Week 4 Flashcards
(33 cards)
What is stage one of metabolism?
Digestion and hydrolysis
What is stage two of metabolism?
Degradation and some oxidation to small molecules
What is stage three of metabolism?
Oxidation to CO2, H2O and energy for ATP
How are macronutrients digested?
Enzymes throughout the digestive tract break polysaccharides (starch)
Identify two ways carbohydrates digested
- In the mouth, salivary amylase hydrolyses a-glycosidic bonds in polysaccharides to give smaller polysaccharides (dextrins), maltose, some glucose
- Insmall intestine: pancreatic amylase hydroglyses dextrins to maltose and glucose
What is energy generated by under aerobic conditions?
Citric acid cycle and oxidative phosphorylation
Where does glycolysis take place?
The cytosol of a cell
What does glycolysis do?
Converts glucose into 2 pyruvates, 2 ATP and 2 NADH
What are the two main phases of glycolysis?
Energy investment phase
Energy generation phase
What is the end result of the Energy Investment Phase?
2 ATP molecules have been spent
Glucose (6 carbon) has been degraded into 2x glyceraldehyde-3-phosphate (3 carbons + 1 phosphorus each)
What is the end result of the Energy Generation Phase?
Glycolysis generates 2 ATP and 2 NADH
2 ATP has been used in energy-investment to add the phosphate groups to glucose and fructose-6-phosphate
4 ATP are formed in energy-generation by direct transfer of phosphate groups to add 4 ADP
Where is NADH produced?
Cytoplasm
What is the role of glycerol-3-phosphate?
To transfer hydrogen and electrons into the mitochondria to FAD, which creates FADH2-
What do the pathways for glycolysis pyruvate depend on?
The availability of oxygen
What happens during the oxygen available (aerobic conditions)?
Pyruvate will decarboxylate to produce acetyl-CoA and CO2
2 pyruvate are oxidised to 2 acetyl CoA and 2 NADH
2 NADH enters the electron transport to provide 3 ATP each
What happens during the oxygen unavailable (anaerobic conditions)?
Pyruvate will reduce to lactate which replenishes NAD+, allowing glycolysis to continue with less energy
What does fermentation do and where does it occur?
Decarboxylates pyruvate to acetaldehyde, which is reduced to ethanol. It occurs in anaerobic microorganisms (yeast)
What happens to excessive glucose?
It is converted to glycogen for storage in liver
What happens when blood sugar levels are too low?
There isn’t enough energy to function
What happens when blood sugar levels are too high?
It can cause nerve damage and elevate blood acidity
How is blood sugar levels controlled?
Hormones insulin and glucagon are released
What is glucose?
The primary energy source for the brain, skeletal muscle and red blood cells
What can glucose deficiency increase?
An impairment to the brain and nervous system
What is the role of glycogenesis?
It stores glucose by converting glucose to glycogen
