1. Energy & Photosynthesis

2. Energy for life processes
Energy is the ability to cause matter to move or to change
The ability to do work
Work for a cell includes
Growth & repair
Active transport
Reproduction
Synthesis of molecules
Lots of other stuff!!!

3. Type of cellular energy
Potential energy
Stored energy
Example: chemical energy in the chemical bonds of molecules such as ATP & glucose
Kinetic energy
Energy of motion
Examples: electrical energy in the flow of electrons, muscle contraction, active transports

4. Biochemical pathways
A series of reactions in which the product of one reaction is the reactant of the next
Examples:
Photosynthesis: only autotrophs are capable of this
Cellular respiration: Both autotrophs & heterotrophs perform this to release energy to do cellular work

5. Biochemical pathways

6. Thermodynamics The study of energy transformations
1st law of thermodynamics
Energy cannot be created or destroyed, only converted from one form to another
Examples: stored chemical energy in glucose  stored chemical energy in ATP  mechanical energy to move your body  heat energy to maintain your body temperature

7. ATP – the energy molecule
ATP = adenosine triphosphate
Monomers:
Adenosine, Ribose, 3 phosphate groups

8. ATP/ADP Cycle

9. ATP Phosphorylation: addition of a phosphate group and ENERGY
The energy is stored in the bonds BETWEEN the phosphate groups (approximately 10 million ATPs are made per second!!)
In order to release the energy – the bond must be broken! Bond between the 2nd & 3rd phosphate (see structure diagram)

10. Light energy & the Electromagnetic Spectrum

11. Wave description
Electromagnetic radiation – form of energy that exhibits wavelike behavior as it travels through space
Longer wavelength = lower energy (& vice versa)
Has the ability to “energize” molecules and move electrons to carry the energy

12. EM Spectrum-background
Shows all forms of electromagnetic radiation
Visible light is the portion we will talk about (although plants absorb other parts of the spectrum). This is the part that we can see.
ROY G BIV is the order of colors from low to high energy (so long to short wavelength (750 nm to 380 nm)

13. EM Spectrum

14. Light When light strikes an object, it is: See next slide for examples
Absorbed – then we can NOT see it
Transmitted – goes through the object so we can see it on the other side of the object (like stained glass). The object must be transparent or translucent (like wax paper) for it to do this
Reflected – then we CAN see it because it bounces back to our eyes.
See next slide for examples
Combinations of the 7 basic colors being A/T/R provide all the shades of color that we see.

15. Color Examples When all colors are absorbed – BLACK
When all colors are reflected – WHITE
If only one color is reflected – OBJECT APPEARS THAT COLOR
IT IS THE PIGMENT MOLECULES THAT ARE PRESENT THAT REFLECT & ABSORB LIGHT ENERGIES AND THUS PROVIDE AN OBJECT WITH ITS COLOR

16. Chloroplasts

17. Pigments Molecules that absorb energy of specific wavelengths.
REMEMBER: whatever they absorb, we DON’T see – but they use it for energy!
Chlorophyll is the main pigment for photosynthesis

18. Chlorophyll
There are several versions of chlorophyll (a & b are the main types)
Chlorophyll a is in all photosynthetic organisms – absorbs RBV light energies
Chlorophyll b is in land plants
FYI: Chlorophyll c and d are the algae and bacteria
These 2 pigments reflect GREEN so that is the color we see!

19. Be able to interpret the diagram What colors are absorbed?
What colors are reflected?
Percentages?
Color of leaf? b

20. Accessory Pigments
Absorb some of the wavelengths that chlorophyll does not
Carotenes & xanthophylls REFLECT oranges & yellows
We see these colors in the fall when chlorophyll declines
Anthocyanins REFLECT reds & purples
Tannin (waste product) gives brown color to dying leaves

21. Chloroplast
Type of plastid
Site of photosynthesis
Has 3 major parts

22. Parts of a chloroplast Thylakoid membranes: Grana (granum)
flattened sacs of photosynthetic membrane
Embedded with chlorophyll & other pigments
Grana (granum)
Stack of thylakoid membranes
Connected to each other
Organizes pigments into 2 types of photosystems
Stroma: gel like material surrounding grana

23. 5 parts to label