front 1 autotroph | back 1 "self-feeders" sustain themselves without eating anything derived from other organisms producers ultimate source of organic compounds |
front 2 where did photosynthesis first evolve? | back 2 prokaryotes |
front 3 prior to the evolution of photosynthesis... | back 3 there was very little oxygen found in Earth's atmosphere (photosynthesis produces oxygen as a waste product) |
front 4 heterotroph | back 4 consumers live on compounds produced by other organisms dependent on the process of photosynthesis for both food and oxygen |
front 5 chloroplasts | back 5 the specific sites of photosynthesis in plant cells |
front 6 stroma | back 6 dense, fluid-filled area enclosed by an envelope of two membranes |
front 7 thylakoids | back 7 within the stroma vast network of interconnected membranous sacs |
front 8 thylakoid space | back 8 compartment, segregated from stroma by thylakoids |
front 9 the thylakoids set up compartments... | back 9 separate from the stroma this allows a proton gradient to be established |
front 10 chlorophyll | back 10 located in the thylakoid membranes is the light-absorbing pigment that drives photosynthesis gives plants their green color |
front 11 stomata | back 11 many tiny pores found in the exterior of the lower epidermis of a leaf the means through which carbon dioxide enters, and oxygen/water vapor exit the leaf |
front 12 transpiration | back 12 the loss of water through open stomata |
front 13 overall photosynthesis reaction | back 13 6 CO2 + 6 H2O + Light Energy -> C6H12O6 + 6 O2 |
front 14 the overall chemical change during photosynthesis is... | back 14 the reverse of the one that occurs during cellular respiration |
front 15 water is split for its electrons... | back 15 which are transferred along with hydrogen ions from water to carbon dioxide, reducing it to sugar an endergonic process, requires energy from the sun |
front 16 oxygen we breathe is formed... | back 16 in the process of photosynthesis when a water molecule is split |
front 17 photosynthesis occurs in how many stages? | back 17 two light reactions and calvin cycle |
front 18 the light reactions | back 18 occur in the thylakoid membranes solar energy -> chemical energy |
front 19 net products of light reactions | back 19 NADPH (which stores electrons), ATP, and oxygen |
front 20 step one of the light reactions | back 20 light energy is absorbed by chlorophyll, which drives the transfer of electrons from water to NADP+, forming NADPH |
front 21 step two of the light reactions | back 21 water is split, oxygen is released |
front 22 step three of the light reactions | back 22 ATP is generated, using chemiosmosis to power the addition of a phosphate group to ADP, a process called photophosphorylation |
front 23 calvin cycle | back 23 occurs in the stroma CO2 from the air is incorporated into organic molecules in carbon fixation uses the fixed carbon plus NADPH and ATP from the light reactions in the formation of new sugars |
front 24 carbon fixation | back 24 CO2 from the air is incorporated into organic molecules |
front 25 light | back 25 the primary energy source for life on earth electromagnetic energy that travels in rhythmic waves |
front 26 visible spectrum | back 26 the portion of light that we can see consists of the colors red, orange, yellow, green, indigo, and violet ie. ROY G BIV |
front 27 photons | back 27 light behaves as though it is made up of discrete particles each of which has a fixed quantity of energy |
front 28 pigments | back 28 substances that absorb light |
front 29 different pigments... | back 29 absorb light of different wavelengths |
front 30 chlorophyll is a... | back 30 pigment it absorbs violet-blue and red while transmitting and reflecting green light this is why we see summer leaves as green |
front 31 absorption spectrum | back 31 a graph plotting a pigment's light absorption as a function of wavelength for chlorophyll, it provides clues to the effectiveness of different wavelengths for driving photosynthesis (confirmed by an action spectrum) |
front 32 action spectrum | back 32 graphs, for photosynthesis, the effectiveness of different wavelengths of light in driving the process of photosynthesis confirms that plants use energy from red and blue light (which is absorbed) and very little energy from green light (which is reflected) |
front 33 photons of light are absorbed by... | back 33 certain groups of pigment molecules in the thylakoid membrane of chloroplasts |
front 34 photosystems | back 34 the groups of pigment molecules in which photons of light are absorbed in the thylakoid membrane of chloroplasts consist of two parts: a light-harvesting complex and a reaction-center |
front 35 light-harvesting complex | back 35 made up of chlorophyll and carotenoid molecules of different colors of green and orange/yellow this arrangement allows the complex to gather light effectively |
