Presentation on theme: "2 01 91 81 71 61 51 41 31 21 0 91 00 80 70 60 50 40 30 20 1 Do all organisms require sunlight to carry out life processes? If not, what do all organisms."— Presentation transcript:
Do all organisms require sunlight to carry out life processes? If not, what do all organisms require? 0 No! All organisms require energy!
Can animals that eat only other animals and no plants still use carbs for energy? 0 You bet!
What molecule is the source of energy for chemical reactions in cells? 0 ATP
What is a biochemical pathway? 0 Series of linked reactions; products of one are used as reactants in the next
Is ATP a stable molecule? 0 NO… phosphate groups are all negatively charged and repel one another
What type of pigment is the major light-absorbing pigment in plants? 0 chlorophyll
Differentiate autotrophs and hetertrophs. Give an example of each. 0 Autotrophs – use sun/inorganic compounds to produce organic compounds; plants Heterotrophs – consume organic compounds; animals, fungi
Why is chlorophyll green? 0 It reflects green light
Why is the sun considered the ultimate energy source for life on Earth? 0 Almost all organisms depend on it directly or indirectly for energy.
What is the role of chlorophyll? 0 To absorb light
Describe the structure of a chloroplast. 0 Its surrounded by two membranes; has a system of membranes inside called thylakoids; stacks of thylakoids = grana; fluid around grana = stroma
What can happen when light strikes an object? 0 It can be reflected, transmitted, or absorbed.
Do plant pigments absorb all wavelengths of light? 0 No… only some wavelengths are absorbed.
What is a photosystem? 0 A cluster of 100s of pigment molecules and proteins
Where are photosystems located? 0 Theyre embedded in the thylakoid membrane.
What happens to light when it hits plant pigments? 0 Its either absorbed or reflected.
Why is NADP + important in photosynthesis? 0 Its needed to make NADPH for the Calvin cycle. It can provide protons and electrons for reactions in the form of H.
Plant cells use light to make what energy storage molecules? 0 ATP and NADPH
What happens to electrons of chlorophyll a molecules when they are raised to a higher energy level? 0 They go to the P.E.A.
What happens to chlorophyll a molecules when they absorb light energy? 0 They lose electrons.
What is the source of the oxygen produced in photosynthesis? 0 Photolysis (water splitting)
What is chemiosmosis responsible for? 0 Providing energy for phosphorylation
What is the phosphorylation reaction that occurs? 0 ADP + PO 4 - ATP
What three things does the proton gradient in the light reaction depend upon? 0 1.Photolysis 2.H+ being pumped into the thylakoid 3.Structure of chloroplasts (thylakoid membrane is semi-permeable)
What product from the light reaction provides the energy for the Calvin cycle? What product shuttles p + and e - ? 0 ATP; NADPH
What happens to the electrons at the thylakoid membrane in terms of energy? 0 Lose energy (return to original state) as they move along ETC
Where do the replacement electrons come from for PS I? 0 PS II
Where do the replacement electrons come from for PS II? 0 Photolysis (splitting of water)
Trace the pathway of electrons from PS II. 0 PS II PEA ETC PS I
Trace the pathway of electrons from PS I. 0 PS I PEA ETC stroma combine with NADP + and H + to form NADPH
Where do the light reactions occur? 0 In the thylakoids
What are our names for the three phases of the Calvin cycle? 0 Carbon fixation, carbon reshuffling, and regeneration
What is removed from ATP to release energy? 0 a PO 4 - group
How many total ATP molecules are needed in the Calvin cycle if 3 CO 2 molecules are used? 0 9 (6 needed in reshuffling phase and 3 needed in the regeneration phase)
Where does the energy that drives the Calvin cycle come from? 0 Light reactions: ATP and NADPH - which provides e -
What molecules does the Calvin cycle require? Does the cycle require light? 0 Requires: ATP for energy, NADPH for protons and electrons, and CO2 for a carbon source It doe not require light!
Where does the Calvin cycle occur? 0 In the stroma
Whats another name for PGAL? 0 G3P
If 3 CO 2 molecules enter the Calvin cycle, how many PGALs are made? How many PGALs remain in the cycle and are converted back into RuBP? 0 6 are made; 5 remain
What products can be produced from the PGAL that leaves the Calvin cycle? 0 Glucose; but also lipids and amino acids to build proteins
Why is NADPH needed in the Calvin cycle? In which phase is it used? 0 To make PGAL; used in carbon reshuffling
During the Calvin cycle, what are the carbon-containing molecules produced from? 0 CO 2 from the air, H from NADPH and RuBP
How many carbon atoms does PGAL have? How many PGALs then are needed to make 1 glucose? 0 PGAL has 3 carbons therefore 2 are needed to make a 6 carbon glucose
Only 1 PGAL leaves the Calvin cycle. What happens to the others? What molecule results? 0 Remain in the cycle for regeneration phase; resulting molecule is RuBP
How does the amount of water used by C4 and CAM plants compare to the amount used by C3 plants? 0 They use less water than C3 plants.
When do CAM plants have their stomata open? How does this compare to C3 and C4 plants? 0 CAM stomata are open at night while C3 and C4 stomata open during the day.
Does the light reaction depend upon light? Does the Calvin cycle? 0 Yes! No!
What is the final overall product that plants make in photosynthesis? 0 Glucose (from PGAL)
Do plants need light to carry out the reactions that generate ATP and NADPH? 0 Yes – these products are made in the light reactions!
What does the rate of photosynthesis depend upon? 0 CO 2 levels; temperature; light intensity
Define photosynthesis. 0 A biochemical pathway that converts light energy into organic compounds
What is the chemical equation for photosynthesis? 0 6CO 2 + 6H 2 O + light C 6 H 12 O 6 + 6O 2
What can the carbon atoms in all organic molecules be traced back to? 0 CO 2 from the atmosphere
In which stage of photosynthesis are carbohydrates produced? 0 Calvin cycle
What major byproduct of photosynthesis is released into the atmosphere? 0 oxygen