Cell Respiration:
Stage 1: Food Breakdown
 Before food can be processed into ATP, large polymeric molecules must
be broken down into their basic units. For example, proteins must be
broken down into amino acids and polysaccharides must be broken
down into glucose. This step is known as digestion. Most of digestion
takes place in the digestive tract of animals and food is broken down by
secreted enzymes.
 Even after all of the molecules have been broken down into their basic
units, most of the non-glucose molecules are subsequently converted
into glycose so that they can be processed during glycolysis. The
following table lists the food molecules and there basic unit.
 Complex Food Molecule Basic Units

Proteins Amino Acids
 Polysaccharides Simple Sugars (e.g. glucose)
 Fats (Lipids) Fatty Acids and Glycerol
Cell Respiration
 Process that releases energy (chemical) by
breaking down glucose and other food
molecules in the presence of oxygen
 Occurs in both plants and animals and fungi
 There are 2 types
Aerobic Respiration
- With OXYGEN
Anaerobic Respiration
- Without OXYGEN
The whole process is divided
into 2 parts:
 Anaerobic
 Aerobic
 No Oxygen
 Oxygen
 Occurs in cytoplasm
 Occurs in mitochondria
 Glycolysis is an
 Divided into 2 stages:
anaerobic process
 Glucose is broken into
pyruvic acid and ATP
 Kreb cycle (citric acid cycle)
 Electron Transport Chain
Glycolysis
 Remember…”-lysis” means “to break”
 Glucose is broken down into 2 molecules of
PYRUVATE
 Glycolysis is anaerobic
 Pyruvate can then be used for cellular
respiration
 Location: cytoplasm
 Occurs before cellular respiration can happen
Glycolysis
 Once glucose is imported into the cell:
 Glucose is broken down into 2 molecules of pyruvate
 Produces 4 ATP per glucose
 2 ATP molecules are “used” up leaving us with a net gain
of 2 ATP molecules produced for the cell to use for
energy.
 Pyruvate enters the mitochondria and provides the
materials needed for the Kreb’s cycle
 http://highered.mcgrawhill.com/sites/0072507470/student_view0/chapte
r25/animation__how_glycolysis_works.html
Electrons carried in NADH
Electrons
carried in NADH
Pyruvic acid
Glucose
Glycolysis
Cytoplasm
and FADH2
Krebs
Electron Transport
Cycle
Chain
Mitochondrion
Aerobic Respiration
 Requires Oxygen
 More effective than anaerobic (without
oxygen), make MUCH MORE ATP
 Location: Mitochondria
Aerobic Respiration
 KNOW THE FORMULA!!!
 C6H12O6 + 6O2  6H2O + 6CO2 + ATP
GLUCOSE (FOOD) OXYGEN
WATER CARBON DIOXIDE
Steps of the Process
 Glycolysis
 Krebs Cycle
 Electron Transport Chain (ETC)
Kreb’s Cycle (citric acid
cycle)
 Breaks pyruvate down into CO2
 Occurs in the mitochondria
 Produces 2 ATP per glucose
 Produces NADH & FADH2
 FADH2 and NADH provide power for the ETC
 FADH2 and NADH are carrying chemical energy
 The carbon dioxide produced here diffuses out of
the mitochondria, out of the cell and into the
bloodstream where it is carried to the lungs and
diffuses into the air that we exhale.
http://highered.mcgrawhill.com/sites/0072507470/student_view0/chapter25/animation__how_the_krebs_cy
cle_works__quiz_1_.html
Electron Transport Chain
(ETC)
 Occurs in the lining of the mitochondrial membrane
 FADH2 and NADH pass some of their electrons onto the ETC
 ETC is like a game of hot potato, where electrons from
FADH2 and NADH are the potato, and proteins in the
mitochondria are the people passing the potato. OXYGEN
IS REQUIRED.
 The flow of electrons down the chain powers a special
protein, called “ATP synthase,” which synthesizes
(makes) ATP
 Produces 32 ATP per glucose!
 Total ATP production per glucose during aerobic
respiration = 36 ATP
http://highered.mcgrawhill.com/sites/0072507470/student_view0/chapter25/animation__electron_transport_system_a
nd_atp_synthesis__quiz_1_.html
Electron Transport
Hydrogen Ion Movement
Channel
Intermembrane
Space
ATP synthase
Inner
Membrane
Matrix
ATP Production
Anaerobic Respiration:
Fermentation
 Sometimes a cell can’t get the oxygen that it
needs to carry out aerobic respiration.
 It carries out fermentation to make energy
instead (ATP)
 Less EFFECTIVE, doesn’t make as much ATP
 Location: Cytoplasm
Fermentation
Isn’t a “clean burn” so nasty, or intoxicating, waste products are left behind
There are 2 types
Alcoholic Fermentation
Lactic Acid Fermentation
-Produces ethanol
(alcohol) as a waste
product
Produces lactic acid as a
waste product
-Used for producing
beer, wine, and rising
bread
-Is part of the burn you feel
in your muscles when you
exercise.
Lactic Acid Fermentation
•Notice that a total of 2 ATP molecules are made for each molecule of
glucose during glycolysis
•Notice that NAD+ is “regenerated” to be used in glycolysis
•This is a low energy yield process (only 2 ATP’s) but this can be enough to
sustain our cells when we can’t get enough oxygen
Alcoholic Fermentation
 alcoholic fermentation, is a biological process in which
sugars such as glucose, fructose, and sucrose are converted
into cellular energy and thereby produce ethanol and carbon
dioxide as metabolic waste products. Because yeasts
perform this process in the absence of oxygen, ethanol
fermentation is classified as anaerobic. Ethanol
fermentation occurs in the production of alcoholic beverages
and ethanol fuel, and in the rising of bread dough.
 C6H12O6 → 2C2H5OH + 2CO2
(ethanol)
*** 2 ATP molecules are made. NAD+ is reused in Glycolysi
Prokaryotic vs Eukaryotic
 Prokaryotic: Remember has no nucleus or no membranes around their
organelles. So where does Aerobic Respiration occur here?





