IMMS: Week 4 Flashcards
What is the consequence of hyperkalemia
Risk of myocardial infarction
What is hypokalaemia
Low potassium levels
What is the consequence of hypokalaemia
Weakness + Cardiac dysrhythmia
How is hypercalcaemia caused
Hyperparathyroidism
What is the consequence of hypercalcaemia
Metastatic calcification
What is the plasma membrane composed of
Lipid, proteins + carbohydrates
What do glycolipids do in the phospholipid bilayer
Used in cell signalling, joins cells to form tissues + stability
What do glycoproteins do in the phospholipid bilayer
Cell to cell recognition + acts as receptors
What is the role of cholesterol in the plasma membrane
Maintains fluidity in membrane
What property do all lipids in the plasma membrane have
Amphipathic
What are roles of the plasma membrane
- Acts as a selective barrier to the outside environment
- Compartmentalisation
- Partially permeable
- Cell signalling
- Insulator (myelin sheath)
How does the plasma membrane prevent leakage of molecules into the cell
Tight junctions help seal cells together in an epithelial sheet to prevent leakage of molecules between them
What is the role of ‘actin filaments’ in the plasma membrane
They allow cell to cell adhesion through adherent junctions + cell to matrix adhesion through adherent junctions too
What are adherens junctions
Joins actin bundle in one cell to the same bundle in another
What are the role of intermediate filaments in the cel plasma membrane
Enables cell to cell adhesion through desmosomes + cell to matrix adhesion through focal adherent junctions
How do desmosomes function
Resist shearing forces + join the intermediate filaments in one cell to those in another
What are hemidesmosomes
Anchor intermediate filaments in a cell to the basal lamina
What are the functions of the gap junction in the plasma membrane
They allow the passage of small water-soluble ions and molecules
What is the role of pinocytes
Bring in dissolved solutes
What is endocytosis mediated by
Receptors found in coated pits
How do receptors function during endocytosis
Ligands bind to the receptor and the complex formed is engulfed, releasing the ligand into the cytosol
What is the cytosol
Fluid portion of the cell in the cytoplasm
What is facilitated diffusion
The movement of substances down their conc. gradient via carrier proteins (if they are large molecules) or protein channels (charged particles)
What form of food provides the most energy per gram
Lipids
Describe the structure of a protein
Amino acids in chain containing carbon, hydrogen, oxygen and nitrogen
Structure of a lipid
Three fatty acids bound to a glycerol molecule by an ester bond
Define metabolism
Chemical reactions that occur in a living organism
Define BMR
The minimum amount of energy needed to keep the body alive in REST state
What factors increase BMR
High BMI HYPERthyroidism Low ambient temperature Fever/infection Pregnancy Excersise
What factors decrease BMR
Age
gender (females have a lower BMR)
Starvation
HYPOthyroidism
Why do females hav a lower BMI
Because they have less metabolically active tissues
Define Daily energy expenditure
Energy to support our BMR and our physical activity + energy required to process food we eat
How much ATP production is contributed to by carbohydrates at rest
30%
How much ATP production is contributed to by lipids at rest
70%
Describe the structure of ATP
Adenine, ribose and phosphate
Where is adenine found
DNA and RNA
NAD and FAD
When does adenine form adenosine
Adenine attached to ribose
Describe the structure of ribose
Simple 5 carbon sugars (monosaccharide) also found in RNA
How many phosphate groups are found in ATP
3
NOTES: Adenine + Ribose = Adenosine
Adenosine + three phosphates = ATP
.
What are the bonds join the phosphate groups together in ATP
Phosphoanhyrdride bonds
How many phosphoanhydride bonds are present in an ATP molecule
Two
Lose one = ADP
Lose second = AMP
What are phosphoanhydride bonds also known as
High energy bonds
How does ATP provide energy
When phosphate bonds are broken energy is released
- Energy put in to break bonds
- Energy released when bonds reform in the products
Energy released > Energy put in
What six physiological ways can produce ATO
- Glycolysis
- Krebs’ Cycle
- Oxidative Phosphorylation
- Substrate level phosphorylation
- Electron transport chain
- Beta Oxidation
In which part of the cell does glycolysis take place
Cytosol
Describe the chemical reaction that takes place during glycolysis
Glucose + 2ADP + 2Pi + 2NAD+ -> 2 Pyruvate + 2ATP + 2NADH + 2H+ + 2H20
What is an isomerase
An enzyme that re-arranges the structure of a substrate without changing its molecular formula
What is a mutase
An enzyme that re-arranges the structure of a substrate without changing its molecular formula
What is aldolase
Enzyme that creates or breaks carbon-carbon bonds
What is a dehydrogenase
An enzyme that moves a HYDRIDE ion (H-) to an electron acceptor
What is an elonase
An enzyme that produces a carbon=carbon double bond by removing an -OH
Describe the process of glycolysis
Check book
How many ATP are produced during glycolysis
Two ATP molecules
What two compounds are used to convert pyruvate into lactate
NAD+ and H+
What happens to pyruvate under anaerobic conditions
Pyruvate can’t undergo the Kreb’s cycle or Oxidative Phosphorylation and is converted to lactate instead
What happens to lactate produced during glycolysis
Used in gluconeogenesis at the Liver
What factor affects Phosphofructokinase-1
pH - inhibited by acidic conditions
How does AMP regulate glycolysis
Activates phosphofructokinase-1 allosteric site to increase enzyme affinity for fructose-6-phosphate
How does ATP regulate glycolysis
This inhibits the allosteric site for PFK-1
What is the first molecule that enters the Kreb’s cycle
Acetyl CoA
What is Acetyl CoA derived from
B Vitamin Pantothenic acid
How does Acetyl CoA function
Transfers acetyl groups (2 carbons) from one molecule to another
What compound is Acetyl CoA produced from
Pyruvate or beta-oxidation of fatty acids or AA breakdown
What condition does Kreb’s cycle take place in
Aerobic conditions since oxidative phosphorylation is needed to convert NADH + FADH2 back to NAD+ and FAD
Where does beta oxidation take place
In the mitochondrial matrix
Can fatty acids over 12 carbon long move through the outer-mitochondrial membrane
No
How do fatty acids pas through the outer-mitochondrial membrane
Acyl CoA is converted to (via Carnitine acyltransferase-1) to Acyl Carnitine
Describe the process by which Acyl CoA is converted to Acyl CArnitine
CoA is removed from Acyl CoA and Carnitine is added
What happens to Acyl Carnitine once it passes through the outer mitochondrial membrane into the mitochondria + what is the entire process known as
The Acyl Carnitine is converted to Acyl CoA
via Carnitine Acyltransferase-2
Known as the carnitine shuffle
What happens to the fatty Acyl CoA in the mitochondria
Beta-oxidation
How many NADH are produced in one round of b-oxidation
1 mol
How many FADH2 are produced in one round of b-oxidation
1 mol
How many Acetyl CoA are produced in one round of b-oxidation
1 mol
What happens to the Acetyl CoA produced in b-oxidationn
Used in Kreb’s Cycle
What happens to the one mol of NADH and FADH2 produced during beta oxidation
Used in oxidative phosphorylation
Do fatty acids act as a fuel source for the nervous system?
No
