How to Calculate the Number of ATP Produced During Beta Oxidation of Fatty Acids?

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Beta oxidation of fatty acids takes place in the mitochondrial matrix. And there are three stages of beta-oxidation:

a) In the first step, the fatty acid undergoes oxidative removal of successive 2C units in the form of acetyl-CoA, starting from the carboxyl end of the fatty acyl chain. For example, palmitic acid (16C) undergoes 7 passes through the oxidation sequence. At the end of the cycle, the last two carbons C15 and C16 remain as acetyl-CoA. It is important to note that in the first step, 2 ATPs are utilized for the activation of fatty acids. Besides, NADH and FADH2 are formed in this stage.

b) In the second stage of fatty acid oxidation, the acetyl groups of acetyl-CoA are oxidized to CO2 in the Citric Acid Cycle, which also takes place in the mitochondria.

c) The reduced power (NADH, FADH2) produced during the first and second stage enter into the ETS cycle.

Now, we will take an example to calculate the number of ATPs in the oxidation of fatty acids.

 1. Palmitic acid (16C) in the first step breaks into acetyl-CoA in seven steps, but total acetyl-CoA formed is 8. It means you can draw a formula as n/2 is the no. of acetyl-CoA formed from a fatty acid compound.

So, here in this example, the number of acetyl-CoA formed is 16 / 2 = 8 Acetyl-CoA

2. The number of NADH and FADH2 produced in the first process: In the above example, 7 NADH and 7 FADH2 are produced. It means, (n/2) - 1

So, here in the above example, the number of NADH and FADH2 produced = (n/2)-1 = (16/2) -1
                                                                                                                                          = 8-1 = 7

3. The acetyl CoA formed in the first process by the oxidation of fatty acids would enter into the Krebs cycle. Now, we know, that in each acetyl-CoA in Kreb cycle produces -- 3 NADH, 1 FADH2, and 1 ATP are produced. So, for 8 Acetyl-CoA, the number of NADH produced would be 8 x 3 = 21
and the number of FADH2 produced = 8 x 1 = 8

Once the reduced power enters into the ETS, it produces ATP.

Now, we can calculate the ATP produced considering 1 NADH produces 3 ATP and 1 FADH2 produces 2 ATP.

Total number of NADH produced during the first process = 7 NADH = 7 x 3     =21 ATP
Total number of FADH2 produced during the first process = 7FAtDH2 = 7 x 2   = 14 ATP
Total number of NADH2 produced during the Krebs cycle = : 24          = 24 x 3 = 72 ATP
Total numbe of FADH2 produced during the Krebs cycle  =  : 8            = 8 x 2   = 16 ATP
Total number of ATP formed during the Krebs cycle =                             = 8 x 1 = 8 ATP
                                                                                   Total ATP == 131
Since 2 ATPs have been utilized for the activation of fatty acids, the net ATP produced would be 131-2 = 129 ATP

If you have understood this concept, can you calculate the number of ATPs produced during the oxidation of Stearic acid (18C)

Note: In exams, only even number carbon compounds are asked because the calculation for odd number of carbon containing fatty acids is complex and varies from one acid to another.














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Multiple Choice Questions on Transport in Plants (Chapter 11, NCERT)

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Q1. In flowering plants the substances that would need to be transported are:
a)      Water
b)      Mineral nutrients
c)       Organic nutrients
d)      Phytohormones

e)      All of the above

Q2. Over small distances, substances move by:
a)      Diffusion
b)      Cytoplasmic streaming
c)       Active transport
d)      All of the above

Q3. Transport over long distances in plants is called translocation. This long-distance transport occurs through:
a)      Diffusion
b)      Cytoplasmic streaming
c)       Vascular system
d)      All of the above

Q4. In rooted plants, transport of water and minerals through xylem is:
a)      Unidirectional
b)      Bidirectional
c)       Multidirectional
d)      None

Q5. In rooted plants, organic and mineral nutrients transport is:
a)      Unidirectional
b)      Bidirectional
c)       Multidirectional
d)      None

Q6. Which of the following statement is true for diffusion?
a)      Movement by diffusion is passive
b)      Diffusion occurs over short distances
c)       No energy expenditure takes place in a diffusion
d)      Molecules move in a random fashion
e)      All of the above

Q7. Which of the following process is independent of a living system?
a)      Diffusion
b)      Osmosis
c)       Both a and b
d)      None

