Respiration and photosynthesis

Presentation about Respiration and photosynthesis, Biology.

1. Cellular RespirationCellular Respiration
&&
PhotosynthesisPhotosynthesis
How do organisms harvest energy?

2. How do organisms harvest energy?
Producers: Autotrophs (“self feeders”)
• make all their own organic matter
• photosynthesis
Consumers: Heterotrophs (“other feeders”)
• cannot make organic molecules from inorganic
• cellular respiration

3. Cellular respiration
aerobic harvest of energy from organic
molecules (food)

4. Three general phases of
cellular respiration
1. Glycolysis
2. Krebs cycle
3. Electron transport chain (ETC)

5. Glycolysis
• takes place outside mitochondria (cytoplasm)
• glucose split into two molecules of pyruvic acid
Krebs cycle
• inside mitochondria
• completes breakdown of glucose into CO
2
Electron transport chain
• also in mitochondria
• e
-’
s transferred to O
2
• majority of ATP made

6. An important player in respiration:
NAD
+
/ NADH
“nicotinamide adenine dinucleotide”
carries electrons (& hydrogen) from glucose
to electron transport phase
NAD
+
+ H  NADH

8. Glycolysis
• outside mitochondria (cytoplasm)
• glucose broken in half  2 pyruvic acid molecules
• 2 ATP consumed, 4 ATP produced
• 2 NADH carry e
-
’s to electron transport phase

9. Kreb’s Cycle
• in mitochondria
• breaks acetic acid molecules (2 per glucose) down to CO
2

• 2 ATP produced
• 6 NADH & 2 FADH
2
carry e-’s to electron transport phase

10. Electron transport chain (ETC)
• in mitochondria
• removes e-’s & H from NADH and FADH2
•uses energy produced by the release of e
-
’s to pump hydrogen ions across
the inner mitochondrial membrane
• 34 ATP produced!

12. Main points:
• primary function is to generate energy for the cell
• 1 glucose = 38 ATP
• ETC generates the most energy
• ETC relies on oxygen!

13. converting light energy to chemical energy
&
building large energy-rich molecules
from CO
2
and H
2
O

14. C
O
HH
O
C
O
O
O
O
C
C
C
H
C
CO
2
H
2
O
Glucose made from
C, H and O
C
6
H
12
O
6
H
H
H

15. Why is it important?
1. The life energy of plants
2. Source of O
2
in atmosphere
• O
2
for aerobic respiration
• ozone (O
3
) shield
2. Chemical energy (food) for “consumers”
(animals)

16. Life energy of plants

17. Ultra violet radiation
(UV)
Ozone layer
O
3
about 20 miles above us
Source of O
2
in atmosphere

18. Energy (food) for “consumers” (animals)

19. The site of photosynthesis...
chloroplasts

20. Where does photosynthesis occur?

21. Chloroplast Close-up
thylakoids

22. thylakoid compartment
thylakoid membrane
contains chlorophyll and other
photosynthetic pigments
stack of thylakoid disks:
granum

23. Two forms of chlorophyll
• chla, chlb
• different forms absorb at slightly different wavelengths
Accessory pigments: carotenoids (e.g. beta-carotene)
• absorb closer to green wavelengths
• also serve photo-protective role
Photosynthetic pigments

25. Light absorption of photosynthetic pigments

26. Why are plants green?
Because chlorophyll does
not absorb radiation at
these wavelengths.

27. Why is chlorophyll
important?

28. Absorption
of light
energy

29. Electrons
can do
“work”
Absorption of
enough light
energy
Electrons so
energized they
are lost from
molecule!
Grabbed up by
NADP
+
to make
NADPH

30. Two stages of photosynthesis
Light reactions
• Take place in thylakoid membranes
• Chlorophyll absorbs light & loses electrons
• Water is split & O
2
is produced
• Electrons “work” = make ATP & form NADPH
Calvin cycle
• Takes place in stroma
• CO
2
molecules used to make glucose with...
• ATP (energy), NADPH (e
-
s) of light reaction

31. Two stages of photosynthesis:

32. What organisms
are capable of
photosynthesis?
Mosses, ferns, &
flowering plants

33. Numerous form of “algae”

34. Cyanobacteria
“blue-green algae”

35. Respiration & Photosynthesis
CELLULAR RESPIRATION

37. Deforestation: U.S. and South America