Energy, Thermodynamics, ATPs, Photosynthesis, Cellular Respiration | BIOL 1050, Study notes of Biology

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Goals for the day:  Energy  Thermodynamics  AtP  Photosynthesis  Cellular Respiration Energy: Energy flows from the sun through (almost) all life on Earth. Plants for example, take sun energy, turn it into chemical energy, that through consumption are then transferred up the food chain. 1: photosynthesis, plants capture energy from the sun and store it in the chemical bonds of sugars and other carbohydrates. 2: Cellular Respiration. Energy defined as the capacity to do work. Work: moving matter against an opposing force. Two basic forms: Potential= stored energy (for ex. : chemical bonds) Kinetic= the energy of moving objects. Ex. Sling shot. Pulled rock = potential, flung rock that is in air = kinetic Food is a form of chemical energy=potential energy. Chemical energy. A form of potential energy stored in chemical bonds, when broken = energy. Glucose can be linear or structural. Ethanol used for chemical energy, combustion. Octane also used for combustion. Triglyceride (fat) has more potential energy, more bonds. Kinetic energy examples: fire, flying, bike riding. Potential energy: skier at top of mountain not yet moving, water damn. Thermodynamics: 1 st^ law of thermodynamics -Energy cannot be destroyed nor created  Only changes forms (ex. kinetic energy to heat) 2 nd^ law of thermodynamics -Every conversion of energy is not efficient and will lose some energy into heat (this is why there is no existent perpetual motion) Ex. Light energy from sun, energy lost in form of heat, chemical energy stored in plants. Energy lost in the form of heat, kinetic energy of forward motion. Energy lost in the form of heat, kinetic energy of forward moving. ATP: The molecular “unit of currency” for energy transfers in the cell. Adenine, Ribose (sugar), Phosphate groups. RNA base style but this one used for energy. Clean off a phosphate group for energy. Adenosine triphosphate. Ex. The sling shot. With a breaking off of a phosphate group, we transfer from potential energy to kinetic. Energy released from breakdown of food, goes to ATP, gain energy to work, loose energy, eat restore.

Photosynthesis: Energy from sunlight is captured as chemical energy. Plants use food storage molecules to use ATP energy to have photosynthesis. Other organisms besides plants carry out photosynthesis, prokaryote, euglena, dinoflagellate, cyanobacteria- prob the first plants to do photosynthesis. Endosymbient. …Cyanobacteria were the endosymbionts! “Photo” Reaction: energy from sun captured and stored. “Synthesis” Reaction; energy used to build sugar molecules. Input: sunlight + water + carbon dioxide= oxygen + sugar. Photosynthetic cells packed with chloroplasts. Two structures in chloroplasts: Thylakoid: where the light energy is converted into chemical energy. Stroma: where the chemical energy is used to make sugar. Thylakoid: the “photo” reaction of photosynthesis occurs here. Stroma: the “synthesis” reaction occurs here. Sunlight+Water goes into the chloroplasts, comes out as ATP and NADPH (energy- storing molecules) and oxygen. Photosynthesis occurs, plants reflect green, are not green themselves. Chlorophyll a (blue) Chlorophyll b (green) carotenoid (orange) pigments reflected by plantlife. Summary of “photo” reaction: Water-splitting photosystem: light energy used to transfer electrons to primary electron acceptor. Electrons acquired by splitting H2O. 1 st^ Electron Transpor Chain: Highe-energy electrons used to pump H+ into thylakoid. Kinetic energy from H+ used to build ATP. Nadph-producing photosystem: identical to the water splitting photosystem, except electrons donated by the electron…. How does carbon dioxide enter the plant? Stoma open, Stoma closed. H2O + CO2 O2 C6H12O Getting CO2: Carbon dioxide enters leaf through stomata = tiny pores usually on lower surface of leaves

H2O & O2 are also lost through stomata. C3 Photosynthesis: Advantage-energy efficient. Disadvantage-water lost to evaporation in hot climates. CO2  CALVIN CYCLE, STOMATA OPEN, DURING THE DAY.  SUGAR. C4 Photosynthesis. Advantage: water loss is minimized in warm climates. Disadvantage: requires more energy. CO2  Carbon uptake (ATP) stomata slightly open, CALVIN CYCLE, happens during the day,  sugar. Example: Corn. CAM Photosynthesis: Advantage: water loss is minimized in hot climates. Disadvantages: requires more energy, slow growth. CO2  CARBON UPTAKE (ATP) STOMATA OPEN DURING NIGHT, CALVIN CYCLE, STOMATA CLOSED, DURING THE DAY  SUGAR. Ex. Saguaro cactus Cellular Respiration: High-energy bonds of food molecules are broken down releasing energy. Ex. Bison slide. Input: O2+Sugar CO2 + WATER + ATP (ENERGY) This is the opposite of photosynthesis. Input: O2 +C6H12O6  Energy +CO2 + H2O Clicker: Most common plants use what type of photosynthesis method? C