this ppt is my report on Botany.

2. What is cellular respiration
in plants?
 Breakdown of food to released energy in
cells
 Is the process that breaks down
complex carbon compounds into simpler
molecules and simultaneously
generates the ATP used to power other
metabolic process
 This is the opposite of photosynthesis

4.  Plants less active than animals
 need lower energy requirement
 Gaseous exchange occur mainly in the leaves
 plants require oxygen for respiration and they
also give out carbon dioxide.
 Plants unlike animals does not have any
specialized organs for gaseous exchange but
they have stomata and lenticels for this purpose.

5.  Gaseous Exchange in the Light
 During photosynthesizing, the [CO2] in the air
space of the spongy layer falls below the 0.04%
 CO2 in the atmosphere → stomata →spongy layer
O2 in the cells →stomata→ atmosphere
 Both respiration & photosynthesis occurs
 The rate of both process depends on the light
intensity

6. Gaseous Exchange in the Dark
 Respiration alone is taking place
 Less O2 inside the spongy layer than outside
 O2 from atmosphere → lenticels → spongy layer
 CO2 from cell respiration → lenticels →
atmosphere

7.  Respiration & Photosynthesis
 Respiration is the reverse of photosynthesis
 Respiration uses the product of photosynthesis,
photosynthesis uses the product of respiration

8. Equation for Respiration
C6H12O6 + 6O2 6CO2 + 6H2O + Energy
Glucose + Oxygen Carbon dioxide + water + energy
Six molecules of carbon dioxide react with
six molecules of water to form 1 molecule of
glucose and six molecules of oxygen.
• Multi step process
• Energy produced is utilized for ATP
synthesis

9. Anaerobic Respiration
 Anaerobic respiration can occur in the
presence of oxygen but it does not need to
use it
 In absence of oxygen
 A small amount of energy is released this way
 In anaerobic respiration Glycolysis occurs this
means glucose is broken into two 3-carbon
molecules

10. Aerobic Respiration
 In presence of oxygen
 Most living things get energy from aerobic respiration and
are called AEROBES
 The energy stored in bonds in glucose is released and
used to make ATP
 When ATP breaks down it supplies energy for all the
reactions in a cell such as movement of muscles, growth
of new cells etc.
 ATP traps and transfers energy within a cell.
 In the light, photosynthesis is faster than respiration.
 CO2 produced is quickly used up by photosynthesis

11. Respiration: understanding
the steps
Multi step process
 Glycolysis
 Pyruvate oxidation
 Krebs cycle
 Electro transport chain (ETC)

12. Glycolysis
 Process in which glucose is broke down
into 2 molecules of pyruvic acid
 Termed as EMP path way
 Multi step process (10 steps)
glycolysis takes place in the cytoplasm of cells

13. Glycolysis: step 1
 Starting material: glucose
 Enzyme: Hexokinase
 Product: glucose 6 phosphate
 ATP is utilized in this step

14. Glycolysis: step 2
 Starting material: glucose 6 phosphate
 Enzyme: phosphoglucoisomerase
 Product: fructose 6 phosphate

15. Glycolysis: step 3
 Starting material: fructose 6 phosphate
 Enzyme: phosphofructokinase
 Product: fructose 1, 6 biphosphate
 2 molecules of ATP are utilized in this
step

16. Glycolysis: step 4
 Starting material: fructose 1, 6
biphosphate
 Enzyme: aldolase
 Product:
- dihydroxyacetone phosphate
- Glyceraldehyde phosphate

17. Glycolysis: step 5
 Starting materials: dihydroxyacetone
phosphate
 Enzyme: triose phosphate isomerase
 Product
- Glyceraldehyde phosphate
 2 molecules of Glyceraldehyde
phosphate are there at the end of step 5

18. Glycolysis: step 6
 Starting material: Glyceraldehyde
phosphate
 Enzyme: triose phosphate
dehydrogenase
 Product: - 1, 3 bisphosphoglycerate
 2 molecules of 1, 3 bisphosphoglycerate
are formed
 2 molecules of NADH are formed

19. Glycolysis: step 7
 Starting material: 1, 3
bisphosphoglycerate
 Enzyme: phosphoglycerokinase
 Product:
- 3-phosphoglycerate
 2 molecules of 3-phosphoglycerate are
formed
 2 molecules of ATP are released in this
step

20. Glycolysis: step 8
 Starting materials: 3-phosphoglycerate
 Enzyme: phosphoglyceromutase
 Product:
- 2-phosphoglycerate
 2 molecules of 2-phosphoglycerate are
formed

21. Glycolysis: step 9
 Starting materials: 2-phosphoglycerate
 Enzyme: Enolase
 Product:
- Phosphoenolpyruvic acid (PEP)
 2 molecules of PEP are formed
 2 molecules of water are released

