Goa Board Class 7 Solutions for Science – Transportation in Animals and Plants (English Medium)
Page No. 131:
Question 1:
Solution :
Question 2:
Fill in the blanks.
(i) The blood from the heart is transported to all parts of the body by the______.
(ii) Haemoglobin is present in ______ cells.
(iii) Arteries and veins are joined by a network of ______.
(iv) The rhythmic expansion and contraction of the heart is called ____________.
(v) The main excretory product in human beings is ______.
(vi) Sweat contains water and ______.
(vii) Kidneys eliminate the waste materials in the liquid form called ______.
(viii) Water reaches great heights in the trees because of suction pull caused by ______.
Solution :
(i) Arteries
(ii) Red blood
(iii) Capillaries
(iv) Heart beat
(v) Urea
(vi) Salts
(vii) Urine
(viii) Transpiration
Concept insight: Important from Exam Point of View.
Page No. 132:
Question 3:
Choose the correct option:
(a) In plants, water is transported through
(i) xylem
(ii) phloem
(iii) stomata
(iv) root hair
(b) Water absorption through roots can be increased by keeping the plants
(i) in the shade
(ii) in dim light
(iii) under the fan
(iv) covered with a polythene bag
Solution :
(a) (i) xylem
Concept insight: Xylem transports water and minerals from soil to leaves.
(b) (iii) under the fan
Concept insight: When plant will be kept under the fan transpiration rate will increase thus plants will absorb more water.
Question 4:
Why is transport of materials necessary in a plant or in an animal? Explain.
Solution :
Transport of materials is necessary in both plants and animals because:
i.Each and every cell needs a constant supply of oxygen and food (water and nutrients in plants).
ii.Also, waste produced during respiration and other life processes are to be excreted otherwise they will cause harm to the organism.
Concept insight: This question is important from exam point of view. Transport is necessary in multicellular organisms so that each and every cell can get food and oxygen and can expel out waste.
Question 5:
What will happen if there are no platelets in the blood?
Solution :
If there are no platelets in the blood, then the blood would not be able to clot. A clot is formed because of platelets. They release blood clotting chemicals at the site of injury. These chemicals form a clot and prevent further bleeding.
Concept insight: Blood has four components. RBC’s, WBC’s, Plasma and Platelets. Platelets help in blood clot formation.
Question 6:
What are stomata? Give two functions of stomata.
Solution :
Stomata are tiny pores present on the surface of a leaf.
Functions of stomata:
(a) Stomata help in the exchange of gases.
(b) Evaporation of water from the leaf surface occurs through stomata.
Concept insight: Stomata help in exchange of gases.
Question 7:
Does transpiration serve any useful function in the plants? Explain.
Solution :
Transpiration is the evaporation of water from the plants. The water evaporates through the stomata present on the surface of the leaves. It is called a necessary evil because:
i.It helps in lowering the temperature of plant thus prevents heat injury to the plant.
ii.Due to transpirational pull water rises in higher plants.
iii.It also causes loss of water absorbed by plants.
Concept insight: Important question from exam point of view. Transpiration is a necessary evil because it lowers the temperature of plant and helps in water absorption by roots.
Question 8:
What are the components of blood?
Solution :
The main components of blood are:
a) Red blood cells (RBCs): Red blood cells are the most abundant cells in the blood. These cells contain a red pigment called haemoglobin. It is the haemoglobin which carries oxygen and transports it to all parts of the body.
b) White blood cells (WBC’s): These cells can change their shape and help body in fighting against diseases. Thus, they constitute the immune system of the body.
c) Platelets: They help in blood clot formation thus prevents excessive bleeding from wounds.
d) Plasma: All the blood cells are present in plasma. It also contains dissolved nutrients.
Concept insight: List the components of blood and their functions.
Question 9:
Why is blood needed by all the parts of a body?
Solution :
Blood is needed by all parts of the body as it is an important part of the transport system of our body. It performs the following important functions:
(i) It transports O2 from the lungs to all the body cells.
(ii) It carries CO2, a waste product back to the lungs so that it can be exhaled easily.
(iii) It transmits heat, thus regulating the body temperature.
(iv) It also fights off diseases and infections.
Concept insight: Blood carries oxygen and food to all the cells and takes waste substances to kidneys and lungs.
Question 10:
What makes the blood look red?
Solution :
The presence of haemoglobin, a red pigment in the red blood cells (RBC’s) makes blood appear red in colour. The haemoglobin carries oxygen and transports it to all the parts of the body.
Concept insight: Haemoglobin is red pigment present in blood due to which blood looks red.
Question 11:
Describe the function of the heart ?
Solution :
Question 12:
Why it is necessary excrete waste products ?
Solution :
All cells of our body produce waste products. These waste products are toxic to the body and therefore need to be excreted out. This process of removing waste product produced in the cells of living organisms is called excretion.
Concept Insight: Waste products are toxic to our body. So, it is necessary to excrete them regularly.
Question 13:
Draw a diagram of the human excretory system and label the various parts.
Solution :