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Understand the processes of photosynthesis and cellular respiration, and how they are interdependent in providing energy for cells. Learn about ATP, the energy molecule of life.
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ESSENTIAL QUESTIONS • Why do cells need energy? • How does ATP release and store energy? • How do plants change the sun’s energy to chemical energy during photosynthesis? • How does cellular respiration work to release energy? • How are photosynthesis and respiration dependent upon each other?
THE STUDENT WILL UNDERSTAND THAT: • ATP is the energy molecule of life. • Photosynthesis is the basic life process that converts the sun’s energy into food energy for all living things. • Cell respiration is the process that extracts the energy from the food made by photosynthesis. • Photosynthesis and cell respiration are complementary processes.
ENERGY THE ABILITY TO DO WORK
WHAT’S IMPORTANT ABOUT ENERGY? • DIFFERENT FORMS – LIGHT, HEAT, ELECTRICAL, CHEMICAL • CHEMICAL REACTIONS IN LIVING THINGS STORE & RELEASEENERGY
CELLS NEED ENERGY TO: • GROW & REPAIR THEMSELVES • REPRODUCE • MOVE • CARRY ON ACTIVE TRANSPORT • BREAKING DOWN LARGE MOLECULES INTO SMALL ONES • BUILDING MOLECULES • MAINTAIN BODY TEMPERATURE
ENERGY STORAGE • ATP = ADENOSINE TRIPHOSPHATE = THE ENERGY STORAGE COMPOUND IN ALL LIVING THINGS
ATP = CHARGED BATTERY • ATP (A - P - P – P) LOSES A P TO BECOME ADP (A - P – P) • ADP = UNCHARGED BATTERY
AUTOTROPHSSTORE ENERGY DURING PHOTOSYNTHESIS • AUTOTROPHS & HETEROTROPHS • RELEASE ENERGY DURING CELLULAR RESPIRATION
1. Who was the first person to see and name cells (in cork)? A) Anton van Leeuwenhoek B) Rudolf Virchow C) Matthias Schleiden D) Robert Hooke 2. Which is NOT a principle of the cell theory? A) Cells are the basic units of life. B) All living cells have a nucleus. C) All organisms are made of one or more cells. D) All cells come from other living cells. 3. Why do scientists call the “Cell Theory” a “scientific theory”? A) It is based on the well-supported work of many scientists and leads to accurate predictions. B) It is based on ideas that have been proven true and that are not subject to revision. C) It based on preliminary evidence but still needs to be confirmed with experiments. D) It is based on a scientific publication that is read by scientists worldwide.
WHY DO PHOTOSYNTHESIS & RESPIRATION DEPEND ON EACH OTHER? GLUCOSE + ATP
I. PHOTOSYNTHESIS6 H20 + 6 CO2 + LIGHT ENERGY C6H1206 + 6 02 A. Process by which green plants use light energy, CO2, and H20to make Glucose (C6H12O6) and O2 B. PLANTS ARE LIKE FACTORIES: RAW MATERIALS: H20 + CO2 END PRODUCTS: O2 + C6H1206 ENERGY SOURCE: LIGHT ENERGY (SUN)
H20 enters through the roots & CO2 enters through these tiny openings (STOMATA) on the bottom of the leaf
WHAT ABSORBS ENERGY: CHLOROPHYLL (green pigment in CHLOROPLAST) C. Chlorophyll absorbs light energy & transfers some of this to ADP that bonds with another Phosphate molecule to form ATP (stores energy until needed)
II. LIGHT ENERGY & PHOTOSYNTHESIS A. ENERGY for photosynthesis ultimately comes from the SUN (although any light will do) B. SUNLIGHT is a mixture of all colors of light. 1. Each color has a different wavelength and a different amount of energy. 2. BLUE light has MORE ENERGY than RED light. 3. When an object REFLECTS a color, that’s the color it appears. 4. GREEN plants have chloroplasts in their leaves that reflectGREEN light. All other colors are ABSORBED. 5. BLUE AND RED wavelengths of light are used most by the plant in photosynthesis
Review! • Why does chlorophyll make plants green? • What three things does a plant need? What two things does it make? • Equation ordering
Summary • Light Dependent: Turns H2O into O2 • Uses light to make ATP for light independent reactions • Light Independent (Calvin Cycle): Changes CO2 into GLUCOSE! • Uses ATP and hydrogen from Light Dependent • Why does the light dependent reactions have to happen first?
