14

Q1. What are respiratory substances?

Solution

Substances which are oxidised during the process of respiration are called respiratory substances.

Q2. Name the enzyme which catalyses the conversion of sucrose into glucose and fructose.

Solution

Invertase

Q3. State the two products formed during glycolysis by the splitting of fructose-1,6-bisphosphate. State the relationship between NADH + H⁺.  

Solution

The splitting of fructose-1,6-bisphosphate during glycolysis forms glyceraldehydes-3-phosphate and dihydroxyacetone phosphate.     1 NADH + H⁺is equivalent to three molecules of ATP.  

Q4. Name the pathway discovered by Gustav Embden, Otto Meyerhof and J. Parnas.

Solution

Glycolysis or EMP pathway

Q5. State the factor on which the respiratory quotient depends.

Solution

The respiratory quotient depends on the type of respiratory substrate used in respiration.

Q6. State the term used for organisms which feed on dead and decaying matter.

Solution

Saprophytes

Q7. How many ATP molecules are generated from one pair of hydrogen atoms or one pair of electrons from NADH₂?

Solution

3 ATP molecules are generated from one pair of hydrogen atoms

Q8. Name the component which transfers electrons from ubiquinol to cytochrome c.   

Solution

Cytochrome bc₁ or complex III transfers electrons from ubiquinol to cytochrome c.   

Q9. Where does the electron transport system take place in the mitochondrion? 

Solution

The electron transport system takes place in the inner membrane of the mitochondrion. 

Q10. What do you understand by the term cellular respiration?

Solution

The term cellular respiration indicates the oxidation of certain macromolecules and the breaking of C-C bonds present in these molecules in the cells to release energy.

Q11. Give the schematic representation of the TCA cycle.  

Solution

TCA Cycle:        

Q12. Write the other name of complex IV. 

Solution

The other name of complex IV is cytochrome c oxidase complex. 

Q13. Write the chemical equations for the Krebs cycle.  

Solution

Q14. State the net gain of ATPs by the oxidation of one glucose molecule.

Solution

38 ATP

Q15. Give the schematic representation of the pathway for anaerobic respiration.

Solution

Pathway of anaerobic respiration:  

Q16. Name the enzymes which catalyse the incomplete oxidation of glucose in yeasts.  

Solution

Pyruvic acid decarboxylase and alcohol dehydrogenase  

Q17. How many molecules of NADH + H⁺ are formed from one molecule of glucose?

Solution

Two molecules of NADH + H⁺are formed from one molecule of glucose.

Q18. How many molecules of pyruvate are formed from one molecule of glucose?

Solution

Two molecules of pyruvate are formed from one molecule of glucose.

Q19. What is the first step of the TCA cycle?

Solution

The first step of the TCA cycle is the condensation of the acetyl group of acetyl CoA with oxaloacetic acid and water to obtain citric acid.

Q20. In which form do the proteins enter the respiration pathway?

Solution

Acetyl CoA

Q21. What will be the RQ if tripalmitin is used as a substrate in respiration?  

Solution

0.7  

Q22. Write the chemical equation of the complete combustion of glucose during respiration.  

Solution

 

Q23. Name the isomer of glucose-6-phosphate formed during glycolysis.  

Solution

Fructose-6-phosphate  

Q24. Name the molecule which is synthesised with the help of F₀ and F₁ particles.   

Solution

ATP   

Q25. State the components of complex IV. 

Solution

Cytochrome a, cytochrome a₃ and two copper centres are the components of complex IV. 

Q26. Write the chemical equation for the decarboxylation of pyruvic acid to acetyl CoA.  

Solution

Q27. Draw a flowchart explaining the interrelationship between the metabolic pathway and the breakdown of different molecules into CO₂ and H₂O.

Solution

 

Q28. Name the two products formed by two successive decarboxylations in the TCA cycle.

Solution

α-ketoglutaric acid and succinyl CoA

Q29. State the site where the oxidative decarboxylation of pyruvic acid takes place.

Solution

Matrix of mitochondrion

Q30. State the net gain of ATP during glycolysis.

Solution

8 molecules of ATP

Q31. How are fats utilised as substrates in aerobic respiration?

Solution

Fats are first broken down into glycerol and fatty acids. Fatty acids are first degraded to acetyl CoA and then they enter the TCA cycle. Glycerols are converted into phosphoglyceraldehyde, and they can then enter the glycolytic pathway.

Q32. What is the value of RQ in germinating wheat grains?

Solution

Respiratory substrate in germinating wheat grains is carbohydrate. When carbohydrates are completely oxidized, RQ is equal to 1.

Q33. State the site of glycolysis in the cell.

Solution

Cytoplasm

Q34. Give the schematic representation of the EMP pathway (glycolysis).  

Solution

EMP Pathway:        

Q35. Draw a well-labelled diagram indicating the synthesis of ATP in mitochondria.   

Solution

Synthesis of ATP in mitochondria:        

Q36. Name the component responsible for the transfer of electrons between complex III and complex IV.

Solution

Cytochrome c

Q37. Describe the first step of TCA cycle.

Solution

The first step is the condensation step which involves the condensation of acetyl CoA with oxaloacetic acid to form citric acid in presence of water.

Q38. How would proteins enter the respiratory pathway?  

Solution

Proteins are first degraded into amino acids by enzyme proteases.     The amino acids either enter the pathway immediately or first get degraded to pyruvate or acetyl CoA.  

Q39. What is the significance of Krebs cycle?

Solution

Krebs cycle serves as a common oxidative pathway for carbohydrates, proteins and fats. The end products of glucose and amino acid change to acetyl co-A to enter Krebs cycle whereas β-oxidation of fatty acid produces acetyl co-A as the end product.          β

Q40. Name the substance which is released during the formation of citric acid in the TCA cycle.

Solution

CoA

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