Topic 4 - Cell Membranes and Transport

Question 1

What is Active Transport?

Answer 1

The active movement of substances from a low concentration to a high concentration, against a concentration gradient, with the use of ATP

Question 2

What is an Antigen?

Answer 2

A marker molecule on a cell membrance (usually a protein or glycoprotein) that can be detected by antibiotics + triggers an immune response

Question 3

What is a Carrier Protein?

Answer 3

Protein involved in active transport that uses energy from ATP to change conformation.

Question 4

What is Cell Signalling?

Answer 4

When cells release chemicals which bind to complementary receptors on their target and trigger an immune response.

Question 5

What is a Cell Surface Receptor?

Answer 5

A component on the cell membrane which binds to extracellular signals.

Question 6

What are Channel Proteins?

Answer 6

Transmembrane non-polar proteins - transport large / charged substances - can do faciliated diffusion or active transport.

Question 7

What is Cholesterol?

Answer 7

A steroid hormone which adds stability to phospholipid bilayer - contains only Carbon, Hydrogen, and one oxygen atom.

Question 8

What is Diffusion?

Answer 8

The movement of substances from a high concentration to a lower concentration, along a concentration gradient - doesn’t require energy.

Question 9

What is Endocytosis?

Answer 9

A method of bulk transport into a cell - relies on invagination of cell membrane, and requires ATP.

Question 10

What is Exocytosis?

Answer 10

A method of bulk tranport out of a cell - vesicles fuse with cell membrane and release contents - requires ATP.

Question 11

What is Facilitated Diffusion?

Answer 11

The passive movement of substances from a high concentration to a low concentration (along concentration gradient) through transport proteins, without using energy.

Question 12

What is the Fluid Mosaic Model?

Answer 12

A model that describes membrane structures as a sea of mobile phospholipids studded with variously shaped proteins.

Question 13

What is a Glycolipid?

Answer 13

A lipid which is bonded to a monosaccharide

Question 14

What is a Glycoprotein?

Answer 14

A protein which is bonded to a carbohydrate chain

Question 15

What is Osmosis?

Answer 15

The passive movement of water from a region of high water potential to a region of low water potential, along a concentration gradient - no ATP required.

Question 16

What is Passive Transport?

Answer 16

The movement of substances without the use of energy.

Question 17

What is a Phospholid?

Answer 17

Type of lipid that forms the cell surface membrane bilayer

Question 18

How is a phospholipid formed?

Answer 18

The condensation of one glycerol molecule, two fatty acid molecules, and a phosphate molecule.

Question 19

How is a phospholipid arranged?

Answer 19

Two fatty acid chains are the non-polar hydrophobic tails whilst the phosphate group is the polar hydrophilic head.

Question 20

What is a Phospholipid Bilayer?

Answer 20

Polar membrane made of two layers of phospholipids, that is a selectively permeable barrier to the passage of ions into and out of the cell.

Question 21

What is Surface Area : Volume ratio?

Answer 21

Volume of an object compared with it’s surface area - the smaller the organism, the higher it’s SA:V ratio.

Question 22

What is Water Potential?

Answer 22

A measure of the tendency of water molecules to move from one area to another measured in kPa and given a the greek letter psi ‘ψ’