AP Biology Period 5
2 October 2013
CHAPTER 7 STUDY GUIDE
AN OVERVIEW OF PHOTOSYNTHESIS
Autotrophs are plants that can feed themselves by making their own food. Photo-autotrophs are organisms that produce organic molecules from inorganic molecules using the energy of light. Producers are when plants make their own organic molecules. A redox reaction is oxidation and reduction. Photosynthesis takes water and carbon dioxide to make glucose and oxygen. Cellular respiration takes glucose and oxygen to make water and carbon dioxide. ● Chloroplasts have an outer and inner membrane. There is intermembrane space and thylakoid space. There is stroma and grana and thylakoid. Chloroplasts are found in mesophyll cells. ●The thylakoids is the part that most light energy is converted into chemical energy. Plants produce oxygen by photosynthesis and breaking the water. The plants extract the oxygen ●The oxygen that is produced from photosynthesis was found to come from water. ●The reactants in light reactions are light and water. The product is oxygen. The Calvin cycle takes in carbon dioxide to make sugar. ● Photosynthesis relates to these reactions. Photosynthesis uses the redox reaction to make glucose and oxygen. Light reactions take in water and light to make oxygen. The Calvin cycle takes in carbon dioxide to make sugar.
THE LIGHT REACTIONS: CONVERTING SOLAR ENERGY TO CHEMICAL ENERGY ● Chlorophyll takes in light energy. Other photosynthetic pigments like carotenoids and phycobilins indirectly participate in the photosynthesis by trapping photons from different wavelength of light and passing it to chlorophylls for photosynthesis as they are not capable of this function. ● Photosystems can capture solar energy. Plants use chlorophyll to get “excited.” The chlorophyll takes in the sun’s energy to convert it into other energy to use it in photosynthesis. ●They can make oxygen by taking in water and splitting it into oxygen and hydrogen. They can make NADPH by reacting NADP+ and H. They make ATP from the ATP synthase. ● Photophosphorylation is the chemiosmotic production of ATP during photosynthesis while oxidation phosphorylation is during cellular respiration is when they use oxygen to extract chemical energy from organic compounds.
THE CALVIN CYCLE: CONVERTING CO2 TO SUGARS
● The reactants of the cycle are carbon dioxide, ATP, and NADPH. The products is an energy-rich three carbon sugar, glyceraldehyde. It depends on light reactions because they get ATP and NADH from the light reactions.
PHOTOSYNTHESIS REVIEWED AND EXTENDED
● Light reactions take in light and water to make oxygen and gives off ATP and NADH to the Calvin cycle. The Calvin cycle takes in carbon dioxide to make sugars and gives off NADP+ and ADP +P to light reactions. C3 plants are the plants where they use the Calvin cycle to use the CO2 from the air. C4 plants use a special adaptation and use a special enzyme to get CO2. CAM plants open its stroma to let CO2 come in only at night. C3: Soybeans, oats, wheat, and rice. C4: sugarcane. CAM: Pineapple.
PHOTOSYNTHESIS, SOLAR RADIATION, AND EARTH’S ATMOSPHERE
The greenhouse effect is when greenhouse gases, i.e. carbon dioxide, allow short radiations from the sun to pass and block long waves which escape into space. If forests’ were lost, then there would be less oxygen in the world since plants make oxygen from carbon dioxide. Fossil fuels would make the air full of more CO2. The ozone layer forms when high energy solar radiation breaks oxygen and frees oxygen atoms. They react with each other. Human activities have damaged it by releasing chemicals that hasten the destruction. KEY TERMS
-Autotrophs - An organism that makes its own food. i.e. plants -Calvin cycle - The second stage of photosynthesis, chemical reactions that happen in the stroma of chloroplast -Carbon fixation - Incorporation of carbon from atmospheric CO2 into the carbon in organic compounds -Electromagnetic energy - Solar energy or radiation which travels in waves. -Global warming - A slow and steady rise of Earth’s temperature. -Grana - Stack of hollow disks formed in thylakoid membrane of chloroplast -Greenhouse effect - The warming of the atmosphere by CO2.
-Light reactions - The first out of two stages of photosynthesis; where solar energy is absorbed and made into chemical energy. -Mesophyll - The green tissue inside the leaf; the leaf’s ground tissue system. -Photoautotrophs- an organism that obtains energy from sunlight and carbon from CO2 by photosynthesis -Photon- a fixed quantity of light energy. the shorter the wavelength of light, the greater the energy of a photon. -Photophosphorylation- the production of ATP by chemiosmosis during the light reactions of photosynthesis. -Photorespiration- in a plant cell, the breakdown of a two carbon compound produced by the calvin cycle. The calvin cycle produces the two carbon compound, instead of its usual three carbon product G3P, when leaf cells fix O2, instead of CO2. photorespiration produces no sugar molecules of ATP. -Photosynthesis- the process by which plants, autotrophic protists, and some bacteria use light energy to make sugars and other organic food molecules from carbon dioxide and water. -Photosystem- a light capturing unit of a chloroplast’s thylakoid membrane, consisting of a reaction center surrounded by numerous light harvesting complexes. -Producers-an organism that makes organic food molecules from CO2, H2O, and other inorganic raw materials; a plant, alga, or autotrophic bacterium -Reaction center- in a photosystem in a chloroplast, the chlorophyll a molecule and the primary electron acceptor that trigger the light reactions of photosynthesis. the chlorophyll donates an electron excited by light energy to the primary electron acceptor, which passes an electron to an electron transport chain -Stomata- a pore surrounded by guard cells in the epidermis of a leaf. when stomata are open, CO2 enters a leaf, and water and O2 exit. a plant conserves water when its stomata are closed -Stroma- a thick fluid enclosed by the inner membrane of a chloroplast. sugars are made in the stroma by the enzymes of the Calvin cycle -Whylakoid- 1 of a number of disk shaped membranous sacs inside a chloroplst. thylakoid membranes contain chlorophyll and the enzyme of the light reactions of photosynthesis. a stack of thylakoid is called granum -Wavelength- the distance between crests of adjacent waves, such as those of the electromagnetic spectrum