Campbell Biology Chapter 10 Exam A+ Pass Verified

Campbell Biology Chapter 10 Exam A+ Pass Verified Absorption Spectrum - Answer- The range of a pigment's ability to absorb various wavelengths of light. action spectrum - Answer- A graph that profiles the relative effectiveness of different wavelengths of radiation in driving a particular process. autotrophs - Answer- An organism that obtains organic food molecules without eating other organisms or substances derived from other organisms. Autotrophs use energy from the sun. bundle-sheath cells - Answer- In C4 plants, a type of photosynthetic cell arranged into tightly packed sheaths around the veins of a leaf. C3 Plant - Answer- A plant that uses the Calvin cycle for the initial steps that incorporate CO2 into organic material, forming a three-carbon compound as the first stable intermediate. C4 plant - Answer- A plant in which the Calvin cycle is preceded by reactions that incorporate CO2 into a four-carbon compound, the end product of which supplies CO2 for the Calvin cycle. calvin cycle - Answer- The second of two major stages in photosynthesis (following the light reactions), involving atmospheric CO2 fixation and reduction of the fixed carbon into carbohydrate. CAM plant - Answer- A plant that uses crassulacean acid metabolism, an adaptation for photosynthesis in arid conditions, first discovered in the family Crassulaceae. Carbon dioxide entering open stomata during the night is converted into organic acids, which release CO2 for the Calvin cycle during the day, when stomata are closed. carbon fixation - Answer- The incorporation of carbon from carbon dioxide into an organic compound by an autotrophic organism. carotenoids - Answer- An accessory pigment, either yellow or orange, in the chloroplasts of plants. By absorbing wavelengths of light that chlorophyll cannot, carotenoids broaden the spectrum of colors that can drive photosynthesis. chlorophyll - Answer- green pigment in plants that absorbs light energy used to carry out photosynthesis electromagnetic spectrum - Answer- The entire spectrum of radiation ranging in wavelength from less than a nanometer to more than a kilometer. glyceraldehyde 3-phosphate (G3P) - Answer- A three-carbon carbohydrate that is the direct product of the Calvin cycle; it is also an intermediate in glycolysis. heterotrophs - Answer- An organism that obtains organic food molecules by eating other organisms or their by-products. light reactions - Answer- chemical reactions that convert the sun's energy to chemical energy; take place in the membranes of thylakoids in the chloroplast light-harvesting complex - Answer- A complex of proteins associated with pigment molecules (including chlorophyll a, chlorophyll b, and carotenoids) that captures light energy and transfers it to reaction-center pigments in a photosystem. linear electron flow - Answer- A route of electron flow during the light reactions of photosynthesis that involves both photosystems (I and II) and produces ATP, NADPH, and O2. The net electron flow is from H2O to NADP+. mesophyll - Answer- Leaf cells specialized for photosynthesis. In C3 and CAM plants, mesophyll cells are located between the upper and lower epidermis; in C4 plants, they are located between the bundle-sheath cells and epidermis. NADP+ - Answer- Nicotinamide adenine dinucleotide phosphate, an acceptor that temporarily stores energized electrons produced during the light reactions. PEP carboxylase - Answer- An enzyme that adds carbon dioxide to phosphoenolpyruvate (PEP) to form oxaloacetate. photon - Answer- A quantum, or discrete amount, of light energy. photophosphorylation - Answer- The process of generating ATP from ADP and phosphate by means of a proton-motive force generated by the thylakoid membrane of the chloroplast during the light reactions of photosynthesis. photorespiration - Answer- A metabolic pathway that consumes oxygen, releases carbon dioxide, generates no ATP, and decreases photosynthetic output; generally occurs on hot, dry, bright days, when stomata close and the oxygen concentration in the leaf exceeds that of carbon dioxide. photosystem - Answer- Light-capturing unit located in the thylakoid membrane of the chloroplast, consisting of a reaction center surrounded by numerous light-harvesting complexes. There are two types of photosystems, I and II; they absorb light best at different wavelengths.