Bio Photosynthesis Guide Answers
Explain th e experi ment reaso ning tha t V an Niel u sed to un derstand photosynthesis.He saw that some plants used carbon dioxide but did not release oxygen, and that some plants used hydrogen sulfide and released sulfide, so he saw that the hydrogen comes from the water molecules and the oxygen is released, rather than from carbon dioxide. Wha t is ca rbo n fi xa tio n? -Inside of the Calvin Cycle, carbon fixation occurs when carbon dioxide is attached to RuBp, a 5-carbon sugar, by the enzyme rubisco forming an unstable 6-carbon sugar, which is then split into two 3-carbon sugars. What a re th e two st ages o f pho tosy nthe sis? -The two stages of photosynthesis are the light reaction, which makes ATP and NADPH, which the Calvin Cycle uses in the second phase to make G3P (sugar). Wh at is a p ho to n? -A separated amount of light energy.
Biology Photosynthesis Study Guide Answers
Why ar e l ea ves gre en? -Because the pigment inside of leaves, chlorophyll, absorbs all colors except for yellow and green, which it transmits and reflects; therefore, giving it its green color. What is the differe nce betw een an ab sorption spectra a nd action spectrum? -An absorption spectra is the wavelength of one specific pigment and the action spectrum is the overall wavelengths of all of the pigments in photosynthesis. What happ ens to ch lorophyll when it i s hit by li ght? How does this relate to potential energy? -When light strikes the chlorophyll, it absorbs the photons of light and the electrons of the molecule, in this case the hydrogen ions from the water molecule, are moved to a higher level where they have more potential energy.
It has to do with potential energy because the absorption of the photon allows the electron to go to an orbital with higher energy; therefore, it becomes “excited”. Iden tify t he fol low ing pa rts of a p hoto syst em: a.
Ph ot os ys te m: -it is made of one centered reaction center surrounded by light harvesting complexes. Lig ht h arv es tin g co mpl ex -It is pigments such as chlorophyll a, chlorophyll b, and carotenoids that are bound to proteins. Re ac ti on c en te r -it is a protein complex that has chlorophyll a and a primary electron acceptor. Pr ima ry e lec tro n ac cep tor -it accepts all of the electrons from chlorophyll a.
What are the step s in n oncyclic electron flow in photosyn thesis? 1) ligh t hits th e pigm ents a nd exc ites t he ele ctro ns 2) the elec trons a re capt ured by the prim ary elec tron ac ceptor 3) an enzym e splits a water int o 2 electr ons (2 h ydrogen a nd 1 oxy gen) and they go to the primary electron acceptor, then oxygen combines with another oxygen immediately making an oxygen molecule, which leaves the cell. 4) The ele ctro ns go into th e elect ron tra nspo rt chai n 5) The falling of elec trons releas es energy to form ADP into A TP by A TP synthesis. This is the end of photosystem 2. 6) Then, ph otosyste m 1 begins because light is a bsorbed by the lig ht harves ting complex and the electrons are once again excited and sent to the primary electron acceptor 7) Then, th e electron s are se nt to a se cond elec tron elec tron tran sport cha in 8) NADP+ r uductase transfers electrons to NADP +, which will reduc e it to NADPH.
What is cyclic elec tron flow? -when there is not enough ATP inside of a cell, it will switch from linear light reaction to cyclic, where only photosystem 1 is used rather than 1 and 2, and it only produces ATP. It is different because the electrons cycle from Fd to the cytochrome complex then to the chlorophyll and to the primary electron acceptor, and then it cycles back. When in the cytochrome system, the energy from the falling of the electrons is used to make ATP for the cell.
Compare and contrast chemiosmosis in mitochondria and chloroplasts.Chemiosmosis is the same in mitochondria than inside of chloroplasts because they both pump hydrogen ions across a membrane from low to high (active transport) and the protons diffuse back through the ATP synthase, which will cause ATP synthesis to occur, but they are different because in mitochondria, the electrons come from organic compounds and in chloroplasts they come from water. Additionally, mitochondria transfer chemical energy from food to ATP and chloroplasts change light energy into chemical energy in ATP. Also, in the mitochondria chemiosmosis occurs in the inner membranes of the mitochondira and chloroplasts it occurs in the thylakoid membranes of the chloroplasts. Use the diagram below to summari ze the activities in the light reactions of photosynthesis.water is split by photosystem 2 and oxygen is released and its h+ ions go to the A TP sy nthase. O ther elec trons mov e from the primary e lectron a cceptor to the cytochrome complex and also go to ATP synthase. More light hits photosystem 1 and a H+ ion and NADP+ get together to form NADPH. The electrons go through A TP sy nthase a nd form A TP, which w ill go to the Calvi n Cycle a long with the NADPH.
Describe and explain the overall purpose of the Calvin cycle and each phase listed below: a. Ca lv in cy cl e -The purpose of the Calvin Cycle is to use ATP and NADPH to fix carbon dioxide and turn it into G3P (sugar) b. Ca rb on fi xa ti on -rubisco combines carbon dioxide with RuBp (5-carbon sugar) to make an unstable 6-carbon sugar, which is then split into two 3-carbon sugars. R e d u c t i o n -phosphate from ATP is given to the 3-carbon sugars and a pair of electrons from NADPH reduces them to G3P, which has more potential energy. Re ge ne ra ti on -the cycle uses more ATP to turn the G3P back into RuBp, ready for the cycle to begin again. 14.What is a plant’s most valuable resource and why did plants need to evolve adaptations for hot, arid climates? -water -because when their stomata was open, it would cause them to do transpiration and lose water, which would bring photosynthesis to a pause and delay it, causing them to do photorespiration, which is bad.