This presentation is made as per the B.Sc-III Botany Syllabus of SGBAU Amravati

1. GOPIKABAI SITARAM GAWANDE
MAHAVIDYALAYA
UMARKHED, DIST. YAVATMAL
NAAC REACCREDITED (3RD CYCLE) GRADE B++ CGPA 2.79
GOPIKABAI SITARAM GAWANDE MAHAVIDYALAYA UMARKHED, DIST. YAVATMAL
PLANT PHYSIOLOGY AND ECOLOGY
BOTANY
B.Sc-III
Semester-V
Presented by—
Mr. Kailash S Sontakke
Assistant Professor
Department of Botany

2. Respiration
 Which nutrients are used for energy production?
 Which is most preferred nutrient among carbohydrate, protein and fat for energy
production ? Why?
 Why organisms take up oxygen and release carbondioxide?
 What is aerobic and anaerobic respiration?
 Which Steps are involved in aerobic respiration?

3. Respiration
Always Remember
 Maintenance of life requires continuous supply of energy.
 Respiration fulfills the continuous need of energy

4. Respiration
 An intracellular catabolic process of oxidation in which complex organic substances
are broken down into simple ones and energy is produced in the form of ATP.
 Complete breakdown of 1 glucose molecule in aerobic respiration yield 686.6 k.cal
energy
 Energy in the form of ATP
 It occurs in mitochondria

5. ATP
 Formation of ATP is called as phosphorylation.
 In nature three different ways-
I. Photophosphorylation
II. Substrate level phosphorylation
III. Oxidative phosphorylation

6. ATP- Adenosine triphosphate
 Molecular formula- C10H16N5O13P3
 The three phosphoryl groups are referred to as the alpha (α), beta
(β), and, for the terminal phosphate, gamma (γ).
 ATP + H2O → ADP + Pi ΔG° = −30.5 kJ/mol (−7.3 kcal/mol)
 ATP + H2O → AMP + PPi
ΔG° = −45.6 kJ/mol (−10.9 kcal/mol)
 Energy currency of cell.

7. Mitochondria
 They were first observed by Kolliker in 1850.
 Benda (1897) gave the present name of mitochondria (Gk. mitos- thread,
chondrion- grain) to the organelles.
 Normally, they have a length of 1.0-4.1 µm and a diameter of 0.2-1.0 µm
(average 0.5 µm).
 Chemical Composition. Proteins. 60-70%, Lipids 25-35%, RNA 5-7%, DNA. Small
quantity. Minerals. Traces, Granules Manganese and Calcium phosphate.

8. Mitochondria
 Outher membrane
 Inner membrane- cristae
 Elementary particles, F0 – F1 particles or
oxysomes, ATP synthase
 A mitochondrion contains 1 x 104 – 1 x
105 elementary particles
 Outer Chamber (Peri-mitochondrial Space)
 Inner Chamber or matrix

9. Mechanism of Respiration
1. Aerobic respiration
2. Anaerobic respiration
 Aerobic respiration is completed in following steps
i. Glycolysis
ii. Oxidation of Pyruvic Acid
iii. Kreb’s Cycle
iv. ETS

10. Glycolysis
 Glycolysis (Gk. glykys = sweet, lysis = splitting), also called glycolytic pathway or
Embden-Meyerhof-Parnas (EMP) pathway
 The sequence of reactions that metabolises one molecule of glucose to two molecules
of pyruvate with the net production of two molecules of ATP.
 Glycolysis is almost an universal central pathway of glucose catabolism.
 It is located in the cytoplasm of the cells of an organism.
 The whole process of glycolysis (i.e., the breakdown of the 6-carbon glucose
molecule into two molecules of the 3-carbon pyruvate) occurs in ten steps.
 The first five-steps constitute the preparatory phase while the rest live-steps
represent the payoff phase (oxidation phase).

11. Glycolysis

12. Significance of Glycolysis
 The glycolytic pathway is employed by all tissues for the breakdown of
glucose to provide energy in the form of ATP.
 Important pathway for the production of energy especially under anaerobic
conditions.
 It is crucial for generation of energy in cells without mitochondria.
 It forms products that are intermediates for other metabolic pathways.

13. Oxidation of Pyruvic Acid (Connecting Link)
PDH

14. Citric acid cycle/TCA cycle/Krebs cycle
 The 1953 Nobel Prize of Physiology or Medicine was awarded to Hans Adolf
Krebs, for his discovery of the citric acid cycle, also known as the Krebs cycle,
and to Fritz Albert Lipmann for the discovery of co-enzyme A and its
importance for intermediary metabolism.
 It is a series of chemical reactions used by all aerobic organisms to release
stored energy through the oxidation of acetyl-CoA derived from
carbohydrates, fats, and proteins

15. Citric acid cycle

18. ETS/Terminal Oxidation/Oxidative Phosphorylation
 Efraim Racker, a respected researcher in the field, to comment at one point,
“Anyone who is not confused about oxidative phosphorylation just doesn’t
understand the situation.”
 Takes Place on Inner Mitochondrial Membrane
 Four Complexes are involved
 Oxidation of NADH2 and FADH2 takes place
 The electron transport chain is a series of proteins and organic molecules found in
the inner membrane of the mitochondria. Electrons are passed from one member
of the transport chain to another in a series of redox reactions. Energy released in
these reactions is captured as a proton gradient, which is then used to make ATP in
a process called chemiosmosis.

19. ETS

20. ETS

21. Significance of ETS
 It generates major amount of energy in the form of ATP (34 ATP)
 It regenerate oxidized coenzymes NAD+ & FAD+ to NADH+H & FADH2
 Provide water molecule necessary for Krebs cycle
 It release energy in stepwise manner to prevent cell damage.

