B2.2 Organelles and compartmentalisation

Question 1

How to distinguish between an eukaryotic organelle and prokaryotic?

Answer 1

prokaryotes doesn’t have any membrane-bound organelles

Question 2

Which organelles are double-membrane bound?

Answer 2

nucleus, mitochondria, chloroplast

Question 3

What are the advantages of compartmentalisation in the cytoplasm?

Answer 3

storing enzymes where needed, different condition in different parts of the cell (np. pH), storing damaging substances

Question 4

Function of inner membrane in mitochondria

Answer 4

contains necessary proteins for electron transport chain and ATP synthesis (ATP synthase, electron carriers)

Question 5

Function of cristae in mitochondria

Answer 5

increase surface area for more electron transport chain etc.

Question 6

Function of matrix in mitochondria

Answer 6

contains enzymes for link reaction and Krebs cycle

Question 7

Function of intermembrane space in mitochondria

Answer 7

accumulates protons (H+) from matrix during ETC

Question 8

Function of outer membrane in mitochondria

Answer 8

separation from the rest of the cell

Question 9

Function of thylakoid in chloroplast

Answer 9

absorb light and produce ATP

Question 10

Function of stroma in chloroplast

Answer 10

store enzymes for Calvin cycle

Question 11

What are the benefits of double-membrane of the nucleus

Answer 11

• larger pores allow large molecules to pass
• mRNA editing
• easy to break down and rebuild

Question 12

What molecules need to pass through nucleus pores?

Answer 12

RNA, ribosomes

Question 13

What is the function of the free ribosomes?

Answer 13

produce proteins within the cell

Question 14

What is the function of ribosomes on rough endoplasmic reticulum?

Answer 14

produce proteins for outside the cell, they are exported

Question 15

What’s the function of Golgi apparatus?

Answer 15

it modifies proteins received from ER, packages them into vesicles and send to the correct place

Question 16

What is the function of vesicles?

Answer 16

substance transport and storage

Question 17

What is clathrin?

Answer 17

protein that is involved in formation of vesicles

Question 18

How does clathrin function?

Answer 18

multiple clathrin molecules form a cage around the area of the membrane that is about to be a vesicle, when membrane folds inward the clathrin surrounds it and brings necessary molecules needed to shape and pinch off a piece of membrane, when vesicle is formed, the clathrin breaks down

Question 19

How vesicles are formed?

Answer 19

through endocytosis and pinching off a piece of a membrane

Question 20

What are secreted proteins?

Answer 20

those are proteins made inside the cell and sent out somewhere else

Question 21

What type of proteins are made in RER?

Answer 21

cells for outside the cell: secreted proteins, transport proteins (membrane proteins)

Question 22

What type of proteins are made by free ribosomes?

Answer 22

cells used inside the cell: cytoplasmic proteins, proteins for mitochondria, nucleus etc.

Question 23

What type of ribosomes are in eukaryotic cells?

Answer 23

80S

Question 24

What type of ribosomes are in prokaryotic cells?

Answer 24

70S

Question 25

What's the size of intermembrane space in mitochondria and why?

Answer 25

it is small, to create a proton gradient quicker during ETC

Question 26

What happens to the protein synthesis in the free ribosome when signal recognition protein attaches?

Answer 26

the protein synthesis (translation) is paused