22. Glycolysis: step 10
 Starting enzyme: Phosphoenolpyruvic acid
(PEP)
 Enzyme: pyruvate kinase
 Product:
- Pyruvic acid
 2 molecules of pyruvic acid are formed
 2 molecules of ATP are released in this step

23. What follows
glycolysis?
 Pyruvic acid
can be used in
2 different
ways:
 Aerobic
respiration
 Fermentation

24. Aerobic respiration
Multi step process
 Glycolysis
 Pyruvate oxidation
 Kreb’s cycle
 Electron transport chain
 aerobic respiration takes place occurs in
the mitochondria on cells

25. Aerobic respiration:
pyruvate oxidation
 Occurs in matrix of mitochondria
 Oxidative decarboxylation occurs
 Enzyme: pyruvate dehydrogenase
 Product:
- Acetyl CoA
- CO2
- NADH

27. Kreb’s cycle
 Named after Hans Kreb who first
demonstrated it
 Termed as citric acid cycle
 Termed as Tricarboxylic acid (TCA)
cycle
 Multi step process (8 steps)
 Citric acid is the first product as well as
final reactant

28. Kreb’s cycle: step 1
 Starting material: Acetyl CoA
 Condensation with Oxaloacetic acid
(OAA) occurs
 Enzyme: Citrate synthesis
 Product:
- Citric acid
- CoA

29. Kreb’s cycle: step 2
 Starting materials: citrate/ citric acid
 Isomerization occurs
 Enzyme: aconitase
 Product:
- Isocitrate

30. Kreb’s cycle: step 3
 Starting material: Isocitrate
 Decarboxylation occurs
 Enzyme: isocitrate dehydrogenase
 Product
- a-ketoglurate
- NADH
- CO2

31. Kreb’s cycle: step 4
 Starting material: a-ketoglutaric acid
 Decarboxylation occurs
 enzyme: a-ketogluterate dehydrogenase
 Product:
- Succinyl CoA
- NADH
- CO2

32. Kreb’s cycle: step 5
 Starting material: succinyl CoA
 Phosphorylation occurs
 enzyme: SUccinyl CoA synthetase
 Product:
- Succinate
- GTP

33. Kreb’s cycle: step 6
 Starting material: succinate
 enzyme: succinate dehydrogenase
 Product:
- Fumeric
- FADH2

34. Kreb’s cycle: step 7
 Starting material: fumerate
 Hydration occurs
 Enyme: Fumerase
 Procduct:
- Malate/malic acid

35. Kreb’s cycle: step 8
 Starting material: malic acid
 enzyme: malate dehydrogenase
 Product:
- Oxaloacetate/OAA
- NADH

37. Electron transport chain
 Termed as ETC
 Main process of ATP synthesis
 Energy stored in NADH and FADH2 are
utilized
 Electrons are pass through chain of
electron carriers until accepted by O2 to
form H2O

38.  ETS occur in the inner membrane of
mitochondria

39.  What complexes form the ETC in the inner
membrane?
 NADH dehydrogenase (complex 1)
Succinate dehydrogenase (complex 2)
 Cytochrome bc1 (complex 3)
 Cytochrome oxidase (complex 4)
 ATP synthase (complex 5)
 Mobile carriers:
 Ubiquinone (CoQ)
 Cytochrome c
 Small protein structure
 Mobile electron carrier
 Attached to outer side of membrane

40. ETS: The process: NADH pathway
1. NADH produced during kreb’s
cycle binds to complex 1
2. Electrons are transferred to
CoQ
3. Electron are further
transferred to complex 3
4. Electrons are picked up by
cytochrome c
5. Electrons are transferred to
complex 4
6. Oxygen binds with protons
and electron pair to form water

41. ETS: the process: FADH2 pathway
1. FADH2 produced during kreb’s
cycle binds to complex 2
2. Electrons are transferred to
CoQ
3. Electron are further transferred
to complex 3
4. Electrons are picked up by
cytochrome c
5. Electrons are transferred to
complex 4
6. Oxygen binds with protons and
electron pair to form water

42. Pentose Phosphate
Pathway
 The pathway begins with the glycolytic
intermediate glucose 6-P.
 It reconnects with glycolysis because
two of the end products of the pentose
pathway are glyceraldehyde 3-P and
fructose 6-P; two intermediates further
down in the glycolytic pathway.
 It is for this reason that the pentose
pathway is often referred to as a shunt.

