PHOTOSYNTHESIS REVIEW

1. Terms to know:

Autotroph- any plant/algae that makes its own food       

Endosymbiotic- chloroplasts that used to live on its own

Pigment- molecules that absorbs light and boosts electrons to a higher energy level 

Photon- light made up of small packets of energy

Wavelength- the length of a single cycle of a wave as measured by the distance between one peak  

Carotenoid- accessory pigments, carbon rings linked to a chain with alternating single and double bonds                           

Reaction centre- a complex of proteins and pigments that contains the primary electron acceptor       

absorption spectra- a plot of the amount of light energy of various wavelengths that a substance absorbs 

2. Know the structure of the chloroplast- be able to label: outer membrane, stroma, thylakoid membrane, lumen, grana and lamellae

• Double membrane 

• Jelly like substance in center is called stroma 

• Flattened discs are called thylakoid 

• Site of light reactions

• Stacks of thylakoid from grana 

• Lamella connect the grana 

3. Know the structure of chlorophyll – know the difference between chlorophyll a and b

• Chlorophyll- mg metal in the center of a complex ring structure called a porphyrin ring 

• Has a long hydrophobic tail that anchors it the thylakoid membrane→ called a phytol tail

• Chlorophyll a- methyl group 

• Chlorophyll b- aldehyde group 

4. What is a photosystem? What is its function? How does it work?

• Photosystems absorb photons of light and uses them to excite electrons 

• Photosystem 1- reaction centre is p700 because its optimal absorption centre p700nm

• Photosystems 2- reaction centre is p680 because it’s optimal absorption is 680nm 

5. What are the 4 pigments in green plants?

1. Chlorophyll a- green 

2. Chlorophyll b- green 

3. Carotenoids- yellow orange 

4. Xanthophyll- yellow 

6. How do stomata and guard cells work to control gas exchange? Know the basic structure of each

• Gas exchange in a leaf occur through tiny openings called stomata in the stems and leaves 

• Plants control stomata opening with guard cells 

• When open CO2 enters and O2 and H2O are lost 

• K+ is pumped into the guard cell using ATP 

• This creates a hypertonic solution so water rushes into the guard cells → they swell → pull apart and open stomata 

• Swell (hypotonic) 

• Open CO2 into plant and O2 out of plant

• When no K+ is pumped in→ no water→ cells remain flaccid and stomata closed 

7. Know what the electromagnetic spectrum is, be able to place the various radiations in order, where is visible light?  What wavelength do plants use?

• Electromagnetic spectrum- shows all wavelengths of light 

• Shortest wavelength- gamma rays 

• Longest wavelength- radio waves 

• Visible light between 380-750 nm 

Plants- reflect 500-600 nm 

8. Know the light reactions - in detail - where is it? What is it? How does it work? Who uses it? When ? reactants, products

Where- chloroplasts thylakoid membrane 

What- protein z breaks water oxygen released through stomata

How- electrons go to photosystem 2 

Who- plants all use it 

When- C3, C4, CAM 

Products- ATP, NADPH, oxygen 

Reactants- photon, H2O, NADPH 

9. Know the Calvin Cycle- in detail - where is it ? What is it? How does it work? Who uses it? When? Reactants and products

Where- stroma of the chloroplast

What- rubisco

How- CO2 came from through the stroma 

Who- plants 

When-

Reactants- 6 CO2, 18 ATP, 12 NADPH

Products- 1 glucose 

10. Know how C4 and CAM plants have adapted to live in their environments.

CAM plants 

• Cacti 

• Extreme heat

• No water 

• Cannot open stomata during the day 

• Must open stomata at night to prevent water loss 

C4 

• Hot, arid regions 

• Palm trees, kentucky bluegrass (florida), corn 

• PEP case

• Open stomata during the day 

• Reduce photorespiration due to heat 

• 30 ATP 

11. What are the factors that affect the rate of photosynthesis– explain how

Sunlight 

Availability of drought