IGCSE Biology Paper-2: Specimen Questions with Answers 106 - 107 of 203

Question 106

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Question

MCQ▾

The photograph shows a cross-section of a root.

The photograph shows a cross-section of a root

The Photograph Shows a Cross-Section of a Root

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From root hair to the xylem, water transport takes place through which method?

Choices

Choice (4)
a.By Apoplastic and Symplastic Pathway
b.By Simple Diffusion
c.By Apoplastic Pathway
d.By Symplastic Pathway

Answer

a.

Explanation

Pathways of Water movements in roots

  • Movement of water from root hair cell to xylem may occur by two methods.
    • Symplast pathway: Water passes from cell to cell by their protoplasm. It involves living continuum cytoplasm & plasmodesmata.
    • Apoplast pathway: Water moves from root hair cell to xylem through cell wall and intercellular spaces.
  • Movement of water from root hair to cortex may be symplastic or Apo plastic. Endodermis has casparian strips so that the movement of water takes place through Symplast.
Pathways of Water movements in roots

Pathways of Water Movements in Roots

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Question 107

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MCQ▾

The diagram shows a plant cell, which has lost water when placed in hypertonic solution for long time.

The diagram shows a plant cell

The Diagram Shows a Plant Cell

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Which part of plant cell is the partially permeable membrane?

Choices

Choice (4)
a.3
b.2
c.1
d.4

Answer

a.

Explanation

  • A permeable membrane allows all substances to flow freely across the membrane. A semi-permeable membrane allows some substances to cross the membrane, but not others. An impermeable membrane blocks the movement of all substances.
  • Semipermeable membrane is a type of biological or synthetic, polymeric membrane that will allow certain molecules or ions to pass through it by diffusion or by other processes, occasionally by more specialized processes of facilitated diffusion, passive transport, or active transport.
  • The rate of passage depends on the pressure, concentration, and temperature of the molecules or solutes on either side, as well as the permeability of the membrane to each solute. Depending on the membrane and the solute, permeability may depend on solute size, solubility, properties, or chemistry of the molecule.
Types of Membrane

Types of Membrane

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