Objective• We will learn that all living things get their energy

from the sun. We will learn the steps of photosynthesis by what reactants are used and which products are made.

PhotosynthesisCh. 8

Welcome to Unit 3

Living things need energy• Autotrophs: _______ and some prokaryotes are

able to use the energy from the _______ to produce food.

• Heterotrophs: __________, some prokaryotes, and most multicellular organisms _________ use the sun’s energy directly, therefore they need to consume ___________ as a food source.

ATP- Adenosine Tri-Phosphate• ATP is the ___________ molecule which plants and

animals use for _________.• 3 Phosphates can be ___________ for energy.• ADP (adenosine di-phosphate) has with only ___

phosphates.

ATP and ADP are like battery strengthOnly 2 phosphate groups vs. all 3 means ______ power.

When does a cell need to use energy?• Active Transport: _____ cross cell membrane thru

protein pump.• Sodium-Potassium ______ (3 Na+ out & 2 K+ in)

• Synthesis of Nucleic Acids: DNA & RNA• Movement:

• ATP needed for cell movement and __________.• ATP is actually only good for ________ term use, its

poor at long-term storage of _______ amounts of energy. • Glucose is much better at long-term storage of _________.• Glucose stores ______ more energy than ATP.

• Cells keep a ______ supply of ATP; they ________ more from ADP when needed, by ___________________carbs like glucose.

Scientists who discovered Photosynthesis• Van Helmont (1643): Discovered

that most of the ______ of a plant comes from ______. He weighed the plant and the soil.

• Joseph Priestley (1771): Discovered a mint plant __________ a substance that kept a candle burning. Plants __________ oxygen.

• Jan Ingenhousz (1779): Discovered that plants _______ produce oxygen in the presence of _________.

• Melvin Calvin (1948): Determined the _________ of the Calvin Cycle.

Photosynthesis• Photosynthesis: is the process of _________ light

energy into biochemical _________.

Where does photosynthesis occur? • Chloroplast: Organelle in plant cells only.• Chlorophyll: _________ that absorbs light. Appears

_______ because it absorbs blue and red light. • Chlorophyll is just one pigment in plants, there are others

colors:• Anthocyanin makes plants _____.• Carotenoids make plants look _________ or orange

• As ___________ breaks down in the fall, we see these colors. Light

Reflected Light

Absorbed Light

Transmitted Light

Reactants & Products• Reactants: CO2 + H2O (______________+ _________)

• Along with light energy (for __________)• Products: C6H12O6 + O2 (__________ + ___________)• Remember, CHO always make carbohydrates in

_:_:_ ratio

Photosynthesis = 2 Reactions• Both occurs in the _________. • Light Reactions: (Light ___________) AKA-

Photophosphorylation• Takes place in two _______________.

• Dark Reactions: (Light ______________) AKA- Calvin Cycle• Dark means __________ light needed, doesn’t necessarily

happen only at night

Light Dependent • AKA- _________________________

• Photo= light, phospho= phosperous to make molecules, lation= process

• Uses ________and _______ to make the energy storing molecules NADPH and ATP (which will be used in the dark reaction) and releases _________ as waste.

• Takes place in the ____________ membrane (stacks).

Light Independent• AKA- ________________• Uses ___________ of light reaction (NADPH and ATP)

to ________ CO2 into C6H12O6 = _________ (sugar)• Takes place in the _________ (spaces)

Converting energy from electrons• The __________ point for photosynthesis• Take the energy from an ________ election (photon

of light) and use it to ________ H2O to make NADPH.

• Occurs by __________ the election from one thylakoid to another.• Stacks of thylakoids = ____________• Chlorophyll pigments are found inside the thylakoid

membranes (green)

Light Dependent Cycle• Photosystem II: Light is ____________ by

chlorophyll, the energy from the light photons are ____________ to electrons, which then perform __________ to break water into ions (H+ and oxygen).

• Photosystem I: Electrons and H+ are _____________ by NADP+ to make NADPH.

• Hydrogen Ion Movement: The inside of the thylakoid ___________ fills up with H+ ions, the makes the inside slightly _________, and the outside of the membrane slightly negative.

• Electron Transport Chain: Electrons from photosystem II move to photosystem I, using their ________ to transport H+ from the stroma space to _________ the thylakoid membrane.

ATP Formation• The _______ phase of light reactions• ATP Synthase: a specialized ________ channel in

the thylakoid membrane, located at the end of the ETC. • Converts ADP to ATP as H+ ions _______ through to the

outside of the membrane. ATP synthase turns/spins like a _________ as ions pass through.

• Chemiosmosis: occurs as H+ ions move across a ___________ to make ATP.

Calvin Cycle (light independent)• Uses ATP and NADPH made from

photophosphorylation to _______ high-energy storage __________ (sugar- glucose).

• Makes NADP+ and ADP (molecules ________ for light reactions).

Calvin Cycle Details• 6 molecules of CO2 enter the cycle from the

___________ (air).• They combine with 6 molecules containing 5 carbons

each, this reactions forms 12 molecules with 3 carbons each.

• ATP and NADPH are used to _________ the 3-carbon molecules into higher-_______ forms.

• 2 of the 3-carbon molecules are used to make 6-carbon sugars such as _________.

• 10 of the 3-carbon molecules remaining are ___________ into 5-carbon molecules, which will be used at the _________ again.

• The Calvin Cycle uses 6 molecules of CO2 to make just __ molecule of 6-carbon glucose at the ____.

Reaction Formulas• Light Dependent Reactions in the _________

• NADP + H excited e- = NADPH• ADP + P ATP Synthase = ATP

• Light Independent Reaction in the _______• ATP + ______ + CO2 = C6H12O6

• Oxidation-Reduction Reactions always take place _______• Oxidation: lose e- and H+, gain O2, _________

energy.• Reduction: lose O2, ______ e- and H+, take in

energy.

Photosynthesis Formula

•6CO2 + 6H2O = C6H12O6 + 6O2

• Reactants: __ carbon dioxides + __ waters

• Products: __ glucose + __ oxygens

Factors that affect photosynthesis• These can either slow down or speed up the

process:• Light Intensity

• More = _______ photosynthesis• Carbon Dioxide amount

• More = ______ photosynthesis• Temperature

• Too high or too low = _______ photosynthesis • High Heat: plants close their ______ (pores in leaves) to conserve

_______. • Different plants have an ideal temperature range.• Trees that lose their leaves in the fall do _____

photosynthesize in the winter.• Type of plant:

• C4 plants perform photosynthesis in different ________ of their leaves

• CAM plants (_________) perform photosynthesis at _______

Plants produce oxygen• Most life on earth depends on ________ to live.• We breathe oxygen every day! • When plants split water during _____________, their

leaves __________ usable O2 in the air/water.