question 30

Ca2+pump

Answer 30

-Carrier protein transports Ca2+ from a lower concentration side inside the cell to a higher concentration, outside the cell -1Ca2+ within the cell binds to a site in the carrier protein 2) ATP is hydrolyzed into ADP and phosphate (Pi), which are bound to the pump; phosphate is added to carrier protein 3) Both exits for Ca2+ are blocked momentarily, release of ADP leads to phosphorylation... -Phosphorylation causes “hinge-like” motion of carrier 4) Hinge-like motion of protein carrier allows Ca2+ to be released in the extracellular fluid

Question 31

Na+/K+ pump

Answer 31

Three Na+ ions in cytoplasm move partway into pump + bind to 3 amino-acid sites 2) ATPase is activated; ATP is hydrolyzed into ADP and Pi, momentarily blocking both exits (as in Ca2+ pump) 3) ADP is released, inducing a conformational change to open a “passage” for the 3 Na+ ions to exit into the extracellular fluid 4) Two K+ ions bind to the carrier, releasing Pi 5) Release of Pi makes pump return to initial state + release 2 K+ ions back into cytoplasm K+ is higher concentration in cytoplasm than extracellular fluid Na+ is higher concentration in extracellular fluid than cytoplasm

Question 32

Secondary active transport

Answer 32

-In conjunction to one another; Na+ is transported against its’ concentration gradient, from low to high concentration (as in Na+/K+ pump) to transport ANOTHER molecule or ion DOWN its’ concentration gradient (this mol/ion is going from high concentration to low concentration) -Cotransport/Symport: Both Na+ and molecule move in the same direction (into/out of the cell) -Countertransport/antiport: Na+ and molecule move in opposite direction (one is in/out; other is out/in) **REQUIRES SODIUM IONS Eg; cotransport of Na+ and glucose: -SGLT2 (carrier protein) transports Na+ and glucose at the same time, moving from kidney tubules to epithelial cell lining -Lower intracellular concentration of Na+ is required **Depends on Na+/K+ pump, which depends on ATP **co-transport indirectly depends on ATP **Na+ will move down its’ concentration gradient **Glucose will move up its’ concentration gradient -Secondary active transport depends on primary active transport

Question 33

membrane potential

Answer 33

-Na+/K+ pumps move three Na+ ions into the extracellular fluid ( against the concentration gradient) -Na+/K+ pumps move two K+ ions into the cytoplasm ( against the concentration gradient) -ATP Pi groups + organic molecules are negatively charged (anions) at pH of the cytoplasm -Anions are fixed within cell membrane, attract cations (K+, Na+, Ca2+, etc) -Plasma membrane is most permeable to K+ ion -This attraction leads to an unequal distribution of cations between intracellular and extracellular component

Question 34

potential difference

Answer 34

cells are negative charge on the inside of plasma membrane and positive charge outside

Question 35

equilibrium potentials

Answer 35

Membrane potential (measure of how much an ion contributes to potential difference) depends on: A) Concentrationgradient B) Membranepermeability -Membrane potential is primarily determined by the K+ concentration gradient -K+ Equilibrium potential: Constant movement of K+ in and out of the cell(s) because of electrostatic attraction to anions till a particular value is reached for inside (higher concentration of K+ ions) and outside (lower concentration of K+ ions) -The amount that goes = the amount that goes out (net diffusion) -Value of Ek (K+ equilibrium potential) = -90mV ** >-90mv ; More K+ into the cell ** <-90mV; More K+ diffuses out of the cell -Na+ Equilibrium potential: >+66mV; more Na+ into the cell<+66mV; more Na+ diffuses out of the cell

Question 36

the three types of cell signaling are:

Answer 36

paracrine, endocrine, and synaptic signaling

Question 37

paracrine signaling is?

Answer 37

Cells in an organ secrete a regulatory molecule.This molecule will travel through an extracellular matrix to nearby target cells.

Question 38

autocrine signaling is?

Answer 38

regulatory molecules released by autocrine cells act on same cells

Question 39

synaptic signaling is?

Answer 39

Axon of neuron innervates target cell; synapse between the axon ending and target cell. A cleft is present between the two cells and neurotransmitters are released by the axon endings.

Question 40

endocrine signaling is?

Answer 40

endocrine glands secrete hormones into the extracellular fluid

Question 41

cells must have specific receptor proteins to respond to any of the above signaling types

Answer 41

true

Question 42

IF regulator cell is NONPOLAR = Diffuses through plasma membrane and enters cell IF regulatorcell is polar = Attaches to receptor on surface of plasma membrane NONPOLAR ; No need for second messengers (“mediators” for regulator cell) POLAR; Need for second messengers

Answer 42

true

Question 43

second messengers are?

Answer 43

Mediator of the regulatory molecule -Second messengers concentration ↑ by regulator cell’s attachment to receptor -Second messengers stimulate metabolism in target cell in a SIMILAR manner of regulator cell -Eg; cAMP (cyclic-AMP): A) Polarregulatormoleculebindstoits’receptoronsurfaceofplasmamembrane B) IndirectactivationofenzymethatproducescAMPfromATPprecursorincytoplasm C) cAMP concentration ↑ , activating inactive enzymes in cytoplasm D) Enzyme activated by cAMP alter cell activities to produce effect of regulator molecule

Question 44

G-proteins are:

Answer 44

Alpha, beta, and gamma subunits

Question 45

G-proteins are:

Answer 45

-Activates the enzyme (indirectly) when regulator molecule binds to receptor protein -When regulator molecule binds to receptor protein; A) Alpha subunit dissociates from Beta-Gamma subunit B) Alpha subunit releases GDP+binds to GTP C) Alpha subunit moves through cell and binds to enzyme (temporary activation) D) Alpha subunit hydrolyzes GTP into GDP and Pi, 3 subunits reassemble and return to receptor protein