CBSE CLASS X BIOLOGY
One mark questions with answers
Q1. What is a nutrient?
Ans1. A nutrient is an organic or an inorganic substance essential for the survival of a living being. Q2. Write down the components of food.
Ans2. The major components of food are carbohydrates, proteins, fats, minerals, vitamins, water and roughage. Q3. A food-stuff gives a red precipitate with Benedict's solution. Name the nutrient constituent of food indicated by the test. Ans3. Sugar.
Q4. A food-stuff shows a positive test with weak iodine solution. Name the nutrient content in the food-stuff. Ans4. Starch.
Q5. Which sugar is obtained from sugar cane?
Q6. Which carbohydrate is present in maize?
Two mark questions with answers
Q1. Why is mother's milk best for the baby?
Ans1. Mother's milk is a balanced diet containing lactose (milk sugar), fats, proteins, vitamins (except vitamin C), mineral salts (except iron) and antibodies (disease-fighting proteins). It is also easily digested and does not leave any waste matter. All these qualities make the mother's milk best for the baby's future growth, development and mental growth. Q2. What type of food should a pregnant woman be given?
Ans2. A pregnant woman should be given protein rich diet because she has to supply nutrition to the developing embryo in addition to her own requirements. Extra proteins are needed for tissue growth of the developing baby. A pregnant woman needs more carbohydrates and fats than usual to get extra energy to carry out all the building processes linked with the developing baby. Q3. Why are infants exposed to sunshine?
Ans3. New born babies are exposed to sun-light because vitamin D can be synthesised by the action of sun light on a cholesterol derivative present in skin. Vitamin D is essential for normal growth and development of bones and teeth. Q4. State the advantages and disadvantages of hydrogenation of oils. Ans4. Advantages of hydrogenation of oils :
(i) The advantage of hydrogenation of oils is that it produces solid fat which is more stable, more convenient to handle and use and has a better taste and flavour. (ii) The hydrogenated oils supply more energy than vegetable oils as such. Disadvantages of hydrogenation of oils :
(i) The disadvantage of hydrogenation of oils is that it eliminates most of the essential fatty acids as the latter polyunsaturated fatty acids. (ii) Excessive use of hydrogenated oils causes obesity which results in many problems such as blood pressure, increased cholesterol etc. Q5. What is food adulteration? Name one food adulterant.
Ans5. Food adulteration is the contamination of food materials with cheap, toxic and low quality substances, example- haldi is mixed with lead chromate. Lead chromate is a cheap & toxic substance. Hence, it acts as a food adulterant. Three mark questions with answers
Q1. What is the chemical composition of carbohydrates, fats and proteins respectively? Ans1. (i) Carbohydrates are the compounds made up of three elements carbon, hydrogen and oxygen, the proportion of hydrogen and oxygen being the same as in water. (ii) Fats are also made of the same elements as carbohydrates- carbon, hydrogen and oxygen, but the proportion of oxygen in fats is much less than that in carbohydrates. (iii) Proteins are the compounds made up of carbon, hydrogen, oxygen and nitrogen. Some of the proteins also contain sulphur. Q2. What are proteins? State two conditions which necessitate a high protein diet. Ans2. Proteins are the highly complex organic compounds made up of carbon, hydrogen, oxygen, nitrogen and sulphur etc. which are needed for the growth and repair of the body. Proteins are polymers of amino acids. Proteins in our body are present in the form of enzymes, hormones, transport proteins, structural proteins, contractile proteins, protective proteins and catalytic proteins. (i) A growing child needs a high-protein diet for the formation of body tissues. (ii) A...
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