Unit 3 Think back to Energy Transfer Living things use energy for Growth Repair Reproduction Metabolism The collection of reactions that occur in a cell Metabolism Involves either ID: 182163
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Slide1
Photosynthesis and Respiration
Unit 3 Slide2
Think back to Energy Transfer…
Living things use energy for
Growth
Repair
Reproduction
Metabolism
The collection of reactions that occur in a cell Slide3
Metabolism
Involves either:
U
sing energy to build molecules (condensation reactions)
or
Breaking down molecules to release the stored energy (hydrolysis) Slide4
Building Molecules That Store Energy
Photosynthesis
is the process by which light energy is converted to chemical energy
Organisms that use energy from sunlight (or from chemical bonds in inorganic substances) to make organic compounds are called
autotrophsSlide5
Breaking Down Food for Energy
Organisms that must get energy from food instead of directly from sunlight (or inorganic substances) are called
heterotrophs
Heterotrophs get energy from food through the chemical process of
cellular respiration,
remember that autotrophs perform cellular respiration also!Slide6
PHOTOSYNTHESIS Slide7
Photosynthesis
Photosynthesis changes the energy of sunlight into the chemical energy stored in glucose bonds
Photosynthesis is the connection between the sun and the energy needs of living systemsSlide8
Equation
6CO
2
+ 6H
2
O
C
6
H
12
O
6
+ 6O
2
c
arbon dioxide
+ water
glucose + oxygenSlide9
Absorption of light
In addition to water and carbon dioxide, photosynthesis requires light and chlorophyll
The chlorophyll inside the chloroplast of leaves absorb light
Chlorophyll does not absorb all the wavelengths of visible light equallySlide10
Inside the Chloroplast
Chloroplast
– organelle in plants where photosynthesis takes
place
Thylakoids
– Saclike photosynthetic membranes
Grana
- Stacks of thylakoids
Stroma
- aqueous region outside the granaSlide11Slide12
Step 1 - Light-Dependent Reactions
Breaks apart CO
2
and H
2
O
Produce oxygen gas
Convert ADP and NADP
+
into ATP and NADPH
Takes place within the thylakoid membranes in the chloroplastSlide13
Step 2 - Calvin Cycle ( aka light-INdependent
reactions)
Uses ATP and NADPH from the light dependent reactions
Produces high-energy sugars
Takes place in the
stroma
of the chloroplasts
Does not require lightSlide14
Factors Affecting Photosynthesis
Water
Temperature
Depends on enzymes that function pest between 0
o
C and 35
o
C
Intensity of light
Increasing light intensity increases the rate of photosynthesis
Carbon Dioxide Concentration
NutrientsSlide15
CELLULAR RESPIRATION Slide16
Cellular Respiration
Glycolysis
does not
require oxygen.
Aerobic respiration
: oxygen is present, glycolysis is followed by the Krebs cycle and then the electron transport chain.
Anaerobic respiration
: no oxygen, glycolysis is followed by fermentation
3 Stages of Aerobic Cellular Respiration:
Glycolysis
the Krebs cycle
the electron transport chain
Each of the 3 stages of cellular respiration uses energy from food to produce ATPSlide17
1.Glycolysis
Respiration begins with a pathway called
Glycolysis
.
Glycolysis releases a
small
amount of energy.
Uses 2 ATP to make 4 ATP and 2 pyruvic acidsSlide18
Next step to the
Mitochondria
The “power house” of the cell, because most of the ATP is produced here. Slide19
2. The Krebs Cycle
Oxygen is
required
During the
Krebs cycle
, pyruvic acid is broken down into:
CO
2
NADH
FADH
2
ATP
: The Krebs Cycle
makes 2 ATPSlide20
3. Electron Transport
Each pair of high-energy electrons moves down the electron transport chain (ETC) and provides the energy to
produce more ATP.
The break down of Glucose by Aerobic Cellular Respiration results in the production
of 36 molecules of ATP.Slide21
What happens when there is NO OXYGEN?
When oxygen is not present
, glycolysis is followed by a different pathway.
2 types of fermentation: anaerobic (no oxygen)
Lactic Acid Fermentation
Alcoholic Fermentation Slide22
Why ATP Adenine
TriPhosphate
A high energy molecule that stores energy needed by cells
M
ade in the mitochondria
Composed of:
Ribose
(5 carbon Sugar
)
Adenine
(nitrogenous base
)
3
phosphate groups
(
group of molecules made up of phosphorous and oxygen)Slide23
Releasing Energy from ATP
The removal of 1 phosphate group from ATP produces ADP (Adenosine
DiPhosphate
)
This reaction releases energy in a way that enables cells to use the energySlide24
PLANTS ALSO PERFORM RESPIRATION
Plants also contain the organelle, mitochondria, which converts the high energy carbohydrates made by the plant through photosynthesis in the chloroplast into ATP for the plant to use to perform cellular functions.