Energy in a Cell Photosynthesis

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Energy in a CellPhotosynthesis Cellular
Respiration
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Overview of Photosynthesis and Respiration
SUN
RADIANT ENERGY
CELL ACTIVITIES
PHOTOSYNTHESIS
RESPIRATION
GLUCOSE
ATP (ENERGY)
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The Need for Energy
In other words who cares!?
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Cell Energy

• Energy is essential for life
• Active transport, cell division, flagella
  movement, protein production
• Some capture energy from light or chemicals
• Autotrophs
• Others eat those that capture energy
• heterotrophs

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So Where Is Energy Found?

• Energy is stored in chemical bonds of ATP
• Adenosine Triphosphate (ATP)
• Adenosine molecule with three phosphate groups
• Energy carrier molecule of the cell

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Question?

• How do you release the energy stored in the bonds?

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Answer

• Break the bond!

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Energy is Stored in the BOND!
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Forming and Breaking Down ATP

• Adenosine monophosphate (AMP)
• Adenosine diphosphate (ADP)
• Adenosine triphosphate (ATP)
• ATP ? ADP P Energy
• Energy P ADP ? ATP

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How Cells Tap Into the Energy Stored in ATP

• Many proteins have sites for ATP binding
• When the phosphate bond is broken, energy is
  released and used to carry out cell processes
• Analogy
• ATP BatteryDevice Protein

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Where Does The Energy Come From!?
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PhotosynthesisTrapping the Suns Energy
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What is Photosynthesis?

• The process of photosynthesis is a chemical
  reaction.
• It is the most important chemical reaction
  on our planet.
• Tell me WHY?

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What is the Equation for the Chemical Reaction of
Photosynthesis in WORDS?
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What is the Equation for the Chemical Reaction of
Photosynthesis (SYMBOLS)?
Remember Six molecules of carbon dioxide react
with six molecules of water to form 1 molecule of
glucose and six molecules of oxygen.
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EQUATION FOR PHOTOSYNTHESIS
WATER
OXYGEN
6CO2
6H2O
ENERGY
C6H12O6
6O2
CARBON DIOXIDE
GLUCOSE
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Describe Photosynthesis

• The process of changing light energy to chemical
  energy
• Energy stored as sugar
• Occurs in plants and some algae
• Plants need light energy, CO2, and H2O
• Takes place in the chloroplasts, using
  chlorophyll, the green pigment in plants

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What Happens During Photosynthesis An Overview

• Plants capture light energy and use that energy
  to make glucose
• Sunlight provides the energy needed by
  chlorophyll to change molecules of carbon dioxide
  and water into glucose
• Oxygen is also released in this reaction

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What Happens During Photosynthesis More
Specific?

• Carbon dioxide enters the leaf through holes
  called stomata
• CO2 combines with the stored energy in the
  chloroplasts through a chemical reaction to make
  glucose
• The sugar is moved through tubes in the leaf to
  the roots, stems and fruits of the plants
• Some of the sugar is used right away by the plant
  for energy some is stored as starch and some is
  built into plant tissue

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Why is this Important?
In other words who cares!?
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The Importance

• The Big Two Reasons
• 1. We cannot make our own food (glucose, energy),
  we must get our food from plants.
• (Plants are the first step in the food chain.)
• 2. The oxygen released during photosynthesis is
  necessary for all living things.

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The Details
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Trapping Energy from Sunlight

• Photosynthesis
• Process that uses the suns energy to make simple
  sugars
• Glucose, Fructose, Galactose
• Light-dependent Reactions
• Convert light into chemical energy (ATP)
• Light-independent Reactions (Calvin Cycle)
• Fueled by ATP
• Produce simple sugars
• 6CO2 6H2O ? C6H12O6 6O2

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Chloroplasts and Pigments

• Pigments
• Molecules in thylakoid membranes that absorb
  specific wavelengths of sunlight
• Cholorophyll is the most common pigment
• Absorbs most wavelengths of light except for
  green.