Q8. Which of the following is the only means for gaseous movement within the plant body?
a)      Diffusion
b)      Osmosis
c)       Both a and b
d)      None

Q9. The rate of diffusion is affected by:
a)      Gradient of concentration
b)      The  permeability of the membrane separating them
c)       Temperature
d)      Pressure
e)      All of the above

Q10. The diffusion rate across the membrane depends on:
a)      Size of the substance
b)      Solubility in lipids
c)       Gradient of concentration
d)      All of the above

Q11. Which of the following substance would diffuse faster across the membrane?
a)      Hydrophilic substance
b)      Hydrophobic substance
c)       Both a and b
d)      None

Q12. Hydrophilic substances find it difficult to pass through the membrane. Such substances are facilitated for diffusion through:
a)      Lipids on the membrane
b)      Proteins on the membrane
c)       Carbohydrates on the membrane
d)      None of the above

Q13. Even for facilitated diffusion, which condition should be universally present?
a)      Concentration gradient
b)      High temperature
c)       High pressure
d)      All of the above

Q14. Which of the following statement is true for facilitated diffusion?
a)      Concentration gradient must be present for facilitated diffusion
b)      Special proteins help move substances across the membrane
c)       No expenditure of energy (ATP) is required
d)      Facilitated diffusion is specific in nature
All of the above

Q15. Which is incorrect for facilitated diffusion?
a)      Facilitated diffusion is independent of concentration gradient
b)      Facilitated diffusion is non-specific in nature
c)       Facilitated diffusion required ATP energy for transport of substances across the membrane
d)      Facilitated diffusion is sensitive to inhibitors
e)      a, b, and c

Q16. Facilitated diffusion is sensitive to inhibitors as:
a)      the inhibitors react with protein side chains
b)      the inhibitors react with lipids
c)       the inhibitors react with carbohydrates
All of the above

Q17. The porins are proteins that help in facilitated diffusion. Porins are present on the outer membrane of:
a)      The outer membrane of plastids
b)      The outer membrane of mitochondria
c)       The outer membrane of bacteria
All of the above

Q18. Water channels, called aquaporins are present on the cellular membrane for the transport of water. Aquaporins are made up of how many protein subunits?
a)      2
b)      4
c)       6
d)      8

Q19. Which of the following comes under facilitated diffusion?
a)      Uniport
b)      Antiport
c)       Symport
d)      All of the above

Q20. Which of the following statements are true for active transport?
a)      It is carried out by specific membrane proteins called pumps
b)      Active transport occurs against a concentration gradient
c)       Active transport required energy in the form of ATP
d)      All of the above

Q21. Which of the following statement is correct for active transport?
a)      Active transport rate reaches a maximum when carrier proteins called pumps are saturated
b)      Like enzymes, carrier proteins are very specific in nature
c)       The carrier proteins are sensitive to inhibitors that react with protein side chains
All of the above

Q22. Water potential is a concept fundamental to:
a)      Understanding water movement
b)      Understanding solute movement
c)       Both a and b
d)      None

Q23. Water potential is determined by:
a)      Solute potential
b)      Pressure potential
c)       Both a and b
d)      None

Q24. Water molecules possess kinetic energy. This kinetic energy will increase with:
a)      Greater concentration of water in the system
b)      Less concentration of water in the system
c)       Greater concentration of solute in the system
d)      None

Q25. Which of the following will have highest water potential?
a)      Pure water
b)      Water mixed with dust
c)       Water mixed with gravel
All of the above

Q26. The process of movement of substance down a gradient of free energy is called:
a)      Diffusion
b)      Osmosis
c)       Both
d)      None

Q27. Water potential of pure water is:
a)      0
b)      1
c)       -1
d)      -2

Q28. All solutions will have:
a)      A lower water potential than pure water
b)      A higher water potential than pure water
c)       Always a negative water potential
d)      Both a and c

Q29. The solute potential is always:
a)      Negative
b)      Positive
c)       Zero
d)      None

Q30. If a pressure greater than atmospheric pressure is applied to a solution, its water potential will:
a)      Increase
b)      Decrease
c)       Remains constant
None

Q31. Solute potential is also known as:
a)      Pressure potential
b)      Osmotic potential
c)       Both
d)      None

Q32. Osmotic pressure is equal and opposite to:
a)      Atmospheric pressure
b)      Osmotic potential
c)       Pressure potential
None

Q33. Plasmolysis occurs when a cell is placed in:
a)      A hypotonic solution
b)      A hypertonic solution
c)       An isotonic solution
d)      All of the above

