Cell Energy Photosynthesis and Respiration

How do Cells Store Energy? Adenosine Triphosphate (ATP) – the molecule where the energy is stored for cell processes. NADP+ and NADPH- carrier molecules that carry high energy electrons for reactions in the cell.

ATP Model Adenine Ribose 3 Phosphate groups

ATP- ADP Cycle When ATP loses a phosphate group it releases energy and becomes ADP (Adenosine Diphosphate).

ATP vs. ADP compared to a battery ADP ATP Adenosine diphosphate (ADP) + PhosphateAdenosine triphosphate (ATP) Partially charged battery Fully charged battery

ATP-ADP Cycle Energy is added with a phosphate to ADP Energy is released with a phosphate ATP is formed ADP is formed

Photosynthesis Photosynthesis – plants trap the sun’s energy and store it in molecules of glucose. Process of using sun’s energy to make food for the plant.

Photosynthesis Formula Process of Photosynthesis sunlight sunlight Carbon Dioxide + Water glucose + oxygen Carbon Dioxide + Water glucose + oxygen chlorophyll chlorophyll Reactants Products Reactants Products

Photosynthesis takes place in leaves (primarily)… Leaves are the major sites of photosynthesis (although any green vegetation can do so).

Within cells of the leaf, photosynthesis takes place in the CHLOROPLASTS… Elodea cells with small, circular chloroplasts

Thought it didn’t go any smaller?

Within those crazy chloroplasts… Thylakoids: sacs containing chlorophyll (pancake) Grana: stack of thylakoid disks (stack of pancakes) Stroma: the region outside the grana. (syrup)

So where’s the juice? Nature of Sunlight— Light = electromagnetic energy (radiation), travels in rhythmic waves (  wavelengths) Entire range = electromagnetic spectrum Visible light drives photosynthesis

Photons & Pigments Light behaves like individual particles called photons Light can be absorbed, reflected, transmitted Things that absorb —called pigments Photosynthesis pigments: chlorophyll a (blue-green) chlorophyll b (yellow-green) carotenoids (yellow-orange)

Two Steps of Photosynthesis: 1. Light Dependent Reaction 2. Light Independent Reaction (also called Calvin Cycle or Dark Cycle).

Light-Dependent Reactions- 1 st step of Photosynthesis Takes place in thylakoid membranes (pancakes). Requires light energy Sunlight and water enter the grana as reactants. Oxygen is produced. ATP and NADPH go to the Calvin Cycle.

Sunlight- reactant Carbon Dioxide- reactant Oxygen- product Glucose/Sugar- product Light- Dependent Reactions Calvin Cycle NADP+ ADP + P ATP NADPH Water- reactant

2 nd Step: Light-Independent Reactions (Calvin Cycle/Dark Cycle) No light required No light required Takes place in the stroma (syrup) Takes place in the stroma (syrup) Carbon dioxide enters as reactant. Carbon dioxide enters as reactant. Glucose is produced. Glucose is produced. For every 6 molecules of CO 2, only one molecule of glucose is formed. For every 6 molecules of CO 2, only one molecule of glucose is formed. ADP and NADP+ go to Light Dependent Step. ADP and NADP+ go to Light Dependent Step.

Sunlight- reactant Carbon Dioxide- reactant Oxygen- product Glucose/Sugar- product Light- Dependent Reactions Calvin Cycle NADP+ ADP + P ATP NADPH Water- reactant

Cell Respiration The process where food molecules are broken down in the presence of oxygen to release energy. The process where food molecules are broken down in the presence of oxygen to release energy. Takes place in mitochondria and cytoplasm. Takes place in mitochondria and cytoplasm. This process may be: This process may be: Aerobic ( in the presence of oxygen) Aerobic ( in the presence of oxygen) Anaerobic (without oxygen) Anaerobic (without oxygen) The equation for cellular respiration is: The equation for cellular respiration is: 6O 2 + C 6 H 12 O 6 6CO 2 + 6H 2 O + Energy

3 Main Stages of Cell Respiration 1. Glycolysis 2. Krebs Cycle 3. Electron Transport Chain

Glycolysis Occurs in cytoplasm Occurs in cytoplasm One molecule of glucose is broken in half, producing pyruvic acids. One molecule of glucose is broken in half, producing pyruvic acids. 2 molecules of ATP are produced 2 molecules of ATP are produced Does not require oxygen (anaerobic) Does not require oxygen (anaerobic) 2 Pyruvic acid

After Glycolysis If oxygen is present ( aerobic) the second stage is the Krebs cycle. If oxygen is present ( aerobic) the second stage is the Krebs cycle. If oxygen is not present, glycolysis is followed by Fermentation. If oxygen is not present, glycolysis is followed by Fermentation.

Krebs Cycle (also called citric acid cycle) At end of glycolysis about 90% of the chemical energy from glucose is still unused. Oxygen needed to extract that energy. At end of glycolysis about 90% of the chemical energy from glucose is still unused. Oxygen needed to extract that energy. Aerobic (requires oxygen) Aerobic (requires oxygen) Occurs in mitochondria. Occurs in mitochondria. Pyruvic acid is broken down into carbon dioxide. Pyruvic acid is broken down into carbon dioxide.

Electron Transport Chain Uses high energy electrons to convert ADP to ATP Uses high energy electrons to convert ADP to ATP 34 more ATP molecules per glucose molecule are produced in addition to the 2 ATP molecules produced during glycolysis. 34 more ATP molecules per glucose molecule are produced in addition to the 2 ATP molecules produced during glycolysis. Water is also a product. Water is also a product.

Glucose Glycolysis Cytoplasm Pyruvic acid Electrons carried in NADH Krebs Cycle Electrons carried in NADH and FADH 2 Electron Transport Chain Mitochondria Respiration: AnOverview Respiration: AnOverview Mitochondria Section 9-1 Go to Section:

Flowchart Section 9-2 Glucose (C 6 H ) + Oxygen (0 2 ) Glycolysis Krebs Cycle Electron Transport Chain Carbon Dioxide (CO 2 ) + Water (H 2 O) Go to Section: Cellular Respiration

Fermentation Releases energy form food molecules in the absence of oxygen (anaerobic) Releases energy form food molecules in the absence of oxygen (anaerobic) The two main types of Fermentation are : The two main types of Fermentation are : Alcoholic fermentation Alcoholic fermentation Lactic Acid Feremtation Lactic Acid Feremtation

Alcoholic Fermentation Occurs in yeasts and other microorganisms. Occurs in yeasts and other microorganisms. Converts pyruvic acid to ethyl alcohol Converts pyruvic acid to ethyl alcohol Causes bread to rise Causes bread to rise

Lactic Acid fermentation Lactic acid is produced in your muscles during rapid exercise. Lactic acid is produced in your muscles during rapid exercise. Lack of oxygen to the muscles- causes muscle soreness. Lack of oxygen to the muscles- causes muscle soreness. Pyruvic acid is converted into lactic acid Pyruvic acid is converted into lactic acid

Glucose Glycolysis Krebs cycle Electron transport Fermentation (without oxygen ) Alcohol or lactic acid Chemical Pathways Section 9-1 Go to Section: