Download CELLULAR RESPIRATION Aerobic Cellular Respiration

CELLULAR RESPIRATION
All living organisms need energy
INTRODUCTION TO CELLULAR
RESPIRATION
Introduction: All living organisms need energy
Respiration:
Respiration: the life process by which organisms
convert the chemical energy stored in food to a
form of energy more easily utilized by the cell
Process of Cell Respiration: a biochemical
process used by cells to release energy from
organic molecules (food) such as glucose
~this energy is stored in the molecule ATP
~ ATP = adenosine triphosphate or A~P~P~P
~ the process is controlled by enzymes
Aerobic Cellular Respiration
Aerobic = with oxygen
Occurs in the mitochondria
The use of oxygen releases more energy per glucose
molecule than anaerobic = without oxygen
Uses oxygen but releases carbon dioxide and water
SUMMARY EQUATION:
Breathing and cellular respiration are closely
related
O2
CO2
BREATHING
Lungs
CO2
Bloodstream
Muscle cells carrying out
O2
Sugar + O2
CELLULAR
RESPIRATION
ATP + CO2 + H2O
OxidationOxidation-Reduction Reactions
Redox for short
Oxidation=
Oxidation= loss of electrons (or H+)
Reduction=
Reduction= gain of electrons (or H+)
OIL RIG:
Oil = Oxidation is loss
Rig = Reduction is gain
~chemical reaction which involve a partial or complete transfer of
electrons form one reactant to another
~ a coupled reaction
Cell Respiration is a redox process that transfers hydrogen form sugar
to oxygen
oxidation
C6H12O6 + 6O2 --
6CO2 + 6H2O + ATP( energy)
reduction
Hydrogen carriers such as NAD+
shuttle electrons in redox reactions
Enzymes remove electrons from glucose
molecules and transfer them to a
coenzyme / electron carriers[ NADH &
FADH2]
Redox reactions release energy when
electrons “fall”
fall” from a hydrogen carrier
to highly electronegative oxygen
NADH ( & FADH2)
FADH2) delivers electrons to a series of
electron carriers in an electron transport chain
– As electrons move from carrier to carrier, their energy is released
released
in small quantities
Energy released and now
available for making ATP
ELECTRON CARRIERS
of the electron transport chain
STAGES OF CELLULAR
RESPIRATION
Respiration occurs in three main stages
High-energy electrons
carried by NADH
GLYCOLYSIS
Cytoplasmic
fluid
KREBS
CYCLE
ELECTRON
TRANSPORT CHAIN
Mitochondrion
1. Glycolysis:
Glycolysis: [Glyco=sweet, sugar
lysis = to split]
~process in which one molecule of glucose is broken in half,
producing 2 molecules of pyruvic acid,
acid, a 33-carbon compound
~ takes place in cytoplasm
~ makes 2 ATP {part of anaerobic respiration too]
~NO OXYGEN NEEDED
~ 2 molecules of NADH are formed
Glucose
Pyruvic
acid
2. Krebs Cycle
Each pyruvic acid molecule is
broken down to form CO2 and
a twotwo-carbon acetyl group,
which enters the Krebs cycle
[Transition phase]
The Krebs cycle completes the
oxidation of organic fuel,
generating many NADH and
FADH2 molecules
2 turns per glucose molecule
Occurs in mitochondria
Produces 2 ATP
6 NADH & 2 FADH2
Acetyl CoA
KREBS
CYCLE
3. Electron Transport Chain
The electrons from NADH and FADH2
travel down the electron transport chain to
oxygen
Oxygen is the final electron acceptor
Occurs in mitochondria
Produces 32 ATP
Lactic Acid Fermentation
GlucoseGlucose->pyruvic acid -> 2 lactic acid
2ATP
GLYCOLYSIS
FERMENTATION
~ used to make cheese and yogurt
~ in humans during strenuous exercise
not enough oxygen from blood “oxygen debt”
debt”
~ lactic acid accumulates in muscle; leads to fatigue and
pain
Both types a of fermentation are considered inefficient ,
only produce 2ATP from glycolysis
Cells use many kinds of organic molecules
as fuel for cellular respiration
Polysaccharides
Sugars
Fats
Proteins
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