Membrane structure and function

Question 1

lipids components

Answer 1

• phosphogylcerides *
• sphingolipids
• sterols

Question 2

Proteins components

Answer 2

• peripheral (membrane interacting)

- integral (through membrane)

Question 3

Carbohydrates components

Answer 3

-mono, di, oligo (glyco- protein and lipids)

Question 4

Selective permability

Answer 4

intrinsic phospolipids

Question 5

energy transduction

Answer 5

• inner mitochondrial membrane- ETC
• chloroplast thylakoid- Photosynthesis
• bacterial plasma membrane

Question 6

transport

Answer 6

proteins transport

Question 7

aquaporins

Answer 7

H2O transport

Question 8

communication

Answer 8

single transduction (hormones) and cell-cell recognition (gylcoprotein identification)
-enyzme activity faciliate intercellular joining

Question 9

E-face

Answer 9

exoplasmic

-outside facing

Question 10

P-face

Answer 10

protoplasmic

-inside facing

Question 11

phospholipids

Answer 11

-can move lateral, rotatate, flex FA chain, and flip flop (enzyme called flipases)

Question 12

Membrane proteins

Answer 12

move slowly but not laterally (diffuse slowly)
membrane must be fluid
too fluid= loss of organization and support
too rigid= poor motility

Question 13

Factors effects membrane fluidity

Answer 13

• less fluid; low temp, longer FA chain, trans double bonds
• more fluid= high temp, shorter FA chain, cis double bonds
• cholesterol= decrease fluidity at high temps and increase at low temps

Question 14

Phosphlipid bilayer

Answer 14

-selective permeable (water can cross) and transport proteins allow additional discrimination

Question 15

hydrophobic molecules

Answer 15

free diffusion

Question 16

small uncharged polar molecules

Answer 16

some resistance, transport protein helps

Question 17

large uncharged polar molecules

Answer 17

large resistance, transport protein required

Question 18

inorganic ions

Answer 18

large resistance, transport protein required

Question 19

Passive transport

Answer 19

diffusion of substances across membrane with no energy investment

Question 20

diffusion

Answer 20

substance moves from high concentration to low via thermal motion

Question 21

concentration gradient

Answer 21

difference in solute concentration across membrane or between two parts

Question 22

Osomsis

Answer 22

simple diffusion of free water across a selectively permeable membrane

Question 23

molarity

Answer 23

concentration of solute (pressure)

Question 24

osmolarity

Answer 24

concentration of solvent (pressure)

Question 25

osmotic pressure

Answer 25

solution to take up water when separated from pure water by semipermeable membrane Higher osM=higher concentration of solvent

Question 26

tonicity

Answer 26

ability of a solution to cause a cell to gain or lose water | solute concentration

Question 27

isomotic vs isotonic

Answer 27

- same osmotic pressure as other fluid | - some solute concentration of solute

Question 28

hyperosmotic vs hypertonic

Answer 28

- same higher osmotic pressure then other fluid | - fluid with greater concentration of solute

Question 29

hypoosmotic vs hypotonic

Answer 29

- lower osmotic pressure then other fluid | - fluid with lower concentration of solute

Question 30

Faciliate diffusion

Answer 30

- channel protein= hydrophilic channels allow ions past - carrier protein= shape changes which takes ions across - No ATP needed

Question 31

Active transport

Answer 31

-moves substance across membrane, through transport protein against a chemical gradient (requires energy)

Question 32

active transport energy sources

Answer 32

- ATP hydrolysis - light absorbance - e- transport (cotransport with something moving down its gradient)

Question 33

Exocytosis

Answer 33

removal of extracellular fluid (out)

Question 34

constitutive exocytosis

Answer 34

continuous, supplies proteins and lipids to plasma membrane and secretes molecules from cell

Question 35

regulated exocytosis

Answer 35

operates in secretory cells, membrane fusion occurs only in response to extracellular signal

Question 36

Endocytosis

Answer 36

uptake of molecules to extracellular fluid (taken in)

Question 37

Phagocytosis

Answer 37

uptake of large bulky material (feeding and defence) | -microfilaments/myosin cause engulphment and then pinching off into cell

Question 38

pinocytosis

Answer 38

ingestion of liquid into cell by budding membrane

Question 39

receptor mediated endocytosis

Answer 39

specific molecules are taken up form extracellular fluid, mediated by cell membrane and cytosolic proteins -forms coated vesicles