CBSE Class 10 Science Important Questions Chapter 6 Life Processes Part 4

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24. Where do plants get each of the raw materials required for photosynthesis?

Ans. (a) Carbon dioxide from atmosphere.

(b) Light from Sun

(c) Water from Soil

(d) Chlorophyll from chloroplast of green plants.

25. What is the role of the acids in our stomach?

Ans. HCl plays following role in our stomach:

(a) Make the medium acidic for action of enzyme pepsin.

(b) Kills the harmful bacteria present in food

(c) Prevents fermentation of food

26. How is small intestine deigned to absorb digested

Ans. The inner lining of small intestine has numerous finger-like projections called villi which increase the surface area for absorption. The villi are richly supplied with blood vessels which transport the absorbed food to each and every cells of the body. Where, it is utilized to obtaining energy and repair of old tissues.

27. What advantage over an aquatic organism does a terrestrial organism have with regard to obtaining oxygen for respiration?

Ans. The rate of breathing is slower in terrestrial organisms as compared to aquatic organisms. This is due to the fact that in water, the amount of oxygen is less as compared to air while in aquatic organisms the rate of breathing is faster.

28. What are different ways in which glucose is oxidized to provide energy in various organisms?

Ans. The pathways of break-down of glucose in various organisms are as below:

Glucose is oxidized to provide energy

Glucose is Oxidized to Provide Energy

29. How is oxygen and carbon dioxide transported in human beings?

Ans. In human beings, a pigment hemoglobin is present in RBC which has high affinity for oxygen, takes up the oxygen from the air in the lungs and carry it to tissues which are deficient in oxygen. Some oxygen is carried in dissolved state in blood plasma. Carbon dioxide is more soluble in water than oxygen is mostly transported in the dissolved form in our blood.

30. What are the components of the transport system in human beings? What are the functions of these components?

Ans. The components of human transport system include:

(a) Heart- receives and pumps the blood.

(b)Arteries- carry oxygenated blood away from the heart to various organs.

(c) Veins- Bring back blood to heart.

(d) Capillaries- exchange of various materials and gases between blood and tissues.

31. Why is it necessary to separate oxygenated and deoxygenated blood in mammals and birds?

Ans. The separation of the right and left side of heart is useful to prevent oxygenated blood and deoxygenated blood from mixing. Such separation allows a highly efficient supply of oxygen to the body. This is useful in animals that have high energy needs, such as birds and mammals that constantly use the energy to maintain their body temperature.

32. What are the components of transport system in highly organized plants?

Ans. The transport system of higher plants consists of xylem and phloem. Xylems have vessels and trachieds to transport water and minerals from root to other part of the plants.

Phloem, which consists of sieve tubes and companion cells, transport food from leaves to storage organs and other parts of plant.

33. How are water and minerals transported in plants?

Ans. Water and minerals are transported in plants through xylem which consists of trachieds and vessels. Water and minerals absorbed by root hairs present in root by osmosis is passed to xylem tissues of root. From root xylem it passes to stem xylem and thus water reaches to leaves.

34. How is food transported in plants?

Ans. Food is transported in plants through phloem which consists of sieve tubes, sieve cells and companion cells. The food prepared in leaves in soluble form transported to leaves phloem. Active transport of food passes to all other parts of plants.

35. What are the methods used by plants to get rid of excretory products?

Ans. (i) Plant produces carbon dioxide as wastes during respiration and oxygen as waste during photosynthesis.

(ii) Excess of water is removed through transpiration.

(iii) Some waste products like gums and resins are stored in older xylem tissue.

36. How is amount of urine produced regulated?

Ans. The amount of urine depends on how much excess of water is in the body and how much a water soluble waste is to be excreted. If the amount of water and dissolved wastes in boy are more than amount of urine will be more and if amount of wastes is less the amount of urine produced will be less.

37. How are fats digested in our bodies? Where does this process take place?

Ans. Digestion of fats takes place in small intestine. Fats entering in intestine are in the form of large globules. Bile juice breaks down these large globules into smaller globules. Afterwards fat digesting enzyme lipase present in pancreatic juice and intestinal juice converts it into fatty acids and glycerol.

38. What are the necessary conditions for autotrophic nutrition and what are its by-products.

Ans. Conditions necessary for autotrophic nutrition are:

(i) Light

(ii) Chlorophyll

(iii) Water and

(iv)Carbon dioxide By-products are:

(i) Oxygen and

(ii) Water

39. What are differences between aerobic and anaerobic respiration? Name some organisms that use anaerobic mode of respiration.

Ans. Difference between aerobic and anaerobic respiration:

Aerobic and Anaerobic Respiration
Aerobic and anaerobic respiration

Aerobic respiration

Anaerobic respiration

(i) Takes place in presence of oxygen.

(ii) Complete oxidation of glucose occurs.

(iii) More energy is produced.

(i) Takes place in absence of oxygen.

(ii) Incomplete oxidation of glucose occurs.

(iii) Less energy is produced.

Anaerobic respiration takes place in yeast, some bacteria and some internal parasites like tapeworm.

