PhotosynthesisPhotosynthesis

Energy & LifeEnergy & Life

Energy – the ability to do work; all living Energy – the ability to do work; all living things depend on energythings depend on energy

Sun = main sourceSun = main source Autotrophs – producers; have ability to Autotrophs – producers; have ability to

make their own foodmake their own food

Ex.) Plants; photosynthetic bacteria; Ex.) Plants; photosynthetic bacteria; algaealgae

Heterotrophs – consumers; obtain energy Heterotrophs – consumers; obtain energy needed from consumption of foodneeded from consumption of food

Ex.) Herbivores, Carnivores, OmnivoresEx.) Herbivores, Carnivores, Omnivores

Chemical Energy & ATPChemical Energy & ATP EnergyEnergy = stored in chemical compounds = stored in chemical compounds ATP ATP – adenosine triphosphate; composed of – adenosine triphosphate; composed of

ribose (sugar); a base (adenine) & 3 Phosphate ribose (sugar); a base (adenine) & 3 Phosphate groups; used by cells for an energy sourcegroups; used by cells for an energy source

How It Works (Releasing Energy)How It Works (Releasing Energy)1.1. Enzymes cause ATP to lose a P-groupEnzymes cause ATP to lose a P-group2.2. Exothermic rxn – large amounts of energy is Exothermic rxn – large amounts of energy is

released for use by the cell; high energy released for use by the cell; high energy bonds are brokenbonds are broken

3.3. ADP (adenosine diphosphate) is resulting ADP (adenosine diphosphate) is resulting productproduct

4.4. A 2A 2ndnd p-group can be extracted to provide the p-group can be extracted to provide the cell with even more energy = AMP (adenosine cell with even more energy = AMP (adenosine monophosphate)monophosphate)

Storing EnergyStoring Energy When an organism is at rest, phosphate When an organism is at rest, phosphate

groups are reattached to the molecule using groups are reattached to the molecule using energy obtained from food or sunlightenergy obtained from food or sunlight

ATP = chemical battery = has ability to store or ATP = chemical battery = has ability to store or release energy depending on the needs of the release energy depending on the needs of the cellcell

ATP UsesATP Uses Powers the Na+/K+ pump = maintains a Powers the Na+/K+ pump = maintains a

balance of ions on either side of the balance of ions on either side of the plasma membraneplasma membrane

Provides energy for locomotionProvides energy for locomotion Protein synthesisProtein synthesis Light production – glow from fireflyLight production – glow from firefly Cells have a small supply on hand = Cells have a small supply on hand =

short-term energy source for the cellshort-term energy source for the cell

Assignment:Assignment:

Pg. 203 (1-5) & Focus on the Big IdeaPg. 203 (1-5) & Focus on the Big Idea

Section 8.1 ws packetSection 8.1 ws packet

Investigating PhotsynthesisInvestigating Photsynthesis PhotosynthesisPhotosynthesis- uses the energy of sunlight - uses the energy of sunlight

to convert water and COto convert water and CO22 into high energy into high energy sugars (glucose) & oxygensugars (glucose) & oxygen

Plants also require chlorophyll to absorb light Plants also require chlorophyll to absorb light energy from the sunenergy from the sun

ChlorophyllChlorophyll –pigment contained in chloroplast; –pigment contained in chloroplast; energy absorbed into this molecule raises the energy absorbed into this molecule raises the energy level of the electrons contained within energy level of the electrons contained within it; high energy electrons enable photosynthesisit; high energy electrons enable photosynthesis

Structure of a ChloroplastStructure of a Chloroplast

ThylakoidsThylakoids – arranged in stacks known as – arranged in stacks known as grana; contain photosystems that absorb grana; contain photosystems that absorb light energylight energy

Stroma Stroma – fluid that fills the inside of the – fluid that fills the inside of the chloroplast; Calvin Cycle takes place herechloroplast; Calvin Cycle takes place here

Overview of PhotosythesisOverview of PhotosythesisSTAGE 1STAGE 1 – called the light dependent reactions – called the light dependent reactions

Energy is captured from sunlightEnergy is captured from sunlight

Water is Split into Hydrogen Ions, Electrons, and Water is Split into Hydrogen Ions, Electrons, and Oxygen (O2). Oxygen (O2).

Oxygen diffuses out of the chloroplasts Oxygen diffuses out of the chloroplasts (Byproduct)(Byproduct)

STAGE 2STAGE 2 – light energy is converted into chemical – light energy is converted into chemical energy, which is temporarily stored in ATP and energy, which is temporarily stored in ATP and NADPH (carrier molecule)NADPH (carrier molecule)

STAGE 3STAGE 3 – Calvin Cycle; the chemical energy – Calvin Cycle; the chemical energy stored in ATP and NADPH powers the formation stored in ATP and NADPH powers the formation of organic compounds (Sugars), using COof organic compounds (Sugars), using CO22

Light-dependent reactionLight-dependent reaction - chlorophyll - chlorophyll converts sunlight energy into chemical converts sunlight energy into chemical energy (ATP and NADPH) energy (ATP and NADPH)

Comparison to solar cells that convert solar Comparison to solar cells that convert solar energy into electricity to do workenergy into electricity to do work

Light-independent reactionLight-independent reaction – Calvin Cycle – Calvin Cycle - uses the energy stored in ATP and - uses the energy stored in ATP and NADPH during the Light Reactions to NADPH during the Light Reactions to produce organic compounds (carbs)produce organic compounds (carbs)

Name:_______________________ Date:____________ Class:______

Bonus: Ch 8 Bonus: Ch 8 Photosynthesis QuizPhotosynthesis Quiz NADPH: Nicotinamide adenine dinucleotide NADPH: Nicotinamide adenine dinucleotide

phosphatephosphate

10 Points 10 Points