Photosynthesis

Question 1

CAM plants

Answer 1

An adaptation for photosynthesis in arid conditions, first discovered in the family Crassulaceae. In this process, a plant takes up CO2 and incorporates it into a variety of organic acids at night; during the day, CO2 is released from organic acids for use in the Calvin cycle.

Question 2

C3 plants

Answer 2

A plant that uses the Calvin cycle for the initial steps that incorporate CO2 into organic material, forming a three-carbon compound as the first stable intermediate.

Question 3

C4 plants

Answer 3

A plant that prefaces the Calvin cycle with reactions that incorporate CO2 into four-carbon compounds, the end product of which supplies CO2 for the Calvin cycle.

Question 4

Photorespiration

Answer 4

A metabolic pathway that consumes oxygen, releases carbon dioxide, generates no ATP, and decreases photosynthetic output; generally occurs on hot, dry, bright days, when stomata close and the oxygen concentration in the leaf exceeds that of carbon dioxide.

Question 5

Chemiosmosis

Answer 5

an energy-coupling mechanism that uses energy stored in the form of a hydrogen ion gradient across a membrane to drive cellular work

Question 6

Photophosphorylation

Answer 6

the process of generating ATP from ADP and phosphate by means of chemiosmosis

Question 7

Linear electron flow

Answer 7

A route of electron flow during the light reactions of photosynthesis that involves both photosystems (I and II) and produces ATP, NADPH, and O2. The net electron flow is from H2O to NADP+.

Question 8

carbon fixation

Answer 8

the initial incorporation of carbon from CO2 into an organic compound by an autotrophic organism

Question 9

Photosynthesis

Answer 9

the conversion of light energy to chemical energy that is stored in sugars or other organic compounds; occurs in plants and algae, some prokaryotes

Question 10

Calvin Cycle

Answer 10

reactions of photosynthesis in which energy from ATP and NADPH is used to build high-energy compounds such as sugars

Question 11

Photosystem I

Answer 11

One of two light-harvesting units of a chloroplast’s thylakoid membrane; it uses the P700 reaction-center chlorophyll

Question 12

Photosystem II

Answer 12

A photosystem that contains a pair of P680 chlorophyll molecules and uses absorbed light energy to split water into protons and oxygen and to produce ATP.

Question 13

Light reaction

Answer 13

reactions of photosynthesis that use energy from light to produce ATP and NADPH

Question 14

autotrophs

Answer 14

an organism that makes its own food

Question 15

heterotroghs

Answer 15

an organism that cannot make its own food

Question 16

Mesophyll

Answer 16

the tissue in the interior of the leaf

Question 17

Stomata

Answer 17

microscopic pores in the leaf

Question 18

Stroma

Answer 18

fluid portion of the chloroplast; outside of the thylakoids

Question 19

Thylakoids

Answer 19

A flattened membrane sac inside the chloroplast, used to convert light energy into chemical energy.

Question 20

Granum

Answer 20

The stacks of thylakoids embedded in the stroma of a chloroplast.

Question 21

chloroplast

Answer 21

organelle that absorbs sunlight and uses it to drive the synthesis of organic compounds from carbon dioxide and water

Question 22

wavelengh

Answer 22

the distance between crests of waves, such as those of the electromagnetic spectrum

Question 23

visible light

Answer 23

Electromagnetic radiation that can be seen with the unaided eye

Question 24

photons

Answer 24

discrete particles of light

Question 25

Chlorophyll

Answer 25

Only pigment that can participate directly in the light reactions.

Question 26

Chlorophyll A

Answer 26

A type of blue-green photosynthetic pigment that participates directly in the light reactions.

Question 27

Chlorophyll B

Answer 27

A type of yellow-green accessory photosynthetic pigment that transfers energy to chlorophyll A.

Question 28

Carotenoids

Answer 28

An accessory pigment, either yellow or orange, in the chloroplasts of plants. By absorbing wavelengths of light that chlorophyll cannnot.