40. How are the alveoli designed to maximize the exchange of gases?

Ans. The walls of the alveoli is folded and has large surface areas. It contain an extensive network of blood vessels which provide a surface where the exchange of gases can take place.

41. What would be the consequence of a deficiency of hemoglobin in our bodies?

Ans. Haemoglobin is a pigment present in RBC. It has a high affinity for oxygen. It carries oxygen from lungs to various tissues which are deficient in oxygen. Presence of less hemoglobin will result in less supply of oxygen to tissues. A person having less hemoglobin will get tired soon and will have a pale look.

42. What are differences between the transport of materials in xylem and phloem?

Ans. Difference between transport in xylem and phloem:

Transport in Xylem
Transport in xylem

Xylem

Phloem

a. Xylem transport minerals and water from root to leaves.

b. Transport is unidirectional.

c. Xylem consists of trachieds and vessels.

a. Phloem transport food from leaves to root and storage organs.

b. Transport is bidirectional.

c. Phloem consists of sieve tubes and companion cells.

43. Compare the functioning of alveoli in the lungs and nephron in the kidneys with respect to their structure and functioning.

Ans. Comparison between alveoli and nephron:

Alveoli and Nephron
Alveoli and nephron

Alveoli

Nephron

They have thin-walled balloon-like structure. The alveoli provide a surface extensively for exchange of gases in lungs. Carbon dioxide released in the cavity of alveoli and oxygen is taken by hemoglobin present in RBC of blood.

Nephron is a cluster of very thin walled blood capillaries found in kidney. Each capillaries cluster remains associated with the cup-shaped end of a tube called Bowman’s capsule that collects the filtered urine, at the same time the useful substance are reabsorbed.

44. Leaves of a healthy potted plant were coated with petroleum jelly. How will it affect the plant? State two reasons.

Ans. The plant will not remain healthy for long due to the following reasons:

1. There will be no transpiration.

2. There will be no exchange of gases which will affect the rate of photosynthesis.

45. How does respiration in plants differ from that in animals?

Ans. In plants, all parts like the root, stem, leaves, etc., perform respiration individually., while in animals, either the general body surface or specific organs like the skin, gills, lungs, etc., are involved in respiration. The rate of respiration is much slower in plants than in animals. Unlike animals, there is little transport of gases from one part of the plant to another.

46. How does respiration in plants differ from that in animals?

Ans. The acid is formed in the mouth after a sugary food (chocolates and sweet) has been taken. This acid lowers the pH in the mouth. Tooth decay starts when the pH of acid formed in the mouth falls below 5.5. This is because then the acid becomes strong enough to attack the enamel of our teeth and corrode it.

47. Name the cartilaginous flap which closes the glottis to check the entry of food into it during swallowing.

Ans. The tissue that got blocked may be xylem. It is through the xylem that water and minerals absorbed by roots from the soil are transported to the leaves and other parts of the plant. So, if xylem is blocked, the leaves will not get the nourishment and will get wilted.

48. How does respiration in plants differ from that in animals?

Ans. In plants, all parts like the root, stem, leaves, etc., perform respiration individually., while in animals, either the general body surface or specific organs like the skin, gills, lungs, etc., are involved in respiration. The rate of respiration is much slower in plants than in animals. Unlike animals, there is little transport of gases from one part of the plant to another.

49. Write one feature which is common to each of the following pairs of the term/organs.

i) Glycogen and starch

ii) Chlorophyll and haemoglobin

iii) Gills and lungs

iv) Arteries and veins.

Ans. i) Carbohydrate (food)

ii) Pigments.

iii) Respiratory organs.

iv) Blood vessels.

50. A certain tissue in a green plant somehow get blocked and the leaves wilted. What was the tissue that got blocked?

Ans. The tissue that got blocked may be xylem. It is through the xylem that water and minerals absorbed by roots from the soil are transported to the leaves and other parts of the plant. So, if xylem is blocked, the leaves will not get the nourishment and will get wilted.

51. Write the functions of the following in the digestive process:

i. Bile

ii. Bicarbonate secreted by the duodenal wall.

iii. Pancreatic amylase.

Ans. i. Bile: It is secreted by the gall bladder and it emulsifies & it into the smaller droplets for their easy digestion.

ii. It provides alkaline medium in the duodenum which is needed for the action of pancreatic enzymes of different food components for their digestion.

iii. Pancreatic amylase enzyme digests starch and changes it into maltose.

52. The two openings of the pharynx, one leading to trachea and the other leading to oesophagus, lie very close to each other. Yet food we swallow normally does not enter into our trachea. Why?

Ans. The food does not enter into trachea because during swallowing, the aperture leading to trachea (glottis) gets covered by a cartilaginous flap called epiglottis and the food has no other passage except going into the oesophagus.

53. How would it affect the digestion of proteins and carbohydrates if the duodenum of man if there is a blockade in the pancreatic duct?

Ans. Duodenum is the region where the pancreatic juice secreted by the pancreas enters. The enzymes pancreatic amylase and trwsin helps in the digestion of carbohydrates and proteins. Thus, if there is a blockade, the digestion of carbohydrates and proteins gets affected.

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