Biology Chapter 7

Question 1

What is photosynthesis?

Answer 1

A process used by plants, algae, and some bacteria to turn light energy (along with water and carbon dioxide) into chemical energy

Question 2

Producers

Answer 2

The organisms in a food chain that produce the energy used by the rest of the ecosystem

Question 3

Chloroplasts are

Answer 3

The site of photosynthesis, usually found in the interior cells of leaves.

Question 4

Chlorophyll

Answer 4

A light absorbing pigment critical to the process of photosynthesis

Question 5

Stomata

Answer 5

Tiny pores in leaves where carbon dioxide enters and oxygen exits.

Question 6

Simplified equation for photosynthesis

Answer 6

Carbon Dioxide + Water–(light energy)–>Glucose + Oxygen Gas

Question 7

What are the two stages of photosynthesis and what happens in each?

Answer 7

1. light reactions (convert solar energy to chemical energy)
2. Calvin Cycle (uses the products of light reactions to make sugar)

Question 8

Carbon Fixation

Answer 8

The incorporation of carbon from the atmosphere into organic compounds

Question 9

How does deforestation contribute to Global Warming (Climate Change)?

Answer 9

It reduces the amount of plants available to absorb carbon from the atmosphere (therefore raising the carbon levels in the atmosphere)

Question 10

Electromagnetic Spectrum

Answer 10

The full range of radiation

Question 11

What colors of light drive photosynthesis?

Answer 11

blue-violet and red-orange

Question 12

Photosystem

Answer 12

A cluster of a few hundred pigment molecules that function as a light-gathering antenna.

Question 13

Describe the advantages of biofuels over fossil fuels.

Answer 13

They are more efficient and they are renewable.

Question 14

Describe the structure of chloroplasts and indicate where the chlorophyll molecules are located. Explain how carbon dioxide and oxygen move in and out of leaves.

Question 15

Wavelength

Answer 15

The distance between the crests of two adjacent waves

Question 16

What colors of light are reflected and absorbed by an object that appears green?

Answer 16

Color is not a property that is inherent to objects, it is perceived by the colors of light that an object reflects.

An object that appears green would reflect green light, and absorb all other colors.

Question 17

Explain how Theodor Engelmann was able to determine that only certain wavelengths of light are used in photosynthesis.

Answer 17

Engellman performed an experiment where he placed freshwater algal cells and oxygen-sensitive bacteria on a slide, and then used a prism to separate the colors of the electromagnetic spectrum. He observed that the algae grew best in the red-orange and blue-violet parts of the spectrum/

Question 18

chlorophyll a

Answer 18

• absorbs mainly blue-violet and red light and
• participates directly in the light reactions.

Question 19

chlorophyll b

Answer 19

• absorbs mainly blue and orange light and
• participates indirectly in the light reactions.

Question 20

Carotenoids

Answer 20

• absorb mainly blue-green light,
• participate indirectly in the light reactions, and
• absorb and dissipate excessive light energy that might damage chlorophyll.

Question 21

Explain how the energy of photons is transferred within a photosystem.

Answer 21

• Electrons in the pigment gain energy.
• As the electrons fall back to their ground state, energy is released as heat or light.

Question 22

C3 plants

Answer 22

• use CO2 directly from the air and
• are very common and widely distributed.

Question 23

C4 Plants

Answer 23

• close their stomata to save water during hot and dry weather and
• can still carry out photosynthesis.

Question 24

CAM plants

Answer 24

• are adapted to very dry climates and
• open their stomata only at night to conserve water.