Question

Which of the following describes the steps of photosystem II and electron transport chain II in terms of energy conversions?

- Kinetic energy from sunlight is converted into potential energy in an electron. The potential energy of the electron is converted to potential energy in NADPH.
- Potential energy from the sun is converted into potential energy in an electron. The potential energy of the electron is converted to potential energy in NADPH.
- Kinetic energy from sunlight is converted into potential energy in an electron. This then is converted to kinetic energy by pumping hydrogen ions. The kinetic energy of the ions flowing back through the membrane is converted to potential energy in ATP.
- Potential energy from sunlight is converted into potential energy in an electron. This then is converted to kinetic energy by pumping hydrogen ions. The kinetic energy of the ions flowing back through the membrane is converted to potential energy in NADPH.
- Kinetic energy from sunlight is converted into kinetic energy in an electron. This then is converted to potential energy in ATP.
- Kinetic energy from sunlight is converted to potential energy by pumping hydrogen ions. The kinetic energy of the ions flowing back through the membrane is converted to kinetic energy in ATP.

Answer 1

The steps in photosystem II and the electron transport chain begin with kinetic energy from sunlight that is converted into potential energy in an electron. This potential energy is used to create an electrochemical gradient that ultimately generates ATP, and the electrons are also used to produce NADPH.

Step-by-step explanation:

The steps of photosystem II and the electron transport chain in plants involve several energy conversions. The process begins with kinetic energy from sunlight which is converted into potential energy in an electron during photosystem II. As the electrons are transferred along the electron transport chain, their energy is used to pump hydrogen ions into the thylakoid lumen, creating an electrochemical gradient. This gradient is then utilized by ATP synthase to convert the kinetic energy of the ions flowing back through the membrane into potential energy, synthesizing ATP in a process known as photophosphorylation. In photosystem I, the electrons are re-energized by sunlight and used to reduce NADP+ to NADPH, another form of potential energy used by the plant.