Block A

Question 1

Who discovered cells - when and what from

Answer 1

Robert Hooke in 1665 from examining cork

Question 2

What are the 4 bullet points of cell theory

Answer 2

• Cells are the building blocks of all living organisms
• Cells arise only through division of other cells and pass on inherited information for control of cell activities
• the cell is the functioning unit of life as metabolism happens here
• Cells are capable of independent life under the right conditions

Question 3

Size of a prokaryote

Answer 3

1-10 micrometers

Question 4

Size of a eukaryote

Answer 4

10-100 micrometers

Question 5

The 3 types of elements in the cytoskeleton

Answer 5

Microtubules, microfilaments, intermediate filaments

Question 6

Describe the sodium- potassium pump

Answer 6

3 Na+ ions bind to the pump protein
ATP is hydrolysed and phosphorylates the pump causing a conformational change
The Na+ ions are released from the cell
2 K+ ions bing to the pump
The pump is dephosphorylated, changing back to its original conformation and pushes the K+ ions into the cell

Question 7

What is the function of cholesterol in membranes

Answer 7

It maintains membranes fluidity
It provides strength and shape

Question 8

What is glycolysation and its purpose, also mention where is occurs

Answer 8

It is when a carbohydrate molecule is covalently attached to a lipid or protein
Purpose is proper protein folding, stability and cell signalling
Occurs in the endoplasmic reticulum and the Golgi apparatus

Question 9

What is glycolysis and its purpose, also mention where is occurs

Answer 9

It is when glucose is broken down to generate energy
Purpose is converting 1 glucose molecule (6 carbons) into 2 pyruvate molecules (3 carbons each) to generate atp and NADH
Occurs in the cytoplasm

Question 10

What is the first phase of glycolysis and what are the 5 enzymatic steps

Answer 10

The energy investment phase
1 — glucose phosphorylation, hexokinase, turns glucose into glucose-6-phosphate (uses 1 ATP)
2 — isomerisation, phosphoglucose isomerase, glucose-6-phosphate to fructose-6-phosphate
3 — second phosphorylation, PFK-1, fructose-6-phosphate to fructose-1,6-biphosphate (uses 1 ATP)
4 — cleavage, aldolase, fructose-1,6-biphosphate to G3P and DHAP
5 — isomerisation of DHAP, triose phosphate isomerase, DHAP to G3P
outcome 2 molecules of G3P

Question 11

What is the second phase of glycolysis and its 5 enzymatic steps

Answer 11

Energy payoff phase
6 — Oxidation and phosphorylation, G3P dehydrogenase, G3P to 1,3-biphosphoglycerate (produces 2 NADH)
7 — ATP generation, phosphoglycerate kinase, 1,3-biphosphoglycerate to 3-phosphoglycerate (produces 2 ATP)
8 — Isomerisation, phosphoglycerate mutate, 3-phosphoglycerate to 2-phosphoglycerate
9 — dehydration, enolase, 2-phosphoglycerate to PEP
10 - second ATP generation, pyruvate kinase, PEP to pyruvate (produces 2 ATP)

Question 12

What is the net products of glycolysis from 1 glucose molecule

Answer 12

2 pyruvate
2 ATP
2 NADH

Question 13

Would the presence of unsaturated fatty acids in the membrane make it more fluid or less fluid and why

Answer 13

More fluid because the double bonds create “kinks” in the membrane that makes it less tightly packed togethet

Question 14

What are the 4 main cell types in the human body

Answer 14

Muscle cells
Nerve cells,
Epithelial cells,
Connective cells

Question 15

What are the 3 types of muscle

Answer 15

Smooth muscle,
Cardiac muscle
Skeletal muscle

Question 16

What are the 3 Types of neurons

Answer 16

Sensory neuron
Motor neuron
Relay neuron (Interneuron)

Question 17

What are the 3 epithelial cell types, describe size and where you’d find them

Answer 17

Squamous - flat and very thin, found lining surfaces
Cubodial - cube shaped, found in tissues that secrete or absorb substances
Columnar - long and thin, found in places that secrete mucus

Question 18

What are the 2 epithelial cell layer types

Answer 18

Simple (single layer)
Stratified (several layers)

Question 19

What are the 3 different fibres

Answer 19

Collagen, elastin, reticular

Question 20

What are the proteins of the ECM - say what ones are adhesive and what ones are structural

Answer 20

Adhesive -
Fibronectin
Lamanin

Structural-
Elastin
Collagen

Question 21

What are the 3 cell junctions and their purpose

Answer 21

Gap junction - direct exchange of ions and small molecules between adjacent cells
Tight junction - seal cells together to prevent leakage of materials
Anchoring junction - attachment of cells to each other or to the ECM

Question 22

What lipid movements in the membrane occur spontaneously

Answer 22

Laterally and rotationally

Question 23

What lipid movements in the membrane require energy

Answer 23

Transverse diffusion (flip-flop) to the other leaflet, requires flippases and floppases
Due to the polar head group having to pass through the hydrophobic region of the membrane

Question 24

How does the length of fatty acyl tails affect fluidity

Answer 24

Shorter tails are less likely to interact with each other, making the membrane more fluid

Question 25

The difference between primary native transport and secondary active transport

Answer 25

Primary creates and electrochemical gradient whereas secondary uses a pre-existing one

Question 26

What are the 3 types of endocytosis

Answer 26

Phagocytosis - cell eating
Pinocytosis - cell drinking
Receptor mediated