Transport 4

Question 1

what is a phospholipid?

Answer 1

similar to triglyceride, but one fatty acid is replaced by a phosphate group.

Question 2

What are fatty acid tails?

Answer 2

Hydrophobic

Question 3

What are phosphate heads?

Answer 3

Hydrophilic

Question 4

how do phospholipids make bilayers?

Answer 4

Hydrophobic tails repel water - face inwards
Hydrophilic heads face attract water - face outwards

Question 5

what is a phospholipid made out of?

Answer 5

2 fatty acids
1 glycerol group
1 phosphate group

Question 6

what does the plasma membrane do?

Answer 6

Separates cell contents from outside environment.
Regulates passage of substances into and out of cells.
Cell recognition/signalling

Question 7

What do organelle membranes do?

Answer 7

Divide the cell into sections.
Isolate harmful enzymes, eg lysozymes
Provide surfaces for holding chlorophyll, enzymes and ribosomes.

Question 8

What are cell membranes usually made of?

Answer 8

Phospholipids

Question 9

What do phospholipids form?

Answer 9

Bilayers

Question 10

What is the fluid mosaic model?

Answer 10

Phospholipids move around, proteins are scattered throughout

Question 11

How is the bilayer partially permeable?

Answer 11

Large lipid-soluble molecules pass through after dissolving

Small molecules can pass through easily.

Question 12

What molecules cannot pass through the bilayer?

Answer 12

Large water soluble molecules.

Question 13

How do large water soluble molecules pass through the bilayer?

Answer 13

Alternate methods

Question 14

What do surface proteins do?

Answer 14

Cell signalling
- hormone receptors

Cell recognition
- antigens for immune system.

Question 15

What is cholestorol?

Answer 15

A constituent of membranes - source of steroid hormones

Question 16

What do glycolipids and glycoproteins do?

Answer 16

Cell signalling (hormone receptors)
Cell recognition (immune system - antigens)

Question 17

3 passive processes of cell membrane transport?

Answer 17

1. diffusion
2. facilitated diffusion
3. osmosis
   DONT REQUIRE ENERGY

Question 18

2 active processes of cell membrane transport?

Answer 18

1. Active membrane protein transport
2. Membrane transport (endo/exocytosis)
   THERE ARE 2 TYPES OF ENDOCYTOSIS : phagocytosis and pinocytosis.

Question 19

What is diffusion

Answer 19

Diffusion is the net movement of particles from an area of higher conc to a lower conc.

Question 20

What is diffusion

Answer 20

Diffusion is the net movement of particles from an area of higher conc to a lower conc.

Question 21

Why does diffusion occur?

Answer 21

Molecules move randomly, using their own kinetic energy.

Question 22

What is facilitated diffusion

Answer 22

The use of transmembrane proteins to move charged ions or large soluble substances, across a membrane, from a high to low concentration.

Question 23

What is active transport?

Answer 23

The use of ‘energy’ to move substances across a membrane, from a high to low conc.
- uses ATP

Question 24

What is Osmosis?

Answer 24

The diffusion of water molecules across a partially permeable membrane - from a region of higher WP to lower WP.

Question 25

What is water potential?

Answer 25

Pressure generated when water molecules hit the cell surface membrane.

Question 26

What carries the highest water potential molecule possible?

Answer 26

Pure water.

Question 27

ENDO VS EXO

Answer 27

Enter (into cells)
Exit