9/7/22

Question 1

to survive and grow cells must…

Answer 1

1) exchange molecules with environment
2) import nutrients (sugars and aa’s)
3) eliminate metabolic waste products
4) regulate concentration of inorganic ions in cytosol and organelles

Question 2

molecules that diffuse across lipid bilayer of plasma membrane

Answer 2

CO2 and O2

Question 3

membrane transport proteins

Answer 3

span lipid bilayer
provide private passageways across the membrane for select substances

Question 4

what type of molecules can be transported across the cell membrane?

Answer 4

inorganic ions and small, water-soluble molecules

Question 5

transporters

Answer 5

shift small organic molecules or inorganic ions from one side of the membrane to the other by changing shape

Question 6

channels

Answer 6

form tiny hydrophilic pores across the membrane through which such substances can pass by diffusion

Question 7

ion channels

Answer 7

permit passage of inorganic ions
ions are electrically charged, their movement causes electrical force (voltage) across the membrane

Question 8

human body function

Answer 8

transform nutrients from foods using metabolic processes into biological structures and chemical energy

Question 9

what type of lipids spontaneously form membrane structures?

Answer 9

amphipathic lipids!
when fatty acid touches water, micelle is formed

Question 10

micelle structure

Answer 10

carboxyl group faces water, hydrophobic groups face inside and hide from water

Question 11

phospholipid

Answer 11

ultimate amphipathic lipid

Question 12

amphipathic

Answer 12

has both hydrophobic (tails) and hydrophilic (heads) properties

Question 13

phospholipid bilayer

Answer 13

tails inside, heads outside

Question 14

cell membrane image

Answer 14

Question 15

cell membrane structure is

Answer 15

• highly dynamic
• FLUID
• phosphatidyl choline bilayer

Question 16

cell membrane is composed of

Answer 16

carbon/palmitic

nitrogen

oleic

oxygen

water oxygens

phosphorous

Question 17

cell membrane structure: heterogeneous or homogeneous?

Answer 17

Highly heterogeneous!

contains lipid fluid and lipid raft domains

Question 18

requirements for unicellular organism to survive and replicate

Answer 18

1. import metabolic substrates
2. export metabolic waste
3. maintain cell volume

Question 19

each membrane type in a cell possesses a…

Answer 19

unique lipid composition

Question 20

where in plasma membrane is cholesterol most present?

Answer 20

lipid rafts!

more rigid structures

Question 21

phosphatidylcholine

Answer 21

most common lipid in organelles

Question 22

where is cholesterol produced and where is it stored

Answer 22

produced in ER, but there is low concentration of cholesterol in ER bc it sends it mostly to plasma membrane

Question 23

sphingolipids

Answer 23

tag our cells for identification

EX: blood type

Question 24

aquaporins

Answer 24

transport water across lipid bilayer

Question 25

carriers aka

Answer 25

transporters

Question 26

transporters

Answer 26

* bind substrates with high stereospecificity * transport rates are well below the limits of free diffusion * saturable

Question 27

channels

Answer 27

* stereospecificity \< transporters * transport \>\>\> transporters * non saturable

Question 28

uniporters

Answer 28

membrane transport protein that transports single species of substrate across cell membrane

Question 29

symporters

Answer 29

proteins that simultaneously transport 2 molecules across a membrane in the same direction

Question 30

antiporters

Answer 30

cotransporter and integral membrane protein that uses secondary active transport of 2 of more DIFFERENT molecules or ions across phospholipid membrane

Question 31

transporters are everywhere in the cell

Answer 31

cell membrane, lysosome, mitochondria

Question 32

types of transporters

Answer 32

facilitated single solute coupled counter transport

Question 33

GLUT

Answer 33

glucose transporter (uniporter or single solute)

Question 34

SGLT

Answer 34

sodium-linked glucose transporter (symporters, or coupled)

Question 35

Slc26

Answer 35

chloride/bicarbonate exchanged (antiporter, or counter)

Question 36

can facilitated transporters generate a conc gradient?

Answer 36

NO!

Question 37

secondary active transport

Answer 37

occurs when endergonic (uphill) transport of one solute is coupled to the exergonic (downhill) flow of a different solute

Question 38

primary active transporters aka

Answer 38

pumps

Question 39

pumps

Answer 39

present in all cells in body directly couples energy of ATP hydrolysis to transmembrane ion movement create ion gradients

Question 40

what are gradients?

Answer 40

a form of chemical energy energy is stored in transmembrane ion gradients

Question 41

what is required to create gradients?

Answer 41

energy

Question 42

if there is a leak of ions across a membrane,

Answer 42

the cell needs to spend energy to restore the gradients

Question 43

how is energy in ion gradients captured?

Answer 43

transport proteins! EX: electron transport chain, proton gradient, and ATP production in mitochondria

Question 44

osmosis

Answer 44

water molecules diffuse directly across lipid bilayer SLOW PROCESS!

Question 45

aquaporins

Answer 45

specialized channel proteins in plasma membrane of some cells that greatly facilitate the flow of water curvy paper towel roll shaped

Question 46

ion channels purpose

Answer 46

speed passage of ions across membranes by providing an aqueous path across the membrane

Question 47

ion channels (rhyme)

Answer 47

diffuse at high RATES have a GATE regulated by a biological signal

Question 48

when ion channel gate is open

Answer 48

ions move through channel, in direction dictated by ion's charge and the electrochemical gradient

Question 49

epithelia function

Answer 49

separates interior of body from external world

Question 50

epithelia structure

Answer 50

multicellular layers of cells joined together, side to side layers contain diff cells: 1. stratified (as in epidermis, outer skin layer) 2. simple epithelium (only one cell thick, lining of gut)

Question 51

epithelial tissue is

Answer 51

purely cellular and avascular

Question 52

what does epithelial tissue cover?

Answer 52

all free surfaces: cutaneous, mucous and serous, glands EX: gut lining, liver, pancreas, gall bladder, lungs, kidneys

Question 53

functions of epithelia

Answer 53

1. protective barrier 2. secretion of specialized products (hormones, milk, tears) 3. excrete waste 4. absorption of nutrient 5. exchange O2 and CO2 6. detect signals (light, sound, chemicals)

Question 54

epithelial lining is…

Answer 54

polarized! displays two faces: apical surface and basal surface

Question 55

epithelial lining apical surface

Answer 55

free and exposed to the air or watery fluid

Question 56

epithelial lining basal surface

Answer 56

attached to a sheet of connective tissue called the basal lamina

Question 57

polarity of epithelial cells depends on…

Answer 57

junctions that the cells form with one another and with the basal lamina

Question 58

tight junctions are formed by…

Answer 58

interactions btwn strands of transmembrane proteins (occludin and claudins) on adjacent cells

Question 59

tight junctions functions

Answer 59

1. restrict paracellular pathway in the epithelia 2. act as a barrier to solute diffusion 3. modulation of tight junctions may alter nutrients and drug bioavailability

Question 60

tight and leaky epithelia BOTH

Answer 60

impermeable to large hydrophilic molecules, including proteins

Question 61

leaky epithelia is more permeable to…

Answer 61

small molecules and ions maybe relation to inflammatory diseases of intestine

Question 62

vectorial transport

Answer 62

transport of an ion or molecule across an epithelium in only one direction (EX: nutrient absorption in the gut) requires transport proteins to be nonrandomly distributed between apical and basolateral plasma membrane

Question 63

transcellular transport

Answer 63

substances travel through cell, passing through both apical and basolateral membrane

Question 64

paracellular transport

Answer 64

substances transfer across an epithelium by passing through the intercellular space between cells