Plasma membrane

Question 1

What is the plasma membrane made of?

Answer 1

A phospholipid bilayer with embedded proteins, cholesterol, and carbohydrates

Question 2

What are they two main parts of a phospholipid?

Answer 2

Hydrophilic (water loving) head
Hydrophobic (water fearing) tails

Question 3

What part of the plasma membrane is hydrophobic?

Answer 3

The fatty acid tails

Question 4

What is passive transport?

Answer 4

Movement of substances without energy (e.g., diffusion, osmosis)

Question 5

What is simple diffusion?

Answer 5

Movement from high to low concentration without energy or proteins

Question 6

What is facilitated diffusion?

Answer 6

Movement down a concentration gradient using a transport protein

Question 7

What is osmosis?

Answer 7

Diffusion of water across a semipermeable membrane

Question 8

What is a aquaporin?

Answer 8

A protein channel that allows water movement

Question 9

What part of the plasma membrane is hydrophilic?

Answer 9

The phosphate heads

Question 10

What is active transport?

Answer 10

Movement against a concentration gradient requiring ATP

Question 11

What is an example of active transport?

Answer 11

The sodium-potassium (Na/K) pump

Question 12

What does the Na/K pump do?

Answer 12

Moves Na+ out and K+ in against their concentration gradients

Question 13

What is a ligand?

Answer 13

A molecule that binds to a receptor (e.g., hormone, neurotransmitter)

Question 14

What is the function of receptors?

Answer 14

Detect ligands and modify cell activity

Question 15

Name one way receptors modify cells

Answer 15

By opening or closing ion channels

Question 16

What is the function of membrane proteins?

Answer 16

Transport, signaling, enzymatic activity, and structural support

Question 17

What is the role of carbohydrate chains in the membrane?

Answer 17

Act as cell markers for cell recognition and communication

Question 18

What is endocytosis?

Answer 18

The process of engulfing substances into the cell

Question 19

What is exocytosis?

Answer 19

The process of expelling substances from the cell

Question 20

What is the main function of cholesterol in the membrane?

Answer 20

Maintains membrane fluidity and stability

Question 21

What molecules easily pass through the membrane?

Answer 21

small, non-polar molecules (e.g., O2, CO2)

Question 22

What is the fluid mosaic model?

Answer 22

Describes the plasma membrane as a dynamic structure with moving components

Question 23

What is the difference between integral and peripheral proteins?

Answer 23

Intergral: Embedded in the membrane
Peripheral: Attached to the surface

Question 24

What is pinocytosis?

Answer 24

A type of endocytosis where the cell “drinks” extracellular fluid

Question 25

What is phagocytosis?

Answer 25

A type of endocytosis where the cell engulfs large particles

Question 26

What is receptor-mediated endocytosis?

Answer 26

The selective uptake of molecules via receptor binding

Question 27

What is the role of glycolipids in the membrane?

Answer 27

Cell recognition and communication

Question 28

Why can't ions cross the membrane freely?

Answer 28

They are charged and require specific protein channels

Question 29

What is resting membrane potential?

Answer 29

The negative charge inside the cell due to Na+/K+ balance

Question 30

How do neurotransmitters interact with the membrane?

Answer 30

The bind to receptors, triggering cellular response

Question 31

Why is ATP needed for active transport?

Answer 31

It provides energy to move substances against their gradient

Question 32

What is the main extracellular ion?

Answer 32

Sodium (Na+)

Question 33

What is depolarisation?

Answer 33

When the inside of a cell becomes less negative, triggering a response

Question 34

What is repolarisation?

Answer 34

Returning the cell to its resting state after depolarisation

Question 35

What is the main intracellular ion?

Answer 35

Potassium(K+)

Question 36

What is the role of ion channels?

Answer 36

Allow specific ions to pass through the membrane

Question 37

What happens to a cell in a hypotonic solution?

Answer 37

Water enters the cell, causing it to swell

Question 38

What happens to a cell in a hypertonic solution?

Answer 38

Water leaves the cell, causing it to shrink

Question 39

What is isotonic?

Answer 39

A solution where water movement is balanced

Question 40

What is the function of glycoproteins in the membrane?

Answer 40

Cell signalling and immune response