Chapter 10

\(\begin{equation}\begin{array}{l}{\text { The light reactions of photosynthesis supply the }} \\ {\text { Calvin cycle with }} \\ {\text { (A) light energy. }} \\ {\text { (B) } \mathrm{CO}_{2} \text { and ATP. }} \\\ {\text { (C) } \mathrm{H}_{2} \mathrm{O} \text { and ATP. }} \\ {\text { (D) ATP and NADPH. }}\end{array} \end{equation}\)

Which of the following sequences correctly represents the flow of electrons during photosynthesis? \(\begin{equation}\begin{array}{l}{\text { (A) } \mathrm{NADPH} \rightarrow \mathrm{O}_{2} \rightarrow \mathrm{CO}_{2}} \\ {\text { (B) } \mathrm{H}_{2} \mathrm{O} \rightarrow \mathrm{NADPH} \rightarrow \text { Calvin cycle }} \\\ {\text { (C) } \mathrm{H}_{2} \mathrm{O} \rightarrow \text { photosystem I } \rightarrow \text { photosystem II }} \\ {\text { (D) } \mathrm{NADPH} \rightarrow \text { electron transport chain } \rightarrow \mathrm{O}_{2}}\end{array}\end{equation}\)

How is photosynthesis similar in C4 plants and CAM plants? (A) In both cases, only photosystem I is used. (B) Both types of plants make sugar without the Calvin cycle. (C) In both cases, rubisco is not used to fix carbon initially. (D) Both types of plants make most of their sugar in the dark.

Which of the following statements is a correct distinction between autotrophs and heterotrophs? (A) Autotrophs, but not heterotrophs, can nourish themselves beginning with CO2 and other nutrients that are inorganic. (B) Only heterotrophs require chemical compounds from the environment. (C) Cellular respiration is unique to heterotrophs. (D) Only heterotrophs have mitochondria.

Which of the following does not occur during the Calvin cycle? \begin{equation}\begin{array}{l}{\text { (A) carbon fixation }} \\ {\text { (B) oxidation of NADPH }} \\ {\text { (C) release of oxygen }} \\ {\text { (D) regeneration of the CO }_{2} \text { acceptor }}\end{array} \end{equation}

. In mechanism, photophosphorylation is most similar to \begin{equation}\begin{array}{l}{\text { (A) substrate-level phosphorylation in glycolysis. }} \\ {\text { (B) oxidative phosphorylation in cellular respiration. }} \\ {\text { (C) carbon fixation. }} \\ {\text { (D) reduction of NAD\(\mathrm{P}^{+}\). }}\end{array}\end{equation}

Which process is most directly driven by light energy? \begin{equation} \begin{array}{l}{\text { (A) creation of a pH gradient by pumping protons across the }} \\ {\text { thylakoid membrane }} \\ {\text { (B) reduction of NAD\(\mathrm{P}^{+}\) molecules }} \\ {\text { (C) transfer of energy from pigment molecule to pigment }} \\ {\text { molecule }} \\ {\text { (D) ATP synthesis }} \end{array} \end{equation}

WRITE ABOUT A THEME: ENERGY AND MATTER Life is solar powered. Almost all the producers of the biosphere depend on energy from the sun to produce the organic molecules that supply the energy and carbon skeletons needed for life. In a short essay \((100-150\) words), describe how the process of photosynthesis in the chloroplasts of plants transforms the energy of sunlight into the chemical energy of sugar molecules.

"Watermelon snow" in Antarctica is caused by a species of photosynthetic green algae that thrives in subzero temperatures (Chlamydomonas nivalis). These algae are also found in high-altitude year-round snowfields. In both locations, UV light levels tend to be high. Based on what you learned in this chapter, propose an explanation for why this photosynthetic alga appears reddish-pink.