Compendium 5. Fuelling the Human Body

Question 1

What is the difference between peripheral and integral proteins?

Answer 1

Peripheral - on the edge on the membrane

Intergral - All the way through the membrane

Question 2

Describe Channel proteins

Answer 2

• Integral
• Only molecules of a certain shape and size can pass through
• Can be gated or non gated

Question 3

What is the difference between gated ion channels and non gated ion?

Answer 3

Non gated - always open for movement

Gated - Can be opened or closed depending on certain stimuli

Question 4

Describe Carrier proteins

Answer 4

• Also known as transporters
• Integral
• Have specific binding sites
• The protein will change shape to allow molecules to pass through
• Uniporters, symporters and antiporters

Question 5

What are uniporters, symporters and antiporter?

Answer 5

Uniporters - (carrier proteins that only transport one molecule)
Symporters - (carrier proteins transports two molecules moving in the same direction)
Antiporters - (carrier proteins that transport two molecules moving in opposite directions across the membrane).

Question 6

Describe ATP - powered transport

Answer 6

• Requires energy in the form of ATP

- Transports molecules AGAINST their concentration gradient

Question 7

What are the 4 main functions of the cell membrane?

Answer 7

• Supports and encloses the cell
• Attaches cells to other cells and to the surrounding matrix
• Communicates to the cell’s environment and other cells
• Determines what moves into and out of the cell (selectively permeable)

Question 8

Define Solute

Answer 8

Dissolved substances in a solution eg glucose, sucrose, ions

Question 9

Define Solvent

Answer 9

The liquids that hold solutes

Question 10

Define Solution

Answer 10

The mixture of the solute in the solvent

Question 11

What is Diffusion?

Answer 11

Molecules moving from areas of high concentration to areas of lower concentration so that they are evenly distributed throughout the solution

Question 12

How do lipid soluble molecules move across the cell membrane?

Answer 12

They diffuse directly through the cell membrane

Question 13

How do non-lipid molecules move across the cell membrane?

Answer 13

• Some specific non-soluble molecules can diffuse through membrane channels
• Other molecules for which channels are not present cannot pass through the cell membrane

Question 14

What is facilitated diffusion?

Answer 14

• The movement of a solute (e.g. glucose) across a plasma membrane via the use of a carrier/channel protein.
• No ATP is used.

Question 15

What is Osmosis?

Answer 15

The diffusion of water across a selectively permeable membrane from areas of high concentration to areas of low concentration

Question 16

What is a Isotonic solution?

Answer 16

When a cell is in a solution that has the same osmolarity as it’s intracellular fluid (ideal state)

Question 17

What is a Hypertonic solution?

Answer 17

When a cell is in a solution that has a higher osmolarity than the intracellular fluid (dehydrating the cell)

Question 18

What is a Hypotonic solution?

Answer 18

When a cell is in a solution that has a lower osmolarity than the intracellular fluid (swelling the cell)

Question 19

Define Metabolism

Answer 19

The chemical processes that occur within a living organism to maintain life

Question 20

Describe Catabolism

Answer 20

• Large molecules are broken down into smaller molecules
• Energy is released due to chemical bonds between molecules being broken
• Energy that has been released can be used in active cell membrane transport, muscle contraction and protein synthesis

Question 21

Describe Anabolism

Answer 21

• Small molecules join together to form larger molecules
• Chemical bonds are made and energy is stored within the bonds
• Responsible for growth, maintenance and repair

Question 22

What is potential energy?

Answer 22

Stored energy that has the potential to be used

Question 23

What is kinetic energy?

Answer 23

Energy that is moving matter

Question 24

Describe conservation of energy

Answer 24

The total energy of the universe is constant and cannot be created or destroyed.
It can, however, be converted from one type to another