BIOL 1103 1st Edition Exam 1 Study Guide Summary of the Assigned readings Summary of Overview of Photosynthesis Reading Through photosynthesis certain organisms convert solar energy sunlight into chemical energy which is needed to build carbohydrate molecules All organisms carrying out photosynthesis require sunlight When an organism breaks down food the energy holding the molecules together is released The energy is used for cellular respiration Photosynthesis requires sunlight carbon dioxide and water It releases oxygen and produces glucose In light dependent reactions chlorophyll absorbs energy from the sunlight and coverts it into chemical energy wit the use of water and it releases oxygen as a byproduct In the Calvin Cycle chemical energy drives the capture of carbon and assembly of glucose Vocabulary from Overview of Photosynthesis Reading Autotroph an organism that can produce its own food Chlorophyll the green pigment that absorbs the light energy which drives photosynthesis Pigment a molecule that is capable of absorbing light energy Chloroplast the organelle where photosynthesis takes place Heterotroph an organism that consumes other organisms for food because it is incapable of photosynthesis Light dependent reaction the first stage of photosynthesis where visible light is absorbed to form two energy carrying molecules ATP and NADPH Stoma the opening that controls the gas exchange and water regulation between leaves and the environment Thylakoid a disc shaped membranous structure inside a chloroplast where the lightdependent reactions of photosynthesis take place using chlorophyll Stroma the fluid filled space surrounding the grana inside a chloroplast where the Calvin cycle reactions of photosynthesis take place Summary of Light dependent Reaction of Photosynthesis Reading All photosynthetic organisms contain a pigment called chlorophyll a which absorbs wavelengths from each end of the spectrum blue and red It does not absorb green wavelengths which is why plants appear green The purpose of light dependent reactions is to convert light energy into chemical energy It does this by grouping pigment molecules and proteins called photosystems Photosystem II absorbs one photon which causes an electron in the chlorophyll to become excited and break free This starts photosynthesis Energy then travels through the electron transport chain series of proteins in the thylakoid forming an electrochemical gradient The ions formed move through ATP synthase from the thylakoid to the stroma in order to form molecules of ATP to be used to form sugar in the second stage of photosynthesis Photosystem I absorbs another photon to create NADPH to be used as a carrier in the Calvin cycle Vocabulary for the Light dependent Reaction of Photosynthesis Reading Absorption spectrum the specific pattern of absorption for a substance that captivates electromagnetic radiation Chlorophyll a the form of chlorophyll that absorbs violet blue and red light Chlorophyll b the form of chlorophyll that absorbs blue and red orange light Photon a distinct quantity or packet of light energy Photosystem a group of proteins chlorophyll and other pigments that are used in the light dependent reactions to absorb light energy and convert it into chemical energy Summary of the Calvin Cycle Reading There are two chemicals in the stroma other than CO2 that help initiate the Calvin cycle the enzyme RuBisCO and the molecule RuBP which has five atoms of carbon and one phosphate group on each end RuBisCO catalyzes a reaction between CO2 and RuBP to form a six carbon compound which is then separated into two three carbon compounds 3 PGA in a process called carbon fixation Using ATP AND NADPH stored energy from the light dependent phase three carbon compound 3 PGA is converted into G3P which is another three carbon compound Then G3P leaves the Calvin cycle to help form glucose Since glucose has six carbon atoms it takes six turns of the Calvin cycle to make one molecule of glucose The remaining G3P regenerate RuBP Vocabulary for the Calvin Cycle Reading Calvin cycle the reactions of photosynthesis that use the energy stored by the lightdependent reactions to form glucose and other carbohydrate molecules Carbon fixation the process of converting inorganic CO2 gas into organic compounds Summary of the Carbon Cycle Reading Carbon is the fourth most abundant element in living organisms and it is present in all organic molecules Carbon compounds store energy or fossil fuels and the burning of fossil fuels releases CO2 into the atmosphere Two interconnected sub cycles One is dealing with the quick carbon exchange between living organisms and the other is dealing with the extended period cycle of carbon through geologic processes Summary of the Nitrogen Cycle Reading Nitrogen enters the living world through symbiotic and free living bacteria Cyanobacteria play an important role in nitrogen fixation because they are able to fix nitrogen gas into ammonia to be transferred to the macromolecules of the organism Rhizobium live symbiotically in things like peanuts peas and beans and can fix nitrogen Nitrogen that enters the living system by nitrogen fixation is converted from organic nitrogen back to nitrogen gas by bacteria in three steps One is ammonification which converts nitrogenous waste into ammonium by certain bacteria and fungi Next through nitrification the ammonium converts to nitrates by nitrifying bacteria Lastly denitrification converts the nitrates into nitrogen gas allowing it to re enter the atmosphere Humans can release nitrogen into the environment through the combustion of fossil fuels and the use of artificial fertilizers Atmospheric nitrogen effects the Earth s ecosystem through the construction of acid rain and greenhouse gas A major effect from fertilizer runoff is saltwater and freshwater eutrophication which is a process where the nutrient runoff causes the algae to overgrow and many other problems In the marine nitrogen cycle sediment is formed and with time being moved to the land Summary of the Lecture Notes Carbon and Energy Transformation The majority of the mass of a plant comes for the compacted CO2 in the plant We know that it is not from the soil because of Helmont s Experiment where he planted a willow tree in 200 pounds of soil and after five years the amount of soil was almost the same but the mass of the plant was exponentially greater Also because plants can grow without soil hydoroponics If a