STPM Biology 2022 Term 1 MCQ

Which is not true about protein?

• The a-helix and P-pleated sheets are formed by the hydrogen bond only.

• The insoluble denatured forms could be renatured if placed in a suitable condition.

• The conformation depends on the physical and chemical environments.

• The sequence of amino acids determines its function.

Which are true about DNA molecules according to Watson and Crick's model?

• I and III

• I and IV

• II and III

• II and IV

The components of native protein of a cell are isolated and analysed using electrophoresis. The components could not be distinctly separated although accurate procedures of electrophoresis are followed. Which is the possible cause of the problem?

• The net charges are identical

• The masses are the same

• The shapes are different

• The sizes are varied

Which is true about the mosaic pattern of the fluid mosaic model of Singer-Nicolson?

• Lipids move laterally within the single layer.

• The transmembrane proteins function as the receptor.

• The characteristic of phospholipid bilayer is amphipathic.

• The attached proteins are constantly moving in the bilayer.

Which structure distinguishes prokaryotes and eukaryotes?

• Cell wall

• Plasma membrane

• Ribosome

• Endoplasmic reticulum

A cross section of a plant stem is shown in the diagram. Which parts of the stem consist of the meristematic tissues?

• W and Y

• W and Z

• X and Y

• X and Z

A U-tube which contains sucrose solution of different concentrations is shown in the diagram. Which statements are true about the water potential, the pressure potential and the solute potential of the sucrose solutions in both arms of the U-tube?

I The water potential in the right arm is zero.

ll The solute potentials in both arms are negative.

Ill The water potential in the left arm is lower than that of the right arm.

IV The solute potential in the right arm is more negative than that of the left arm.

• I and III

• I and IV

• II and III

• II and IV

The rate of reaction against temperature in an enzyme catalysed reaction is shown in the graph. Which is true about P and Q?

• P: The kinetic energies of the substrate and the enzyme increase.
  Q: The kinetic energies of the substrate and the enzyme decrease.

• P: The concentration of the substrate increases.

  Q: The concentration of the substrate decreases.

• P: The number of collisions between the enzyme and substrate increases.

  Q: The hydrogen and ionic bonds of the enzyme break.

• P: The formation of the enzyme-substrate complex increases.

  Q: The peptide bonds and disulphide bridges of the enzyme break.

An enzyme immobilisation technique is shown in the diagram. Which is not true about the technique?

• The enzymes remain in the natural state.

• The method is called an entrapment of enzymes.

• The enzymes are chemically bound to the lattice.

• The interaction between large molecules and enzymes is difficult.

Which are the similarities between Fe²⁺ and FAD in an enzymatic reaction?

• I and III

• I and IV

• II and III

• II and IV