Energy Reactions In Cells - Lec1 Flashcards
Define metabolism
Metabolism is the set of processes that derive energy and raw materials from food stuffs and use them to support the growth repair and activity in tissues needed to sustain life
Describe catabolic pathways
Break down large molecules into smaller molecules
Release large amounts of energy
Oxidative (takes e-)- reducing power
Describe anabolic pathways
Synthesise larger important molecules from intermediary metabolites
Use energy released by catabolism
Reductive (use H released in catabolism)
Name 4 products of catabolic metabolism
Energy (ATP)
Reducing powers- NADH, NADPH
Building block materials (sugars, amino acids, fatty acids)- growth, repair
Organic precursors (Acetyl CoA)
What is the definition of energy
Capacity to work
What is energy needed for? ( 5 examples)
Anabolism- synthesis of cellular components
Transport- Maintenance of ion gradients, nutrient uptake
Mechanical work- muscle contraction
Electrical work- nervous impulses
Osmotic work- Kidney function
What is an exergonic reaction?
A reaction that releases energy
What is an endergonic reaction?
A reaction that requires energy
What type of reactions can occur spontaneously?
Only exergonic reactions can occur spontaneously. The value for Gibbs Free Energy must be negative for this to occur.
Why is ATP a good energy store?
It is very stable without the presence of a catalyst which means energy is not wasted.
Small so easily transported
Releases manageable amounts of energy to the cell so doesn’t damage the cell.
What type of pathway is activated when ATP is high?
Anabolic pathways
What type of pathway is activated when ATP is low?
Catabolic pathways
What does AMP signal?
Low energy which signals catabolic pathways
What is the enzyme called which converts creatine into creatine phosphate by phosphorylation?
Creatine Kinase. ATP is also needed
When is phosphocreatine formed and when is it used?
It is formed when ATP levels are high and broken down when ATP levels fall it can provide a short term boost of energy
What is a clinical use for the enzyme creatine kinase (CK)?
CK can act as an indicator of a myocardial infarction (MI) as it is released into the blood from cardiac cells when they are damaged.
Why is creatinine a useful clinical marker?
Creatinine excretion per 24hrs is proportional to muscle mass.
It is excreted at a constant rate daily so can be used to measure urine dilution and the conc. of hormones eg in a pregnancy test as the conc of creatinine is constant daily
