Bio_SC 1010 1st Edition Lecture 5Outline of Last Lecture I. EnzymesII. Metabolism Outline of Current Lecture I. Cellular Respiration Current LectureI. Cellular Respiration How do cells obtain and use energy?1. Ultimately, nearly all cells depend on solar energy2. Plants use light energy to build glucose3. Both plant and animal cells then break down the glucose to obtain usable energyWhen light strikes an object, 3 things can happen1. Reflected2. Transmitted3. Absorbed-energy of light is transferred to the molecules of the objectPhotosynthesis • The process by which plants use light energy to make food molecules from the CO2 and water• Takes place in chloroplasts (organelle inside of the cell, has 2 membranes)These notes represent a detailed interpretation of the professor’s lecture. GradeBuddy is best used as a supplement to your own notes, not as a substitute.• Chloroplasts contain the pigment chlorophyll-pigment: molecules that absorb light of a particular wavelength (color)-chlorophylls absorbs violet, blue, and red light • What does chlorophyll do with the energy?-2 steps1. light-dependent reaction ATP is synthesized Water (H2O) is split apart in the process, releasing oxygen (O2) as a by-product 2. light-independent reactionWhat do cells use the glucose for?1. As a source of carbon to build other organic molecules in the cell2. To make ATP • Cellular respiration produces an energy-carrying molecule called ATP• 3 steps for making ATP from glucose1. Glycolysis: glucose is broken into pyruvic acid (pyruvate); yielding 2 ATP-takes place in cytoplasm-splits glucose into 2 pyruvic acids-small amount of ATP produced2. Citric acid cycle -takes place in the mitochondria-uses O2-pyruvic acid broken to CO2-high-energy electrons produced-small amount of ATP produced (2 ATPs)3. Electron transport chain-inner membranes of mitochondria-high-energy electros move through chain-electrons combine with O2 to form H2O-lots of ATP produced • In fermentation, energy is harvested from sugar without oxygen -aerobic respiration-anaerobic respiration• Fermentation harvests the energy from glucose without O2• -only a small bit of ATP is produced • -fermentation produces much less ATP than aerobic respiration• Sometimes no O2 is available -deep in soil-in guts of animals-bogs-when we’re exercising vigorously • What if no O2 is available?-the pyruvic undergoes fermentation (instead of respiration)-is converted into either (alcohol and CO2; lactic acid; various other byproducts)-no ATPs are produced• Respiration -lots of ATP-water, CO2• Fermentation-no ATP-alcohol and CO2 or lactic
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