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Cell Energy
ATP, Photosynthesis, and
Respiration
The Energy Molecule- ATP
n
n
Energy in the body is used to maintain
homeostasis
Homeostasis- maintaining a constant
internal environment even though
external conditions change
Examples of Homeostasis
n
Body temperature regulation
When it is cold we shiver
When it is hot we sweat
Examples of Homeostasis
n
Glucose
regulation
in the
blood
The Energy Molecule- ATP
n
ATP is the molecule in the body that
stores energy in the bonds between
phosphate groups. When a bond
between the phosphate groups is
broken, energy is released.
The Energy Molecule- ATP
n
Parts of an ATP molecule
n
n
ATP stands for the molecule adenosine
triphosphate.
ATP contains one base, one sugar, and 3
phosphate groups
Base-adenine
Sugarribose
P
P
P
The Energy Molecule-ATP
n
ADP- Adenosine Diphosphate- 2
phosphate groups
Base-adenine
n
Sugarribose
P
P
AMP – Adenosine Monophosphate – 1
phosphate group
Base-adenine
Sugarribose
P
The Energy Molecule-ATP
n
Cycling of ATP
ATP loses a
phosphate-energy
is released
ATP gains a
phosphate
through cellular
respiration-stores
energy
The Energy Molecule-ATP
Photosynthesis
n
n
n
Producers like plants, algae and some
bacteria
Plants trap energy from the sun, and
build glucose molecules
Light energy is converted to chemical
energy.
Photosynthesis
n
n
n
chloroplast
Pigments
Light is absorbed by pigments in the
chloroplasts called chlorophyll.
Chlorophyll is a green pigment that
absorbs most wavelengths of light.
Other pigments include the colors red,
orange, and yellow.
Photosynthesis
n
Overall reaction for photosynthesis
Energy, light,
n
6 CO2
+ 6 H2 O
& chlorophyll
®
C6H12O6 + 6O2
Photo synthesis
n
2 phases of photosynthesis
n
n
The light-dependent reaction
The light-independent reaction (dark reaction)
Photosynthesis
n
n
n
Light-dependent reaction
Light is converted to ATP, a form of
chemical energy
The electron transport chain is when
electrons from light are passed from
one protein to another. Small amounts
of energy are released along the way
that convert ADP to ATP.
Photosynthesis
Light-Dependent Reaction
H2O
sunlight
Electron
Transport
Chain
ATP &
H+
Products go to
Light-Independent
Reaction ® ® ®
Photosynthesis
n
n
n
Light-independent reaction (dark
reaction)
ATP is converted to glucose
The Calvin Cycle is a series of reactions
that use CO2 to form carbohydrates,
mainly glucose.
Photosynthesis
Light-Independent Reaction
ATP & H+
CO2
Calvin Cycle
Glucose
Summary of Photosynthesis
H2O
Light &
enzymes
Light
Reaction
O2
CO2
ATP & H+
Dark
Reaction
H2O
Glucose
Cellular Respiration
n
n
Cellular Respiration
Process of breaking down food
molecules to produce energy (ATP)
Cellular Respiration
n
Types of respiration
n
Aerobic respiration requires oxygen
n
Anaerobic respiration uses no oxygen
Cellular Respiration
n
3 stages of aerobic respiration
n
n
n
Glycolysis
Citric acid cycle
Electron transport chain
Cellular Respiration
n
1. Glycolysis- Glucose, a six carbon
sugar, is broken down into 2 molecules
of pyruvic acid, a 3 carbon molecule.
n
n
n
2 ATP used, 4 ATP made or gained,
therefore there is a net gain of 2 ATP.
This reaction does not use oxygen and is
therefore an anaerobic process.
This reaction occurs in the cytoplasm
Cellular Respiration
n
n
Pyruvic acid now moves to the
mitochondria where aerobic respiration
can take place.
2. Citric Acid Cycle (Kreb’s cycle)
n
Pyruvic Acid is broken down to release CO2
and 2 ATP.
Cellular Respiration
n
Electron Transport Chain
n
Oxygen is used to make water and 32
ATP.
Cellular Respiration
n
Overall Reaction for Aerobic Respiration
C6H12O6 + 6O2 → 6 CO2 + 6 H2O + E (ATP)
n
NOTE: Photosynthesis is the opposite reaction of
respiration. The reactants of one are the
products of the other.
Cellular Respiration
Cellular Respiration
n
Anaerobic Respiration – 2 types
n
Lactic Acid Fermentation
n
Alcoholic Fermentation
Cellular Respiration
n
Lactic Acid Fermentation- occurs when
oxygen is scarce.
n
n
Pyruvic acid is converted into 2 molecules
of lactic acid and 2 molecules of ATP.
Lactic Acid causes muscle fatigue in the
body.
Cellular Respiration
n
Alcoholic fermentation- organisms like yeast
and bacteria use this process to produce
energy without the use of oxygen
n
n
Pyruvic acid is converted to ethyl alcohol, carbon
dioxide and 2 ATP
When yeast is used to make bread, the carbon
dioxide causes bubbles to form in the dough.
Cellular Respiration Summary
Anaerobic
In
cytoplasm
Lactic Acid
Fermentation
Lactic Acid
2 ATP
Glucose
Glycolysis
Pyruvic acid
2 ATP
Alcoholic
Fermentation
Ethyl Alcohol,
CO2, 2 ATP
Aerobic
In
mitochondrion
Kreb’s Cycle
2 ATP
Electron Transport
Chain
32 ATP
36 ATP, CO2
& H2O
Summary of Respiration
Characteristic
Starting
materials
1st step
Uses
oxygen
Cell location
Products
Aerobic
Respiration
Glucose
Glycolysis
Yes
Mitochondria
Lactic Acid
Fermentation
Glucose
Glycolysis
No
Alcoholic
Fermentation
glucose
Glycolysis
No
Number
of ATP
produced
Net Gain
of ATP
CO2 , H2 O,
energy
(ATP)
38 ATP
36 ATP
Cytoplasm
Lactic
acid, ATP
4 ATP
2 ATP
cytoplasm
Ethyl
alcohol,
CO2 , ATP
4 ATP
2 ATP
Comparison of Photosynthesis
and Respiration
Characteristics
Photosynthesis
Aerobic Respiration
Reactants/requirements
CO2 , H2 0, light,
chlorophyll, enzymes
Glucose, O2
Products
Glucose, O2
CO2 , H2 0, 36 ATP
Location
chloroplasts
mitochondria
Use of energy
storage
release
Use of food molecules
Food made
Food broken down