BIOA01H3 Lecture Notes - Lecture 23: Photosystem Ii, Photosynthetic Reaction Centre, Thylakoid

Photosynthesis

Light Reactions:

Photosynthesis is the process of reducing/oxidizing (circle one) _____________________ to produce ___________________. This overall reduction-oxidation reaction requires _________________ to begin the flow of __________________. Photosynthetic ____________________ absorb light energy and are located in ___________________ found embedded within the membranes of __________________. The most prevalent one include the ___________________ which reflect ________________ light and absorb the other wavelengths of light. Accessory pigments include ___________________. When light energy is absorbed in photosynthesis, electrons of pigment molecules become _________________ and move into higher potential energy _______________. When the electrons return to their previous position, _____________ is passed to the ______________________ pigment molecule. Electrons within this pigment molecule move to a high potential energy state and are “grabbed” by _________________________ chains. Electrons from photosystem II are passed to ______________________. Electrons from photosystem I are passed to _________________. As electrons move in the electron transport chain associated with photosystem I/II (circle one), the energy released is used to power ___________ pumps and __________ is produced via a process known as ________________________. Photosystem I/II (circle one) electrons must be replaced to continue the reaction so ____________ is split for its electrons. The products _______________ & _______________ then proceed to the ______________________ cycle.

Calvin Cycle:

The Calvin Cycle can be broken into 3 main series of reactions. In the first group, known as the __________________ step, ______________________ combines with 3 molecules of ____________________ to form 6 molecules of _____________________. This reaction is catalyzed by ___________________. ________________ can act as a competitive inhibitor of this enzyme, shutting down this step in a process known as ______________________________. In the second series of reactions known as the __________________ steps, the molecules produced in the previous step get oxidized/reduced (circle one). The source of electrons is _________from the light reactions. This step is endergonic/exergonic (circle one) and thus requires _______ from the light reactions. Six molecules of _____________________ are produced, ______ (#) of which will continue in biosynthetic pathways to produce __________________. The remaining molecules will then enter the ______________________ steps which require _____________ from the light reaction. In this step, 3 molecules of _______________ are produced so that this cyclic reaction can continue.

In a thylakoid membrane, absorbed light energy is passed from one chlorophyll molecule to another until it is:

Select one:

a. dissipated as heat.

b. released as fluorescence

c. passed to a reaction center.

Question 2

Protons in a chloroplast flow through an ATP synthase from the:

Select one:

a. cytoplasm to the intermembrane space.

b. stroma to the intermembrane space.

c. thylakoid lumen to the stroma.

d. stroma to the thylakoid lumen.

e. intermembrane space to the stroma.

Question 3

Which of the following are produced directly as a result of the movement of electrons through the photosynthetic electron transport chain?

Select one:

a. oxygen and carbohydrates

b. carbohydrates and ATP

c. ATP and NADPH

d. water and carbohydrates

Question 4

If a mutation occurs such that photosystem II no longer functions as efficiently as it should, what might be most directly affected?

Select one:

a. The amount of H2O produced.

b. The rate at which NADPH is produced.

c. The rate at which protons are transported into the stroma.

d. The rate of ATP synthesis by ATP synthase in the chloroplast.