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Public Service Commission Biology MCQs
Q.1: The active site of an enzyme——-?
- Never changes
- Forms no chemical bond with substrate
- Determined by structure and the specificity of the enzyme
- They are non specific in their action
Q.2: Factory of Ribosomal systhesis is—–?
- Endoplasmic reticulum
Q.3: If more substrate to already occurring enzymatic reaction is added and there is no effect on the rate of the reaction what is the form given to this situation——?
Q.4: Who opposed the idea the cell is an empty space bounded by thick wall?
- Lorenz Oken
- Robert Brown
- Rudolph Virchow
Q.5: Extreme change in pH results in——-?
- Change in ionization of amino acids at the active site of the enzyme
- Change in the ionization of the substrate
- Denaturation of the enzyme
- Increase in the reaction rate
Q.6: Resolution power of a compound microscope is——?
- 2.0 m
- 2-4 A
- 24 m
- 24 A
Q.7: Excessive increase in temperature of medium causes the enzyme molecule to——?
- None of these
Q.8: If enzyme concentration is low than substrate pH and temperature values are equal to requirement then which of the following will increase rate of reaction———-?
- increase in concentration of enzyme
- increase in concentration of substrate
- increase in pH
- increase in temperature
Q.9: In cell fractionation various components of cells including its organelles can be isolated in different layers depending upon——?
- Their physical properties like size And weight.
- Physical properties of the medium like its density.
- Their electrical properties like their charges
- Both a and b
Q.10: The structure of an enzyme is altered by——?
- Irreversible inhibitor
- Reversible inhibitor
- Competitive inhibitor
- Non-competitive inhibitor