Check For Understanding: Light-Dependent Reactions

What part of the plant cell performs photosynthesis?

• The Mitochondrion

• The Nucleus

• The Chloroplast

• The Cell Wall

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NGSS.HS-LS2-5

What does light do when it strikes the chlorophyll molecules of photosystems I and II?

• Light causes glucose to be synthesized directly inside the chlorophyll molecules of the photosystems.

• Light causes electrons to get excited (gain energy) and travel down the electron transport chain embedded in the thylakoid membrane.

• Light causes the conversion of water into carbon dioxide, oxygen, and electrons.

• Light directly causes carbon dioxide to attach to RuBP during the carbon fixation stage of the Calvin Cycle.

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NGSS.HS-LS1-5

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After light excites the electron and they leave Photosystem II to travel down the first electron transport chain, how are these electrons replaced to Photosystem II?

• Oxygen is reduced and the electrons are given to the chlorophyll molecules of photosystem II.

• Carbon dioxide is split, and the electrons are given to the chlorophyll molecules of photosystem II.

• Hydrogen undergoes fusion, and the electrons are given to the chlorophyll molecules of photosystem II.

• Water is split, and the electrons are given to the chlorophyll molecules of photosystem II.

The splitting of water at photosystem II is known as ____ and results in the production of _____.

• photosynthesis: carbon dioxide, G3P, and electrons that are given to photosystem II.

• photolysis: oxygen, hydrogen ions (protons), and electrons that are given to photosystem II.

• the Calvin cycle: carbon dioxide, G3P, and electrons that are given to photosystem II

• chemiosmosis: oxygen, hydrogen ions (protons), glucose and electrons that are given to photosystem II.

As the electrons travel from photosystem II down the first electron transport chain, their energy is used to….

• form oxygen, water, NADPH, and glucose.

• pump hydrogen ions into the stroma, producing a concentration gradient that will later be used by an enzyme to form ADP and phosphate.

• pump hydrogen ions into the thylakoid space, producing a concentration gradient that will later be used by ATP synthase to form ATP.

• create glucose directly.

Tags

NGSS.HS-LS1-5

Why do hydrogen ions flow from the thylakoid space to the stroma through ATP synthase?

• They are pumped actively through the ATP synthase. This uses ATP energy and causes the production of ADP and phosphate.

• They flow through the Calvin cycle and produce light.

• Hydrogen ions do not actually flow from the thylakoid space to the stroma. They flow the opposite way.

• They flow passively from the high to low concentration via facilitated diffusion. As they flow through ATP synthase, the enzyme spins and produces ATP.

After electrons get excited by light a second time (at photosystem I), where do they go?

• They travel down a second electron transport chain and are donated to ADP, which is then converted to ATP.

• They remain excited and then travel to photosystem II where they get even more excited until they spontaneously combust.

• They travel down a second electron transport chain and are donated to NADP+ which becomes NADPH (an electron carrier).

• They travel down a second electron transport chain and are donated to oxygen which then bonds to hydrogen ions to form water.

Tags

NGSS.HS-LS1-5