Endomembrane system I - Key organelles

Question 1

percentage of eukaryotic genes directly involved in the endomembrane system

Answer 1

10-20%

Question 2

origin of endomembrane organelles

Answer 2

endogenous

Question 3

origin of mitochondria and chloroplast organelles

Answer 3

symbiotic

Question 4

What proteins get delivered to the ER

Answer 4

proteins that will become plasma membrane proteins

proteins that will be secreted out of the cell

Question 5

Rough endoplasmic reticulum

Answer 5

• studded with ribosomes translate and translocate proteins
• controlled environment for protein folding
• continuous with the outer membrane of the nuclear envelope

Question 6

How do proteins get from the ER to extracellular space or to the plasma membrane?

Answer 6

vesicle trafficking

Question 7

membrane vesicle size

Answer 7

30-100nm

Question 8

Smooth ER

Answer 8

site of cellular lipid and sterol synthesis

Question 9

Golgi Apparatus structure

Answer 9

series of flattened sacks called cisternae

Functionally compartmentalised with cis, medial and trans cisternae

Question 10

Cis golgi is where

Answer 10

proteins and lipids arrive

Question 11

Trans golgi is where

Answer 11

proteins, lipids and polysaccharides leave

Question 12

What factory is the golgi

two things it processes

Answer 12

polysaccharide factory

• synthesis of glycolipids and sphingolipids
• processing of N-linked glycans on glycoproteins

Question 13

How is secretion of some proteins regulated?

Answer 13

Vesicles containing the protein only fuse with the PM if a signal is released

Question 14

Endocytic pathway

Answer 14

transports macromolecules from the external environment to the lysosomes/vacuoles for digestion

Question 15

What kind of macromolecules are endocytosed?

Answer 15

1. nutrients (proteins, cells…)
2. signalling molecules
3. pathogens

Question 16

Two internalisation mechanisms

Answer 16

phagocytosis by engulfment

enodcytosis via small vesicles

Question 17

Lysosomes

Answer 17

digestive organelle containing digestive enzymes

Question 18

Endocytic pathway is increasingly…

Answer 18

acidified

Question 19

Comparison of cellular digestion by prokaryotes and eukaryotes

Answer 19

Prokaryotes secrete enzymes and externally digest macromolecules before absorbing them.
Eukaryotes internally digest macromolecules by hydrolyses them in specialised hydrolytic compartments.

Question 20

What kind of internalisation mechanism cannot happen with cell walls?

Answer 20

phagocytosis

Question 21

percentage of cell volume that plant and fungal vacuoles make up

Answer 21

sometimes up to 90%

Question 22

What do vacuoles provide

Answer 22

turgor pressure for cell growth