Energy in a Cell Photosynthesis & Cellular Respiration

Overview of Photosynthesis and Respiration SUN RADIANT ENERGY CELL ACTIVITIES PHOTOSYNTHESIS RESPIRATION GLUCOSE ATP (ENERGY)

Cell Energy Energy is essential for life Active transport, cell division, flagella movement, protein production Some capture energy from light or chemicals Autotrophs Others eat those that capture energy heterotrophs

So Where Is Energy Found? Energy is stored in chemical bonds of ATP Adenosine Triphosphate (ATP) Adenosine molecule with three phosphate groups Energy carrier molecule of the cell

Question…? How do you release the energy stored in the bonds?

Answer Break the bond!

Energy is Stored in the BOND!

Forming and Breaking Down ATP Adenosine monophosphate (AMP) Adenosine diphosphate (ADP) Adenosine triphosphate (ATP) ATP  ADP + P + Energy Energy + P + ADP  ATP

What is Photosynthesis? The process of photosynthesis is a chemical reaction. It is the most important chemical reaction on our planet.

What is the Equation for the Chemical Reaction of Photosynthesis in WORDS?

What is the Equation for the Chemical Reaction of Photosynthesis (SYMBOLS)?

Describe Photosynthesis The process of changing light energy to chemical energy Energy stored as sugar Occurs in plants and some algae Plants need light energy, CO2, and H2O Takes place in the chloroplasts, using chlorophyll, the green pigment in plants

What Happens During Photosynthesis – An Overview Plants capture light energy and use that energy to make glucose Sunlight provides the energy needed by chlorophyll to change molecules of carbon dioxide and water into glucose Oxygen is also released in this reaction

What Happens During Photosynthesis – More Specific? Carbon dioxide enters the leaf through holes called stomata CO2 combines with the stored energy in the chloroplasts through a chemical reaction to make glucose The sugar is moved through tubes in the leaf to the roots, stems and fruits of the plants Some of the sugar is used right away by the plant for energy; some is stored as starch; and some is built into plant tissue

The Importance… The Big Two Reasons: 1. We cannot make our own food (glucose, energy), we must get our food from plants. (Plants are the first step in the food chain.) 2. The oxygen released during photosynthesis is necessary for all living things.

Trapping Energy from Sunlight Photosynthesis Process that uses the sun’s energy to make simple sugars Glucose, Fructose, Galactose Light-dependent Reactions Convert light into chemical energy (ATP) Light-independent Reactions (Calvin Cycle) Fueled by ATP Produce simple sugars 6CO2 + 6H2O  C6H12O6 + 6O2

Chloroplasts and Pigments Molecules in thylakoid membranes that absorb specific wavelengths of sunlight Cholorophyll is the most common pigment Absorbs most wavelengths of light except for green.

Light-Dependent Reactions Light energy hits thylakoid discs Electrons are charged with energy and EXCITED! HOT! Electron Transport Chain Electrons travel through a series of proteins Lose energy which is used to make ADP into ATP Electrons reach a second photosystem (pigments) and are recharged Travel down a 2nd transport chain

Light-Dependent Reactions Electrons, at end of chain, transferred to a carrier molecule (NADP+ ) NADP+ + electron + H = NADPH Carries the electron to the Stroma NADPH used in Calvin Cycle

Restoring Electrons Photolysis (lysis = to break down) Chemiosmosis Reaction where water is split H20  O + 2H+ + 2e Oxygen released into air (O2) The electrons are used by chlorophyll Hydrogen ions are taken to thylakoid discs Chemiosmosis H+ moves across membrane due to concentration gradient Creates charge / energy = used to make ATP

Light-Independent Reactions The DARK Reactions Calvin Cycle Series of reactions that uses CO2 to create sugars Takes place in the Stroma Named for Melvin Calvin

Summary of Calvin Cycle 1. Co2 combines with RuBP to form 2 molecules of PGA 2. Each molecule of PGA is converted into a molecule of PGAL 3. Most of PGAL is converted back into RuBP, but some PGAL can be used to make a variety of organic compounds

The Leaf

What is this? Guess?

A Summary of Photosynthesis + H2O CO2 Energy ATP and NADPH2 Which splits water Light is Adsorbed By Chlorophyll Calvin Cycle ADP NADP Chloroplast Used Energy and is recycled. O2 + C6H12O6 Light Reaction Dark Reaction

What is Cellular Respiration? The release of chemical energy for use by cells. Once the energy that was in sunlight is changed into chemical energy by photosynthesis, an organism has to transform the chemical energy into a a form that can be used by the organism. This process is cellular respiration.

Describe Cellular Respiration 1. The breakdown of glucose molecules to release energy 2. Takes place in all living things 3. Is a step by step process

What is the chemical equation for cellular respiration?

EQUATION FOR RESPIRATION CARBON DIOXIDE ATP GLUCOSE C6H12O6 + 6O2 6CO2 + 6H2O + ENERGY OXYGEN WATER

Do You See The Relationship with Photosynthesis!? Respiration has the SAME formula as photosynthesis except it is backwards!

Cellular Respiration Process by which mitochondria break down food molecules to produce ATP Three Stages Glycolysis – Anaerobic Citric Acid Cycle – Aerobic Electron Transport Chain - Aerobic

Glycolysis Net gain = 2 ATP Glucose gets broken into two three carbon pyruvic acids 2 ATP used to start this reaction Reaction produces 4 ATP Net gain = 2 ATP NAD+ = electron carrier = NADH when it accepts two electrons

Pyruvic molecules move into Mitochondria IF OXYGEN IS PRESENT then the Citric Acid cycle takes place Pyruvic acid loses one carbon (CO2) Combines with Coenzyme A to create Acetyl-CoA

Citric Acid Cycle (Krebs)

Electron Transport Chain

Fermentation Net Gain = 2 ATP Times when there is not enough oxygen to do Citric Acid Cycle Net Gain = 2 ATP Two major types Lactic Acid Alcoholic

Respiration CYTOPLASM GLYCOLOSIS HAPPENS HERE! CO2 IS RELEASED PROTEINS CARBO’S (SUGARS) FATS (LIPIDS) GLUCOSE C6H12O6 AMINO ACIDS MAKES 2 ATPS GLYCOLOSIS IN CYTOPLASM NO OXYGEN! ATP TOTALS GLYCOLOSIS=2 RESPIRATION=34 BOTH=36! PYRUVIC ACID CO2 IS RELEASED ACETYL-CoA O2 ENTERS HERE KREBS CYCLE AND ELECTRON TANSPORT MAKES 34 ATPS MITOCHONDRIA RESPIRATION HAPPENS IN THIS ORGANELLE!

Compare and Contrast Photosynthesis & Cellular Respiration

Photosynthesis & Cellular Respiration are Interconnected

The End