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Unformatted text preview: ore beginning this tutorial, watc h the Light Reac tions animation.
Pay partic ular attention to the s teps where light is inv olv ed, the pattern of elec tron flow, and the c oupling of elec tron trans port to the formation of a proton se ssion.ma ste r ingbiology.c om/myc t/a ssignme ntPr intVie w? a ssignme ntI D= 2242937 14/41 13- 10- 13 Cha pte r 10 gradient and ATP s y nthes is . Part A F unctions of the photosystems
The light reac tions require the c ooperation of two photos y s tems to power linear elec tron flow from water to NADP+.
Drag each item into the appropriate bin depending on whether the process is associated with Photosystem II (PS II) only, Photosystem I (PS
I) only, or both PS II and PS I.
Note that “ electron transport chain” here refers to the electron transport chain between the two photosystem s, not the one that functions
after PS I. Hin t 1. Roles of chlorophylls in the light reactions
Chlorophy lls play two roles in the light reac tions : abs orption of light and reduc tion of a primary elec tron ac c eptor. Cons ider where the
c hlorophy lls are loc ated among the v arious c omponents of the light reac tions . Hin t 2. What redox reactions occur in Photosystem II?
In Photos y s tem II (PS II), the ex c ited s tate of P680 c hlorophy ll trans fers an elec tron to the PS II primary elec tron ac c eptor. The res ulting
pos itiv ely c harged P680+ is the s tronges t k nown biologic al ox idant (elec tron ac c eptor).
What is the role of P680+ in the light reactions?
ox idation of the elec tron trans port c hain between the photos y s tems
reduc tion of the elec tron trans port c hain between the photos y s tems
ox idation of water to O2
reduc tion of NADP+ to NADPH Hin t 3. What redox reactions occur in Photosystem I?
In Photos y s tem I (PS I), the ex c ited s tate of P700 c hlorophy ll trans fers an elec tron to the PS I primary elec tron ac c eptor. The res ulting reduc ed
primary elec tron ac c eptor in PS I is one of the s tronges t k nown biologic al reduc t...
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This document was uploaded on 02/17/2014 for the course BIOCHEMIST 2550 at Ohio State.
- Spring '14