Light and Photosynthesis

Question 1

What is photosynthesis?

Answer 1

The process used by plants to produce all their own organic substances using only light energy and simple inorganic substances.

Question 2

What does photosynthesis involve?

Answer 2

The conversion of light energy into chemical energy.

Question 3

Where does photosynthesis occur?

Answer 3

In the plant’s chloroplasts.

Question 4

What does photosynthesis consist of?

Answer 4

Light-dependent and light-independent reactions.

Question 5

What organic compounds are produced in the light independent reactions?

Answer 5

Glucose and amino acids (and some others)

Question 6

What organic compounds are produced from light-dependent reactions?

Answer 6

“Intermediate compounds” that are used in light-dependent reactions

Question 7

When are intermediate compounds used up?

Answer 7

In the dark.

Question 8

What is a spectrum?

Answer 8

A range of wavelengths of electromagnetic radiation.

Question 9

What is the spectrum of light?

Answer 9

The range of wavelengths from 400nm-700nm.

Question 10

Which wavelength has the lowest energy?

Answer 10

Red, at 700-750nm.

Question 11

Which wavelength has the highest energy?

Answer 11

Purple, at 350-400nm.

Question 12

In photosynthesis, what is efficiency?

Answer 12

The percentage of light of a wavelength that is used in photosynthesis.

Question 13

What is the action spectrum?

Answer 13

A graph that profiles the relative effectiveness of different wavelengths of radiation in driving a particular process.

Question 14

According to the action spectrum graph, what colors of light are used the most efficiently?

Answer 14

Violet and blue (400-425)

Question 15

According to the action spectrum graph, what color of light is used least efficiently?

Answer 15

Green and yellow (525-625)

Question 16

What colors of light are mediocre at efficiency in photosynthesis?

Answer 16

Orange and red (625-700).

Question 17

What is the main photosynthetic pigment?

Answer 17

Chlorophyll

Question 18

What kinds of light are reflected rather than absorbed?

Answer 18

Green and yellow

Question 19

What are pigments?

Answer 19

Substances that absorb light of different wavelengths such as chlorophyll a and b.

Question 20

What does chlorophyll a do in light reactions?

Answer 20

Directly participates and absorbs violet-blue light and red light.

Question 21

What do accessory pigments chlorophyll b, carotene, and xanthophylls do?

Answer 21

They broaden the amount of good light colors that can be absorbed and use for photosynthesis.

Question 22

What is the main difference between the graphs of absorption and action?

Answer 22

Absorption shows little green-yellow light absorbed by chloroplasts.
Action shows some green-yellow light absorbed BECAUSE of carotene and xanthophylls.

Question 23

Where are pigments found?

Answer 23

In photosystems two and one, within proteins found in the thylakoid membrane.