Prokaryotic Cells
Glycolysis: Cytoplasm
Krebs Cycle: Cytoplasm
ETC: Cell Membrane
Fermentation: cytoplasm
Eukaryotic Cells
Glycolysis: Cytoplasm
Krebs Cycle: Mitochondria
ETC: Mitochondrial Membrane
Ferm: Cytoplasm
Prokaryotic cells can yield a maximum of 38 ATP molecules while
eukaryotic cells can yield a maximum of 36. In eukaryotic cells, the NADH
molecules produced in glycolysis pass through the mitochondrial
membrane, which "costs" two ATP molecules
http://biology.about.com/library/quiz/blcellres
quiz.htm
Chemical formulas for Photosynthesis and
Cell Respiration
 Photosysthesis:
6CO2 + 6H2O + Light Energy = C6H12O6 + 6O2

Cell Respiration
C6H12O6 + 6O2  6H2O + 6CO2 + ATP
Products of Photosynthesis
O2 + C6H12O6
(Reactants of photosynthesis
CO2 + H2O + ATP)
Reactants of Respirations
(products of respiration
CO2 + H2O + ATP)
Photosynthesis
Light
To Make
 Photosynthesis is the process of converting
light energy to chemical energy and storing it as
sugar.
 This process occurs in plants and some algae
(Kingdom Protista).
 Plants need only light energy, CO2, and H2O to
make sugar.
 The process of photosynthesis takes place in the
chloroplasts, specifically using chlorophyll, the
green pigment involved in photosynthesis.
Why does Chlorophyll have a
green color?
 Chlorophyll absorbs red and blue wavelengths of light.
However, it can not absorb the green wavelengths of
light very well. As a result, it reflects the green
wavelengths, which when they hit our eyes, we perceive
as the color green.
6CO2 + 6H2O + Light Energy = C6H12O6 + 6O2
Photosynthesis
 Step 1: Absorb light and break down H 2O into H+, H+, and O.
a.The remaining O’s from the water join together to form O2
 Step 2: Light Energy converted to ATP (Light reaction)
a. Occurs in the thylakoid membranes o f the chloroplasts
 Step 3: Dark Reaction (Calvin Cycle)
a. Occurs in the Stroma of the chloroplasts
 The reactions of photosynthesis can be categorized as light-
dependent reactions and dark reactions.
1. light dependent reactions
The light dependent reaction happens when
solar energy is captured to make a molecule
called ATP (adenosine tri-phosphate).
2. light independent or dark reactions. The dark
reaction happens when the ATP is used to make
glucose (the Calvin Cycle).
Light Reactions:
Making ATP and NADPH
 light dependent reactions The light dependent reaction happens when
solar energy is captured to make a molecule called ATP (adenosine triphosphate).
 Thylakoid Membrane: Electron Transport Chain

Light causes the movement of hydrogen ions through the protein (enzyme)
provides energy to make ATP (photosystem 2: blue )
 Also provides energy to make NADPH (electron acceptor) (photosystem 1 )

Red

Oxygen is given off
Dark Reactions:
Calvin Cycle
 light independent or dark reactions. The dark reaction
happens when the ATP and CO2 is used to make glucose (the
Calvin Cycle).
 6 CO2 are added to a five Carbon Compound sugar
P-C-C-C-C-C-P + CO2
ATP ADP, NADPH NADP+
 These break down into Six 3 carbon sugars
(6) P-C-C-C
 One 3 carbon sugar is used to make Starch or Sucrose
 The other 5 3carbon sugars are used to regenerate the initial
5carbon compound
http://www.dnatube.com/video/2899/Photosynthesis-101presented-by-Dr-Undergrad
What affects Photosynthesis?
 Amount of Light
- Rate of photosynthesis increases with more light
- one saturation is reached it will level off: Pigments
cannot absorb any more light.
 Amount of CO2
- Rate of photosynthesis increases with more CO2
- Saturation level reached cannot rate will level off
 Temperature
- Decreased temps will decrease rate
- WHY? Enzyme activity

Photosynthesis

Cellular Respiration
Function
Energy capture
Energy release
Location
Chloroplast
Mitochondria
Reactants
CO2 and H2O
C6H12O6 and O2
Products
C6H12O6 and O2
CO2 and H2O
Equation
6CO2 + 6H2O 
C6H12O6 + 6O2
6O2 + C6H12O6 
6CO2 + 6 H2O