43. One fate of G6P is the
pentose pathway.

44. Oilseeds are able to convert stored oil
to carbohydrate
 Many seeds store a significant portion of
photo assimilate as oil, not carbohydrate
 This oil is mobilized as an energy source
upon germination
 e.g., canola (45% oil by dry weight versus
maize 5%)
• Oil – not water soluble, not transportable
• Most plants convert oil droplets (triglycerides) 
sucrose to mobilize its energy
• Animals cannot interconvert lipids and
carbohydrates!
• This gives plants metabolic flexibility in allocating
carbon between lipids and carbohydrates
– Seeds can be smaller because lipids store more energy
per gram!

45. Mobilizing the energy in stored oil involves
the glyoxylate cycle and gluconeogenesis
 Triglyceride conversion to sucrose
involves 3 organelles + cytosol
 Fatty acids are removed from triglyceride
by lipase
 FA imported into glyoxysome –
specialized plant organelle
 Cleaved at every 2nd C to generate
acetyl CoA via ß-oxidation
 Glyoxylate cycle take home messages:
 Borrowing oxaloacetate from the
mitrochondrion allows citrate synthesis
from fatty acids
 It’s a cycle! Regeneration of OAA in mt
keeps acetyl CoA incorporation high
 The products of the cycle enter
gluconeogenesis to generate sucrose
 Glycerol from triglyceride also enters
gluconeogenesis for sucrose biosynthesis
 NADH enters oxidative phosphorylation
Figure 7.13
a/k/a
_____________

46. Respiration in the Absence of Oxygen
 What happens when there is not enough
oxygen for aerobic respiration to occur?
 When oxygen is not present, NAD+ is
recycled in another way
 Under anaerobic conditions, electrons
carried by NADH are transferred to
pyruvate produced during glycolysis.
 This process recycles NAD+ needed to
continue making ATP through glycolysis.
 This recycling of NAD+ using an organic
hydrogen acceptor is called fermentation.

47. Heterotrophic plants
 Heterotrophic plants are incapable of
feeding themselves
 They draw all or part of their nutrition
from other living beings
 In symbiosis, the heterotrophic plant and
its host both benefit from their
association. Parasitic plants, on the
other hand, use their host’s resources
for themselves alone.

48.  Hemiparasites
- Have chlorophyll and produce
all, or at least part, of their
own glucose, they merely
obtain water, minerals, and
perhaps some organic
compounds from their host
 Holoparasitic plants
- Have neither chlorophyll and
photosynthesis: all of their ATP is
produce by aerobic respiration of
glucose obtain from the host
plant, and they probably need
little reducing power

49.  Photorespiration
 (also known as the oxidative photosynthetic
carbon cycle, or C2 photosynthesis) refers to a
process in plant metabolism where the enzyme
RuBisCO oxygenates RuBP, causing some of the
energy produced by photosynthesis to be wasted
used for:
 The photorespiration pathway is an enzymatic
one that is not coupled to any electron transfer
system. It does not generate ATP. It does use
oxygen and it does produce carbon dioxide, and it
uses a sugar-phosphate as its primary fuel.

50. Environmental and internal factors
 Temperature
- Greatly influence respiration in a plant growing
under natural condition
 Lack of oxygen
- Because plants are not as active as animals,
much lower oxygen concentrations — as little as
1% to 2% — are sufficient to maintain full rales of
plant respiration.

51.  Internal regulation

52.  Total energy yield of respiration
-

54. Fermentation of alcohol beverages
 Alcoholic fermentation is a two-
step process.
 First, pyruvate is converted to a
two-carbon compound, releasing
carbon dioxide.
 Second, electrons are transferred
from a molecule of NADH to the
two-carbon compound, producing
ethanol.

55. Alcoholic Fermentation
 Alcoholic fermentation by yeast, a
fungus, has been used in the preparation
of many foods and beverages.
 Wine and beer contain ethanol made
during alcoholic fermentation by yeast.
 Carbon dioxide released by the yeast
causes the rising of bread dough and the
carbonation of some alcoholic
beverages, such as beer.
 Ethanol is actually toxic to yeast. At a
concentration of about 12%, ethanol kills
yeast.
 Thus, naturally fermented wine contains
about 12% ethanol.

56.  Beer
- Any alcoholic beverage produced by
the fermentation of sugars obtained from grain.
In western culture, barley is the grain generally
used. Ethanol: Alcohol that is the metabolic
product of yeast in the wine and beer making.
Specifically, it is produced by the yeast
during fermentation.
 Wine
- The process of fermentation in winemaking turns
grape juice into an alcoholic beverage. During
fermentation, yeasts transform sugars present in
the juice into ethanol and carbon dioxide (as a by-
product).

57.  Spirits
- Are alcoholic beverages with an ethanol content
above 20%
 Warning
- Fermentation of plant material always produces ethyl
alcohol (ethanol), and is classified as depressant

58. Thank you