Bio chapter 10

Calvin Cycle

*Occurs in Stroma *Part of Dark Reaction Stage of Photosynthesis * Using ATP and NADPH Carbon dioxide is converted to sugar. *End Product = Sugar CH2O *Similar to Citric acid cycle (Krebs cycle)

What kind of Process is Photosynthesis?

*Redox Process *Oxidized = H2O (water) *Reduced = CO2 ( carbon dioxide)

Why do leaves appear Green?

* Because Chlorophyll reflects and transmits Green Light. *Chlorophyll does not absorb green light

Photosynthesis Formula

* Light energy + 6 CO2 + 12 H2O → C6H12O6 + 6 O2 + 6 H2O *But because water is both a reactant and a product, the equation can be simplified accounting for net water consumption, which is: Light Energy + 6 CO2+ 6 H2O → C6H12O6+ 6 O2 *Carbon dioxide + Water + Light energy → Glucose + Oxygen + Water *Chloroplast Splits H2O into Hydrogen and Oxygen Electrons of Hydrogen turn into Sugar Molecules.

Heterotrophs

* Organisms that cannot make their own food , so they eat other plants or animals to survive. * The CONSUMERS *ex. People

Photosynthesis

* The Process of converting: Light Energy >>>>>>Chemical Energy

What is the purpose of Photosystem I and Photosystem II ?

* They use light energy to make ATP and NADPH

Photosystem

* Two types of photosystems ( I and II ) * In thylakoid membrane * a reaction center associated with light harvesting * When a reaction center chlorophyll molecule absorbs energy, one of its electrons gets bumped up to a primary electron acceptor * primary electron acceptor = a location within chlorophyll molecule

Photosystem I

* in Thylakoid membrane * absorbs 700 nm wavelength * Photosystem I takes place second

Photosystem II

* in Thylakoid membrane *absorbs wavelength of 680 nm * Photosystem II takes place first

Noncyclic Electron Flow

* in photosystem II * produces: NADPH, ATP, Oxygen

Stomata

* microscopic Pores *Stomata, which means "mouths" in Greek, do indeed resemble tiny mouths surrounded by swollen lips *pores on the surfaces of leaves called stomata (singular: stoma) which plants use to "breathe." *Plants need carbon dioxide, just as we need oxygen, and stomata allow the plant to take in carbon dioxide to perform photosynthesis. *CO2 enters and O2 exits

Photoautotrophs

** a category name for organisms that can convert Sun's Energy to Organic Molecules from water and CO2

Chloroplast

*** an organelle ****Food producers of plant cells ****in photosynthesizing organism (ex. Plants) ****Located in Mesophyll (interior tissue of the leaf)

C4 plants

*A plant in which the CO2 is first fixed into a compound containing four carbon atoms in the Mesophyll. *Minimize the cost of Photorespiration (Photorespiration occurs when the CO2 levels inside a leaf become low.) ***Carbon Fixation and Calvin Cycle occur in Different Cells. Example= Sugarcane

CAM Plants

*CO2 >>is converted to>> Organic Acids *Open their Stomata At night *During Day Stomata is Closed, and then CO2 is released from Organic Acids for use in Calvin Cycle ****Carbon fixation and Calvin Cycle occur in the SAME Cells at DIFFERENT Times! *CO2>>Organic Acid>>Calvin Cycle>>Sugar Example = Pineapple

What are two types of Chlorophylls?

*Chlorophyll a - Main photosynthetic pigment *Chlorophyll b - Accessory Pigment

Thylakoids

*Connected sacs in Chloroplast *They contain Chlorophyll * A saclike membrane that is the structural unit of the Grana in the Chloroplasts of plant cells.

Mesophyll

*Interior Tissue of the leaf * where Chloroplasts are located * Mesophyll cell has 30 to 40 Chloroplasts

Order of structure in plants

*Leaf>>Mesophyll>>Chloroplast>>Thylakoids>>Chlorophyll

What are two stages of photosynthesis?

*Light Reactions: The light reactions take place in the presence of light. *Dark Reactions: The dark reactions do not require direct light.

Pigments

*Substances that absorb visible light *Different Pigments have the ability to absorb different wavelengths. * When a wavelength is not absorbed by the pigment then it is reflected off or transmitted

The Light Reactions

*Takes Place in Grana (Grana = Thylakoids stacked in columns) *Water is split *Oxygen is released *ATP is Produced *NADPH is formed *end result of reaction = ATP, NADH, Oxygen *The light reactions convert light into energy (ATP and NADHP) *Both ATP and NADPH are used in the dark reactions to produce sugar.

Dark Reactions

*Takes Place in Stroma (stroma = dense fluid) *Includes the Calvin Cycle *During Calvin Cycle : Sugar is formed from CO2, Using ATP as Energy and NADPH for reducing Power *end product: Sugar ( CH2O)

In what Structure is Chlorophyll located in?

*Thylakoids

Grana

*Thylakoids stacked in columns

Excitation of Chlorophyll by light

*When a pigment absorbs LIGHT, it goes from : Ground State>>> Excited State (unstable) *When excited electrons fall back to the ground state, photons are given off, an after glow called fluorescence. Heat is also given off.

Where is Chloroplast Located?

*in Mesophyll

Cyclic Electron Flow

*in Photosystem I * Produces: ONLY ATP

Structure of Chlorophyll a and Chlorophyll b

-Both have a Hydrocarbon Tail -Porphyrin Ring (light absorbing head) - Magnesium atom at the center ****Chlorophyll a has CH3 ****Chlorophyll b has CHO

3 phases of the Calvin Cycle

1. Carbon Fixation 2. Reduction 3. Regeneration of CO2 acceptor

Where is the Major Location of Photosynthesis?

Leaves

Why are Leaves Green?

Their color comes from a pigment called Chlorophyll Chlorophyll is located within Chloroplast .

Function of Chlorophyll

This green pigment absorbs Light Energy and drives the synthesis of Organic Molecules in Chloroplast

Stroma

a dense fluid inside the Chloroplast