Cellular Respiration Unit 3 – Lecture 10

Cellular Respiration Cellular Respiration: process used by all living organisms to make energy in the form of ATP. Equation: C6H12O6 + O2  E + H2O +CO2 for eukaryotic organisms, this takes place in the mitochondria

Cellular Respiration – cont’d Two Kinds: Aerobic: describes a process that requires oxygen [Krebs Cycle & ETC] Anaerobic: describes a process that does not require oxygen [Glycolysis & Fermentation]

Cellular Respiration – cont’d Aerobic Respiration AND Anaerobic respiration BOTH start with Glycolysis Glycolysis: breaks down glucose [6-carbons] to form pyruvate [3-carbons] glyco – refers to glucose [remember glycogen?] lysis – to break down takes place in the cytoplasm

Glycolysis ATP used to break glucose [6-C] into two, 3-Carbon molecules

Glycolysis – cont’d additional phosphates added to 3-C molecules makes NADH + H [similar to NADPH except without the phosphate] NADH = electron carrier NADH + H goes to the ETC of CR

Glycolysis – cont’d 3-C molecule is stripped of extra phosphates by other ADP molecules to form two pyruvate molecules pyruvate = another 3-C molecule

Glycolysis – cont’d TO SUM UP: three products of Glycolysis = ATP [little bit – 2 molecules!] NADH +H Pyruvate

Aerobic CR [begins with Glycolysis anyway, even though that does not require oxygen] Krebs Cycle: produces CO2 and H2O from the pyruvate & NADH+H [made in glycolysis] takes place inside of the mitochondrial matrix. Electron Transport Chain takes place at inner membrane

Krebs Cycle aka Citric Acid Cycle pyruvate from Glycolysis becomes a 2-carbon compound by releasing CO2

Krebs Cycle – cont’d that 2-C compound goes through changes which produce ATP [from ADP+P] produce NADH +H (electron carrier) to be used later in ETC of Cellular Respiration remember – Photo- synthesis has NADPH [both have the ‘P’]; CR has NADH [no P]

Krebs Cycle – cont’d that 2-C compound goes through changes which produce FADH2 (another e- carrier) to be used later in the ETC of Cellular Respiration] this repeats over and over…

Krebs Cycle – cont’d TO SUM UP: products of Krebs = CO2 ATP [little bit – 1 molecule!!] filled e- carriers FADH2 NADH +H

ETC e-s from FADH2 and NADH [from Glycolysis & Krebs] move down proteins in membrane creates NAD+ e-s pass through the ETC, releasing E [like in photo- synthesis] NAD+ Glycolysis & Krebs

ETC – cont’d this moves H+ ions through ion pumps, forming a gradient of charge & concentration [electrochemical gradient] in the inter- membrane space NAD+ Glycolysis & Krebs

ETC – cont’d oxygen combines with the e-s & H from the carriers to make water opposite of ETC in photo- synthesis where we split water with the E… we form it here! H2O NAD+ Glycolysis & Krebs

ETC – cont’d H+ ions funnel through the ATP Synthase to make ATP from ADP+P 32-36 molecules!!! ATP Synthase H2O NAD+ ADP + P Glycolysis & Krebs

ETC – cont’d Processes: ETC Chemiosmosis – ATP Synthesis ATP H2O NAD+ ADP + P Glycolysis & Krebs ETC Chemiosmosis

Anaerobic Respiration [begins with Glycolysis] Fermentation: recycles the products from glycolysis [pyruvate and NADH+H] if there is no oxygen no ATP made here takes place in the cytoplasm of the cell

Fermentation can take two forms: lactic acid fermentation pyruvate from Glycolysis  lactic acid uses NADH, producing NAD+ NAD+ then goes back to Glycolysis lactic acid builds up in your tissues [makes you sore!]

Fermentation – cont’d can take two forms: alcoholic fermentation pyruvate from Glycolysis into ethanol [drinking alcohol] releases CO2 uses NADH, producing NAD+ NAD+ then goes back to Glycolysis this is how alcohol is made & bread rises [yeast], and how how yogurt, cheese & sour cream are made [bacteria&fungi]

ATP Production If Oxygen Present = Aerobic Respiration [Glycolysis] Glucose in 2 ATP out

ATP Production If Oxygen Present = Aerobic Respiration [Glycolysis] Krebs Cycle Oxygen in CO2 out 1 ATP out

ATP Production If Oxygen Present = Aerobic Respiration [Glycolysis] Krebs Cycle ETC Oxygen in Water out LOTS of ATP out [32-36]

ATP Production – cont’d If no Oxygen Present = Anaerobic Respiration [Glycolysis] Fermentation If no Oxygen present, only Glycolysis makes ATP. [questions follow]

Where does glycolysis take place? Where does the Krebs Cycle take place? Where does the ETC take place? Where does fermentation take place? What are the folds in the inner membrane called? Why is the inner mitochondrial membrane folded into cristae?

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