Energy Reactions in Cells Flashcards
Define metabolism
- oxidative pathways
- fuel storage and mobilisation
- biosynthetic pathways
- detoxification pathways
What is the difference between anabolic and catabolic pathways?
Catabolic pathways:
- oxidative
- release protons
- breakdown large products into smaller intermediates
- break down molecules to release energy in the form of of reducing power
Anabolic pathways:
- building up of smaller molecules into bigger molecules
- reductive (use protons)
- use energy and raw materials to make larger molecules for growth and maintenance
List some high energy signals
- NADH
- NADPH
- FAD2H
- ATP
-show that reducing power is available for anabolic functions
List some low energy signals
- ADP
- AMP
- NAD+
- NADP+
- FAD
-signal that catabolism needs to take place for energy
Describe the use of creatine phosphate as a reserve of high energy stores
- Creatine phosphate is an immediate source of energy. Useful in cells such as skeletal muscle which need to increase metabolic activity quickly.
- Reversible reaction
- Creatine converted into creatine phosphate. Phosphate group is from ATP (which is converted to ADP).
- Creatine Kinase
- When ATP levels are high, forward reaction occurs, creatine phosphate forms. When ATP levels drop suddenly, the reaction reverses and creatine forms with ATP as a product.
- Creatine Kinase is a marker of myocardial infarction.
Describe the use of phosphorylated compounds as a source of energy
- Phosphoenolpyruvate
- creatine phosphate
- ATP
-phosphate/phosphate bond releases a high amount of energy
What is the minimum glucose requirement for a healthy adult?
180g/day
- 140g required by CNS
- 40g for tissues that only utilise glucose e.g red blood cells, white blood cells, kidney medulla, lens of eye
List sources of biosynthetic reducing power
- NADH
- NADPH
- FAD2H
List the major carrier molecules
- NAD+/NADH + H+
- FAD/FAD2H
- NADP+/NADPH + H+
Describe the action of Adenylate Cyclase
Adenylate Cyclate converts ATP into cAMP. cAMP activates specific kinases which phosphorylate compounds.
Why are nutrients metabolised?
For:
- Energy for cell function and the synthesis of cell components (ATP)
- Building block molecules that are used in the synthesis of cell components needed for the growth, maintenance, repair and division of the cell.
- Organic precursor molecules that are used to allow the inter-conversion of building block molecules (eg acetyl CoA)
- Biosynthetic reducing power used in the synthesis of cell components (NADPH)
What is creatinine
- breakdown product of creatine and creatine phosphate
- produced in a spontaneous reaction at a constant rate unless muscle is wasting
- excreted via kidneys
- renal function indicator
Describe the origins and fates of cell nutrients
Origin:
- The diet
- Synthesis in body tissues from precursors
- Released from storage in body tissues
They are transported to body tissued to be metabolised:
- Degradation to release energy
- Synthesis of cell components – all tissues except RBCs
- Storage – Liver, adipose tissue, skeletal muscle
Why is ATP a good energy molecule?
-phosphodiester bond is high energy
