Lecture 3 - Photosynthesis Flashcards
Five major physiological processes of plants?
photosynthesis, respiration, transpiration, translocation of nutrients, nutrient uptake
They produce their own food through photosynthesis
autotrophs
what do you call the food of plants
glucose
Where does photosynthesis mainly occur?
leaves
True or False. Photosynthesis is the manufacture of sugars and its precursors by all plants in the presence of light and chlorophyll.
False.
Photosynthesis only happens in green plants.
chemical equation for photosynthesis
6CO2 + 12 H2O –> C6H12O6 + 6O2 + 6H2O
Carbon dioxide is taken from the air through the ____________
stomata
Water is absorbed from the ____________ by the ___________ and is transported in the ____________ to sites of photosynthesis.
soil, roots, xylem
______ 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.
90%, 10%, 7-8%, 2-3%
light energy (_______) + water (H2O) –> glucose
photons
How many membranes does the chloroplast have? What is this called?
2, bi-layer
Sub-organelles where photosynthesis takes place
thylakoids
A stack of thylakoids is called ________?
granum / grana
What is the space surrounding the grana?
stroma
Found in the green internal organs of the chloroplast and embedded in the thylakoid membrane
chlorophyll molecules
Chlorophyll acts like a light ________ and absorb energy from sunlight/solar radiation
antenna
Leaf is an ideal organ for photosynthesis because:
1) its typically ________ form
2) its usually _________ angle to incident light
3) its __________ internal surface
expanded, perpendicular, extensive
A typical mature mesophyll cell of higher plants contain about _________ chloroplasts
50
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.
True
Basic unit of the chlorophyll
porphyrin ring system
The center of porphyrin is occupied by a single ___________ atom
magnesium
Absorption of wavelength in the green region of the spectrum is (high / low) as green is typically ____________
low, reflected
True or False. The Calvin Cycle is light-dependent.
False
3 inputs from the environment required for photosynthesis to proceed
sunlight / visible light, CO2, water
Photosynthesis is most efficient in the ___________ range (425-450 nm) and ___________ range (600-700 nm)
blue, red
Describe how light energy is harvested by plants
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
Clusters of thylakoid membranes (with chlorophyll pigments) that harvest light energy
photosystem
1 molecule of CO2 fixed / used to make glucose uses ______ ATP and _______ NADPH
3, 2
Major enzyme involved in the fixation of carboxylation in the Calvin cycle
Rubisco
True or False. Rubisco can function as carboxylase and oxygenase.
True
the process wherein Rubisco acts as an oxygenase to produce 1 molecule of 3 PG and 1 molecule of CO2
photorespiration
For MAXIMUM photosynthesis, we want Rubisco to act as a (carboxylase / oxygenase) always
carboxylase
rate of photorespiration is stimulated by four factors:
______ light levels, ______ O2 levels, ______ CO2 levels, ______ temperatures
high, high, low, high
photorespiration loses _____% of the carbon it takes from the Calvin cycle wasteful process
25%
Photorespiration is a ________ process and is exhibited by C__ plants
wasteful, C3
