Membrane + Organelles

Question 1

Primary Function of Cell membrane

Answer 1

Controls substance movement into/out of cell

Question 2

Saturated vs unsaturated phospholipids

Answer 2

Saturated are viscous (packed together), unsaturated are fluid ( bent tails prevent packing)

Question 3

Role of Cholesterol within cell membrane

Answer 3

Stabilises membrane fluidity

Question 4

Name the 5 key organelles in animal cells:

Answer 4

• Endoplasmic reticulum
• Nucleus
• Golgi apparatus
• Lysosome
• Mitochondrion

Question 5

Name the 6 key organelles in Plant Cells:

Answer 5

• Nucleus
• Endoplasmic reticulum
• Central Vacuole
• Chloroplast
• Mitochondrion
• Golgi apparatus

Question 6

What is a plasma membrane?

Answer 6

A semi-permeable barrier composed of a phospholipid bilayer

Question 7

What is the function of a plasma membrane?

Answer 7

• controls movement of substances into and out of the cell

Question 8

What factor limits the maximum size of a cell or organelle

Answer 8

Surface area to volume ratio

Question 9

What are the two types of passive transport?

Answer 9

• Diffusion

- facilitated diffusion

Question 10

How does diffusion across a plasma membrane work?

Answer 10

• membrane are permeable to lipid soluble ( hydrophobic) molecules such as steroid molecules and gasses
• The move across the membrane down the concentration gradient so don’t require energy

Question 11

What are the two types of membrane proteins that aid in facilitated diffusion?

Answer 11

channels and carriers

Question 12

What are the key points to consider about facilitated diffusion?

Answer 12

• It is the movement of hydrophilic molecules across the membrane using channels and carriers
• Substances are moving down the concentration gradient and thus do not require energy
• Channels can open/ close in response to signals
• carriers undergo shape change to help guide the molecule

Question 13

What is the name of the channels that are required for osmosis?

Answer 13

• aquaporins

Question 14

What does osmoregulation prevent?

Answer 14

Swelling of cell in hypotonic conditions and shrinking of cell under hypertonic conditions

Question 15

What are the key points of Active transport?

Answer 15

• Requires transport proteins that use ATP energy
• Move specific substances against concentration gradient
• Active transport allows a cell to have different internal/ external concentration of substances

Question 16

What is co-transport?

Answer 16

indirect active transport where active transport of one substance creates a gradient used to passively move another substance into/ out of a cell

Question 17

What diseases can be caused by defects in transport proteins? (3)

Answer 17

• Albinism ( tyrosine transporter)
• Wilsons disease ( Cu2+ and Ag+ transporter)
• Cystic Fibrosis ( chloride channel)

Question 18

What are the roles of membrane proteins? (5)

Answer 18

• signal transduction
• Cell recognition
• intercellular joining
• linking cytoskeleton and ECM
• transport

Question 19

What does a membrane protein do that is involved in signal transduction?

Answer 19

Relay messages from the body into the cell ( grow, divide, move, make something …)

Question 20

What does a membrane protein that is responsible for intercellular joining do?

Answer 20

Forms long-lasting connections between cells

Question 21

What does a membrane protein do that in responsible for linking cytoskeleton and ECM?

Answer 21

Allows the cell to physically connect with protein structures outside the cell