Module 1

Question 1

What type of molecules are phospholipids?

Answer 1

Amphipathic - (both hydrophobic and hydrophilic parts)

Question 2

What is cholesterol’s role in the cell membrane?

Answer 2

Controlling the fluidity in relationship to temperature (fluidity buffer)

Question 3

6 major functions of membrane integral proteins

Answer 3

Transport (ions, ATP)
Enzymatic activity (catalysing reactions)
Signal transduction (receptors)
Cell-cell regulation (glycoproteins)
Intercellular joining
Attachment to cytoskeleton/extracellular matrix

Question 4

Definition: passive transport

Answer 4

Diffusion of a substance across a membrane with no energy investment. Occurs along the concentration gradient

Question 5

Definition: Osmosis

Answer 5

Diffusion of water through a selectively permeable membrane into another aqueous compartment containing solute at a higher concentration

Question 6

Definition: Osmotica

Answer 6

Osmotically active, affecting osmosis

e.g. Ions, sugars, proteins, nutrients

Question 7

Definition: Tonicity

Answer 7

The ability of a solution to cause a cell to gain or lose water

Question 8

Isotonic

Answer 8

No difference

Question 9

Hypertonic

Answer 9

Greater solute concentration, cell loses water

Question 10

Hypotonic

Answer 10

Lower solute concentration, cell gains water

Question 11

Definition: Facilitated diffusion

Answer 11

Transport proteins and channels used for passive movement

Question 12

Definition: Electrogenic pump

Answer 12

Transport that changes the charge across the membrane

Question 13

Definition: Cotransport

Answer 13

Active transport linked with facilitated diffusion

Question 14

What are the 3 types of endocytosis?

Answer 14

Phagocytosis - engulfing particles
Pinocytosis - drinking
Receptor mediated

Question 15

What are the two types of local cell-cell communication?

Answer 15

Paracrine: A secreting cell acts on nearby cells
Synaptic: Nerve cell releases neurotransmitter molecules

Question 16

Long-distance cell-cell communication example

Answer 16

Hormone signalling: Hormones reach virtually all cells through blood flow

Question 17

What are the four families of receptors?

Answer 17

Plasma membrane

• Ion channel receptors
• G protein-coupled receptors
• Tyrosine kinase linked receptors

Intracellular receptors

Question 18

What is the process of G protein-coupled receptors?

Answer 18

• Signal molecule binds to G-protein-linked-receptor on cell membrane
• Sends signal to G-protein which forms GTP (like ATP but made of guanine)
• ATP coverts to cyclic AMP (cAMP)
• Causes a cellular response

Question 19

Definition: Heterotrimeric

Answer 19

Formed of three different peptides

Question 20

Details of tyrosine kinase

Answer 20

Kinases add phosphate groups to molecules (phosphorylation)

Causes the movement of many molecules and proteins