Transcript Energy - West Linn High School

PHOTOSYNTHESIS
Chapter 8
ENERGY & LIFE
ENERGY
 The
ability to do work.
 Can
be stored in chemical bonds.
 Cells
need energy to do things like
active transport, dividing, moving,
and producing and storing proteins.
http://www.youtube.com/watch?v=qyb
UFnY7Y8w
AUTOTROPHS VS.
HETEROTROPHS
Autotrophs
Heterotrophs
 Organisms
 Organisms
 AKA:
 AKA:
that
make their own
food.
 Ex:
producers
plants
that
obtain energy from
the food that they
eat.
consumers or
decomposers
 Ex:
sheep, wolves,
mushrooms
ATP (ADENOSINE TRIPHOSPHATE)



The main energy storage compound for living
things.
ATP is NOT good to store lots of energy for a long
time (glucose is used then).
Has three phosphate groups.
ADP (ADENOSINE DIPHOSPHATE)



Same as ATP, but with only two phosphate
groups.
When a cell has extra energy, it stores it by
adding a phosphate group to ADP, making ATP.
To release the energy, the bond is broken,
converting ATP back to ADP.
Video Clip:
ATP, The
Energy
Currency
PHOTOSYNTHESIS: AN
OVERVIEW
LIGHT & PIGMENT
 White
light is actually a mixture of different
wavelengths of light.
 Pigments:
light absorbing molecules that gather the
sun’s energy.

The plant’s principle pigment is chlorophyll.
 Energy
absorbed by chlorophyll is transferred directly
to electrons in the chlorophyll molecule. These high
energy electrons make photosynthesis work.
SO WHY ARE LEAVES GREEN?
• Look at the
wavelengths of
light that
chlorophyll
absorbs & uses in
photosynthesis
• The colors that
are left are
reflected back and
that is what you
see.
ELECTRON CARRIERS

NADP+: can accept 2 high-energy electrons by
bonding with an H+; an “uncharged” energy
carrier
•

Similar to ADP
NADPH: the “charged” version

Similar to ATP
PHOTOSYNTHESIS: AN OVERVIEW
● THE PROCESS THAT CAPTURES LIGHT ENERGY
AND USES IT TO MAKE CARBOHYDRATES (GLUCOSE).
sunlight
6H2O + 6CO2 ----------> C6H12O6+ 6O2
Water:
Comes in
through
the roots
Carbon
Dioxide:
Comes in
from the
air
Glucose:
Stored as
chemical
energy
Oxygen:
leaves
back to
the air
WHERE DOES IT TAKE PLACE?

In the chloroplasts.
PHOTOSYNTHESIS

2 Parts:
Light dependent reactions
 Light independent reactions (AKA dark reactions or
the Calvin Cycle)

THE PROCESS OF
PHOTOSYNTHESIS
LIGHT DEPENDENT REACTIONS
Where? The granum
1.) chlorophyll absorbs
light
2.) H2O is split; O2 is
released
3.) ATP & energy
carriers (NADPH) are
formed & take the
energy (stored in their
bonds) to the light
independent reaction

LIGHT INDEPENDENT
REACTIONS/ THE CALVIN CYCLE
Where? The stroma
1.) ATP & NADPH are
broken down (ADP &
NADP+) are recycled
back to the light
dependent reaction
2.) the energy released
is used to convert CO2
to C6H12O6

FACTORS AFFECTING
PHOTOSYNTHESIS

Temperature


Light intensity


Best between 0 & 35˚C
A higher intensity increases the rate of
photosynthesis until a maximum rate is reached.
Water

A shortage can stop photosynthesis.
Video Clip: Photosynthesis
http://www.youtube.com/watch?v=LgYPeeABoUs
CELLULAR
RESPIRATION &
FERMENTATION
Chapter 9
CELLULAR
RESPIRATION: AN
OVERVIEW
CALORIE
 The
amount of energy needed to
raise 1g of H2O 1○ C.
 When burned, 1g of glucose
releases 3811 calories of heat
energy.
 Food
labels show Calories (= 1000
calories).
TWO MORE ELECTRON
CARRIERS
 NAD+ &
FAD: “uncharged” energy
carriers
• Similar to ADP
 NADH
& FADH2: the “charged”
versions
 Similar to ATP
CELLULAR RESPIRATION

Releases energy (ATP) by breaking down food in
the presence of oxygen.
C6H12O6 + 6O2 ----------> 6H2O + 6CO2
Glucose:
Plants- have it
stored from
photosynthesis;
Animals- get it
from food
Oxygen:
taken in
from the
air
Water:
released
as waste
Carbon
Dioxide:
released
into the
air
THE PROCESS OF
CELLULAR RESPIRATION
CELLULAR RESPIRATION
Three parts:
• Glycolysis
• Kreb’s cycle
• Electron Transport Chain
GLYCOLYSIS
Where? The cytoplasm
1.) C6H12O6 is split to form 2 pyruvic acids (2C3H6O3)
2.) the energy is captured in ATP & energy carriers (NADH)

KREB’S CYCLE
Where? The
mitochondria
1.) 2 pyruvic acids
(2C3H6O3) are broken
down into CO2
2.) the energy is
captured in ATP &
energy carriers
(NADH& FADH2)

ELECTRON TRANSPORT CHAIN
Where? The
mitochondria
1.) Energy carriers
(NADH & FADH2) are
broken apart; the
energy released is
used to make ATP
2.) O2 bonds with
leftover H+ to make
H 2O

Video Clip:
Glycolysis &
Cellular
Respiration
FERMENTATION
AEROBIC VS. ANAEROBIC

When O2 is present & all of cellular respiration occurs, 36
ATPs are made from 1 C6H12O6.


Aerobic: reactions that require oxygen (the Kreb’s cycle &
electron transport chain)
When there is no O2, only glycolysis occurs & 2 ATPs are
made from 1 C6H12O6.

Anaerobic: reactions that do not need oxygen (glycolysis)
GLYCOLYSIS
 Advantage:
ATP can be made
without oxygen
 Disadvantage:
the cell will run out of
NAD+ & glycolysis will stop
So…
Fermentation occurs!
FERMENTATION

Allows glycolysis to continue by converting NADH
into NAD+


Anaerobic
Two types:

Alcoholic fermentation


Pyruvic acid + NADH -> alcohol + CO2 + NAD+
Lactic Acid fermentation

Pyruvic acid + NADH -> lactic acid + NAD+