Today’s Learning Goals
In plants, chlorophyll (found in chloroplasts) captures energy from the sun in order to make food during photosynthesis (Review)
Cells release energy from food through either cellular respiration or fermentation
Why it matters: Understanding how plants & animals get energy to grow & develop is an important part of biology.
How Does a Plant Make Its Own
Food? (REVIEW)
Plants use carbon dioxide (CO2), water (H2O), and
sun’s energy to make food.
This is called “photosynthesis”
The food gives plants energy
Animals get the
energy stored in
plants when they
eat them.
How Do Plants Get Energy From Sun?
(REVIEW)
Plants have pigments that
absorb energy from light
Chlorophyll (found in
chloroplasts) is the pigment
used in photosynthesis
What “Food” do Plants Make? (REVIEW)
The “food” plants
make is a sugar
called glucose
(C6H12O6).
Glucose and oxygen
(O2) are made during
photosynthesis.
How Do Organisms Get Energy
From Food?
Animals cannot make their own food like plants can.
But, BOTH plants and animals must break down
(digest) food in order to get energy from it (so they
can live, grow, & develop)
Cells do this 2 ways: cellular respiration and
fermentation
Cellular Respiration Produces
ATP Energy obtained from food must be transferred
into ATP.
This is done through cellular respiration.
Oxygen speeds up the process = AEROBIC
Can be done without oxygen = ANAEROBIC
Cellular Respiration
Cellular Respiration =
chemical process that
happens in cells
In prokaryotes, it
happens in the cell
membranes
In eukaryotes, it
happens mostly in the
mitochondria
Cellular Respiration has 3 Main
Stages
1. GLYCOLYSIS
2. CITRIC ACID CYCLE (KREB’S CYCLE)
3. ELECTRON TRANSPORT CHAIN
STAGE 1 - GLYCOLYSIS
Glycolysis = Glucose is broken down in the
cytoplasm of the cell.
ATP is made.
Glycolysis uses two ATP molecules but it
produces four ATP molecules = net gain of
two ATP molecules.
STAGE 1 – GLYCOLYSIS
Glycolysis can occur WITH or WITHOUT oxygen
WITH OXYGEN
AEROBIC (Produces more ATP than without)
WITHOUT OXYGEN = FERMENTATION
ANAEROBIC (Small amounts of ATP produced)
So most eukaryotes
(ex: plants & animals)
get their energy through
cellular respiration
In Stage 2, More ATP is Made by
Aerobic Respiration
Krebs Cycle = A series of reactions that
produce ATP
Aerobic = Oxygen
AKA = Citric Acid Cycle
www.progressivegardens.com
Stage 3: Electron Transport
Chain
Makes ATP
Occurs in the membranes of mitochondria
Aerobic Respiration
No oxygen? Then Fermentation
follows Glycolysis
Two kinds of fermentation
1. Lactic Acid Fermentation
2. Alcoholic Fermentaion
Fermentation
Happens when cells cannot
get the oxygen they need for
cellular respiration
Fermentation is a way to get
energy when oxygen isn’t
available
Ex: In short, fast races you
might get a burning feeling
in you leg muscles because of
a build up of lactic acid (made
during fermentation)
Lactic Acid Fermentation
Vigorous exercise produces a build up of
pyruvate in muscles
Pyruvate converts to lactate in the absence of
oxygen
ATP is still produced in glycolysis BUT you
will likely be sore due to a build up of lactate.
http://www.uic.edu/classes/bios/bios100/su
mmer2002/alchferm.gif
Alcoholic Fermentation
In other organisms, pyruvate is broken down into
alcohol.
Can be done by yeast
Two step process:
1. Pyruvate is broken down which releases CO2.
2. Electrons are transferred and ethanol is produced.
http://www.uic.edu/classes/bios/bios100/su
mmer2002/alchferm.gif
Summary
https://eapbiofield.wikispaces.com/Chapter+9+Cellular+Respiration-Harvesting+Chemical+Energy+AK
Photosynthesis vs Respiration
http://www.kensbiorefs.com/cellchem.html
Facts
Human body uses 1 million molecules of ATP
per cell per second.
Much of the body’s energy is released as heat.
Skunk cabbage generates heat when it flowers
in Feb/Mar. How is this helpful?
Review of Cellular Respiration
Food (glucose) is broken down into CO2 and H2O and
energy is released
C6H12O6 + 6 O2 6 CO2 + 6 H2O + energy (ATP)
This energy can be used for:
Keeping a constant body temperature
Storage (ATP) - to be used later for things like growth
Pop Quiz
1) Plants use carbon dioxide (____), water (____), and the sun’s energy to make food.
CO2 and H2O
2) What type of cell has chloroplasts?
PLANT CELL
3) BOTH plants and animals must break down food in order to get ________from it.
ENERGY
4) How are respiration and photosynthesis related?
THEY ARE THE REVERSE (OPPOSITE) OF EACH OTHER.
5) Fermentation is a way to get energy when ______ isn’t available.
OXYGEN
Gotta Get that ATP
https://www.youtube.com/watch?v=V_xZuCPI
Hvk
Gotta Get that ATP Answers
1. ATP
2. Energy
3. Glycolysis
4. Mitochondria
5. Electron Transport Chain
Today’s Learning Goals
In plants, chloroplasts capture energy from the sun in order to make food during photosynthesis
Cells release energy from food through either cellular respiration of fermentation
Why it matters: Understanding how plants & animals get energy to grow & develop is an important part of biology.