1. Bill Nye: Plants
Open-notes Quizzie

2. 1. Plants make _________ & _________ for animals (and other organisms).
2. Plants convert the sun’s light energy into __________ (type of energy).
3. Carbon dioxide is made of what 2 elements?
4. What does the word “photosynthesis” mean?

3. 5. ________ is the green chemical found in leaves that traps light for photosynthesis
6. EXPLAIN one way plants have to disperse seeds.
7. EXPLAIN one adaptation desert plants have for living in this environment.
8. What biological process puts some of the carbon dioxide necessary for photosynthesis into the atmosphere?

4. 9. In addition to carbon dioxide, what other 2 things are needed for plants to do photosynthesis?
10. Explain one SPECIFIC medicinal use of plants.

5. Where does the mass come from?

6. Photosynthesis
Ch. 8

7. Photosynthesis 6CO2 + 6H2O --(light) C6H12O6 + 6O2
Carbon + water  glucose + oxygen
Dioxide

8. Anabolic vs catabolic reactions
Catabolic processes
break down molecule
release energy
Anabolic processes
construct molecules
require input of energy
Is photosynthesis catabolic or anabolic? What about respiration?

9. Leaves CO2 enters and O2 exits through stomata
water travels through veins
Leaves contain the most chloroplasts
Concentrated in the mesophyll

10. Chloroplasts – where PS takes place
Thylakoids are suspended in the stroma of the chloroplast

11. Chlorophyll – plant pigment
Absorbs light
Chlorophyll a is the most important
Also have accessory pigments
Pigments are bundled in photosystems in the thylakoid membrane

12. Photosynthesis Two sets of reactions:
Light reactions: Light dependent reactions
Calvin cycle: Light independent reactions
The light reactions make the materials needed for the light independent reactions!

13. Two steps of photosynthesis

14. Light energy  chemical energy
A molecule of water is split, releasing an electron
Electron is passed to chlorophyll a in photosystem II
Light energy “excites” the electron

15. Light energy  chemical energy
PS II passes its electron to the electron transport chain

16. Light reactions Energy from the chain is used to make ATP
Electron is passed to photosystem I

17. Light reactions Photosystem I re-excites electron
Electron bonds to a NADP+ creating a NADPH
ATP and NADPH are used to power the Calvin cycle

18. The _____________ reactions occur in the ______________ membrane
The _____________ reactions occur in the ______________ membrane. It begins with splitting a _____________ molecule to release an electron. The electron is grabbed by a ______________ in photosystem _______. The electron is excited by the energy from ____________. The electron is passed to an _________ _________ chain, where its energy is used to make _________. The electron is grabbed by a pigment in photosystem _________ where it is ___________ again by light. A molecule of _________ picks up the excited electron becoming _________. The two high energy molecules, __________ & ___________, leave the thylakoid membrane to go to the next step, the _______________ _______________.

19. Light dependent reactions
Take place in the thylakoid membrane
The photosystems absorb light energy; electrons will travel from:
Photosystem II
Electron transport chain
Photosystem I

20. Calvin Cycle – Light independent reactions

21. The Calvin Cycle Takes in 3 molecules of carbon dioxide
Where does CO2 comes from?
The energy in ATP and electrons in NADPH turns the 3CO2 into a G3P molecule
2 G3P = 1 glucose!

22. Calvin Cycle Start with 3 RuBPs, 5 carbon sugar
3 CO2 are added to RuBP, forming 3 unstable 6 carbon molecules
3 molecules split into 6 PGAs
ATP and NADPH (from light rxns) add energy and electrons to convert 6 PGAs into 6 G3Ps (direct product of photosynthesis)
ADP and NADP+ return to the thylakoid membrane

23. Calvin Cycle 1 G3P drops out of the cycle
will be used to make glucose, cellulose, etc.
ATP is used to rearrange the remaining carbon atoms into 3 RuBPs, and it starts again!