Organization in the Living World-Conceptual Questions with Answers
Question 1. In Arctic area where temperature is recorded in minus degrees and land is frozen we can see polar bears. What made their survival possible in such conditions?
In animals, fat storing adipose tissue is found below the skin and between internal organs. The cells are filled with fat globules.
This fat layer acts as an insulator. Polar bears are equipped for survival in arctic area due to presence of 2 coats of insulating fur and a very thick layer of body fat. This thick fat layer protects the animal from outside cold.
Question 2. Although a layer of fat is present below the skin in all animals, man needs to wear woolen clothes in winter but cows and buffaloes don’t. Why?
A layer of body fat is present in man as well as in cows and buffaloes. But this layer is very thin in man and is not sufficient to protect from outside .cold, however it is thick enough to protect cows and buffaloes from cold.
Question 3. An accident case with brain injury is considered more critical than an accident case with fractured arm. Why?
All the cells of our body except nerve cells or neurons have power of regeneration and healing. Cells of arms regenerate and repair and wound heals after sometime. But nerve cells or neurons lacks the power of regeneration. They can’t be repaired after a wound. Therefore, any injury to the brain cells could lead to any permanent disorder of brain.
Question 4. Study of muscles fibers show abundant mitochondria in their cells as compared to other tissues. Give reason.
Muscles help in the movement of our body. For this they require a lot of energy. To fulfill this energy requirement, they have mitochondria in abundance in their cells as mitochondria produces energy rich compound ATP (Adenosine triphosphate) by respiration.
Question 5. Why blood is called ‘fluid connective tissue ?
Blood is called fluid connective tissue because it has liquid matrix plasma in which blood cells keep on floating. It circulates or flows in the body to transport oxygen, food, hormones and waste materials to the organs where they are required. Thus blood remains in contact with all organs of the body.
6. Match the following:
(i) Jute (a) Cutin
(ii) Bottle cork (b) Lignin
(iii) Cuticle (c) Suberin
(iv) Pear (d) Sclereids
(i) – (b), (ii) – (c), (iii) – (a), (iv) – (d).
Question 7. Though plant are exposed to Sun throughout the day. But they don’t burn. Explain.
Presence of enough water is necessary in plants to prevent them from burning in sun. Transpiration play an important role in absorbing water by plants. Transpiration is loss of water in the form of vapour from aerial parts of the plants through stomata. This loss of water creates a pressure in roots to absorb more water from the soil. Thus transpiration helps the plants in retaining enough water. Also transpiration causes cooling of plant surface and don’t let them burn.
Question 8. We feel pain when our finger is cut but we don’t feel pain on cutting nails. Give reason.
Nails are a type of modified skin. Nails are formed by keratinization. keratinization is the process by which cells becomes horny due to deposition of a protein called keratin. Nail cells are dead so we don’t feel pain on cutting them while finger cells are living.
Question 9. Xylem is poorly developed or absent in water plants or hydrophytes. Explain.
Xylem is a vascular tissue that helps in conduction of water in plants from roots to the leaves. But hydrophytes are water plants and their whole body remain in water. So, water simply diffuses in through general body surface of the plants. Hence, xylem is absent in hydrophytes.
Question 10. What kind of sclerenchymatous cells are found in Jute and Pear.
Jute – Fibres
Pear – Sclereids