Transportation in Plants ICSE Class-8th Concise Selina Biology Solutions
Transportation in Plants ICSE Class-8th Concise Selina Biology Solutions Chapter-1 .We Provide Step by Step Answer of Objective, True False , Fill in the blanks ,Match the following , Short/Long Answer Type of Exercise-1 Transportation in Plants. Visit official Website CISCE for detail information about ICSE Board Class-8.
Transportation in Plants ICSE Class-8th Concise Selina Biology Solutions Chapter-1
Multiple Choice Questions:
1. Put a tick mark (✓) against the correct alternative in the following statements:
(a) Diffusion occurs when molecules move:
- from lower concentration to higher concentration.
- from higher concentration to lower concentration through a membrane.
- They are from higher concentration to lower concentration.
- when energy is used.
Answer: (3) from higher concentration to lower concentration.
(b) Ascent of sap in plants takes place through:
Answer: (3) Xylem
(c) If the xylem vessels of a plant are plugged:
- The leaves will turn yellow
- No food will be made
- The plant will wilt (shrivel)
- The plant will continue to grow
Answer: (3) The plant will wilt (shrivel)
(d) Force responsible for the ascent of sap is:
- Capillary force
- Root pressure
- Transpirational pull
- All the three
Answer: (4) All the three
(e) Raisins swell when put in:
- Rain water
- Tap water
- Mustard oil
- Saturated sugar solution
Answer: (1) Rain water
(f) The root-hairs are suited for absorbing water from the soil because:
- They have a large surface area
- and They have a semi-permeable membrane
- They contain a solution of higher concentration than the surrounding water.
- All the three.
Answer: (4) All the three.
(g) Transpiration is defined as:
- the rise of water up to the stem of a plant.
- the elimination of water with dissolved water products.
- the loss of water as water vapour from the aerial parts of a plant.
- the loss of water as water vapour from the roots as well as the leaves of the plant.
(3) the loss of water as water vapour from the aerial parts of a plant.
(h) Which one of the following favours the fastest transpiration rate ?
- A cool, humid, windy day,
- A hot, humid, windy day,
- hot, humid, still day,
- A hot, dry, windy day.
Answer: (4) A hot, dry, windy day.
Short Answer Questions:
An experiment was set up as shown in the figure below. After some time, the Water level in test tube A fell down but not in test tube B
Why was there a fall in the water level of test tube A and not in that of test-tube B ?
In test tube A the water level falls because the water was absorbed by the plant through its roots dipped in water. Here no water loss occurs due to evaporation from the water surface due to presence of oil.
In test tube B the water level remains unchanged as it does not contain a rooted plant. Due to the presence of oil on surface no water loss occurs due to evaporation.
How are roots useful to the plants? Give any two points.
Roots are useful to the plants in the following way:
- It absorbs water and minerals from the soil and transport it upward to various parts of a plant.
- Roots fix the plant firmly in the ground.
What do xylem vessels carry?
The xylem vessels carry the water and minerals absorbed by the roots to the stem and leaves.
Name the plant tissue which helps in carrying the food to different parts.
Define the terms:
(a) semi-permeable membrane
(a) Semi-permeable membrane:
It is a membrane that allows the movement of solvent molecules (e.g. water molecules) through it but prevents the movement of solute particles (e.g. sugar or salt molecules).
For example: Egg membrane, parchment membrane, cellophane paper etc. are semi-permeable membranes.
The diffusion of water molecules through a semi-permeable membrane from a region where water is more concentrated to a region where it is less concentrated is called osmosis.
In other words, osmosis is the diffusion of water from its pure state or dilute solution into a stronger or concentrated solution through a semi-permeable membrane.
Under what conditions do plant transpire (a) more quickly and (b) most slowly?
(a) Transpiration is faster on hot summer days as compared to cold winters.
(b) Transpiration is reduced if the air is humid. Air cannot hold any water molecules when it is already laden with moisture (humidity).
Given here is an enlarged diagram of a part of the root. Draw arrows on the diagram to show the movement of water passing through different parts.
Path of water through the root hair to the xylem vessels.
Why is the structure of the root hair is quite suitable for absorbing water from the soil ?
The root hair are suitable for absorbing water from the soil in the following three ways:
- The root hairs present a large surface area. More the surface area, greater is absorption.
- The cell wall is of cellulose nature and forms permeable membrane and the plasma membrane around the vacuole forms the semi-permeable membrane.
- Root hairs have solution (cell sap) of a higher concentration than the surrounding soil water.
In an experimental set-up, a dye was placed at the bottom of a beaker filled with water as shown in figure A, below. After some time, the entire water in the beaker got coloured uniformly as shown in figure D.
Name and define the phenomenon shown in the experiment.
Answer: The phenomenon is diffusion. Diffusion is the movement of the molecules or atoms of a substance (whether in a solid, liquid or gaseous state) from the region of higher concentration to the region of lower concentration.
In all the four figures, two kinds of molecules are shown symbolically – larger and smaller. Which molecules are of the solute and which are of the solvent?
(a) Larger: ………… (b) Smaller: …………..
Answer: (a) The larger molecules are of the solute (dye)
(b) The smaller molecules are of the solvent (water)
If all the dark shaded molecules in A are tightly enclosed in a cell membrane, what will be the nature of movement of the molecules, if any ?
Answer: As the concentration of solvent molecules is more in the left side of the figure A. The cell membrane will act as semi permeable membrane and will allow only the solvent molecules of water to move towards the solute particles. So the solvent molecules will move towards the solute particles. This will show the phenomenon or process of osmosis.
Briefly explain, how transpiration helps in upward conduction of water in plants? (a) ………… (b) ……………