Exam 1

Question 1

Integral protein

Answer 1

channels, pores, carriers, enzymes, that go all the way through the membrane (extracellular– intracellular)

Question 2

Peripheral protein

Answer 2

enzymes, intracellular signal mediators; protein on only one side of the membrane

Question 3

Glycolipid

Answer 3

carbohydrate attached directly to the lipid bilayer

Question 4

Glycoprotein

Answer 4

carbohydrate attached to integral protein, majority of integral proteins and glycocalyx

Question 5

Proteoglycans

Answer 5

protein core between two carbohydrates but not connected to membrane or integral protein– attached via a charge (membrane + and molecule -)

Question 6

Glycocalyx

Answer 6

protects the cell by surrounding it with a negative charge– repels other negatively charged molecules; involved in cell-cell attachment/interactions; play role in immune reactions

Question 7

Cholesterol

Answer 7

increases membrane flexibility

Question 8

Rough endoplasmic reticulum

Answer 8

outer membrane covered in ribosomes (processing protiens) and newly synthesized proteins are extruded into the ER matrix from the nucleus
–proteins processed inside ER matrix: crosslinked, folded, glycosated, cleaved

Question 9

Golgi apparatus

Answer 9

4 or more stacked layers of flat vesicular structures, creates vesicles to secrete contents into extracellular space– bloodstream– target cell; some release contents into lysosomes
- receives vesicles from smooth ER and processes them (phosphorylated/glycosylated); contents are concentrated, sorted, and packaged for secretion
– provides enzymes for lysosomes to use

Question 10

Smooth endoplasmic reticulum

Answer 10

site of lipid synthesis, growing ER membrane buds continuously to form vesicles that travel to the Golgi apparatus

Question 11

Constitutive vs stimulated secretion

Answer 11

constitutive= random
stimulated= requires a stimulus to occur

Question 12

Lysosomes

Answer 12

contain hydrolytic enzymes (acid hydrolases); fuse with pinocytotic/phagocytotic vesicles to form digestive vesicles
– issues with enzymes= lysosomes become engorged with undigested substrate– disease

Question 13

Peroxisomes

Answer 13

similar to lysosomes except for formed by self replication and contain oxidases

Question 14

Chromatin

Answer 14

condensed DNA found in the nucleoplasm, functions to form the granular subunits of ribosomes

Question 15

clathrin-coated pits

Answer 15

receptors coated in pits and receptor binding causes cell to change shape around material to form vesicle, endocytosis is ATP-dependent and involves recruitment of actin and myosin

Question 16

Cytoskeleton

Answer 16

Intermediate filaments (keratins), microtubules, thin filaments (f-actin), thick filaments (myosin)S

Question 17

Simple diffusion

Answer 17

molecules move readily across the membrane based on their concentration gradient (water soluble molecules require channels/pores/transport protein)

Question 18

Ungated channels

Answer 18

example of simple diffusion- transport based on size, shape, and charge of channel and ion

Question 19

Gated channels

Answer 19

voltage: membrane potential reaches correct value– opens and falls below– closed (action potential)
chemical: neuromuscular junction (substrate binds to receptor–opens)
-facilitated diffusion

Question 20

Facilitated vs simple diffusion rate

Answer 20

simple=linear
facilitated= starts out linear and plateaus because proteins can only bind so fast (limited by Vmax of carrier proteins)

Question 21

Active transport

Answer 21

occurs against a concentration gradient, required energy (ATP)

Question 22

Primary vs secondary active transport

Answer 22

Primary= required ATP
Secondary=energy from electrochemical gradient (usually Na)

Question 23

Na- K ATPase

Answer 23

–antiporter, sodium ions (3) out and potassium ions (2) in
–uses about 20% typical cells energy and 67% neurons energy

Question 24

Ca ATPase

Answer 24

present on cell membrane and sarcoplasmic reticulum– maintains a low cytosolic Ca concentration– pumps Ca from cytosol back into sarcoplasmic reticulum

Question 25

H ATPase

Answer 25

-parietal cells of stomach (HCl secretion) and intercalated cells of renal tubules (controls blood pH) -pumps H ions

