Energy Ability to do work, moves or changes matter. Comes in many different forms (chemical energy, potential energy, solar energy, electricity, heat). Never created or destroyed only transformed.

Autotrophs - Organisms which make their own food, directly utilize the sun’s energy (i.e trees). Heterotrophs - Organisms who obtain energy from the food they consume, cannot directly utilize the sun’s energy (i.e. bears)

ATP - Adenosine Triphosphate Cells’ energy molecule. Energy is stored within the bonds of the phosphates. ATP is used to run all cellular activity (protein synthesis, membrane pumps, DNA regulation). ADP (2P) would be a dead battery while ATP (3P) would be a charged battery.

Photosynthesis: Using light to make food The gift of a green world.

Life on Earth is solar powered. By converting the energy in sunlight into chemical energy, photosynthesis produces 160 billion metric tons of carbohydrates each year.

THE BASICS OF PHOTOSYNTHESIS Almost all plants are photosynthetic autotrophs, as are some bacteria and protists. They generate their own organic matter through photosynthesis. (c) Euglena (d) Cyanobacteria (b) Kelp (a) Mosses, ferns, and flowering plants Figure 7.2

Kingdom Plantae

Simple Plants: (a) Mosses

Simple Plants: (a) Mosses, (b) Hornworts, (c) Liverworts

Ferns

Cone Trees

Flowering Plants With flowers for reproduction Seeds are produced inside the fruit (matured ovary)

Water Lily Leaf

Victoria regia

Succulent cacti

Cacti

Carnivorous plants obtain some of their nutrients from animal tissues.

Photosynthesis Plant process whereby the energy in the sun is used to convert H2O and CO2 into high energy sugars and O2 waste. 6CO2 + 6H2O + sun energy  C6H12O6 + 6O2

Light Sun: white light (energy) is composed of a range of wavelengths (colors) Gamma rays Micro- waves Radio waves X-rays UV Infrared Visible light Wavelength (nm)

Chloroplasts absorb light energy and convert it to chemical energy Reflected light Light Absorbed light Transmitted light Chloroplast

The location and structure of chloroplasts LEAF CROSS SECTION MESOPHYLL CELL LEAF Mesophyll Stoma (pl. stomata) CHLOROPLAST Intermembrane space Outer membrane Granum Inner membrane Grana Stroma Thylakoid compartment Stroma Figure 7.2 Thylakoid

Chloroplasts contain several pigments Chloroplast Pigments Chloroplasts contain several pigments Chlorophyll a Chlorophyll b Carotenoids

Pigments – The Rainbow Catchers Light-absorbing molecules Absorb some wavelengths and reflect others Color you see are the wavelengths NOT absorbed chlorophyll a chlorophyll b Wavelength (nanometers)

LIGHT REACTIONS (in grana) CALVIN CYCLE (in stroma) An Overview of Photosynthesis H2O CO2 Chloroplast Light NADP+ ADP + P LIGHT REACTIONS (in grana) CALVIN CYCLE (in stroma) Electrons ATP NADPH O2 Sugar

Chloroplast Organelle found inside plant cell where photosynthesis occurs. Thylakoids - sac-like photosynthetic membranes found inside the chloroplasts, contain chlorophyll and other light absorbing pigments. Site of the Light-Dependent reactions. Stroma - region outside the thylakoid membrane, but still inside the chloroplast. Site of the Calvin Cycle reactions.

Photosynthesis is comprised of two reactions Light Dependent Reactions Calvin Cycle (Dark Cycle) Reactions

Light-Dependent Reactions Requires light. Occurs in the thylakoid membranes. Breaks H2O molecule and produces O2. Converts ADP into ATP and NADP+ into NADPH.

Light Reactions (Photolysis) Light energy is used to split water and give Oxygen and hydrogen 2 H2O + light  4 H+ + O2 Light energy is used to make ATP

Electron Carrier Molecule which carries sunlight excited electrons from chlorophyll to other chemical reactions in the cell. Hot Coals / Fire / Tongs analogy

Chlorophyll is the main synthetic pigment

Plants produce O2 gas The O2 liberated by photosynthesis is a byproduct made by splitting water (H2O)

Calvin Cycle Reactions Does not require light. Occurs in the stroma. Uses energy in NADPH and ATP to convert CO2 into high energy sugars.

Dark Reactions (Carbon Fixation) ATP and Hydrogen (H) are used to “fix” CO2 To make organic molecules C6H12O6 (glucose)

Variables effecting Photosynthesis Light Intensity CO2 Concentration Temperature Graphs Shape required

Increase in Biomass (glucose, plant growth) MEASURE PHOTOSYNTHESIS Production of Oxygen Uptake of CO2 Increase in Biomass (glucose, plant growth) Carbon dioxide Water Glucose Oxygen gas PHOTOSYNTHESIS

Photosynthesis & Cellular Respiration

Linked Processes Aerobic Respiration Photosynthesis Energy-releasing pathway Requires oxygen Releases carbon dioxide Photosynthesis Energy-storing pathway Releases oxygen Requires carbon dioxide Ps provides a carbon source for all of life

Predominant producers on land are plants such as oak trees and cacti

In aquatic environments, algae and photosynthetic bacteria are the main food producers

How Photosynthesis Moderates the Greenhouse Effect Old-growth forests: Are important for lumber Are important for moderating world climates Are homes to many species of plants and wildlife that exist nowhere else

The Greenhouse effect: Warms the atmosphere Is caused by atmospheric CO2 Sunlight Atmosphere Radiant heat trapped by CO2