Photosynthesis

What is the definition of photosynthesis?

plants convert solar energy into energy stored in chemical bonds (chemical energy)

What is the chemical formula for photosynthesis?

6CO2 + 12H2O --> C6H12O6 + 6O2 + 6H2O

What are the two main processes of photosynthesis?

Light and Dark Reactions

Are light reactions light independent or light dependent reactions?

dependent

Are dark reactions light independent or light dependent reactions?

independent

What is the function of a light reaction?

it uses light energy directly to produce ATP

What is the function of a dark reaction?

it usually produces sugars

How are dark reactions powered?

by ATP from Light Reactions

Can dark reactions occur in DARK or LIGHT areas?

YES!

Are authotrophs producers or consumers?

PRODUCERS

What are two types of authotrophs found in photosynthesis?

Photoautotrophs and chemoautotrophs

How do autrotrophs obtain organic food?

WITHOUT eating other organisms

Are heterotrophs producers or consumers?

CONSUMERS

How do heterotrops obtain organic food?

BY EATING other organisms or their by-products

Decomposers count as heterotrophs!

:)

What is the function of pigments?

to absorb certain wavelengths (colors) and reflect all others

What color are Chlorophyll a and b pigments?

GREEN

Chlorophyll a and b absorb what kind of wavelengths?

wavelengths in the red, blue, and violet wavelengths

Chlorophyll a and b absord high or low energy wavelenths?

HIGH

What color are carotenoid and Xanthiphyll pigments?

YELLOW, ORANGE, and RED

Carotenoids and Xanthophyll pigments absord what kind of wavelengths?

blue, green, and violet wavelengths

Phycobillin wavelengths are what color?

Reddish

What is the function of antenna pigments?

to capture wavelengths of light not absorbed by chlorophyll a

What do antenna pigments expand?

the spectrum of light that can be used to drive photosynthesis

What are examples of antenna pigments?

Chlorophyll b and carotenoids

Antenna pigments absorb light energy, AND..

pass it to chlorophyll a

therefore, antenna pigments are directly involved in transforming what into what?

light E into sugar

Describe the structure of cholorplasts.

Outer, double membrane

What is the site of dark reactions?

STROMA

What is the site of light reactions?

GRANA

The Grana consists of what? (it increases surface area for reactions)

stacks of thlyakoid membranes

What are photosystems?

light harvesting complexes

where exactly are the photosystems located?

in the Grana, in the tylakoid membranes

how many photosystems are there?

several hundred per chloroplast

What do photosystems consist of?

a reaction center containing chloropyhyl a, AND antenna pigments

What are the two types of photosystems?

Photosystem 1 and Photosystem 2

What is PS1 aka?

P700

PS1 absorbs light in what nm range?

700

What is PS2 aka?

P680

PS2 absorbs light in what nm range?

680

What photosystem comes first?

PS2, then PS1

In light dependent (LR) reactions, how is light absorbed?

by PS1 and PS2

How is ATP Produced in light dependent reactions?

Exergonic flow of e- through ETC is couples with phosphorylation of ADP to ATP

What is photolysis?

when water is split

Photolysis provides what?

Electrons for PS2 AND protons to reduce NADP to NADPH

NADP carries what to Dark Reactions?

H's

What is non-cyclic photophosphorylation?

the main process occuring during light reactions

Where does non-cyclic photophosphorylation begin and end?

Begins at PS2, ends at PS1

What happens during non-cyclic photophosphorylation?

Electrons from photolysis enter 2 ETCs; ATP and NADPH are formed

During non-cyclic photophosphorylation, what powers ATP production, and how?

Chemiosmosis, ATP Synthase

During non-cyclic photophosphorylation, the NADP reduced to NADPH after H+ does what?

Diffuses through ATP Synthase channel across the thylakoid membrane

Cyclic photophosphorylation is --- of non-cyclic.

MODIFICATION

What is the function of cyclic photophosphorylation?

replenishes ATP levels only -- no NADPH is formed

When does clyclic photophosphorylation occur?

when the Calvin Cycle uses up available ATP

Does the Calvin Cycle require little or lots of energy?

LOTS OF ENERGY!

During cyclic photophosphorylation electrons travel from where to where?

from PS2 to PS1, then back again to PS2 (cyclic)

Where do light independent reactions occur?

in the stroma

do dark reactions depend directly on light?

NO

What do light independent reactions require?

Products of light reactions

What major process do light independent reactions consist of?

THE CALVIN CYCLE

What does the Calvin cycle produce?

PGAL or G3P (same thing)

What is the LONG name for PGAL and G3P?

phosphoglyceraldehyde

what is the primary job of the Calvin cycle?

Carbon Fixation

The Calvin Cycle produces PGAL, which is what?

a 3-carbon sugar

Where does the Calvin cycle occur?

In the stroma

During the Calvin Cycle, CO2 combines with what? and what does it produce?

combines with RuBP (a 5-carbon molecule) -- produces 2, 3-carbon molecules

What are an example of 3-carbon molecules?

C-3 Plants

The calvin cycle is catalyzed by what enzyme?

Rubisco (RuBP carboxlase)

What is photrespiration?

a dead end process

What does photorespiration do?

diverts energy from photosynthesis

Does photorespiration produce ATP?

NO

Does photorespiration produce sugar?

NO

How does photorespiration occur?

When rubisco binds with O2 instead of CO2

Does rubsico have a greater affinity for CO2 or O2?

O2!

What type of plants have adaptation for dry environments?

C-4 Plants

C-4 plants are a biochemical and anatomical modification of what?

C-3 photosynthesis

C-4 plants involve what?

Krantz anatomy and Hatch Slack Pathway

Krants Anatomy refers to what?

the structure of a C-4 leaf

Krantz Anatomy minimizes what?

the time stomates are open

The Hatch-Slack Pathway precedes what?

the Calvin Cycle

What is the function of the Hatch-Slack Pathway?

it pumps C02 into bundle sheath cells, deep within the leaf

During the Hatch-Slack Pathway, what binds with C02 to produce MALATE?

PEP carboxylase

What is the function of the MALATE pumped into the bundle sheath cells?

it maintains a steep C02 gradient neat stomates --reduces time stomates need to be opened

what does CAM refer to?

Crassulacean Acid Metabolism

CAM plants are a modification for what?

dry (xerophytic) environments

When do stomates open and close in CAM PLANTS?

open at night, close during day

In CAM PLANTS, what stores C02 inorganic molecules synthesized at night?

Mesophyll

What supplies ATP so the Calvin Cycle can run during the Day in CAM PLANTS?

Light Reactions

In CAM PLANTS, C02 is released from organic compounds and synthesized into what?

Sugars