Photosynthesis, Cellular Respiration, and Fermentation Cellular Processes A unit to review 3 main processes cells undertake that deal with energy creation: Photosynthesis, Cellular Respiration, and Fermentation

Candles release energy as HEAT & LIGHT Energy Takes Many Forms such as light, heat, electrical, chemical, mechanical, etc. Energy can be changed from one form to another Energy can be stored in chemical bonds & then released later Candles release energy as HEAT & LIGHT

PHOTOSYNTHESIS The process of converting sunlight into FOOD that can be used by the plant cell. This process DOES NOT create energy for the plant.

It Begins with Sunlight!

Energy for Life on Earth Sunlight is the ULTIMATE energy source for all life on Earth Plants store energy in the chemical bonds of sugars Chemical energy is released as ATP during cellular respiration

Photoautotrophs Absorb Light Energy

Autotrophs Autotrophs include organisms that make their own food Some use the sun’s energy directly Euglena

Autotrophs Plants, and some other organisms that contain chlorophyll, are able to use light energy from the sun to produce food.

Heterotrophs Heterotrophs can NOT directly use the sun’s energy Heterotrophs are organisms that must consume (eat) other organisms for food

Plants Autotrophs – produce their own food (glucose) Process called photosynthesis Mainly occurs in the leaves: a. stoma - pores b. mesophyll cells Mesophyll Cell Chloroplast Stoma

Stomata (stoma) Pores in a plant’s cuticle through which water vapor and gases (CO2 & O2) are exchanged between the plant and the atmosphere. Oxygen (O2) Guard Cell Carbon Dioxide (CO2)

Chlorophyll Molecules Located in the thylakoid membranes Chlorophyll pigments harvest energy (photons) by absorbing certain wavelengths (blue-420 nm and red-660 nm are most important) Plants are green because the green wavelength is reflected, not absorbed.

Inside A Chloroplast

Absorption of Light by Chlorophyll Chlorophyll absorbs blue-violet & red light best violet blue green yellow orange red Absorption wavelength

Fall Colors In addition to the chlorophyll pigments, there are other pigments present During the fall, the green chlorophyll pigments are greatly reduced revealing the other pigments Carotenoids are pigments that are either red, orange, or yellow

Photosynthesis Anabolic (small molecules combined) Endergonic (stores energy) Carbon dioxide (CO2) requiring process that uses light energy (photons) and water (H2O) to produce organic macromolecules (glucose). 6CO2 + 6H2O  C6H12O6 + 6O2 + ATP glucose SUN photons

The Photosynthesis Equation

Factors Affecting the Rate of Photosynthesis Amount of available water Temperature Amount of available light energy

Two Parts of Photosynthesis Two reactions make up photosynthesis: Light Reaction or Light Dependent Reaction Produces energy from solar power (photons) in the form of ATP and NADPH. Calvin Cycle or Light Independent Reaction Also called Carbon Fixation or C3 Fixation Uses energy (ATP and NADPH) from light reaction to make sugar (glucose).

Photosynthesis Overview

Light Dependent Reaction Reactants: H2O Light Energy Products: ATP NADPH

The Calvin Cycle Uses ATP and NADPH from light reaction as energy Uses CO2 To produce glucose

C3 Plants Temperate environement 85% of all plants (evergreens, grain plants, deciduous trees) Stomates open during day and closed at night Leaves with larger air spaces

C4 Plants Hot, moist environments 3% of plants (weeds [crabgrass], corn, sugarcane) Stomates open during day and closed at night Thinner leaves with less air space

CAM Plants Hot, dry environments 8% of plants (cactus and ice plants) Stomates closed during day and open during the night Thick fleshy leaves

Structure of ATP ATP stands for adenosine triphosphate Composed of a nitrogen base (adenine), the pentose (5C) sugar (ribose), and three phosphate groups. The last phosphate group is bonded with a HIGH ENERGY chemical bond This bond can be broken to release ENERGY for cells to use High Energy Phosphate Bond

Removing a Phosphate from ATP Breaking the last phosphate bond from ATP will: Release ENERGY for cells to use Form ADP Produce a free phosphate group Energy

Releasing Energy From ATP ATP is constantly being used and remade by cells ATP provides all of the energy for cell activities The high energy phosphate bonds can be broken to release energy The reforming the ATP molecule is called phosphorylation (joining free phosphate and ADP together)

Releasing Energy From ATP Adding A Phosphate Group To ADP stores Energy in ATP Removing A Phosphate Group From ATP Releases Energy & forms ADP Lose Gain

More on ATP Cells have enough ATP to last for a few seconds ATP must constantly be made ATP transfers energy very well ATP is NOT good at energy storage

Cells Using Biochemical Energy Cells Use ATP For: Active transport Movement Photosynthesis Protein Synthesis Cellular respiration All other cellular reactions

Glucose Glucose is a monosaccharide C6H12O6 One molecule of glucose stores 90 times more chemical energy than one molecule of ATP

Cell Respiration The process of using glucose (sugar) and O2 (oxygen) to create energy (ATP) for all cells.

When is ATP Made in the Body? During a process called Cellular Respiration that takes place in both plants & animals Cellular Respiration breaks down the glucose molecules to release energy.

Equation for Cellular Respiration C6H12O6 + 6O2 yields 6CO2 + 6H20 + 36-38ATP’s

Cellular Respiration Requires oxygen Metabolic Pathway that breaks down carbohydrates Breakdown of one glucose results in 36 to 38 ATP molecules Glucose is oxidized and O2 is reduced, therefore is an oxidation-reduction reaction. Process is Exergonic as High-energy Glucose is broken into CO2 and H2O Process is also Catabolic because larger Glucose breaks into smaller molecules

Where Does Cellular Respiration Take Place? It actually takes place in two parts of the cell: Glycolysis occurs in the cytoplasm Krebs Cycle & ETC take place in the mitochondria

Stages of Cellular Respiration Glycolysis Occurs in cytoplasm, anaerobic and aerobic, uses two ATP and produces 4, splits glucose into two pyruvate molecules The Krebs Cycle Occurs in matrix (mitochondria), aerobic, occurs twice (creates 1 ATP each cycle), releases CO2 and two ATP molecules

Stages of Cellular Respiration Electron Transport Chain Occurs in the inner membrane (mitochondria), aerobic, creates 34 ATP molecules and releases H2O The end result of Cellular Respiration is 38 ATP molecules.

Fermentation The process of creating energy in the absence of O2.

Fermentation Occurs when O2 NOT present (anaerobic) Called Lactic Acid fermentation in muscle cells (makes muscles tired) Called Alcoholic fermentation in yeast (produces ethanol) Nets only 2 ATP

Fermentation Alcoholic Fermentation Lactic Acid Fermentation