22. Summary of Aerobic Respiration

23. Overview of Carbohydrate Metabolism

24. Anaerobic Respiration
 It is the process of release of energy in enzymatically controlled step-wise incomplete
degradation of organic food without oxygen being used as oxidant.
 It occurs in the roots of some water-logged plants, muscles of animals and as
supplementary mode of respiration in massive tissues.
 Anaerobic respiration is the exclusive mode of respiration in some parasitic worms, many
prokaryotes, several unicellular eukaryotes and moulds.
 In micro-organisms the term fermentation is more commonly for anaerobic respiration.
 e.g. alcoholic fermentation, lactic acid fermentation.
 Fermentation is defined as the anaerobic breakdown of carbohydrates and other organic
compounds into alcohols, organic acids, gases, etc. with the help of micro-organisms or
their enzymes.

25. Anaerobic Respiration
 Anaerobic respiration produces very little energy (about 5%) as compared to
aerobic respiration.
 The reasons are
 (a) There is incomplete breakdown of respiratory substrate,
 (b) At least one of the products of anaerobic respiration is organic. It can be
further oxidised to release energy,
 (c) NADH produced during glycolysis is often used up.
 (d) ATP formation does not occur during regeneration of NAD+.
 (e) Electron transport chain is absent,
 (f) Oxygen is not used for receiving electrons and protons.

26. Anaerobic Respiration

27. Alcoholic & Lactic Acid Fermentation
PDC
ADH
LD

28. Chemiosmotic ATP Generation
 The chemiosmotic hypothesis was proposed by Peter Mitchell in 1961.
 Complexes I, III, and IV of the electron transport chain are proton pumps. As electrons
move energetically downhill, the complexes capture the released energy and use it to
pump H+ ions from the matrix to the intermembrane space.
 This pumping forms an electrochemical gradient across the inner mitochondrial
membrane.
 The gradient is sometimes called the proton-motive force, and you can think of it as a
form of stored energy, kind of like a battery.
 This process, in which energy from a proton gradient is used to make ATP, is
called chemiosmosis.
 Uncoupling proteins/Uncouplers
 These proteins are simply channels that allow protons to pass from the intermembrane
space to the matrix without traveling through ATP synthase. By providing an alternate
route for protons to flow back into the matrix, the uncoupling proteins allow the energy
of the gradient to be dissipated as heat.

29. Chemiosmotic ATP Generation

30. Chemiosmotic ATP Generation

31. Respiratory Quotient (RQ)
 Ratio of volume of CO2 released to the volume of O2 consumed in
respiration is called respiratory quotient (RQ) or respiratory ratio.
 It depends on the type of respiratory substrate.
 Its value can be one, zero, more than 1 or less than one.
 RQ = Volume of C02 evolved/Volume of 02 absorbed

32. RQ
RQ Equal to Unity:
 Respiratory quotient is equal to unity if carbohydrates are the respiratory
substrate and the respiration is aerobic.
 C6H1206 + 602 → 6C02 + 6H20 RQ = 6C02/602 = 1
RQ Less than Unity:
 RQ is less than one when respiration is aerobic but the respiratory substrate is
either fat or protein. RQ is about 0.7 for most of the common fats.
 It occurs during germination of fatty seeds.
 C57H104O6 + 80 02 → 57C02 + 52H20 RQ = 57C02/8002 = 0.71 triolein
 2(C51H9806) + 14502 → 102C02 + 98H20 RQ = 102C02/14502 = 0.7 tripalmitin
 RQ is about 0.9 in case of proteins, peptones, etc.

33. RQ Zero:
 Succulents do not evolve carbon dioxide during night (when their stomata
are open) as the same is used in carbon fixation. They also change
carbohydrates to organic acids which utilise oxygen but do not evolve carbon
dioxide.
 2C6H1206 + 302 —» 3C4H605 + 3H20 RQ = Zero C02/302 = Zero
RQ More than Unity:
 (a) RQ slightly more than unity is found when organic acids are broken down
as respiratory substrates under aerobic conditions, e.g.,
 2(COOH)6 + 02 —» 4C02 + 2H20 RQ = 4 C02/1 02 = 4.0 oxalic acid
 C4H60 + 3 02 —» 4C02 + 3H20 RQ = 4 C02/3 02 or 1.3 malic acid
 2C4H604 + 7 02 —» 8C02 + 6H20 RQ = 8 C02/7 02 or 1.14 succinic acid

34.  (b) In anaerobic respiration there is no consumption of oxygen.
Carbon dioxide is produced in most of the cases. Therefore,
respiratory quotient is infinity. Carbohydrate is the usual substrate.
 An intermediate value is obtained where an organ is undergoing both
aerobic and anaerobic modes of respiration.
 Importance:
 (i) Knowledge of respiratory quotient helps in determining respiratory
substrate.
 (ii) It helps in knowing the type of respiration being performed,
 (iii) It provides some information about major transformation of food
materials.

35. Significance of Respiration
 Respiration provides energy for biosynthesis of cellular materials like carbohydrates,
protins, fats, lipids vitamins, pigments etc.
 Source of energy for cell division, growth, repairs, and replacement of worn out parts,
movements, locomotion etc.
 Various intermediates of krebs cycle are used as building blocks for synthesis of other
complex compounds.
 It helps to maintain the balance between CO2 and O2 in the atmosphere.
 Fermentation is used in various industries such as diaries, bakeries, distilleries, leather
industries, paper industries etc.
 It is used in commercial production of alcohol, organic acids, vitamins, antibiotics etc.

36. Photosynthesis Vs Respiration

38. Photosynthesis and Respiration Process

39. Thank You