IV. WHY IS PHOTOSYNTHESIS IMPORTANT? • Food • Oxygen • Fuel (wood, coal, oil, natural gas) • Wood for paper and building • Fibers (cotton) • Removes greenhouse gas CO2 prevents global warming
Now that we know how plants change light energy into the chemical energy in glucose molecules, how do we break down those molecules to produce energy that our cells can use? CELL RESPIRATION!
CELL RESPIRATIONC6H12O6 + 6O2 6H20 + 6 CO2 + 38 ATP • PROCESS BY WHICH CELLS USE O2+ GLUCOSE TO PRODUCE ATP, CO2, + H20 • RAW MATERIALS: O2AND C6H1206(GLUCOSE) • END PRODUCTS: ATP, CO2, AND H20
CELL RESPIRATION D. OCCURS IN THE MITOCHONDRIA (OF EUKARYOTES) • THIS PROCESS IS DONE BY ALL CELLS, ALL THE TIME, TO PRODUCE ENERGY IN THE FORM OF ATP
2 Types of Cell Respiration • Aerobic respiration: requires oxygenand carried out by most organisms, such as plants, animals, and some bacteria • Anaerobic respiration: requires NO OXYGEN and carried out by yeast, some bacteria, and some animals
AEROBICRESPIRATION - occurs in cells when there is plenty of O2; 3 STAGES: 1. GLYCOLYSIS – glucose (6C) is broken down into 2 PYRUVIC ACIDS (3C) 2 ATP in cytoplasm outside mitochondria 2. KREBS CYCLE (CITRIC ACID CYCLE)takes the pyruvic acid and traps H from it 2 ATP mitochondria 3. ELECTRON TRANSPORT CHAIN – takes the H and makes it release energy a little bit at a time. This energy is used to attach a phosphate to ADP to make ATP. When the energy from the H is used up, O2 is attached to it to make H2O. 34 ATP occurs in mitochondria Total = 38 ATP
CELLULAR RESPIRATION PATHWAYS GLYCOLYSIS 2 ATP + 2 PYRUVIC ACID CYTOSOL FERMENTATION– RESTARTS GLYCOLYSIS KREBS CYCLE2 ATP + CO2 NO O2 PRESENT ANAEROBIC 02 PRESENT AEROBIC RESP. MITOCHONDRIA ETC (ELECTRON TRANSPORT CHAIN)34 ATP + H20
QUESTION: What happens if you can’t get enough oxygen to carry out aerobic cell respiration?
ANSWER: LACTIC ACID FERMENTATION (Have you ever felt like this?)
ANAEROBICRESPIRATION (FERMENTATION) • occurs in cells when there is NO OXYGEN • Inefficient (IN EUKARYOTES)- only produces 2 ATP for every glucose; RESTARTS GLYCOLYSIS
WHY DO PHOTOSYNTHESIS & RESPIRATION DEPEND ON EACH OTHER? GLUCOSE + ATP
CELLULAR RESPIRATION PATHWAY FERMENTATION – RESTARTS GLYCOLYSIS GLYCOLYSIS • 2 ATP • 2 PYRUVIC ACID CYTOSOL • KREBS – 2 ATP, CO2 • ETC (ELECTRON TRANSPORT CHAIN) - 34 ATP, H20 NO O2 PRESENT ANAEROBIC 02 PRESENT AEROBIC RESP. MITOCHONDRIA