Carbohydrate Metabolism Flashcards
(72 cards)
Primary Metabolic Pathways to produce ATP
glycolysis, citric acid cycle, oxidative phosphorylation
Main Anabolic pathways to produce new carbohydrate molecules
Gluconeogenesis and Pentose Phosphate Pathway
Purpose of Pentose Phosphate Pathway
To produce sugar rings (Ribose) that are found in DNA and RNA; pathway also produces the most NADPH
Gluconeogenesis
Pyruvate to form glucose
Glycolysis
Glucose 6-phosphate - Triose Phosphate - Pyruvate
Glycogenesis
Glucose 6-phosphate to produce glycogen
Glycogenolysis
Glycogen to produce Glucose 6-phosphate
Catabolism and Anabolism
Catabolism - breakdown and Anabolism (synthesis)
Calculate Calories or Kilocalories
(Enthalpy will be given); energy per gram (kJ/g) = enthalpy/one mole of mass; Kcal (kcal/g) = Energy per gram X (1 kcal/4.18kJ)
Which releases more energy gram for gram, lipids or carbohydrates/glucose? Why?
Lipids release more energy gram for gram compared to glucose/carbohydrates; more bonds to break therefore higher the energy released.
Glycolysis Products
2 Pyruvate + 2 ATP + 2 NADH + 2 H2O + 2 H
Glycolysis Key Regulatory Steps (3)
- Start with Hexokinase OR Glucokinase (Isozymes -
depends on location in body); Glucose to glucose 6-phosphate - Phosphofructo-kinase-1 : fructose-6-P to Fructose-1,6-bisphosphate
- Pyruvate Kinase : Phosphoenolpyruvate to pyruvate
Location of glycolysis and 2 phases
cytoplasm; phosphorylation phase (adding phosphate group) and energy production phase (ATP production)
What will happen to phosphofructo-kinase-1 if you have a high concentration of ATP?
It will inhibit it
How many ATP are formed during Phosphorylation Phase?
Zero ATP produced; you actually use 2 ATP during this phase
Net ATP Produced during Glycolysis phase?
2 ATP
How many ATP are produced during the Energy Production Phase?
4 ATP
What is the role of Magnesium Ion in Adenosine Triphosphate?
Keeps the molecule stable due to the 4 negative charges of Oxygen on the phosphate groups; “peacemaker”
Adenosine Triphosphate Role
primary energy source in the body, but not the only one
Purpose of the phosphate groups in ATP?
high energy bonds between the phosphate groups (phosphoric anhydride bonds); entropy increased; electrostatic repulsion of the positively charged phosphates and negatively charged oxygen stabilized the products (ADP + Pi) of breaking these bonds
What is the role of NADH ? (Nicotinamide Adenine Dinucleotide)
Alternative energy storage
Oxidation and Reduction
Identify any molecule that is oxidized or reduced on test; Oixidation is loss of election and Reduction is gain of election
For example NAD+ is reduced (Gains 2e-) when added to Hydrogen ion to produce NADH
NAD+ added with H+ has a net 2+ charge therefore you need two electrons to cancel the charge making NADH neutral
Glucokinase
Enzyme needed to catalyze glucose to glucose-6-phosphate. Replaces Hexokinase in liver/pancreas
Can only have one of these enzymes for Phosphorylation phase
What happens when energy levels are high? (Relating to Glycolysis)
The glycolytic pathway is inhibited or alternative pathways are promoted for storage of glucose