Endomembrane System

Question 1

What is endomembrane system

Answer 1

collection of membranes inside and surrounding eukaryotic cells
- related by either physical contact or transfer vesicles

Question 2

function of endomembrane system

Answer 2

1. metabolism
2. proteins trafficking

Question 3

cisternae

Answer 3

network of tubules and sacs called cistern (reservoir for liquid)

Question 4

Organelles in end-membrane system

Answer 4

• plasma membrane
• nuclear envelope
• rough and smooth ER
• golgi
• lysosomes
• vacuoles

Question 5

Smooth ER function

Answer 5

depends on cell type
- synthesis of lipids
- metabolism of carbs
- detox of toxins (Ex: drugs and alc)
- stores calcium ions

Question 6

Smooth ER ribosomes?

Answer 6

No ribosomes on the surface, smooth appearance

Question 7

How does smooth ER detox

Answer 7

adds hydroxl grip to make toxin more soluble to water (flushes out)
- increased drug abuse increases smooth ER tolerance

Question 8

how does smooth ER store calcium ions

Answer 8

• regulates cell responses, releasing certain things at certain times
  Ex: release of Ca2+ into cytoplasm –> muscle contraction

Question 9

Rough ER function

Answer 9

protein synthesis from cytosol
- select proteins captures from cytosol and further synthesized in rough ER

Question 10

types of proteins used in rough ER

Answer 10

1. transmembrane proteins
2. soluble protein

Question 11

water soluble protein

Answer 11

fully translocated across membrane and release into ER

Question 12

transmembrane proteins

Answer 12

partly translocated across ER membrane
- destined for plasma membrane or membrane of another organelle

Question 13

signal recognition particle

Answer 13

binds to peptide and ribosome and mRNA to ER
- binding of SPR causes pause in translocation
- binds to receptor in ER membrane

Question 14

function within cytosol

Answer 14

one mRNA can encode and be used by multiple ribosomes in order to code and synthesize proteins at a faster rate

Question 15

vesicular transport

Answer 15

road map of pathway and communication via transport vesicles

Question 16

order of vesicular transport

Answer 16

nuclear envelop –> endoplasmic reticulum –> Golgi (cis face –> trans face) –> lysosome, endosome –> plasma membrane –> cell exterior

Question 17

Golgi apparatus

Answer 17

shipping and receiving center of the cell
- flattened membranous sacs (cisternae) –> stack of pita
- products from ER are modified, stored and sent to other destinations

Question 18

2 secretion pathways from golgi

Answer 18

1. consecutive secretory pathway
2. regulatory secretary pathway

Question 19

consecutive secretory pathway

Answer 19

• operate continuously to secrete soluble proteins
• no signal needed, supply plasma membrane with newly synthesized lipid and protiens

Question 20

regulatory secretory pathway

Answer 20

• selected proteins concentrated and stored
• extracellular signals stimulate secretion
  Ex: digestive enzymes, pancreatic cells

Question 21

lysosomes

Answer 21

digestive system of cell (animal cell)

Question 22

lysosome function

Answer 22

enables cell to digest components outside and inside cell

Question 23

lysosome structure

Answer 23

• large vesicle enclosed by single membrane
• membrane made by Rough ER
• enzymes produced in ER sent to Golgi sent to lysosomes
• proteins on inner side of membrane maintain shape

Question 24

acid hydrolases (lysosome)

Answer 24

work best at low pH

Question 25

phagocytosis

Answer 25

large particle taken into phagocytic valueless - phagosomes bind with lysosome to form phagolysosomes

Question 26

autophagy

Answer 26

internal organelle gets enclosed by a membrane fragment from ER - autophagosomes fuse with lysosomes - damaged organelles = digested

Question 27

vacuoles

Answer 27

digestive system in plant cells, contain hydrolytic enzymes

Question 28

vacuole function

Answer 28

- storage for organelles - degrade - controller of turgor pressure

Question 29

turgor pressure

Answer 29

controls growth of cell - changes through vacuole Ex: cells lose water they close (like a Venice flytrap)

Question 30

contractile vacuoles

Answer 30

in protists - pumps excess water out of cell - maintains concentration of salts and other molecules - expansion of vacuole --> expansion of cell

Question 31

tonoplast

Answer 31

vacuole membrane - mature plant cells have one large central vacuole enclosed by tonoplast

Question 32

peroxisome

Answer 32

specialized metabolic compartment enclosed by one membrane

Question 33

peroxisome function

Answer 33

- oxidation reaction that forms hydrogen peroxide (corrosive and must be detoxed) - detox --> catalase decomposed H2O2 by converting to H2O - breaks down fatty acids and oxidizes alc