"AKC SCIENCE CLASSES"
CLASS 10 TH (CBSE AND MP BOARD)
CHAPTER 06
LIFE PROCESSES
EXERCISE QUESTIONS AND ANSWERS
Q.01:- The kidneys in human beings are a part of the system for
(a) nutrition
(b) respiration
(c) excretion
(d) transportation.
Ans:- (c) excretion.
Q.02:- The xylem in plants is responsible for
(a) transport of water
(b) transport of food
(c) transport of amino acids
(d) transport of oxygen.
Ans:- (a) transport of water.
Q.03:- The autotrophic mode of nutrition requires
(a) carbon dioxide and water
(b) chlorophyll
(c) sunlight
(d) all of the above.
Ans:- (d) all of the above.
Q.04:- The breakdown of pyruvate to give carbon dioxide, water and energy takes place in
(a) cytoplasm
(b) mitochondria
(c) chloroplast
(d) nucleus
Ans:- (b) mitocondria.
Q.05:- How are fats digested in our bodies? Where does this process take places?
Ans:- Digestion of fat takes place in the small intestine.
Digestion of fat :- The fats are present in the form of large globules in the small intestine. Fats digesting enzymes are not able in act upon large globules efficiency.
Bile juice secreted by the liver is poured in the intestine along with pancreatic juice. The bile salts present in the bile juice emulsify the large globules of fats. So, by emulsifications large globules breakdown into fine globules to provide large surface area to act upon by the enzymes.
Lipase enzymes present in the pancreatic juice causes breakdown of emulsified fats. Glands present in the wall of small intestine secretes intestinal juice which contains lipase enzymes that converts fats into fatty acids and glycerol.
Small intestine :- Region of digestion of fats.
Q.06:- What is the role of saliva in the digestion of food?
Ans:- Role of saliva in digestion of food :-
(ⅰ) The saliva contains salivary amylase enzymes that breaks down starch to sugar like maltose.
starch + salivary amylase → sugar
(complex (simplar
molecules) molecules)
(ⅱ) The saliva moisten the food that help in chewing and breaking down the big pieces of food into smaller ones. So, that salivary amylase can digest the starch efficiently.
Q.07:- What are the necessary conditions for the autotrophic nutrition and what are its by-products?
Ans:- Necessary conditions for autotrophic nutrition :-
(ⅰ) Presence of chlorophyll in the living cells.
(ⅱ) Provision of supply of water to green parts or cells of the plant either through roots or by surrounding environment.
(ⅲ) Availability of sufficient sunlight to provide light energy required to carry out photosynthesis.
(ⅳ) Sufficient supply of carbon dioxide which is one of the important components for the formation of carbohydrates during photosynthesis.
Q.08:- Name some organisms that use the anaerobic mode of respiration.
Ans:- Organisms which use anaerobic respirations are yeasts, bacteria, and parasites like tape worm (Taemia), Ascaris etc.
Q.09:- How are the alveoli designed to maximize the exchange of gases?
Ans:- (ⅰ) The alveoli are thin-walled and richly supplied with a network of blood vessels to facilitate exchange of gases between blood and the air filled in alveoli.
(ⅱ) Alveoli have balloon like structure. Thus, provides maximum surface for exchange of gases.
Q.10:- What would be the consequences of a deficiency of haemo-globin in our bodies?
Ans:- The average haemoglobin content of blood, irrespective of sex, is 14.5 g per 100 ml. If haemoglobin content reduces in blood, its oxygen carrying capacity decreases. So, the person shows symptoms of deficient oxygen such as breathlessness, often one of the first indications of iron deficiency, anaemia.
Q.11:- Describe double circulation in human beings. Why is it necessary?
Ans:- Double circulation :- In human beings the blood goes through the heart twice during each cycle i.e., the blood passes through the human heart two times to supply once to the whole body. So, it is called double circulation of blood.
The double circulation of blood includes
(ⅰ) Systemic circulation and
(ⅱ) Pulmonary circulation.
(ⅰ) Systemic circulation :- It supplies oxygenated blood from left auricle to left ventricle thereby pumped to various body parts. The deoxygenated blood is collected from the various body organs by the veins to pour into vena cavae and finally into right atrium (auricle). Right atrium transfers the blood into the right ventricle.
(ⅱ) Pulmonary circulation :- The deoxygenated blood is pushed by the right ventricles into the lungs for oxygenation. The oxygenated blood is brought back to left atrium of the human heart. From left atrium the oxygenated blood is pushed into the left ventricle. The left ventricle pumps oxygenated blood into aorta for systemic circulation.
Necessity of double circulation :- The right side and left side of the human heart is useful to keep deoxygenated and oxygenated blood from mixing. This type of separation of oxygenated and deoxygenated blood ensures a highly efficient supply of oxygen to the body. This is useful in case of humans which constantly require energy to maintain their body temperature.
Q.12:- What are the differences between the transport of materials in xylem and phloem?
Ans:- The difference are as follows :-
| SL No. | Xylem | Phloem |
|---|---|---|
| 1 | Xylem conducts water and dissolved minerals from roots to leaves and other parts. | Phloem conducts prepared food material from leaves to other parts of plant in dissolved form. |
| 2 | In xylem, the transport of material take place through vessels and tracheids which are dead tissues. | In phloem, transport of material takes place through sieve tubes with the help of companion cells, which are living cells. |
| 3 | In xylem, upward movement of water and dissolved minerals is mainly achieved by transpiration pull. It is caused due to suction created by evaporation of water molecules from the cells of leaves. | In translocation, material is transferred into phloem tissue using energy from ATP. This increases the osmotic pressure that moves the material in the phloem to tissues which have less pressure. |
| 4 | Movement of water is achieved by simple physical forces, there is no expenditure of energy. So ATP molecules are not required. | The translocation in phloem is an active process and requires energy. This energy is taken from ATP. |
Q.13:- Compare the functioning of alveoli in the lungs and nephrons in the kidneys with respect to their structure and functioning.
Ans:- Comparison between Alveoli and Nephron
| SL No. | Alveoli | Nephron |
|---|---|---|
| 1 | Alveoli have thin walled balloon like structure. Surface is fine and delicate. | Nephron have thin walled cup shaped structure attached with thin walled tubule. |
| 2 | Alveoli are supplied with extensive network of thin walled blood vessels i.e., capillaries for exchange of gases. | Bowman's capsule is supplied with a cluster of capillaries, called glomerulus for filtration. A network of blood vessels around the tubular part of nephron for reabsorption of useful substances and water. |
| 3 | Alveoli increase surface area for diffusion of CO2 from blood to air and O2 from air to blood. | Nephrons also increases surface area for filtration of blood and reabsorption of useful substances and water from filtrate leaving behind urine. |
| 4 | Alveoli only provide surface for exchange of gases in the lungs. | Tubular part of nephron also carries the urine to collecting duct. |
| 5 | Alveoli are very small and a large number of them are present in each lung. | A large number of nephrons, basic filtration unit, are present in each kidney. |