Q34. The process of plasmolysis is reversible if the plasmolysed cell is placed in:
a)      Hypotonic solution
b)      Hypertonic solution
c)       Isotonic solution
All of the above

Q35. Which of the following statement is associated with flaccid condition?
a)      A flaccid condition is one where the cell is placed in an isotonic solution and water flows into and out of the cell and are in equilibrium
b)      A flaccid condition is one where the cell is placed in hypertonic solution and water comes out of the cell
c)       A flaccid condition is one where the cell is placed in hypotonic solution and water goes out of the cell
d)      None of the above

Q36. Turgor pressure builds in a cell when it is placed in:
a)      A hypotonic solution
b)      A hypertonic solution
c)       An isotonic solution
d)      None

Q37. What would be the pressure potential of a flaccid cell?
a)      Zero
b)      Positive
c)       Negative
d)      Infinite

Q38. Bulk flow can be achieved through:
a)      Positive hydrostatic pressure
b)      Negative hydrostatic pressure
c)       Both a and b
d)      None

Q39. Bulk movement of substances through the conducting or vascular tissues in plants is called:
a)      Transpiration
b)      Translocation
c)        Transition
d)      None

Q40. Xylem is responsible for the translocation of:
a)      Water
b)      Mineral salts
c)       Organic nitrogen
d)      Hormones
e)      All of the above

Q41. Phloem is responsible for the translocation of:
a)      Water
b)      Organic solutes
c)       Inorganic solutes
d)      Both b and c
e)      None

Q42. In plants, water is absorbed along with mineral solutes through
a)      Root hairs by diffusion
b)      Root hairs by osmosis
c)       Root hairs through transpiration
d)      Stem hairs by diffusion
e)      Stem hairs by osmosis

Q43. The movement of water and minerals using apoplast pathway is dependent on gradient and occurs through:
a)      The system of adjacent cell walls
b)      The system of adjacent cell wall and cytoplasm
c)       The system of interconnected protoplasts
d)      Both a and b
e)      None

The pathway of water movement in the root through apoplast pathway includes:
a)      Epidermis -- > Cortex -- > Endodermis -- > Pericycle -- > Xylem
b)      Epidermis -- > Cortex -- > Endodermis
c)       Epidermis -- > Cortex
d)      Epidermis

Q45. Symplastic system is the system of interconnected protoplasts. The path of movement includes:
a)      Epidermis -- > Cortex -- > Endodermis -- > Pericycle -- > Xylem
b)      Epidermis -- > Cortex -- > Endodermis
c)       Epidermis -- > Cortex
d)      Epidermis

Q46. The apoplatic movement is stopped at:
a)      The cortex region though casparian strips
b)      The endodermis region through casparian strips
c)       The pericycle region through casparian strips
d)      None

Q47. Most of the water flow in the roots occurs via:
a)      The apoplast due to loosely packed cortical cells
b)      The apoplast due to loosely packed endodermal cells
c)       The symplast due to loosely packed cortical cells
d)      The symplast due to loosely packed endodermal cells

Q48. In plant roots, apoplastic movement is seen up to the cortical regions only. In young roots, water enters directly into the xylem vessels and / or tracheids through:
a)      Apoplast pathway
b)      Symplast pathway
c)       Both apoplast and symplast pathway
d)      None

Q49. Mycorrhizal association helps in the absorption of water and minerals from the soil. Fungus provides water and minerals to plants. On the other hand, the mycorrhizal association gets:
a)      Sugars
b)      N-containing compounds
c)       Both a and b
d)      None

Q50. Which plant seeds cannot germinate without the presence of mycorrhizae?
a)      Pinus seeds
b)      Cycas seeds
c)       Both
d)      None

Q51. Minerals are absorbed by root hairs through active transport.  This creates potential gradient in the root cells and eventually a pressure is created in the xylem, which is referred to as:
a)      Root pressure
b)      Osmotic pressure
c)       Turgor pressure
d)      Atmospheric pressure

Q52. Water loss in its liquid phase from the veins near the tip of grass blades or leaves of many herbaceous plants is referred to as:
a)      Exudation
b)      Guttation
c)       Evaporation
Transpiration

Q53. Transportation of water up to the tip of a plant is caused by:
a)      Transpirational pull
b)      Root pressure
c)       Guttation
d)      Evaporation

