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Chapter 07(cellular respiration and fermentation) - Coggle Diagram
Chapter 07(cellular respiration and fermentation)
Cellular respiration: process by which living cells obtain energy from organic molecules
Primary role to make ATP and NADH
Aerobic respiration uses oxygen and releases CO2/ primarily uses glucose but other organic molecules are also used
Glucose metabolism
Glycolysis
-Stage 1 of cellular respiration.-can happen with or without oxygen.
Energy investment
2 ATP hydrolized to creat fructose 1,6 bisphosphate
Cleavage
6 carbon molecules broken into two 3 carbon molecules of glyerldhyse-3- phosphate.
Energy liberation
Two glyecerldehyde-3-phosphate molecules broken down into two pyrovate molecules- produces 2NADH and 4ATP (net yield= 2ATP)
Breakdown of pyruvate
-stage 2 of cellular respiration. -in eukaryotes puruvate is transported into the mitochondrial matrix -broken down by pyruvate dehydrogenase -molecule of CO2 removed from each pyruvate. -remaining acetyl group attached to CoA to make acetyl CoA (yield= 1 NADH for each pyruvate)
-pyruvate is made in the cytosol by glycolysis. It travels through a channel in the outer membrane and an H+/ pyruvate symporter in the inner membrane to reach the mitochondrial matrix
Pyruvate is oxidized via pyruvate dehydrogenase to an acetyl group and CO2. NADH is made. During this process the acetyl group is transferred to coenzyme A (CoA) and is later removed and enters the citric acid cycle
Citric acid cycle
-Stage 3 of cellular respiration.
-METABOLIC CYCLE: 1)some molecules enter while others leave 2)series of organic molecules regenerated in each cycle.
-Acetyl is removed from Aceyl CoA and attached to Oxaloacetate to form citrate (aka citric acid)
series of step releases 2 co2, 1 ATP, 3NADH and 1FADH2 -oxalocetate is regenerated to start the cycle again.
Oxidative phosphorylation
-stage 4 of cellular respiration.
-high energy electrons removed from NADH and FADH2 to make ATP
typically requires oxygen.
oxidative process involves (ETC)
phosphorylation occurs by ATP synthase.
Oxidation by (ETC)
-protein complex’s and small organic molecules embedded in the inner mitochondrial membrane.
-series of redox reactions happen.
-when electrons move H+ electrochemical gradient is generated.
-this provides energy for the next step( synthesizing ATP)
Phosphorylation by ATP synthase
-lipid bilayer of inner mitochondrial membrane is relatively impermeable to H+
-protons can pass through ATP synthase only.
-Harness free energy to synthesize ATP for, ADP.
-chemiosmosis: chemical synthesis of ATP as a result of pushing H+ across the membrane.
..NADH oxidation makes the most of the cells ATP.- NADH oxidation creates the H+ electrochemical gradient used to synthesize ATP.- yield= up to 30-34 ATP molecules/ glucose -but rarely achieve maximal amount.
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For environments that lack oxygen (TWO STRATEGIES CAN BE USED):
2)produce ATP only via substrate-level phosphorylation
There are other acceptors: -E.coli uses nitrate (NO3-) under anaerobic conditions. -also makes ATP via chemiosmosis even under Aerobic conditions.
1) use substance other than O2 as final electron acceptor in (ETC)
Fermentation
-Is the breakdown of organic molecules without net oxidation.
-many organisms can use O2 as final electron acceptor , so under anaerobic conditions they need a different way to produce ATP, like using GLYCOLYSIS.
-But glycolysis uses up NAD+ and makes too much NADH under anaerobic conditions(dangerous situation).
-muscle cells solve problem by reducing pyruvate into lactate.
-yeast solve problem by making ethanol.
-fermentation produces far less ATP than oxidative phsphrylation.