Chapter 10 Questions Flashcards
What are the reactants and products of photosynthesis?
6CO2 + 6H2O + Light energy —> C6H12O6 + 6O2
How does photosynthesis relate to cellular respiration? (see figure 9.2)
the net reaction for photosynthesis is essentially the reverse of the net reaction for cellular respiration
What cellular location does photosynthesis take place?
Leaves - chloroplasts
Which types of organisms undergo photosynthesis?
plants, algae, and some bacteria
Does photosynthesis rely on redox reactions? If so, what is being oxidized and what is being reduced in the overall equation for photosynthesis?
Yes
oxidation of H2O and the reduction of CO2
How does CO2 enter and O2 exit from plant leaves?
through microscopic pores called stomata
What are the two major locations inside chloroplasts?
Stroma and thylakoids
What are the two reactions that carry out photosynthesis?
Light Reactions and Calvin cycle
What is the wavelength range for visible light?
380-750 nm wavelengths
If chlorophyll appears green, which colors of the visible spectrum are being absorbed and which are being transmitted?
chlorophyll reflects and transmits green light
Which colors of the visible spectrum are mainly being used to fuel photosynthesis?
violet-blue and red light
Which colors of the visible spectrum are not being used for photosynthesis?
Green
What is the primary photosynthetic pigment in green plants?
chlorophyll a
What are the accessory pigments we talked about during class?
chlorophyll b and carotenoids
What is the purpose of having accessory pigments?
to broaden the amount of light that can be harnessed to fuel photosynthesis
Know how to read an absorption spectrum to determine which colors are being absorbed and which are being transmitted
An absorption spectrum is a graph plotting a pigment’s light absorption versus wavelength
How does the action spectrum for photosynthesis compare to the absorption spectrum for photosynthesis?
An action spectrum profiles the relative effectiveness of different wavelengths of radiation in driving a process (figure b)
What happens to the electrons in a solution of chlorophyll (i.e. chlorophyll that is outside of a cell) when they are excited by UV radiation?
When excited electrons fall back to the ground state, photons are given off, an afterglow called fluorescence
What happens to the electrons in chlorophyll that are found in intact plant cells once they become excited? (i.e. would chlorophyll molecules that are found in living cells fluorescence when exposed to UV radiation?)
If illuminated, an isolated solution of chlorophyll will fluoresce, giving off light and heat
Which specific location do light reactions take place?
in the thylakoids of chloroplasts
What are the requirements for light reactions?
Photosystems II and I H2O Light energy ADP and 3 Pi NADP+ NADP+ reductase
What are the products of light reactions?
O2
ATP
NADPH
What is the basic structure of photosystems?
consists of a reaction-center complex (a type of protein complex) surrounded by light-harvesting complexes
What are the two photosystems used during the light reactions?
Photosystem II
Photosystem I
Which photosystem absorbs light?
Photosystem II
Which photosystem uses H2O?
Photosystem II
Which photosystem produces the electrons that are used to make ATP?
Photosystem II
What two processes are carried out to make ATP during the light reactions)
photophosphorylation
chemiosmosis
Which photosystem provides the electrons that will be used to make NADPH?
Photosystem I
What is the structural and functional difference between NADH and NADPH?
NADP+ is reduced to NADPH (electron carrier for anabolic processes)
NADPH has a phosphate group attached to its 2 carbon
Which photosystem functions first during the light reactions?
photosystem II
Which photosystem functions second during the light reactions?
photosystem I
Compare the process of chemiosmosis for photosynthesis vs cellular respiration:
- -What is the source of energy for each?
- -Where are the hydrogen protons pumped from and where are they pumped to for each?
- -What process causes the pumping of hydrogen protons?
- -Which enzyme is used to make the ATP for both processes?
—Chloroplasts - light energy into chemical energy of ATP. Mitochondrion - chemical energy from food to ATP
–In mitochondria, protons are pumped to the intermembrane space and drive ATP synthesis as they diffuse back into the mitochondrial matrix
In chloroplasts, protons are pumped into the thylakoid space and drive ATP synthesis as they diffuse back into the stroma
Which specific location do these reactions (Calvin cycle light independent reactions) take place?
in the stroma chloroplasts
What are the requirements for these light independent reactions?
CO2
ATP
NADPH
What are the products of light independent reactions in Calvin cycle
Glyceraldehyde 3-phosphate (C3H6O3); two combine to form glucose
ADP + Pi
NADP+
To obtain a net gain of one G3P It takes:
Three turns of the cycle (three CO2 molecules)
6 ATP
6 NADPH
The other five G3P molecules are then phosphorylated to reform three molecules of the CO2 acceptor (RuBP)
If it takes two molecules of G3P to make one molecule of glucose, how many turns of the Calvin cycle are required to make one molecule of glucose?
6
