the ER and the golgi

Question 1

what is the ER

Answer 1

network of phospolipid bilayer membranes arranged into tubes, vesicles & sacs

Question 2

what are the flattened sacs called?

Answer 2

cisternae

Question 3

what are the functions of the ER

Answer 3

Synthesis of intracellular & secreted lipids & proteins

Protein maturation

Storage within cisternae

Question 4

what can the er store?

Answer 4

glyocgen and calcium

Question 5

what are microsomes

Answer 5

ER vesicles formed when cells are disrupted

Question 6

how can rough and smooth er vesicles be seperated?

Answer 6

separated by density- gradient centrifugation

Question 7

why are the vesicles from the RER more dense than smooth ER

Answer 7

presence of ribosomes

Question 8

does the smooth ER have ribsomes?

Answer 8

no

Question 9

what is the smooth er involved with?

Answer 9

lipid metabolism

Question 10

what are the 2 things the smooth er involved with?

Answer 10

Synthesis of membrane lipids, & steroid hormones from cholesterol

Detoxification of lipid drugs into excretable forms

Question 11

ER vesicles

Answer 11

the ser is where the vesicles form and fuse with other orgnalles

Question 12

what does the SER store?

Answer 12

calcium storage

Question 13

what does the ser iniate>

Answer 13

Ca2+ signalling processes
channels in the PM
channels in the ER membrane

Question 14

what does the ser terminate?

Answer 14

caclium signalling
Pump Ca2+ into ER ‘store
Pump Ca2+ out of cell

Question 15

what is membrane lipid syntehsis?

Answer 15

involves lipid synthesis and essentail componenets of cell membranes

Question 16

how are phosphlipids made?

Answer 16

made from FAs on cytosolic face of ER membrane

Question 17

how is the membrane formed?

Answer 17

Growing Fatty Acid (FA) chains are elongated to 16 carbons [16C]

Question 18

what enzyme helps the membrane lipid synthesis?

Answer 18

by acetyl CoA carboxylase

Question 19

where does physophelration syntehsis occur?

Answer 19

occurs in the cytosol adjacent to ER membrane that is studded with proteins that act in synthesis

Question 20

explain the process membrane lipid syntehis?

Answer 20

2 molecules of FA are esterified onto glycerol-3-phosphate to form phosphatidic acid (catalysed by GPAT enzymes)

An alcohol is then esterified onto the phosphate of phosphatidic acid to form a phospholipid

Question 21

what does the rough er consist off?

Answer 21

cisternae which have ribosomes on their outer surface

Question 22

what are the functions of the ER?

Answer 22

Functions in protein synthesis/maturation

Question 23

What is each ribsome in the rer composed off?

Answer 23

50 different proteins (ribosomal proteins)
Several RNA molecules – the ribosomal RNAs (rRNAs

Question 24

where does translation occur?

Answer 24

Occurs at the Ribosome, using mRNA as template

Question 25

how are cytoplasmic protein sysntehised?

Answer 25

are synthesised by free ribosomes.