biol 1406 chapter 7

autotrophs

able to reproduce their own organic molecules through photosynthesis

heterotrophs

live on organic compounds produced by other organisms, these organisms eat other heterotrophs or autotrophs

cellular respiration

converts nutrients (glucose) into ATP, occurs in the mitochondria of eukaryotes and the cytoplasm/cell membrane of bacterial cells

cellular respiration equation

C₆H₁₂O₆+6O₂ → 6CO₂+6H₂O+36ATP

electron carries

molecules that use electrons to help transfer energy between molecules, all can be reversibly oxidized/reduced, ex: NADH and FADH₂

anaerobic respiration

final electron receptor is an inorganic molecule, final electron receptor is oxygen

fermentation

final electron acceptor is an organic molecule, occurs when oxygen is not available, 2 ATP per glucose

nicotinamide adenosine dinucleotide (NAD⁺)

important electron carrier and enzyme cofactor, accepts 2 electrons and 1 proton to become NADH during redox reactions

ATPase

enzyme helps hydrolyze ATP into ADP

ATP synthase

enzyme helps phosphorylate ADP to ATP

substrate-level phosphorylation

mechanism for ATP synthesis, transfers phosphate group directly to ADP, occurs during glycolysis

oxidative phosphorylation

mechanism for ATP synthesis, ATP synthase uses energy from a proton gradient created in the electron transport chain

how much energy is released by ATP hydrolysis

-7.3 kcal/mol

cellular respiration stages

glycolysis, kreb’s cycle, electron transport chain

glycolysis

occurs in the cytoplasm, anaerobic process, breaks down glucose into 2 pyruvate molecules, net production of 2 ATP and 2 NADH

glycolysis formula

glucose + 2 ADP + 2 Pi + 2 NAD⁺ → 2 pyruvate + 2 ATP + 2 NADH + 2H⁺ + 2H₂O

kreb’s cycle (citric acid cycle)

occurs in the matrix of the mitochondria, aerobic process, produces 3 NADH, 1 FADH₂, 2 CO_2, and 1 ATP for each turn per glucose molecule (twice)

electron transport chain

occurs in the inner membrane of mitochondria, aerobic process, net 32 ATP molecules are produced

chemiosmosis

accumulation of protons in the intermembrane space drives protons into the matric via diffusion, ATP synthase aids in the phosphorylation of ADP (adding phosphate to ADP to create ATP)

energy yield of respiration

32 ATP per glucose for bacteria, 30 ATP per glucose for eukaryotes

phosphofructokinase

enzyme that regulates glycolysis (inhibited by ATP or citrate)

pyruvate dehydrogenase

enzyme that regulates pyruvate oxidation (inhibited by NADH)

two types of fermentation

alcoholic and lactic acid

alcoholic/ethanol fermentation

occurs in yeast, decarboxylation of pyruvate, CO_2, ethanol, and NAD⁺ are produced

lactic acid fermentation

occurs in animal cells, anaerobic, sugars are converted into cellular energy, electrons are transferred from NADH to pyruvate to produce lactic acid