Download Biology Ch 8 and 9 - Photosynthesis and Respiration

Chapters 8 & 9
Photosynthesis & Respiration
- All living organisms need ENERGY (humans, trees, fish, bacteria)
- Cells use energy for everything they do
- Where does energy come from?
SUN
Plants/trees/veggies
animals
- Our cells get energy from food, all energy originates in the sun.
AUTOTROPHS: make their own food by PHOTOSYNTHESIS
(plants, some bacteria)
HETEROTROPHS: can’t make their own food, get it from
other living things (humans, other animals)
Which of the following are autotrophs (make their own food from
the sun)?
Trees Foxes Peas Blueberries Humans Rabbits Deer Roses
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Humans get energy from food, what is ENERGY?
ATP: Adenosine Triphosphate – 3 phosphates
ADP: Adenosine Diphospate – 2 phosphates
AMP: Adenosine Monophosphate – 1 phosphate
Energy is stored inside phosphate bonds of ATP, ADP, & AMP
(like electricity is stored in batteries)
BREAKING the phosphate BONDS releases ENERGY
ATP = full charged battery (3 phosphate bonds that can be broken)
ADP = partly charged battery (only 2 phosphate bond)
AMP = very little charged battery (only 1 phosphate bond)
- Cells make ATP using energy stored in food
- Food is broken down into chemicals:
Carbs
to sugars like glucose.
Energy is stored in those bonds forming glucose.
- Plants make their own food (glucose) during photosynthesis
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Ch 8 - Photosynthesis
If all energy originally comes from the sun, how does it get into our
food (our hamburgers, salads, fries, pasta, etc?)
- The answer is Photosynthesis. Plants make their own sugar
(glucose) during photosynthesis and then we eat that plant
and its glucose, and break apart those glucose bonds to
release energy, OR we eat something else that ate the plant
and its glucose (ex: we eat the cow that ate the plant)
Photosynthesis: process by which green plants use the energy of
sunlight to produce glucose (sugar)
During photosynthesis, plants soak in sunlight through their leaves,
and combine it with water and carbon dioxide (CO2) to make sugar
(glucose). That sugar is used as their food supply and can be used
to create energy ATP. Luckily for us, during photosynthesis, Oxygen
is released as a waste product – and that is the Oxygen we breathe.
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Formula for Photosynthesis:
Water + CO2 + Energy from Sun
Glucose (sugar) + Oxygen
6H2O + 6CO2 + Energy from Sun
Glucose (C6H12O6) + 6O2
The energy from the sun is stored in the bonds of glucose to be
used later by the plant OR animals that feed on the plants. When
needed, the glucose is broken down in the process of respiration to
release that energy (ATP) stored in glucose bonds.
How do plants trap sunlight energy for photosynthesis?
Plants have a green pigment called CHLOROPHYLL that absorbs
sunlight
CHLOROPHYLL is found in CHLOROPLASTS in stacked membranes
called thylakoids. In the thylakoids the chlorophyll is arranged in
clusters called photosystems.
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2 Stages of Photosynthesis:
Light-Dependent & Light-Independent Reactions
Light-Dependent Reactions: requires light from sun
- Light is absorbed by chlorophyll to produce high energy
electrons in the thylakoid membranes.
- These electrons move to an electron transport chain (ETC). As
electrons move thru ETC energy is released to form ATP.
- At end of ETC more light is absorbed to raise energy level of
electrons. These high energy electrons are passed to electron
carrier NADP+ to form NADPH.
- Electrons removed from chlorophyll are replaced with
electrons taken from the splitting of water. Enzymes in
chloroplast break apart water to use its electrons leaving
hydrogen ions and oxygen ions behind – these OXYGEN ions
are released to form most of the oxygen in the atmosphere.
Light-Dependent reactions produce: ATP (energy), and highenergy electrons carried by NADPH, and OXYGEN as a byproduct
released into atmosphere (how we get our oxygen)
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Light-Independent reactions: Does not require light
- Takes ATP and NADPH produced by the Light-Dependent
reactions and stores it in bonds forming glucose
- CO2 in the atmosphere is used in a series of reactions called
the CALVIN CYCLE to produce glucose (C6H12O6)
6 turns of the Calvin Cycle makes 1 glucose molecule
Light-Dependent reactions absorb energy from sun, this energy is
then used in the Light-Independent reactions to build high energy
bonds of glucose.
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Chapter 9 – Respiration
How do we break apart the glucose sugar to get the energy stored
in its bonds? Through the process of RESPIRATION
Respiration: process of breaking down glucose to use its high
energy electrons to make ATP (energy)
When we are hungry, we get weak because we lack energy. We
need to eat (take in glucose) so we can break it down and create
energy. Food contains chemical energy and when digested the
chemical bonds break and release energy for cells to use.
