Monday, December 8, 2014



Life Process class 10 Trend setter solved CBSE Test paper-04
SCIENCE & TECHNOLOGY (Class-10)       Chapter 6 : Life Process
1. Name the artificial method for the removal of liquid nitrogenous waste from body. (1 mark)
Ans:  Dialysis
2. Name any three waste products of plants? (1 mark)
Ans:  The gums, resins and latexes
3. Name three excretory organs of man. (1 mark)
Ans:  lungs, kidney and skin
4. Name the part of plants which helps in transportation. (1 mark)
Ans:  Phloem tissue
5. Name the juice secreted by the liver. (1 mark)
Ans:  Bile
6. What is the function of digestive enzymes? (2 marks)
Ans:  Digestive enzymes such as amylase, lipase, pepsin, trypsin, etc. help in the breaking down of complex food particles into simple ones. These simple particles can be easily absorbed by the blood and thus transported to all the cells of the body.
7. What is the role of saliva in the digestion of food? (2 marks)
Ans:  The salivary glands secrete the first of the digestive juices, the saliva. In the digestion process, the saliva helps the teeth and tongue to masticate and mix up the food thoroughly. Mucus in saliva helps in lubricating and adhering food particles into a bolus.  Then the bolus conveyed to pharynx for further digestion. Lysosomes present in saliva acts as an antibacterial agent that prevents infection.
8. Point out two differences between an artery and a vein. (2 marks)
Ans:  Artery
a. Vessels which carry blood from the heart to various body parts
b. Arteries carry oxygenated blood from the heart except pulmonary artery
a. Vessels which carry blood from the various body parts to the heart
b. Veins carry deoxygenated blood from the various body parts except pulmonary vein
9. What do you mean by double circulation of blood? (2 marks)
Ans:  The human heart is divided into four chambers − the right atrium, the right ventricle, the left atrium, and the left ventricle.
Flow of blood in the heart  :
·         The heart has superior and inferior vena cava, which carries de-oxygenated blood from the upper and lower regions of the body respectively and supplies this de-oxygenated blood to the right atrium of the heart.
Flow of blood in   the human heart
·         The right atrium then contracts and passes the de-oxygenated blood to the right ventricle, through an auriculo-ventricular aperture.
·         Then the right ventricle contracts and passes the de-oxygenated blood into the two pulmonary arteries, which pumps it to the lungs where the blood becomes oxygenated. From the lungs, the pulmonary veins transport the oxygenated blood to the left atrium of the heart.
·         Then the left atrium contracts and through the auriculo-ventricular aperture, the oxygenated blood enters the left ventricle.
·         The blood passes to aorta from the left ventricle. The aorta gives rise to many arteries that distribute the oxygenated blood to all the regions of the body.
Therefore, the blood goes twice through the heart. This is known as double circulation
10. Write any two points of difference between respiration in plants and animals? (2 marks)
Ans:  Respiration in plants. 
a)    In plants separate respiratory organs are absent 
b)    The rate of respiration is slow. 
c)    They lack respiratory surface 
Respiration in animals 
a)    In animals respiratory organs are generally present 
b)    The rate of respiration is fast. 
c)    Respiratory surface is generally present. 
11. What criteria do we use to decide whether something is alive? (3 marks)
Ans:  The main criteria to check for life, is the sign of breathing and respiration. If there is no sign of breathing or respirations then the given organism is not alive.
12. What are the differences between autotrophic nutrition and heterotrophic nutrition? (3 marks)
Autotrophic nutrition
Heterotrophic nutrition
Food is synthesized from simple inorganic raw materials such as CO and water.
Food is obtained directly or indirectly from autotrophs. This food is broken down with the help of enzymes.
Presence of green pigment (chlorophyll) is necessary.
No pigment is required in this type of nutrition.
Food is generally prepared during day time.
Food can be prepared at all times.
All green plants and some bacteria have this type of nutrition.
All animals and fungi have this type of nutrition.
13. Where do plants get each of the raw materials required for photosynthesis? (3 marks)
the raw materials for photosynthesis
Ground water
14. What are the different ways in which glucose is oxidized to provide energy in various organism? (3 marks)
Ans:  At first glucose (6 carbon molecules) is broken in the cytoplasm of cells of all organisms. This process yields a  three carbon molecule compound called pyruvate.
Further break down of pyruvate takes place in different manners in different organisms.
1. Anaerobic Respiration
This process takes place in absence of oxygen, e.g. in yeast during fermentation. In this case pyruvate is converted into ethanol and carbon dioxide.
2. Aerobic Respiration
In aerobic respiration, breakdown of pyruvate takes place in presence of oxygen to give rise 3 molecules of carbon dioxide and water. The release of energy in aerobic respiration is much more than anaerobic respiration.
3. Lack of Oxygen
Sometimes, when there is lack of oxygen, especially during vigorous activity, in our muscles, pyruvate is converted into lactic acid (3 carbon molecule compounds). Formation of lactic acid in muscles causes cramp.

15. (i) Draw a labelled diagram of the human respiratory system. (5 marks)
(ii) How oxygen and carbon dioxide exchanged in our body during respiration?
(iii) Explain, how the air we breathe in gets cleaned while passing through the nasal passage.
Ans:  (1) respiratory system
(ii) When the air enters into the lungs through nostrils, trachea and bronchi it enters into the bronchioles, from bronchioles it moves into thin walled alveolar sacs or alveoli. Alveoli are rich in blood capillaries, at this place oxygen from air diffuses into the blood and reaches to all the cells and tissues of body this oxygen now diffuses into the cell and is utilized for the oxidation of food and production of energy in mitochondria as a result of this carbon dioxide is produced in cells, due to this increased concentration of CO2, it diffuses into the blood and is brought back to alveoli and expelled out of the lungs through trachea and nostrils.

(iii) Nasal passage: This passage is separated from oral cavity by means of a hard and bony palate. It is lined by ciliated columnar epithelial cells that are rich in mucus; it brings about warming, moistening and sterilization of air. It contains hair and mucus which entrap the dust particles.

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