Notes

Slide Show

Outline

1	HOW DO CELLS MAKE ENERGY?
2	Have you ever noticed that the leaves on trees turn different colors in the fall?
3	Why does this happen?
4	Plant cells contain pigments.
5	During the spring and summer, the most common pigment is chlorophyll.
6	Chlorophyll does not absorb green light.
7	That’s why plants appear to be green.
8	The purpose of chlorophyll is to absorb light energy.
9	Sunlight decreases during the fall and winter.
10	It requires energy for plant cells to make chlorophyll.
11	And, it is less useful when there is little sunlight.
12	So, plants stop making chlorophyll during the fall and winter.
13	When plants stop making chlorophyll, you see the other pigments in their leaves.
14	During spring and summer, plants use their chlorophyll to make glucose.
15	This process is called photosynthesis.
16	The equation for photosynthesis is… CARBON DIOXIDE + WATER (IN THE PRESENCE OF SUNLIGHT) = GLUCOSE + OXYGEN
17	One more time! 6CO₂ + 6H₂O à C₆H₁₂O₆ + 6O₂
18	There are two reactions: the light-dependent reactions and the light-independent reactions
19	What happens during the light-dependent reactions? Sunlight is necessary, so these happen during the day.
20	Sunlight energy splits water to form oxygen.
21	Let’s see how that works H₂O à 2H + O
22	The hydrogen is transferred to carrier molecules
23	These “carriers” will use the hydrogen for energy to make glucose
24	Where do the light-dependent reactions occur?
25	Specifically, in the “thylakoid membranes”
26	Sunlight energy is also used to make ATP during the light-dependent reactions
27	So, what do plants do at night? The light-independent reactions
28	What happens? Energy from the hydrogen carriers and the ATP made in the light-dependent reactions are used to make glucose
29	Where does the carbon and oxygen come from? Carbon dioxide
30	Where do the light-independent reactions occur? In the chloroplast
31	Specifically, in the “stroma”
32	Let’s review!
33	The carbon dioxide is used in the light-independent reactions to make glucose
34	The water is split in the light-dependent reactions to make oxygen
35	Glucose will be used by the plant cells to make ATP This process is called Cell Respiration