Calorie: used to measure energy stored in food
Carbs & Proteins = 4000 kilocalories (4 Calories) of energy per gram
Fats = 9000 kilocalories (9 C) of energy per gram
Glucose bonds in food are broken a little at a time during
respiration in the cytoplasm of cells with the help of enzymes.
RESPIRATION: breaking down glucose to produce energy.
During respiration, glucose and oxygen react to produce ATP
(energy). During the reaction CO2 and H2O are released as waste
while the ATP is being made
Glucose (C6H12O6) + 6O2
6H2O + 6CO2+ 34 ATP (Energy)
!! Respiration is the reverse of Photosynthesis !!
Photosynthesis:
6H2O + 6CO2 + Energy from Sun
Glucose (C6H12O6) + 6O2
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Glycolysis: process of breaking down glucose
Glyco: glucose lysis: break down (lysosomes)
Need energy to start glycolysis; requires 2 ATP
-Start with Glucose (6 Carbon sugar)
-Add 2 phosphates from ATP (turns to ADP)
-breaks into two 3 Carbon sugars with a phosphate called PGAL
-Add another phosphate to these 2 PGALs
-2 NAD+ steals 2 pairs of high energy electrons and H atoms,
becomes NADH
-4 ADP steal the 2 phosphates and become 4 ATP energy molecules.
-NADH gets rid of high-energy electrons by passing them to Oxygen.
- Left with two 3 Carbon Pyruvic Acid
GLYCOLYSIS – net gain of 2 ATP, 4 NADH that give electrons to O.
IF OXYGEN IS NOT PRESENT TO TAKE THOSE ELECTRONS:
FERMENTATION TAKES PLACE.
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FERMENTATION (Anaerobic Respiration):
When OXYGEN IS NOT PRESENT. If Oxygen is not present at end of
Glycolysis, fermentation occurs. 2 Types of fermentation:
1. Lactic Acid Fermentation: pyruvic acid accumulates due to
glycolysis and is converted to lactic acid.
Vigorous exercise causes cells to run out of oxygen and
fermentation occurs with build up of lactic acid. This build up
of lactic acid cause burning or soreness in muscles.
2. Alcoholic Fermentation: Occurs in Yeasts. Pyruvic acid breaks
down into alcohol and CO2. The CO2 causes bread to rise, have
bubbles, bubbles in beer. Alcohol produced as a byproduct.
AEROBIC RESPIRATION: Occurs when OXYGEN IS PRESENT
Gylcolysis only produces a net gain of 2 ATP, not much energy. For
more energy, the cell turns to Respiration - the reason why we
BREATHE in OXYGEN:
Respiration: breaking down food in presence of Oxygen to release
more energy.
- Occurs in Mitochondria (power house)
Formula for Respiration:
Glucose (C6H12O6) + 6O2
6H2O + 6CO2+ 34 ATP (Energy)
After glycolysis the 2 pyruvic acids produced then go through
another series of reactions called the KREBS CYCLE to produce
more energy. Oxygen is required for these reactions, and that is
why we breathe in Oxygen so that it can be used during respiration
to help break down food and release its energy.
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Krebs Cycle
1. One carbon from pyruvic acid breaks off released as CO2 in
presence of co-enzyme A.
2. The other carbons join with 4 carbons to make citric acid.
3. Citric acid broken down in series of steps releasing CO2 and
high energy electrons go to electron carriers NAD+ and FAD
to form NADH and FADH2.
4. NADH and FADH2 take their electrons into mitochondria’s
inner membrane and go thru electron transport chain (ETC)
5. ETC: electrons are passed gradually dropping energy level
while their energy is picked up by ADP to make ATP.
6. At end of chain, OXYGEN picks up the electrons and 2 H+
ions to make H2O. This is why we breathe in Oxygen, so it
can pick up these electrons. H2O and CO2 are released as
byproducts.
Krebs Cycle
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CELLULAR RESPIRATION – the whole process of getting energy:
Glucose
Glycolysis
2 Pyruvic acid + 2 ATP
Krebs Cycle & Electron Transport Chain (Oxygen needed here)
34 ATP produced
Total energy produced during Respiration = 2 ATP from Glycolysis
+ 34 ATP from Krebs Cycle & Electron Transport Chain = 36 ATP
Oxygen picks up electrons at the end of the Electron Transport
Chain, combines with H+ and forms H2O
Respiration releases CO2 and H2O while producing the ATP
Glucose (C6H12O6) + 6O2
6H2O + 6CO2+ 34 ATP (Energy)
ATP SYNTHASE ENZYME: helps turn ADP into ATP energy in the Electron Transport Chain
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Review
Photosynthesis
Respiration
Autotrophs
Heterotrophs & Autotrophs
Chloroplasts
Mitochondria
Reactants:
H20 + CO2 + Sun energy
Reactants:
C6H12O6 + O2
Products:
C6H12O6 + O2
Products:
H20 + CO2 + 34 ATP
Aerobic Respiration – Oxygen present
Anaerobic- NO Oxygen = Fermentation
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