Chapter 10: Photosynthesis

These flashcards cover the fundamental processes of photosynthesis including the light reactions, the Calvin cycle, chloroplast structure, and the differences between C3, C4, and CAM plants.

How is photosynthesis defined in terms of energy conversion?

The process of converting light energy (kinetic) into energy stored in the covalent bonds of glucose molecules (potential).

What is the summary chemical equation for photosynthesis?

$$6\text{CO}_2 + 6\text{H}_2\text{O} \rightarrow \text{C}_6\text{H}_{12}\text{O}_6 + 6\text{O}_2$$

Which sea slug is noted for stealing photosynthesis genes from algae?

Elysia chlorotica

What are the two main stages of photosynthesis?

The Light Reactions and the Calvin Cycle.

Identify the inner fluid of the chloroplast and the folded membrane stacks within it.

The inner fluid is the stroma, and the stacks of thylakoid membranes are called grana (singular: granum).

What are photons?

Mass-less particles that travel in a wave-like pattern at the speed of light, each possessing a specific energy level.

According to Theodor Engelmann's 1883 experiment, which colors of light drive the most photosynthesis?

Red and blue light.

Where are photosynthetic pigments located within the chloroplast?

In the thylakoid membranes.

What is the primary difference in the porphyrin ring structure between chlorophyll a and chlorophyll b?

Chlorophyll a has a $-CH_3$ group, while chlorophyll b has a $-CHO$ group.

What are the two components found in every photosystem?

1. Light harvesting complexes (pigments and proteins) and 2. A reaction center (special pair of chlorophyll a molecules and a primary electron acceptor).

What are the specific names for the chlorophyll a pairs in Photosystem II and Photosystem I?

Photosystem II contains P680, and Photosystem I contains P700.

In the light reactions, what is the role of water splitting?

It provides 2 electrons to replace those lost by P680, releasing $2\text{H}^+$ and $\frac{1}{2}\text{O}_2$ as byproducts.

What are the three components of the electron transport chain between PSII and PSI?

Plastoquinone (Pq), the Cytochrome complex, and Plastocyanin (Pc).

What is the final electron acceptor in the noncyclic electron flow of the light reactions?

$\text{NADP}^+$ (which is reduced to NADPH by $\text{NADP}^+$ reductase).

What is the function of cyclic electron flow?

It generates extra ATP to satisfy the Calvin cycle's higher demand for ATP compared to NADPH, without producing oxygen or NADPH.

Where does the Calvin cycle take place?

In the stroma of the chloroplast.

What are the three phases of the Calvin cycle?

1. Carbon fixation, 2. Carbon reduction, and 3. Regeneration of the $\text{CO}_2$ acceptor (RuBP).

Which enzyme is responsible for attaching $\text{CO}_2$ to Ribulose bisphosphate (RuBP)?

RUBISCO

What are the energy requirements for the net synthesis of one G3P sugar molecule in the Calvin cycle?

9 ATP and 6 NADPH.

How do C4 plants minimize photorespiration in hot, dry weather?

They use spatial separation: $\text{CO}_2$ is fixed into a 4-carbon molecule in mesophyll cells and then moved to bundle-sheath cells where the Calvin cycle occurs.

How do CAM plants differ from C3 and C4 plants regarding their stomata?

CAM plants open their stomata only at night to take up $\text{CO}_2$ and keep them closed during the day to conserve water.