Chapter 7 Key Terms

Question 1

The second of two stages of photosynthesis; a cyclic series of chemical reactions that occur in the stroma of a chloroplast, using the carbon in CO2 and the ATP and NADPH produced by the light reactions to make the energy-rich sugar molecule G3P, which is later used to produce glucose.

Answer 1

Calvin Cycle

Question 2

The initial incorporation of carbon from CO2 into organic compounds by autotrophic organisms such as photosynthetic plants, algae, or bacteria.

Answer 2

Carbon Fixation

Question 3

A light-absorbing pigment in chloroplasts that plays a central role in converting solar energy to chemical energy.

Answer 3

Chlorophyll

Question 4

An organelle found in plants and photosynthetic protists. Enclosed by two membranes, a chloroplast absorbs sunlight and uses it to power the synthesis of organic food molecules (sugars).

Answer 4

Chloroplast

Question 5

A stack of hollow disks formed of thylakoid membrane in a chloroplast. Grana are the sites where light energy is trapped by chlorophyll and converted to chemical energy during the light reactions of photosynthesis.

Answer 5

Granum

Question 6

The first of two stages in photosynthesis; the steps in which solar energy is absorbed and converted to chemical energy in the form of ATP and NADPH. The light reactions power the sugar-producing Calvin cycle but produce no sugar themselves.

Answer 6

Light Reactions

Question 7

An electron carrier (a molecule that carries electrons) involved in photosynthesis. Light drives electrons from chlorophyll to NADP+, forming NADPH, which provides the high-energy electrons for the reduction of carbon dioxide to sugar in the Calvin cycle.

Answer 7

NADPH

Question 8

The process by which plants, algae, and some bacteria transform light energy to chemical energy stored in the bonds of sugars. This process requires an input of carbon dioxide (CO2) and water (H2O) and produces oxygen gas (O2) as a waste product.

Answer 8

Photosynthesis

Question 9

A light-harvesting unit of a chloroplast’s thylakoid membrane; consists of several hundred molecules, a reaction-center chlorophyll, and a primary electron acceptor.

Answer 9

Photosystem

Question 10

A thick fluid enclosed by the inner membrane of a chloroplast. Sugars are made in the ____ by the enzymes of the Calvin cycle.

Answer 10

Stroma

Question 11

One of a number of disk-shaped membranous sacs inside a chloroplast. Thylakoid membranes contain chlorophyll and the enzymes of the light reactions of photosynthesis. A stack of thylakoids is called a granum.

Answer 11

Thylakoid