Bill Nye: Plants

Open-notes Quizzie

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?

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?

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.

Where does the mass come from?

Photosynthesis

Ch. 8

Photosynthesis

6CO2 + 6H2O --(light) C6H12O6 + 6O2

Carbon + water glucose + oxygen

Dioxide

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?

Leaves

CO2 enters and O2 exits through stomata

water travels through veins

Leaves contain the most chloroplasts Concentrated in the

mesophyll

Chloroplasts – where PS takes place

Thylakoids are suspended in the stroma of the chloroplast

Chlorophyll – plant pigment

Absorbs light Chlorophyll a is the most important Also have accessory pigments Pigments are bundled in photosystems in the

thylakoid membrane

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!

Two steps of photosynthesis

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

Light energy chemical energy

PS II passes its electron to the electron transport chain

Light reactions

Energy from the chain is used to make ATP Electron is passed to photosystem I

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

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 _______________ _______________.

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

Calvin Cycle – Light independent reactions

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!

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

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!