Unit 4 - Cellular Respiration (& Photosynthesis) Flashcards
Activated Carrier Molecules
- contain one or more high energy content bonds
- provides energy for biosynthetic reactions
- ATP, NADPH, NADH, FADH2, Acetyl CoA
Electron Carriers
- modified nulceotides
- coenzymes which carry electrons from one reaction to another
- key players in harvesting of energy during oxidation of glucose
Catabolism
-breakdown of complex molecules into simpler ones by enzymes
Anabolism
-formation of complex molecules from simpler ones
Substrate Level Phosphorylation
-generates few ATP
Oxidative Phosphorylation
- aerobic respiration
- electrons harvested from organic fuel molecules in redox reactions are used to pump H+ across a membrane
- protons allowed to diffuse down gradient and run ATP synthase
Photo-phosphorylation
- occurs in chloroplasts
- cyclic & non-cyclic
Glycolysis
- occurs in cytosol
- 2ATPs spent to make glucose more reactive
- 6C sugar is split into 2 3C sugars (G3P)
- each 3C joins with free phosphate
- 2 phosphate groups are transferred to ATP
- 2 molecules pyruvate per glucose
- net 2 ATP, 2 NADH
Pyruvate Oxidation
- mitochondrial matrix
- decarboxylation reaction –> carbon is removed
- NAD+ is reduced to NADH
- Coenzyme A is added
- produces: 2 NADH, 2 Acetyl CoA, 2 CO2
Krebs Cycle/TCA
- mitochondrial matrix
- 2 acetyl CoAs oxidized to yield 4 CO2, 2 ATP, 6 NADH, 2 FADH2
- two turns of cycle for each molecule glucose
ETC
- inner mitochondrial membrane
- series of molecules embedded in inner mitochondrial membrane
- NADH delivers electrons to top of chain, oxygen catches them at bottom
- oxygen is reduced with hydrogen to form water
- for every 2 electron carriers, one oxygen molecule is reduced to 2 molecules of water
- energy released by movement of electrons generates proton gradient
Chemiosmotic Theory
- most ATP synthesis comes from electrochemical gradient across inner mitochondrial membranes
- generated using energy from NADH & FADH2, derived from breakdown of fuel molecules
Lactic Acid Fermentation
glycolysis –> pyruvate –> lactic acid (NAD+ regenerated)
Alcoholic Fermentation
glycolysis –> pyruvate –> ethanol (NAD+ regenerated)
Fats as fuel molecules
- digested into fatty acids + glycerol
- fatty acids broken down into acetyl CoA
Proteins as fuel molecules
- digested into amino acids
- amino acids deaminated and fed into TCA cycle
Regulation of Glycolysis
-high levels of ATP inhibit enzyme phosphofrucktokinase
Photosynthesis
Light Reactions: photosynthetic electron-transfer reactions in thylakoid membrane
Dark Reactions: carbon-fixation reactions in stroma
