Lecture 3 - Photosynthesis

Question 1

Five major physiological processes of plants?

Answer 1

photosynthesis, respiration, transpiration, translocation of nutrients, nutrient uptake

Question 2

They produce their own food through photosynthesis

Answer 2

autotrophs

Question 3

what do you call the food of plants

Answer 3

glucose

Question 4

Where does photosynthesis mainly occur?

Answer 4

leaves

Question 5

True or False. Photosynthesis is the manufacture of sugars and its precursors by all plants in the presence of light and chlorophyll.

Answer 5

False.

Photosynthesis only happens in green plants.

Question 6

chemical equation for photosynthesis

Answer 6

6CO2 + 12 H2O –> C6H12O6 + 6O2 + 6H2O

Question 7

Carbon dioxide is taken from the air through the ____________

Answer 7

stomata

Question 8

Water is absorbed from the ____________ by the ___________ and is transported in the ____________ to sites of photosynthesis.

Answer 8

soil, roots, xylem

Question 9

______ of the total world’s photosynthetic output occurs in the oceans, and the remaining ________ by land plants. Among the land plants, about ________ is accounted for by forest and grasslands, while the remaining ________ by cultivated crops.

Answer 9

90%, 10%, 7-8%, 2-3%

Question 10

light energy (_______) + water (H2O) –> glucose

Answer 10

photons

Question 11

How many membranes does the chloroplast have? What is this called?

Answer 11

2, bi-layer

Question 12

Sub-organelles where photosynthesis takes place

Answer 12

thylakoids

Question 13

A stack of thylakoids is called ________?

Answer 13

granum / grana

Question 14

What is the space surrounding the grana?

Answer 14

stroma

Question 15

Found in the green internal organs of the chloroplast and embedded in the thylakoid membrane

Answer 15

chlorophyll molecules

Question 16

Chlorophyll acts like a light ________ and absorb energy from sunlight/solar radiation

Answer 16

antenna

Question 17

Leaf is an ideal organ for photosynthesis because:

1) its typically ________ form
2) its usually _________ angle to incident light
3) its __________ internal surface

Answer 17

expanded, perpendicular, extensive

Question 18

A typical mature mesophyll cell of higher plants contain about _________ chloroplasts

Answer 18

50

Question 19

True or False. Chlorophyll a is ALWAYS found in all plants, while chlorophyll b may be replaced by some other isomers in some plant species.

Answer 19

True

Question 20

Basic unit of the chlorophyll

Answer 20

porphyrin ring system

Question 21

The center of porphyrin is occupied by a single ___________ atom

Answer 21

magnesium

Question 22

Absorption of wavelength in the green region of the spectrum is (high / low) as green is typically ____________

Answer 22

low, reflected

Question 23

True or False. The Calvin Cycle is light-dependent.

Answer 23

False

Question 24

3 inputs from the environment required for photosynthesis to proceed

Answer 24

sunlight / visible light, CO2, water

Question 25

Photosynthesis is most efficient in the ___________ range (425-450 nm) and ___________ range (600-700 nm)

Answer 25

blue, red

Question 26

Describe how light energy is harvested by plants

Answer 26

light energy hits a chlorophyll molecule –> the energy from light is transferred from one chlorophyll molecule to another –> electron transfer to a primary electron acceptor

Question 27

Clusters of thylakoid membranes (with chlorophyll pigments) that harvest light energy

Answer 27

photosystem

Question 28

1 molecule of CO2 fixed / used to make glucose uses ______ ATP and _______ NADPH

Answer 28

3, 2

Question 29

Major enzyme involved in the fixation of carboxylation in the Calvin cycle

Answer 29

Rubisco

Question 30

True or False. Rubisco can function as carboxylase and oxygenase.

Answer 30

True

Question 31

the process wherein Rubisco acts as an oxygenase to produce 1 molecule of 3 PG and 1 molecule of CO2

Answer 31

photorespiration

Question 32

For MAXIMUM photosynthesis, we want Rubisco to act as a (carboxylase / oxygenase) always

Answer 32

carboxylase

Question 33

rate of photorespiration is stimulated by four factors:

______ light levels, ______ O2 levels, ______ CO2 levels, ______ temperatures

Answer 33

high, high, low, high

Question 34

photorespiration loses _____% of the carbon it takes from the Calvin cycle wasteful process

Answer 34

25%

Question 35

Photorespiration is a ________ process and is exhibited by C__ plants

Answer 35

wasteful, C3