Chapter 6 - Where It Starts - Photosynthesis

Question 1

A cat eats a bird, which ate a caterpillar that chewed on a weed. Which organisms are autotrophs? Which ones are heterotrophs?

Answer 1

autotroph: weed
heterotroph: cat, bird, caterpillar

Question 2

Photosynthetic autotrophs use __________ from the air as a carbon source and __________ as their energy source.

Answer 2

carbon dioxide

sunlight

Question 3

Chlorophyll “a” appears green because it absorbs mainly ___________ light.

a. violet and red
b. green
c. yellow
d. Blue

Answer 3

a. violet and red

Question 4

Light-dependent reactions in plants proceed in the ____________.

a. thylakoid membrane
b. plasma membrane
c. stroma
d. cytoplasm

Answer 4

a. thylakoid membrane

Question 5

When a photosystem absorbs light, _____________.

a. sugar phosphates are produced
b. electrons are transferred to ATP
c. RuBP accepts electrons
d. electrons are ejected from its special pair

Answer 5

d. electrons are ejected from its special pair

Question 6

In the light-dependent reactions, _________.

a. carbon dioxide is fixed
b. ATP forms
c. sugars form
d. CO2 accepts electrons
e. b and c
f. a and c

Answer 6

b. ATP forms

Question 7

What accumulates inside the thylakoid compartment during the light-dependent reactions?

a. glucose
b. hydrogen ions
c. O2
d. CO2

Answer 7

b. hydrogen ions

Question 8

Light-dependent reactions in plants proceed in the ___________.

a. thylakoid membrane
b. plasma membrane
c. stroma
d. cytoplasm

Answer 8

c. stroma

Question 9

The Calvin-Benson cycle starts when ___________.

a. light is available
b. carbon dioxide is attached to RuBP
c. electrons leave a photosystem II

Answer 9

b. carbon dioxide is attached to RuBP

Question 10

Which of the following substances does not participate in the Calvin-Benson cycle?

a. ATP
b. NADPH
c. RuBP
d. PGAL
e. O2
f. CO2

Answer 10

e. O2

Question 11

In the light-independent reactions, ____________.

a. carbon dioxide is fixed
b. ATP forms
c. sugars form
d. CO2 accepts electrons
e. b and c
f. a and c

Answer 11

f. a and c

Question 12

Match each with its most suitable description.

\_\_\_\_ PGAL formation
\_\_\_\_ CO2 fixation 
\_\_\_\_ photolysis
\_\_\_\_ ATP forms; NADPH does not 
\_\_\_\_ photorespiration 
\_\_\_\_ photosynthesis
\_\_\_\_ pigment
\_\_\_\_ autotroph

a. absorbs light
b. converts light to chemical energy
c. self-feeder
d. electrons cycle back to photosystem I
e. problem in C3 plants
f. ATP, NADPH required
g. water molecules split
h. rubisco function

Answer 12

f
h
g
d
e
b
a
c