front 36 carotenoid molecules | back 36 accessory pigments in the thylakoid membrane |
front 37 when chlorophyll absorbs light energy in the form of photons... | back 37 one of the molecule's electrons is raised to an orbital of higher potential energy chlorophyll is in an "excited state" |
front 38 reaction center | back 38 where the energy is transferred consists of two chlorophyll a molecules that donate electrons to the second member of the reaction center |
front 39 primary electron acceptor | back 39 chlorophyll a molecules donate electrons to these a molecule capable of accepting electrons and becoming reduced |
front 40 first step of the light reactions | back 40 the solar-powered transfer of an electron from the reaction-center chlorophyll a pair to the primary electron acceptor conversion of light energy to chemical energy |
front 41 elections donated from the reaction center... | back 41 must be replaced splitting of water is the source of the replacement electrons |
front 42 the thylakoid membranes contain... | back 42 two photosystems that are important to photosynthesis |
front 43 PS I (Photosystem 1) | back 43 sometimes designated P700 - chlorophyll a in the reaction center of this photosystem absorbs red light of this wavelength best |
front 44 PS II (Photosystem 2) | back 44 P680 - absorbs light of this wavelength best |
front 45 the key to the light reactions is... | back 45 the flow of electrons through the photosystems in the thylakoid membrane |
front 46 STEP ONE, light reactions | back 46 PS II absorbs light energy, exciting an electron in the P680 reaction center of two chlorophyll a molecules to a higher energy state |
front 47 STEP TWO, light reactions | back 47 electron is transferred to the primary electron acceptor reaction-center chlorophyll is oxidized and now requires an electron |
front 48 STEP THREE, light reactions | back 48 enzyme splits a water molecule into two hydrogen (H+) ions, two electrons, and an oxygen atom electrons are supplied to the P680 chlorophyll a molecules oxygen immediately combines with another oxygen atom (forms O2, released in atmosphere) H+ released into thylakoid space |
front 49 STEP FOUR, light reactions | back 49 original excited electron passes from the primary electron acceptor of PS II to PS I through an electron transport chain energy from the transfer of electrons down the electron transport chain is used to pump protons (H+) into the thylakoid space |
front 50 STEP FIVE, light reactions | back 50 H+ accumulates in the thylakoid space creating a gradient that is used in chemiosmosis to phosphorylate ADP to ATP ATP used as energy in the formation of carbohydrates in Calvin cycle |
front 51 STEP SIX, light reactions | back 51 light energy has also activated PS I, resulting in the donation of an electron to its primary electron acceptor electrons donated by PS I are replaced by the electrons from PS II |
front 52 STEP SEVEN, light reactions | back 52 the primary electron acceptor of PS I passes the excited electrons along to another electron transport chain |
front 53 STEP EIGHT, light reactions | back 53 excited electrons are transmitted to NADP+, then reduced to NADPH (second of the two important light reaction products) this process removes H+ from the stroma, increasing the proton gradient high energy electrons of NADPH available for use in Calvin cycle |
front 54 chemiosmosis | back 54 how chloroplasts and mitochondria generate ATP |
front 55 electron transport chain uses... | back 55 flow of electrons to pump protons across the thylakoid membrane stroma -> thylakoid space this creates an electrochemical gradient |
front 56 what is the electrochemical gradient that is created used for? | back 56 ATP synthase is able to phosphorylate ADP to ATP occurs when protons flow out of the thylakoid space, down electrochemical gradient, through ATP synthase, and into stroma |
front 57 where is proton-motive force generated? | back 57 3 places 1) hydrogen ions from splitting of water 2) hydrogen ions pumped across the membrane by cytochrome complex 3) removal of hydrogen ions from the stroma when NADP+ is reduced to NADPH |
front 58 differences between chemiosmosis in cellular respiration and photosynthesis | back 58 spatial differences mitochondria uses chemiosmosis to transfer chemical energy from food molecules to ATP chloroplasts transfer light energy into chemical energy of ATP (difference between consumer and a producer) |
front 59 calvin cycle | back 59 carbon enters in the form of CO2, leaves in the form of a sugar |
front 60 what does the calvin cycle spend and consume? | back 60 ATP as an energy source, NADH for reducing power |
front 61 to net one molecule of G3P, the calvin cycle must go through... | back 61 three rotations, fix three molecules of CO2 |
front 62 to produce one molecule of glucose, the calvin cycle must go through... | back 62 six rotations, fix six molecules of CO2 |