other parts of the cell

Question 1

name the major membrane bound organelles in eukaryotic cells

Answer 1

nucleus
endoplasmic reticulum
Golgi apparatus
lysosomes
endosomes
peroxisomes

Question 2

function of Golgi apparatus

Answer 2

modification, sorting, packaging proteins and lipids
major sites of carbohydrate synthesis

Question 3

function of lysosomes

Answer 3

intracellular degradation

Question 4

function of endosomes

Answer 4

intracellular sorting organelles, part of transport pathway from Golgi

Question 5

peroxisomes function

Answer 5

oxidation of toxic molecules
by hydrogen peroxide

Question 6

role of ER

Answer 6

synthesis / modification
of most lipids, and proteins for distribution

Question 7

three ways that proteins move around in the cell

Answer 7

gated, transmembrane and vesicular transport

Question 8

define endo/exocytosis

Answer 8

the process by which substances are moved into / out of the cell

Question 9

define budding / fusing

Answer 9

budding - vesicles bud off from one membrane
eg. in endocytosis
fusion - vesicles fuse w membrane
eg. in exocytosis

Question 10

define exosomes

Answer 10

extracellular vesicles that are generated by cells
easily cross cell borders

Question 11

exosomes in therapeutic products

Answer 11

for diagnostics (pick up from blood/urine and analyse composition)
delivery (of precision medicine / nucleic acid based therapies bc they easily cross cell borders)

Question 12

define glycosylation

Answer 12

attaching of sugars on proteins
forming glycoproteins

Question 13

where does glycosylation take place

Answer 13

in the ER
proteins converted to glycoproteins by the covalent attachment of short branched oligosaccharides

Question 14

define phagosome

Answer 14

formed from the cell membrane when it engulfs bacteria / other solid debris (phagocytosis)

Question 15

what happens when an endosome fuses with a lysosome?

Answer 15

late endosomes often fuse and the contents is destroyed
(line of defence)

Question 16

what is the significance of the asymmetry of the cell membrane

Answer 16

different lipid compositions of inner and outer leaflet
different charges –> membrane potential
eg. glycolipids only on non-cytosolic membrane

Question 17

what type of molecule moves easily through lipid bilayer? give examples.

Answer 17

small non-polar (hydrophobic) molecules
eg. O2, CO2, N2, steroids, hormones

Question 18

the lipid bilayer is highly impermeable to ___?

Answer 18

ions / charged molecules

Question 19

what type of molecules have limited permeability across the lipid bilayer?

Answer 19

small uncharged polar molecules (H2), urea)
large uncharged polar molecules (glucose, sucrose)

Question 20

typical Na+ concentration in vs out of cell

Answer 20

in: 5-15 mM
out: 145 mM

Question 21

typical K+ concentration in vs out of cell

Answer 21

in: 140 mM
out: 5 mM

Question 22

types of passive transport

Answer 22

simple diffusion
channel / transporter mediated diffusion

Question 23

types of channels

Answer 23

voltage, ligand and mechanically gated
note: ALL PASSIVE TRANSPORT

Question 24

three ways of driving active transport

Answer 24

coupled tranporters: couple uphill transport w downhill transport of another solute
ATP driven pumps: coupled w hydrolysis of ATP
light driven pumps: mainly bacteria’ archea

Question 25

function of the Na+/K+ leak pump

Answer 25

maintain osmotic balance across membrane by keeping intracellular conc of Na+ low
maintains cytosolic pH