ICSE class 8 Biology solutions

Chapter –Transportation of food and minerals in plants

1.Define the following

(a)Osmosis - osmosis is the process by which water molecules moves from a weaker solution to a stronger solution  through a partially permeable membrane.There are basically two types of osmosis—Endosmosis and Exosmosis.

(b)Transpiration- transpiration is the process of loss of water in vapour from the leaves in plants.

(c)Diffusion- diffusion is the movement of particles from a higher concentration  to a low concentration until they are spread out evenly. 

                   

 (d)Root pressure- root pressure is the pressure under which water moves from a living cell of a root into the xylem.

2.Describe the functions of the following:-

(a)Xylem- Xylem tissues are also called as the conducting tissues, their major function is to conduct water and minerals from the roots of the plant to the plant body.

(b)Phloem-  The phloem tissues are also called as the conducting tissues , their major function is the transportation of the food materials synthesized in the leaves to the plant body.

3.Answer the following questions:-

Qa.Name two aspects of transport in higher plants?

Ans-In higher plants there are special tubes called the xylem and phloem ,which comprises of conducting tissues or vascular tissues .It is through these tubes that the transport of materials take place .There are two aspects of transport of substances in higher plants:-

1. Movement of water and minerals- takes place from the roots upward to the other plant parts.This movement takes place through the stem and its branches.

2. Movement of food materials-synthesised in the leaves ,to the other plant parts.

Qb. How does the transport of materials take place in unicellular plants?

Ans-Diffusion is a major method by which the transport of materials occurs in a single celled organisms like chlamydomonas  and simple multicellular organisms like spirogyra.

Qc.What are the root hairs? Mention the functions performed by the root hairs?

Ans-There are certain unicellular microscopic hairs present in the roots these are called as the root hairs .water passes into the root hair by the process of osmosis, there major function is to absorb the water and mineral salts present in the soil.

Qd. How does movement and absorbtion of water take place through the roots?

Ans-The movement and absorbtion of water in the roots takes place through the root hairs.This process is conducted through the osmosis ,(osmosis is aspecial kind of diffusion involving the water molecules)

There are tiny holes in the membrane which allow the small water molecules to pass through them.

Qe.Name the process by which water loss takes place trough the leaves?

Ans-Transpiration Is the process of loss of water in the form of vapour  from the leaves in the plants ,it occurs trough the stomata present in the leaves by the process of diffusion.

Qf.Mention the significance of transpiration?

Ans-The significance of the transpiration is as followed:-

(1) It results in the transport of water and minerals from the soil to the leaves.In the leaves , water forms the raw materials for photosynthesis.

(2)  It produces a cooling effect which helps in preventing hot sunlight from damaging delicate leaves.

Qg. Differentiate between :-

1. Osmosis and transpiration

Ans- Osmosis is the process by which water molecules move from a weaker solutions move to a stronger solution while Transpiration is the process of loss of water in vapour from the leaves in plants.

 Osmosis occurs through a partially permeable membrane in the roots while Transpiration occurs to stomata in the leaves.

2. Micronutrients and macronutrients

Ans- Macronutrients are those nutrients which are required in large quantities while the Micronutrients are those nutrients which are required in trace amounts.

The examples of macronutrients are-carbon, hydrogen ,oxygen .

.The examples of micronutrients are- chlorine, copper and boron.

Qh.What are the factors affecting transpiration?

Ans-The factors affecting the transpiration are:-

1. Intensity of light

2. Temperature

3. Wind

4. Humidity of the atmosphere

5.  Availibility of soil water

Qi.  What are the importance of minerals?

Ans- The importance of minerals are:-

1. Essential for the growth of plants

2. Involved in the nutrition of plants

3. In the absence, either the vegetative or reproductive phase cannot be completed.

4. In the case of deficiency ,disorders may develop, which can only be corrected by the supply of  that mineral. 

  KEY WORDS

1. Diffusion is the method of transport of materials in single celled and simple multicellular plants.

2. In tall plants diffusion is too slow .It cannot move materials quickly enough and in sufficient quantities so conducting tissues  in plants have developed.

3. A plant does not have blood or a heart.

4. Circulation in plants is carried out by a liquid called sap, movement of sap occurs through xylem and phloem  elements.

5. Sap does the same job for plants as blood does for animals.

6. Living root cells produce energy that is used to  help in the take up of water.

           --------------END----------------