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Light-Dependent Reactions

• Light energy hits thylakoid discs
• Electrons are charged with energy and EXCITED!
  HOT!
• Electron Transport Chain
• Electrons travel through a series of proteins
• Lose energy which is used to make ADP into ATP
• Electrons reach a second photosystem (pigments)
  and are recharged
• Travel down a 2nd transport chain

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Light-Dependent Reactions

• Electrons, at end of chain, transferred to a
  carrier molecule (NADP )
• NADP electron H NADPH
• Carries the electron to the Stroma
• NADPH used in Calvin Cycle

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Restoring Electrons

• Photolysis (lysis to break down)
• Reaction where water is split H20 ? O 2H
  2e
• Oxygen released into air (O2)
• The electrons are used by chlorophyll
• Hydrogen ions are taken to thylakoid discs
• Chemiosmosis
• H moves across membrane due to concentration
  gradient
• Creates charge / energy used to make ATP

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Light-Independent ReactionsThe DARK Reactions

• Calvin Cycle
• Series of reactions that uses CO2 to create
  sugars
• Takes place in the Stroma
• Named for Melvin Calvin

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A Summary of Photosynthesis

H2O
CO2
Energy
ATP and NADPH2
Which splits water
Light is Adsorbed By Chlorophyll
Calvin Cycle
ADP NADP
Chloroplast
Used Energy and is recycled.
O2
C6H12O6

Light Reaction
Dark Reaction
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Getting Energy to Make ATP
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What is Cellular Respiration?

• The release of chemical energy for use by cells.
• Once the energy that was in sunlight is changed
  into chemical energy by photosynthesis, an
  organism has to transform the chemical energy
  into a a form that can be used by the organism.
• This process is cellular respiration.

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Describe Cellular Respiration

• 1. The breakdown of glucose molecules to
  release energy
• 2. Takes place in all living things
• 3. Is a step by step process

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What is the chemical equation for cellular
respiration?
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EQUATION FOR RESPIRATION
CARBON DIOXIDE
ATP
GLUCOSE
C6H12O6
6O2
6CO2
6H2O
ENERGY
OXYGEN
WATER
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Do You See The Relationship with Photosynthesis!?

• Respiration has the SAME formula as
  photosynthesis except it is backwards!

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Cellular Respiration

• Process by which mitochondria break down food
  molecules to produce ATP
• Three Stages
• Glycolysis Anaerobic
• Citric Acid Cycle Aerobic
• Electron Transport Chain - Aerobic

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Glycolysis

• Glucose gets broken into two three carbon pyruvic
  acids
• 2 ATP used to start this reaction
• Reaction produces 4 ATP
• Net gain 2 ATP
• NAD electron carrier NADH when it accepts
  two electrons

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• Pyruvic molecules move into Mitochondria
• IF OXYGEN IS PRESENT then the Citric Acid cycle
  takes place
• Pyruvic acid looses one carbon (CO2)
• Combines with Coenzyme A to create Acetyl-CoA

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Citric Acid Cycle (Krebs)
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Electron Transport Chain
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Fermentation

• Times when there is not enough oxygen to do
  Citric Acid Cycle
• Net Gain 2 ATP
• Two major types
• Lactic Acid
• Alcoholic

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Respiration
CYTOPLASMGLYCOLOSIS HAPPENS HERE!
PROTEINS
CARBOS (SUGARS)
FATS (LIPIDS)
GLUCOSE C6H12O6
AMINO ACIDS
MAKES 2 ATPS
GLYCOLOSIS IN CYTOPLASM NO OXYGEN!
PYRUVIC ACID
ATP TOTALS GLYCOLOSIS2 RESPIRATION34 BOTH36!
CO2 IS RELEASED
ACETYL-CoA
O2 ENTERS HERE
KREBS CYCLE AND ELECTRON TANSPORT
MAKES 34 ATPS
MITOCHONDRIARESPIRATION HAPPENS IN THIS
ORGANELLE!
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Compare and Contrast Photosynthesis
Cellular Respiration
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Photosynthesis Cellular Respiration are
Interconnected
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The End