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Life Processes

Exemplar MCQ 3

Which of the following is an incorrect statement?

1. Organisms grow with time
2. Organisms must repair and maintain their structure
3. Movement of molecules does not take place among cells
4. Energy is essential for life processes
   
   Answer:(c) Movement of molecules does not take place among cells

The internal (cellular) energy reserve in autotrophs is

1. Glycogen
2. Protein
3. Starch
4. Fatty acid
   
   Answer: (c) Starch [Plants store food in the form of starch]

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Choose the event that does not occur in photosynthesis

1. Absorption of light energy by chlorophyll
2. Reduction of carbon dioxide to carbohydrates
3. Oxidation of carbon to carbon dioxide
4. Conversion of light energy to chemical energy
   
   Answer: (c) Oxidation of carbon to carbon dioxide [Reduction of carbon dioxide releases oxygen which is utilised for making carbohydrates.]

The opening and closing of the stomatal pore depends upon

1. Oxygen
2. Temperature
3. Water in guard cells
4. Concentration of CO₂ in stomata
   
   Answer: (c) Water in guard cells [Entry of water in guard cells results in opening of stoma and reverse of it results in closing of stoma.

Choose the forms in which most plants absorb nitrogen

1. Proteins
2. Nitrates and Nitrites
3. Urea
4. Atmospheric nitrogen

1. (1) and (2)
2. (2) and (3)
3. (3) and (4)
4. (1) and (4)
   
   Answer: (b) (2) and (3) [Protein is made by plants by utilising nitrogen. Plants cannot take up atmospheric nitrogen.]

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Which is the first enzyme to mix with food in the digestive tract?

1. Pepsin
2. Cellulase
3. Amylase
4. Trypsin
   
   Answer: (c) Amylase [salivary amylase from saliva is the first enzyme to mix with food.]

Which of the following statement(s) is (are) correct?

1. Pyruvate can be converted into ethanol and carbon dioxide by yeast
2. Fermentation takes place in aerobic bacteria
3. Fermentation takes place in mitochondria
4. Fermentation is a form of anaerobic respiration

1. (1) and (3)
2. (2) and (4)
3. (1) and (4)
4. (2) and (3)
   
   Answer: (c) 1 and (4) [Fermenation is a form of anaerobic respiration whic takes place in cytoplasm and liberates ethanol/lactic acid and carbon dioxide.]

Lack of oxygen in muscles often leads to cramps among cricketers. This results due to

1. Conversion of pyruvate to ethanol
2. Conversion of pyruvate to glucose
3. Non conversion of glucose to pyruvate
4. Conversion of pyruvate to lactic acid
   
   Answer: (d) Conversion of pyruvate to lactic acid [Accumulation of lactic acid in muscles results in muscle cramps.]

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Choose the correct path of urine in our body

1. kidney → ureter → urethra → urinary bladder
2. kidney → urinary bladder → urethra → ureter
3. kidney → ureters → urinary bladder → urethra
4. urinary bladder → kidney → ureter → urethra
   
   Answer: (c) kidney → ureters → urinary bladder → urethra

During deficiency of oxygen in tissues of human beings, pyruvic acid is converted into lactic acid in the

1. Cytoplasm
2. Chloroplast
3. Mitochondria
4. Golgi body
   
   Answer: (a) Cytoplasm [Lactic acid is formed after anaerobic respiration in muscle cells and this happens in cytoplasm.]

Which of the following shows the correct equation for photosynthesis?

1. 6CO₂ + 12H₂O → C₆H₁₂O₆ + 6CO₂ + 6H₂O
2. 6CO₂ + H₂O + Sunlight → C₆H₁₂O₆ + O₂ + 6H₂O
3. 6CO₂ + 12H₂O + Chlorophyll + Sunlight → C₆H₁₂O₆ + 6O₂ + 6H₂O
4. 6CO₂ + 12H₂O + Chlorophyll + Sunlight → C₆H₁₂O₆ + 6CO₂ + 6H₂O
   
   Answer: (c) 6CO₂ + 12H₂O + Chlorophyll + Sunlight → C₆H₁₂O₆ + 6O₂ + 6H₂O

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