Question

photosynthesis

1. on diagram 6, complete the following tasks.

a) label psi and psii.
b) draw the path of the electron transport chain
the events of the light reactions

1. for psii, the cytochrome complex, and psi, draw and label what happens at that structure on diagram 6. then describe the events in a bulleted list in table 1.

table 1: descriptions of the steps in the light reactions.

structure	what is happening with matter?	what is happening with energy?
psii
cytochrome complex
psi

1. at the end of the electron transport chain, where is the light energy that was absorbed and converted by chlorophyll stored? list two answers.

Explanation:

Step1: Identify the tasks

The tasks involve diagram - related activities (labeling and drawing) and descriptive tasks about the light - reactions of photosynthesis.

Step2: Understand the light - reactions

In the light - reactions, PSII, the cytochrome complex, and PSI are key components. PSII starts the process by splitting water and exciting electrons.

Step3: Analyze the role of the cytochrome complex

The cytochrome complex is involved in electron - transfer and proton - pumping, which is crucial for ATP production.

Step4: Analyze the role of PSI

PSI further excites electrons and is involved in the reduction of NADP+ to NADPH.

Step5: Determine energy storage

At the end of the electron - transport chain, the energy is stored in the high - energy bonds of NADPH and ATP.

Answer:

a) (Labeling PSI and PSII on the diagram is a visual - task. One would identify the two photosystems on the thylakoid membrane and label them clearly. Since this is a text - based response, we can't actually draw on the diagram, but in practice, PSII is usually the first one in the electron - transport chain sequence and PSI is the second).
b) (To draw the path of the electron - transport chain: Electrons are excited in PSII by photons. They are passed through a series of electron carriers including the cytochrome complex. Then they move to PSI where they are further excited by photons and used to reduce NADP+ to NADPH. The path would start from PSII, go through the cytochrome complex, and end at PSI with the production of NADPH).
3.

Structure	What is happening with matter?	What is happening with energy?
Cytochrome complex	Electrons are passed through a series of protein carriers. Protons are pumped from the stroma into the thylakoid lumen.	Energy from the electron transfer is used to pump protons across the membrane, creating a proton - gradient.
PSI	Electrons are excited again by photons. NADP+ is reduced to NADPH using electrons and protons.	Light energy excites electrons in PSI, and this energy is used to drive the reduction of NADP+.

1. The light energy absorbed and converted by chlorophyll is stored as:

• Chemical energy in NADPH.
• Chemical energy in ATP (from the proton - gradient used in chemiosmosis to phosphorylate ADP to ATP).