Unit 3 – Lecture 10

Cellular RespirationCellular 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’dTwo 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’dAerobic Respiration AND Anaerobic

respiration BOTH start with GlycolysisGlycolysis: breaks down glucose [6-

carbons] to form pyruvate [3-carbons]glyco – refers to glucose [remember

glycogen?]lysis – to break downtakes place in the cytoplasm

GlycolysisATP used to break glucose [6-C] into

two, 3-Carbon molecules

Glycolysis – cont’dadditional 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’d3-C molecule is stripped of extra phosphates

by other ADP molecules to form two pyruvate moleculespyruvate = another 3-C molecule

Glycolysis – cont’dTO SUM UP: three products of Glycolysis =

ATP [little bit – 2 molecules!]NADH +HPyruvate

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 Cycleaka Citric Acid Cyclepyruvate from Glycolysis

becomes a 2-carbon compound by releasing CO2

Krebs Cycle – cont’dthat 2-C compound goes through changes

whichproduce 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’dthat 2-C compound goes through changes

whichproduce FADH2

(another e- carrier)to be used later in the ETC of Cellular Respiration]

this repeats over and over…

Krebs Cycle – cont’dTO SUM UP: products of Krebs =

CO2

ATP [little bit – 1 molecule!!]filled e- carriers

FADH2 NADH +H

ETCe-s from FADH2 and NADH [from Glycolysis &

Krebs] move down proteins in membranecreates NAD+e-s pass

throughthe ETC, releasingE [like in photo-synthesis]

Glycolysis & KrebsNAD+

ETC – cont’dthis moves H+ ions through ion pumps,

forming a gradient of charge & concentration [electrochemical gradient] in the inter-membrane space

Glycolysis & KrebsNAD+

ETC – cont’doxygen combines with the e-s & H from the

carriers to make water opposite of ETC

in photo-synthesis where wesplitwater with the E… we form ithere!

Glycolysis & KrebsNAD+

H2O

ETC – cont’dH+ ions funnel through the ATP Synthase

to make ATP from ADP+P 32-36 molecules!!!

Glycolysis & KrebsNAD+

H2O

ADP + P

ATPSynthase

ETC – cont’dProcesses:

ETCChemiosmosis – ATP Synthesis

Glycolysis & KrebsNAD+

H2O

ETC Chemiosmosis

ADP + P

ATP

Anaerobic Respiration[begins with Glycolysis]Fermentation: recycles the products from

glycolysis [pyruvate and NADH+H] if there is no oxygenno ATP made heretakes place in the cytoplasm of the cell

Fermentationcan take two forms:

lactic acid fermentationpyruvate 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’dcan take two forms:

alcoholic fermentationpyruvate 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 ProductionIf Oxygen Present = Aerobic Respiration

[Glycolysis]Glucose in2 ATP out

ATP ProductionIf Oxygen Present = Aerobic Respiration

[Glycolysis]Krebs Cycle

Oxygen inCO2 out1 ATP out

ATP ProductionIf Oxygen Present = Aerobic Respiration

[Glycolysis]Krebs CycleETC

Oxygen inWater outLOTS of ATP out [32-36]

ATP Production – cont’dIf 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 takeplace?

What are the foldsin the inner membrane called?

Why is the inner mitochondrial membrane folded into cristae?

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