Cellular Respiration
Chapter 8
Respiration=
=conversion of chemical e
(glucose) into ATP.
=breathing???
--What is the object of Respiration?
Chemical Description:
C6H12O6+6O26CO2+6H2O+Energy
(heat & ATP)
What is involved:
-Oxidation of glucose
-reduction of oxygen
-release of energy
Use of:
NAD+
FAD
2 Methods of Respiration:
1. Aerobic Respiration=
-produces 36-38 ATP from 1 glucose
-occurs in most all organisms
2. Anaerobic Respiration=
or Fermentation
-occurs only in bacteria (anaerobes)
or under harsh conditions in some
eukaryotes.
-produces only 2 ATP from 1 glucose
4 Steps to Breakdown Glucose (with O2):
1. Glycolysis
2. Transition Rxn.
3. Citric Acid Cycle
5. Electron Transport
***Remember How Cells Assemble ATP:
phosphorylation=ADP + P = ATP
Step 1: Glycolysis
-occurs in cytoplasm
-ATP produced by:
substrate-level phosphorylation=
-produces only 2 ATP
Chemical Description:
C6H12O6+2ATP4ATP+2NADH+2pyruvate
--energy investment phase
--energy production phase
Products: 2NADH=high e electrons
4ATP (2 profit gain)
2 pyruvates (glucose leftover)
Steps 2,3,4 Occur in Mitochondria:
Mitochondria Structure:
-outer membrane
-inner membrane
-cristae
-inner-membrane space
-matrix
Step 2: Transition Rxn:
-occurs in mitochondrial matrix
-Pyruvate is combined with a coenzyme
-CO2 is released
Products: 2 acetyl-CoA
2 CO2
2 NADH
Step 3: Citric Acid Cycle
-occurs in mitochondria matrix.
-the cycle occurs twice, once for each
acetyl-CoA that enters the cycle.
2 Aectyl-CoA6NADH+2FADH2+2ATP+4CO2
Products: 6NADH
2FADH2
2ATP
-CO2 in breathing is produced here.
-ATP produced by sub-level phosph.
-What is Citric Acid?
-What is Oxaloacetate?
Step 3: Electron Transport Chain (ETC)
-occurs on the cristae of the inner
mitochondrial membrane.
-produces 32-34 ATP using
Chemiosmosis
- e- of NADH & FADH2 (produced in steps 1&2).
-the ETC consists of:
1.NADH dehydrogenase or reductase
protein
2.Cytochromes (proteins)
3.at the end of the chain is oxygen
-the energy derived from the ETC is used
to power the proton pump which services
ATP synthase (Chemiosmosis).
=Oxidative phosphorylation
--686 Cal in Glucose
--7.3 Cal in ATP x 36 =
263 Cal out of 686 Cal are conserved
=39% Efficiency
Is that Good?
-Unless Oxygen is available at the end of
the ETC steps 2 & 3 do not proceed.
-If No oxygen is present, then anaerobic
respiration takes over.
Anaerobic Respiration (Fermentation)-ATP
production w/o oxygen.
-Glycolysis occurs...but can’t continue (and
steps 2 & 3) can’t proceed unless something
besides oxygen restores NAD+.
-Only the 2 ATP of glycolysis are produced by
fermentation.
Several Types of Fermentation:
-Prokaryotic (Bacteria) fermentation
-Sulfer Bacteria (Coal Mines)
-Iron Bacteria (TITANIC Rusticles)
-Decomposing Bacteria
-indicated by a black color &
aromatic methane smell.
-found in:
-Eukaryotic Fermentation (2 types):
1. Alcohol Fermentation
-occurs in the fungus, Yeast.
-converts pyruvate into acetaldehyde.
-which restores NAD+ but forms
ethanol as a by-product.
-What do fungi do with ethanol?
-What are the human uses of ethanol?
2. Lactic Acid Fermentation
-occurs in multicellular organisms,
usually in muscle tissue, resulting in
cramps.
-serves as a back-up or emengency
method for producing ATP when
oxygen is used faster than it can be
supplied to the tissue area.