PhotosynthesisChapter 4

http://www.youtube.com/watch?v=pE82qtKSSH4

KEY CONCEPTThe overall process of photosynthesis produces sugars that store chemical energy.

Photosynthetic organisms are producers.

• Producers make their own source of chemical energy.

• Plants use photosynthesis and are producers.

• Photosynthesis captures energy from sunlight to make sugars.

Bill Nye: The Science Guy on Plants

• http://www.youtube.com/watch?v=zVD6n5mOw2E (2min)• http://www.youtube.com/watch?v=pdgkuT12e14

• Chlorophyll is a molecule that absorbs light energy.

chloroplast

leaf cell

leaf

• In plants, chlorophyll is found in organelles called chloroplasts.

How chloroplasts work

• http://education-portal.com/academy/lesson/chloroplast-structure-chlorophyll-stroma-thylakoid-and-grana.html#lesson

• The light-dependent reactions capture energy from sunlight.

– take place in thylakoids– water and sunlight are needed– chlorophyll absorbs energy– energy is transferred along thylakoid membrane then to

light-independent reactions– oxygen is released

• The light-independent reactions make sugars.– take place in stroma– needs carbon dioxide from atmosphere– use energy to build a sugar in a cycle of chemical

reactions

• The equation for the overall process is:

6CO2 + 6H2O C6H12O6 + 6O2

C6H12O6

granum (stack of thylakoids)

thylakoid

sunlight

1 six-carbon sugar

6H2O

6CO2

6O2

chloroplastchloroplast1

2

43

energy

stroma (fluid outside the thylakoids)

Bozeman Science

• http://www.youtube.com/watch?v=g78utcLQrJ4