Some more questions on Biology for students

102. When a person eats sugary food, then organisms A present in his mouth act on sugar to produce a substance B. The substance B first dissolves the calcium salts from the top part C of the tooth and then from its middle part D forming holes E. These holes ultimately reach the part F in the lower part of tooth which contains nerves and blood vessels. The substance B irritates the nerve endings inside the tooth causing toothache.

(a) What are (i) organisms A, and (ii) substance B?

(b) What are (i) part C, and (ii) part D, of tooth known as?

(c) By what name are the holes E in the tooth known?

(d) Name the part F of the tooth.

(e) What will happen if organisms A reach part F of the tooth?

103. If the teeth are not cleaned regularly, they become covered with a sticky yellowish layer W of food particles and bacteria. Since layer W covers the teeth, the alkaline liquid X secreted by glands Y inside the mouth cannot reach the teeth surface to neutralise the acid formed by the action of organisms Z on sugary food, and hence tooth decay sets in.

(a) What is W known as?

(b) What is (i) X, and (ii) Y?

(c) What are organisms Z?

(d) State one way of removing layer W from the teeth.

104. When a person puts food in his mouth, then teeth cut it into small pieces, chew and grind it. The glands A in the mouth secrete a substance B which is mixed with the food by tongue. The substance B contains an enzyme C which starts the digestion of food in the mouth. The slightly digested food from the mouth goes down a tube D. The special type of movements E in the walls of tube D pushes the food into stomach for further digestion. The stomach wall secretes gastric juice containing three substances F, G and H. One of the functions of F is to kill bacteria which may enter the stomach with food. The substance G protects the inside layer of stomach from the damaging effect of substance F whereas substance H is an enzyme for digestion. The partially digested food then enters into small intestine for further digestion.

(a) What is (;) gland A (ii) substance B, and (iii) enzyme C?

(b) Name the tube D.

(c) What is the movement E known as?

(d) What are (i) F (ii) G, and (iii) H?

105. The partially digested food coming from the stomach of a person enters a long and narrow organ A in his body. The organ A receives the secretions of two glands : liver and pancreas. Liver secretes a greenish- yellow liquid B which is normally stored in the organ C. Pancreas secretes pancreatic juice which contains three digestive enzymes D, E and F. The intestinal juice completes the process of digestion of food. The inner wall of organ A has millions of tiny finger-like projections G which help in the rapid absorption of digested food into blood stream. The undigested part of food then passes into wider tube H which absorbs most of the water from undigested food. The last part of tube H called stores this undigested food (or waste) for some time. The undigested food is then passed out though opening as faeces in the process known as K.

(a) Name the organ A.

(b) Name (i) liquid B, and (ii) organ C.

(c) What are the digestive enzymes D, E and F?

(d) Name the projections G present on the inner wall of organ A.

(e) Name (i) tube H (ii) part I (iii) opening J, and (iv) process K.

106. A unicellular animal P having no fixed shape ingests a food particle by forming temporary finger-like projections Q. The food particle is engulfed with a little surrounding water to form a temporary stomach R inside it. The chemicals S from surrounding cytoplasm enter into R and break down food into small and soluble molecules by chemical reactions. The digested food is absorbed directly into cytoplasm by the process T. The undigested food is thrown out of the body by the rupture of a cell organelle U in a process called V.

(a) Name the unicellular animal P.

(b) What are (?) Q, and (ii) R?

(c) Name (?) chemical S, and (ii) process T.

(d) Name (i) organelle U, and (ii) process V.

107. There are four organisms A, B, C and D. The organism A eats only the flesh of other animals as food. The organism B can eat grains, fruits and vegetables as well as meat and fish. The organism C can make the food itself from simple inorganic substances present in the environment by utilising sunlight energy. On the other hand, organism D eats only plants and their products as food.

(a) Which organism is (i) omnivore (ii) herbivore, and (ii) carnivore?

(b) Which organism is an autotroph?

(c) Which organism is/are heterotroph(s)?

(d) Which organism can be a producer?

(e) Which organism is/are consumer (s)?

(f) Give one example each of organisms which could be like (i) A (ii) B (iii) C, and (iv) D

108. The organisms A, B and C can obtain their food in three different ways. Organism A derives its food from the body of another living organism which is called its D, without killing it. The organism B takes in the solid food by the process of ingestion, digests a part of this food and throws out undigested food in the process called E. The organism C obtains its food from dead and decaying plants.

(a) What is the mode of nutrition of (i) organism A (ii) organism B, and (iii) organism C?

(b) What is the organism like D called?

(c) Name the process E.

(d) Give one example each of organisms like (z) A (ii) B, and (ii) C.

(e) What is the general name of three modes of nutrition exhibited by organisms A, B and C?

109. An organism A which cannot move from one place to another, makes a simple food B from the substances C and D available in the environment. This food is made in the presence of a green coloured substance E present in organs F in the presence of light energy in a process called G. Some of the simple food B also gets converted into a complex food H for storage purposes. The food H gives a blue-black colour with dilute iodine solution.

(a) What is (i) organism A (ii) food B, and (iii) food H?

(b) What are C and D?

(c) Name (i) green coloured substance E, and (ii) organ F.

(d) What is the process G?

110. X is a wild animal which eats only the flesh of other animals whereas Y is a domestic animal which fee mainly on green grass.

(a) What are animals like X known as?

(b) What are animals like Y known as?

(c) Which animal, X or Y, has a longer small intestine? Why?

(d) Name one animal which is like X.

(e) Name one animal which is like Y.

102. (a) (i) Bacteria (ii) Acid (b) (i) Enamel (ii) Dentine (c) Dental caries (d) Pulp cavity (e) Inflammation and infection will occur leading to severe pain 103. (a) Dental plaque (b) (i) Saliva (ii) Salivary glands (c) Bacteria (d) Brushing the teeth regularly after eating food 104. (a) (i) Salivary gland (ii) Saliva (iii) Salivary amylase (b) Oesophagus (c) Peristaltic movement (d) (i) Hydrochloric acid (ii) Mucus (iii) Enzyme pepsin 105. (a) Small intestine (b) (i) Bile (ii) Gall bladder (c) Pancreatic amylase, Trypsin and Lipase (d) Villi (e) (i) Large intestine (ii) Rectum (iii) Anus (iv) Egestion 106. (a) Amoeba (b) (i) Pseudopodia (ii) Food vacuole (c) (i) Enzymes (ii) Diffusion (d) (i) Cell membrane (ii) Egestion 107. (i) B (ii) D (iii) A (b) C (c) A, B and D (d) C (e) A, B and D if) (i) Lion (ii) Human (Man) (iii) Green plant (iv) Cow 108. (a) (i) Parasitic (ii) Holozoic (iii) Saprophytic (b) Host (c) Egestion (d) (i) Tapeworm (ii) Man (iii) Mushroom (e) Heterotrophic nutrition 109. (a) (i) Green plant (ii) Glucose (iii) Starch (b) Carbon dioxide and Water (c) (0 Chlorophyll (ii) Green leaf (d) Photosynthesis 110. (a) Carnivores (b) Herbivores (c) Animal Y has a longer small intestine. The animal Y is an herbivore which eats grass (and other green plants). The grass contains a carbohydrate called cellulose which is digested with difficulty. A longer small intestine allows the cellulose present in grass to be digested completely, (d) Tiger (e) Cow.