Metabolism Intro Flashcards
Metabolism Def
Sum of chemical reactions essential for life. 2 Types: Catabilic and Anabolic. All metabolic paths are linked (products produced in 1 are reactants in the other)
Catabolic Reaction
Breakdown of large molecules to small releasing energy
Anabolic Reaction
Forming large molecules out of small molecules. Requiring (taking in) energy
Catabolism Stage 1
Hydrolysis (breaking of bonds) of large molecules into smaller molecules
Catabolism Stage 2
Conversion of amino acids, fatty acids, glycerol or monosaccharides to Acetyl Co A (2 C chain)
Catabolism Stage 3
Oxidation of acetyl Co. A. Oxidative phosphorylation (ATP generation). TCA cycle
(Protein) Electron Carriers
NAD+, NADP+ and FAD. Undergo redox reactions in catabolic pathways (eg glycolysis, TCA)
Amount of energy ATP Releases
-8 kCal/mol
Free energy functions in cell
Mechanical (eg muscle contraction), transport (cell pumps), thermogenesis and biosynthetic (anabolic reactions)
Anabolic forming of ATP
Oxidation of food stores
Energetically Favourable Reactions
Substances go from high energy to low energy
What encourages energetically unfavourable reactions in body
ATP and Enzymes. Enzyme inhibition and activation occur with different environmental changes to ensure metabolic pathways are only done to extent necessary
Endergonic Reactions Def
Energetically unfavourable, positive delta G. Anabolic reactions (requires energy)
Exergonic Reactions Def
Gavourable reaction, negative delta G. Catabolic, releases energy
1st step of glucose metabolism
Glucose is phosphorylated (phosphate added) by glucokinase (hexokinase) to form glucose-6-phosphate. This is an unfavourable reaction made possible by ATP hydrolysis (adding of 2 delta G values in reaction results in net negative delta G)
NAD+ and NADH relationship
NAD+ (oxidised) and NADH (reduced). A protein reactant is reduced and oxidised in relation to eachother (as NAD+ gains electrons and a proton the other reactant loses them)
Last electron carrier in ETC
O2 (inner mitochondrial membrane)
How do mitochondria signal other cells
Break down their Calcium stores
What cell doesn’t contain mitochondria
Erythrocytes. ETS and TCA can’t happen
TCA location
Matrix. Except for succinate dehydrogenase (enzyme shared with ETC) in membrane
Amount of ATP per glucose produced in NADH pathways
38
Amount of ATP per glucose produces in FADH pathways
36
Where do products of TCA cycle end up
IN ETC
What can be used as TCA cycle intermediates
amino acids
Energy not converted to ATP in ETC Function
Thermogenesis, cell signaling (Ca store breakdown),
Triglycerides as energy stores
High energy stores in adipose tissue. Breaks down to form acetyl co A and NADH
Amino Acid as energy stores
Converted to pyruvate
ATP production under anaerobic conditions
Only 2ATP per Glucose (Glycolysis only). Pyruvate converted to lactic acid
Intermediate of glucose in glucogenesis
Oxaloacetate
Intermediate fatty acids, cholesterol and ketone
Acetyl Co A
Glucogenesis Def
Production of glucose from non-carbohydrate (protein and fat) substrates. Used to maintain blood glucose while fasting
Amphibolic Def
Pathways that are both catabolic and anabolic. Eg TCA cycle
Metabolic Pathway Regulation
Feedback (enzymes), phosphorylation, hormonal regulation (conc of hormones), allosteric regulation (changes enzyme function), substrate and oxygen availability
Hypoxia Def
Low oxygen
Anoxia Def
No oxygen
Rate Limiting Enzyme Def
regulated by the most mechansims. Determines rate of enzyme eg phosphofructase 1
Dehydrogenases Function
Removes H from 1 molecule and gives to other
Kinase
Transfer phosphate from 1 molecule to another
Consequnces of impaired enzyme action
Substrate accumulation (toxic), product deficency (disease), alternative product (toxic)
