Ch. 8 Flashcards
What is the balanced equation for photosynthesis?
6CO2 + 6H2O –> C6 H12 O6 + 6O2
What is the balanced equation for cellular respiration?
C6 H12 O6 + 6O2 –> 6CO2 + 6H2O
What are autotrophs?
“self-feeders”; capable of making their own food
capable of utilizing photosynthesis
What are heterotrophs?
“other-feeders”; must consume other organisms for consumption
What is the mesophyll?
- leaf cells specialized for photosynthesis
- allows CO2 to diffuse into the plant and O2 to diffuse out
What are stomata?
- pores on the surfaces of leaves
- take in CO2 and release O2
What substances are leaving through leaf openings?
O2 and water
What substances are entering leaf openings?
CO2
What are chloroplasts?
sites of photosynthesis in plant cells
What are thylakoids?
flattened sacs within the chloroplast responsible for converting sunlight to chemical energy during photosynthesis
What is the stroma?
the dense fluid surrounding the thylakoid membrane and is involved in the synthesis of organic molecules from CO2 and H2O
What are grana?
individual stacks of thylakoid discs that function in the light reactions of photosynthesis
How many membranes surround the chloroplast?
2
What are the 2 major stages of photosynthesis?
light reactions and the Calvin Cycle (dark reactions)
What is required and made in light reactions?
H2O is required, O2 is made
What is required and made in the Calvin Cycle?
CO2 is required, CH2O is made
What is the wavelength range for visible light?
380-750 nm
What is a photon?
a particle of light energy that comes from the sun
What are pigments?
proteins that, in plants, are responsible for absorbing sunlight during photosynthesis
Where are pigments found in plants?
the thylakoids of chloroplasts
How is color perception determined?
which colors are absorbed by pigments and which ones are reflected
What is chlorophyll a?
- the prodominant pigment found in green plants
- reflects the color blue-green
What is chlorophyll b?
- a workhorse for chlorophyll a
- reflects the color green-yellow
What are carotenoids?
- another workhorse for chlorophyll a
- reflects the color orange
What happens when pigments absorb photons?
electrons in the chlorophyll get excited
What are photosystems?
- light-capturing units found in the thylakoid
- consist of a reaction-center complex surrounded by light-harvesting complexes
What are the two types of photosystems?
photosystems I and II
What substance is required in light reactions?
water b/c it acts as a source of electrons
How do electrons travel in non-cyclic pathways?
shuttled through the linear flow of electrons
What is required in PSII in order to produce NADPH?
more sunlight
What is chemiosmosis?
the process of hydrogen ions (protons) moving through ATP synthase
How many atoms of carbon does RuBP have?
5
What is rubisco?
the enzyme responsible for combining RuBP w/ CO2
What is required to convert 3PGA to G3P?
6 ATP, 6 NADPH
What role does G3P play in the making of RuBP?
the molecules that stay in the cycle are formed back into RuBP, requiring ATP
What is carbon fixation?
first stage of the Calvin Cycle that forms sugar and other organic compounds for energy
What is reduction?
second stage of the Calvin Cycle where energy is obtained from ATP and NADPH formed during the light reactions
What is regeneration?
third stage of the Calvin Cycle where some G3P molecules are used to produce glucose, while others are recycled to regenerate the RuBP acceptors
What occurs when RuBP is not available?
photorespiration
What is photorespiration?
a metabolic pathway that consumes O2 and ATP, releases CO2, and decreases photosynthetic output
What are the 3 types of photosynthesis in plants?
C3, C4, CAM
What are C3 plants?
- accounts for majority of plants
- have no special features to combat photorespiration
“normal” plants, stomata open day, cool, wet environments
What are C4 plants?
- minimize photorespiration by separating initial CO2 fixation and the Calvin Cycle
- performs these steps in different cells
bundle-sheath cells, stomata open day, hot, sunny environment
What are CAM plants?
- Crassulacean acid metabolism
- minimize photorespiration and save water by separating steps between night and day
different time, stomata open night, very hot, dry environment