Question 26

symporters vs antiporters

Answer 26

--symporters= molecules traveling in same direction (driver must bind first- down concentration gradient- where energy comes from) --antiporters= ions moving in opposite directions (both must bind before moving-- driver first)

Question 27

Digoxin

Answer 27

--cardiac glycoside, increase cardiac muscle performance in patients with heart failure --blocks Na/K pump-- increase Na concentration in cell-- decrease Na ability to lower Ca levels in cell-- facilitate a stronger more forceful contraction of muscle because more Ca available

Question 28

Transcellular Transport of Glucose/AA

Answer 28

-AA and glucose pulled from lumen into epithelial cell- Na symporter (diffusion to get into extracellular fluid) -Na/K pump pumping Na against conc. gradient- creating it so other side can pull in AA/glucose

Question 29

Osmosis

Answer 29

net diffusion of water-- water moves toward higher salt concentration (down gradient)

Question 30

Osmotic pressure

Answer 30

the minimum amount of pressure required to halt the flow of water down conc. gradient/ to counter osmosis; higher concentration of solute= higher pressure of osmotic pressure to move against conc. gradient; water moves down concentration gradient until reach equilibrium

Question 31

Osmolarity

Answer 31

--mOsm= index of the concentration of PARTICLES per liter solution (molecules disassociate: NaCl --> Na/Cl --if the molecule disassociates then multiple mM by how many particles it disassociates into

Question 32

Molarity

Answer 32

--mM= index of concentration of MOLECULES per liter solution

Question 33

Tonicity (effective osmotic pressure)

Answer 33

depends on the properties of both the membrane and the solute

Question 34

Steady state cell volume

Answer 34

--dependent upon the concentration of IMPERMEANT particles in the extracellular fluid --higher permeability= more transient the change

Question 35

Hypernatremia

Answer 35

-increased plasma Na-- water leaves cells-- cells shrink -central/nephrogenic diabetes insipidus -decreased release/response to ADH

Question 36

Hyponatremia

Answer 36

-decreased plasma Na-- water enters cells-- cells swell -syndrome of inappropriate ADH secretion -too much ADH

Question 37

K equilibrium potential (Ek)

Answer 37

-electrochemical potential that counters net diffusion of K -Ek= -94 mV -Ek= -61 x log (Ki/Ko)

Question 38

Na equilibrium potential (ENa)

Answer 38

- electrical potential that counters net diffusion of Na -ENa= +61 mV -ENa= -61 x log (Nai/Nao)

Question 39

Resting membrane potential (Vm)

Answer 39

--the membrane is more permeable to K than Na-- more potassium leak channels-- favors loss of K over uptake of Na -- Vm= -90 to -70

Question 40

Resting membrane potentials of various cells

Answer 40

Skeletal muscle fibers= -85 to -90 Smooth muscle fibers= -50 to -60 Neurons= -60 to -70

Question 41

Net driving force of ions

Answer 41

the difference in millivolts between the membrane potential and the equilibrium potential for that ion (Eion)

Question 42

Depolarized

Answer 42

-membrane potential moves toward 0 mV (becomes more positive) -Na leak channels opening cause-- close in downshoot

Question 43

Hyperpolarization

Answer 43

goes below resting membrane potential

Question 43

Overshoot

Answer 43

membrane goes above 0mV

Question 43

Repolarization

Answer 43

-membrane goes back down toward Vm-- towards resting potential -K leak channels open and cause-- open in downshoot

Question 44

Excitability

Answer 44

ability of membrane to increase in mV

Question 44

Threshold

Answer 44

-cutoff for cell of where we see action potential-- membrane potential must exceed -Na volted gated (leak) channels open when membrane potential reaches threshold

Question 45

Na/K activation gate

Answer 45

Na= activation gate opens when membrane potential reaches certain voltage--closes when membrane reaches Vm-- inactivation gate opens and activation gate closes K= K has slow activation when Na inactivation gate closes

Question 46

Absolute refractory period

Answer 46

a second response isn't possible no matter the strength or duration of stimulus

Question 47

Relative refractory period

Answer 47

a second response can be elicited, but requires a stronger stimulus