Block A Flashcards
(26 cards)
Who discovered cells - when and what from
Robert Hooke in 1665 from examining cork
What are the 4 bullet points of cell theory
- 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
Size of a prokaryote
1-10 micrometers
Size of a eukaryote
10-100 micrometers
The 3 types of elements in the cytoskeleton
Microtubules, microfilaments, intermediate filaments
Describe the sodium- potassium pump
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
What is the function of cholesterol in membranes
It maintains membranes fluidity
It provides strength and shape
What is glycolysation and its purpose, also mention where is occurs
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
What is glycolysis and its purpose, also mention where is occurs
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
What is the first phase of glycolysis and what are the 5 enzymatic steps
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
What is the second phase of glycolysis and its 5 enzymatic steps
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)
What is the net products of glycolysis from 1 glucose molecule
2 pyruvate
2 ATP
2 NADH
Would the presence of unsaturated fatty acids in the membrane make it more fluid or less fluid and why
More fluid because the double bonds create “kinks” in the membrane that makes it less tightly packed togethet
What are the 4 main cell types in the human body
Muscle cells
Nerve cells,
Epithelial cells,
Connective cells
What are the 3 types of muscle
Smooth muscle,
Cardiac muscle
Skeletal muscle
What are the 3 Types of neurons
Sensory neuron
Motor neuron
Relay neuron (Interneuron)
What are the 3 epithelial cell types, describe size and where you’d find them
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
What are the 2 epithelial cell layer types
Simple (single layer)
Stratified (several layers)
What are the 3 different fibres
Collagen, elastin, reticular
What are the proteins of the ECM - say what ones are adhesive and what ones are structural
Adhesive -
Fibronectin
Lamanin
Structural-
Elastin
Collagen
What are the 3 cell junctions and their purpose
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
What lipid movements in the membrane occur spontaneously
Laterally and rotationally
What lipid movements in the membrane require energy
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
How does the length of fatty acyl tails affect fluidity
Shorter tails are less likely to interact with each other, making the membrane more fluid