Q54. Which of the following statement is true regarding the movement of water?
a)      Water is pushed through the plant
b)      Water is pulled through the plant
c)       Both a and b
d)      None

Q55. How much percentage of water is utilized for photosynthesis by the plant?
a)      Less than one percent
b)      Less than two percent
c)       About 5 percent
d)      About 4 percent

Q56. Which of the following statement is true about stomata?
a)      The inner wall of guard cells is thick and elastic
b)      The outer wall of guard cells is thin
c)       Cellulose microfibrils are oriented radially
d)      In flaccid condition, the stomatal aperture closes
e)      All of the above

Q57. The transpiration driven ascent of xylem sap depends mainly on the following physical properties of water:
a)      Cohesion
b)      Adhesion
c)       Surface tension
All of the above

Q58. Which of the following statements are correct in relation to transpiration?
a)      It creates transpiration pull for absorption and transport of plants
b)      It supplies water for photosynthesis
c)       Cools leaf surface, sometimes 10 to 15 degrees by evaporative cooling
d)      Maintains the shape and structure of plants by keeping cells turgid
e)      All of the above

Q59. Which of the following statements are true?
a)      The evolution of the C4 photosynthetic system is a strategy to maximize the availability of CO2 while minimizing H2O loss.
b)      C4 plants are twice as efficient as C3 plants in terms of fixing CO2
c)       C4 plant loses only half as much water as a C3 plant for the same amount of CO2 fixation
d)      All of the above

Q60. Unlike water, minerals cannot be passively absorbed (except a few) by the roots because:
a)      Minerals are present in the soil as charged particles which cannot move across cell membrane
b)      The concentration of minerals in the soil is usually lower than the concentration of minerals in the root
c)       Both a and b are correct
d)      None


Q61. After the ions have reached xylem through active or passive uptake, their further transport up the stem to all parts of the plant is through:
a)      Diffusion
b)      Osmosis
c)       Transpiration
d)      Osmotic pressure

Q62. Elements most readily mobilized in plants include:
a)      Nitrogen
b)      Phosphorus
c)       Sulphur
d)      All of the above

Q63. The direction of movement of sucrose in phloem is:
a)      Unidirectional
b)      Bidirectional
c)       Multi-directional
d)      None

Q64. Xylem exudates consist of:
a)      Water
b)      Nitrogen as inorganic ions and organic form
c)       Phosphorus and Sulphur as organic compounds
d)      Mineral ions
e)      All of the above

Q65. Phloem sap mainly consists of:
a)      Water
b)      Sucrose
c)       Hormones
d)      Amino acids
e)      All of the above

Q66. The accepted mechanism used for translocation of sugars from source to sink is called:
a)      Pressure flow hypothesis
b)      Mass flow hypothesis
c)       Both
d)      None

Q67. Sucrose is loaded from the source cell (leaf) to the companion cell through:
a)      Active transport
b)      Passive transport
c)       Both a and b
d)      None

Q68. Sucrose from companion cell reach sieve tube element through:
a)      Active transport
b)      Passive transport
c)       Both
d)      None

Q69. Water from the adjacent xylem moves towards phloem through:
a)      Diffusion
b)      Osmosis
c)       Mass flow
d)      None

Q70. At the sink, the movement of sucrose out of the phloem into the cell is through the process of:
a)      Diffusion
b)      Osmosis
c)       Active transport
d)      All of the above

Q71. At the sink, the food manufactured at source is transported as:
a)      Glucose
b)      Sucrose
c)       Starch
d)      Fructose

Q72. Which of the following experiment proves that phloem is the tissue responsible for translocation of food?
a)      Girdling Experiment
b)      Avena Curvature Experiment
c)       Guttation Experiment
d)      None of the above


ANSWE|RS: 

1. e                                                               
2. d
3. c
4. a
5. c
6. e
7. a
8. a
9. e
10. d
11. b
12. b
13. a
14. e
15. e
16. a
17. d
18. d
19. d
20. d
21. d
22. a
23. c
24. a
25. a
26. a
27. a
28. d
29. a
30. a
31. b
32. b
33. b
34. a
35. a
36. a
37. a
38. c
39. b
40. e
41. d
42. a
43. a
44. c
45. a
46. b
47. a
48. a
49. c
50. a
51. a
52. b
53. a
54. b
55. a
56. e
57. d
58. e
59. d
60. c
61. c
62. d
63. b
64. e
65. e
66. d
67. a
68. a
69. b
70. c
71. c
72. a





























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