Transcript Energy
5.1 Energy &
Photosynthesis
Chapter 9
Energy:
All
organisms require energy for survival
All energy in food ultimately comes from
the sun
Energy: How do we get it?
Make
it! Autotrophs
Organisms that make their own food
(glucose) using energy from the sun
Examples: plants, algae & some bacteria
Energy: How do we get it?
Eat
it! Heterotrophs
Organisms that eat plants or animals to get
energy
Examples: animals & fungi
Energy: What’s it all for?
Why
To move, breathe & reproduce
Why
do organisms need energy?
do cells need energy?
Active transport, cell division & make
biomolecules
Where
does energy come from?
Food: Carbs – quick energy; Lipids – long
term energy
Energy Molecules:
ATP
ADP
Energy Molecules: ATP
ATP
(adenosine triphosphate)
1 ribose (sugar) molecule
3 phosphate groups
Adenine (nitrogenous base)
Energy Molecules: ADP
ADP
(adenosine diphosphate)
1 ribose (sugar) molecule
2 phosphate groups
Adenine (nitrogenous base)
Created when ATP loses energy & a
phosphate
Energy Molecules
So what happens?
ATP
ADP
Bond between 2nd & 3rd phosphate is
broken
Energy is released
Energy
can be used by the cell
So what happens?
ADP
ATP
Energy is stored when 3rd phosphate adds
to ADP
How do cells get ATP?
Break
down carbohydrates & lipids
Creates energy – energy used to make ATP
Where
do animals get carbohydrates &
lipids from?
Their FOOD
That
food is produced by autotrophs in
the process of photosynthesis
Photosynthesis
Ability
to capture
light energy from
the sun and
change it into
chemical bond
energy while
making oxygen
Photosynthesis Equation
6CO2 + 6H2O + Light energy
C6H12O6 + 6O2
Photosynthesis Questions:
Where
does it occur in plants?
What are the reactants?
How do the reactants get into the plant?
What are the products?
What happens to the products?
Location?
In
the chloroplast of plant cells
Where does it occur?
Chloroplast
structure:
Thylakoids:
Sacs of membrane with
pigment molecules
Grana:
Stacks of thylakoids
Stroma:
Liquid surrounding
thylakoids
Contains enzymes for PS
Photosynthesis process
Occur
in two steps:
Light-dependent reactions
Purpose:
Make energy for light-independent
reactions
Light-independent reactions
Also
called Calvin cycle
Purpose: Use energy from light reactions to make
glucose
Lightdependent
Reactions
thylakoid
Lightindependent
Reactions
Electrons
Glucose
Photosynthesis process:
light-dependent reactions
Location: Thylakoids
1. Light energy is absorbed by chlorophyll
2. Energy used to make ATP
3. Electrons are stored for Calvin Cycle
Photosynthesis process:
light-dependent reactions
Water is split to produce oxygen and
hydrogen atoms
4.
2H2O + Light
2H2 + O2
Oxygen is released as a product
Photosynthesis process:
light-dependent reactions
Used:
Light
Made:
energy
ATP
electrons
H 2O
Oxygen
Light-independent
rxns
(product)
Photosynthesis process:
light-independent reactions
Called
No
Calvin cycle
light required!
Location:
Stroma of chloroplast
Photosynthesis process:
light-independent reactions
ATP broken apart to release energy
1.
ATP
ADP + P + energy
Energy used to bond electrons with CO2 to
make glucose
2.
1.
Equation: CO2 + H2
C6H12O6
ADP goes back to light reactions to get
recharged
3.
Turned back into ATP
Photosynthesis process:
light-independent reactions
Used:
Made:
CO2
ATP (from light rxns)
Electrons (from light rxns)
GLUCOSE
!!!
Photosynthesis review:
Where
How
did the CO2 come from?
did water enter the plant?
What
What
absorbed the sunlight?
reactant is used in the lightindependent reactions?
Photosynthesis questions:
What
is made in the light-dependent
reactions that is used in the lightindependent reactions?
What
reactant is responsible for making
oxygen?
Photosynthesis questions
Where
do the light-dependent reactions
take place?
Where
do the light-independent reactions
take place?
What
is the final product of the lightindependent reactions?
H
Factors that influence PS Rates
Lack
of water
Example/Adaptation:
Desert
plants/conifers (pines): waxy coating
and “needle” leaves to reduce water loss
Factors that influence PS Rates
Temperature:
influences enzymes involved
in the PS reactions
What is the best temperature?
Factors that Influence PS rates
Intensity
of light (varies by plant)
Excess UV rays/sunlight can decrease PS