NCERT Exemplar Solution Class 10 Science Chapter 6 Life Processes all Questions Answer Solution. NCERT Exemplar Class 10 Science Chapter 6 Solution PDF.
NCERT Exemplar Solution Class 10 Science Chapter 6: Overview
NCERT Exemplar Solution Class 10 Science Chapter 6 |
|
Board |
NCERT |
Topic |
Exemplar Problem Solution |
Class |
10 |
Subject |
Science |
Chapter |
6 |
Chapter Name |
Life Processes |
NCERT Exemplar Solution Class 10 Science Chapter 6 Life Processes
Multiple Choice Questions
1.) Which of the following statements about the autotrophs is incorrect?
(a) They synthesize carbohydrates from carbon dioxide and water
in the presence of sunlight and chlorophyll
(b) They store carbohydrates in the form of starch
(c) They convert carbon dioxide and water into carbohydrates in
the absence of sunlight
(d) They constitute the first trophic level in food chains
Answer: Answer is C. Because autotrophs can synthesize food in presence of light. They receive the light and can prepare the food.
2.) In which of the following groups of organisms, food material is broken down outside the body and absorbed?
(a) Mushroom, green plants, Amoeba
(b) Yeast, mushroom, bread mould
(c) Paramecium, Amoeba, Cuscuta
(d) Cuscuta, lice, tapeworm
Answer: Answer is B. Because these yeast, mushroom, bread mold are saprophytes. As they feed on decaying organic matter.
3.) Select the correct statement
(a) Heterotrophs do not synthesize their own food
(b) Heterotrophs utilize solar energy for photosynthesis
(c) Heterotrophs synthesize their own food
(d) Heterotrophs are capable of converting carbon dioxide and water into carbohydrates
Answer: Answer is A. Because other options are characteristics of autotrophs. The option A is only characteristics of heterotrophs. They cannot synthesize their own food material instead depend on others.
4.) Which is the correct sequence of parts in human alimentary canal?
(a) Mouth, stomach, small intestine, esophagus, large intestine
(b) Mouth, esophagus, stomach, large intestine, small intestine
(c) Mouth stomach esophagus small intestinelarge intestine
(d) Mouth esophagus stomach small intestine large intestine
Answer : Answer is D. Because the correct pathway of food from mouth to esophagus which 25 cm long tube to stomach and small intestine and large intestine.
5.) If salivary amylase is lacking in the saliva, which of the following events in the mouth cavity will be affected?
(a) Proteins breaking down into amino acids
(b) Starch breaking down into sugars
(c) Fats breaking down into fatty acids and glycerol
(d) Absorption of vitamins
Answer: Answer is B. Salivary amylase responsible for digestion of starch which is polysaccharide and with the help of salivary amylase starch can be break down into its monomers.
6.) The inner lining of stomach is protected by one of the following from hydrochloric acid. Choose the correct one
(a) Pepsin
(b) Mucus
(c) Salivary amylase
(d) Bile
Answer: Answer is B. Mucus is present in the inner lining of stomach for the smooth movement of food.
7.) Which part of alimentary canal receives bile from the liver?
(a) Stomach
(b) Small intestine
(c) Large intestine
(d) Esophagus
Answer: Answer is B. Bile enters into the small intestine from liver.
8.) A few drops of iodine solution were added to rice water. The solution turned blue-black in colour. This indicates that rice water contains
(a) complex proteins
(b) simple proteins
(c) fats
(d) starch
Answer: Answer is D. Because when iodine comes in contact with starch, colour of the solution will turn to blue.
9.) In which part of the alimentary canal food is finally digested?
(a) Stomach
(b) Mouth cavity
(c) Large intestine
(d) Small intestine
Answer: Answer is D. Within the small intestine, the al form of food is finally digested.
10.) Choose the function of the pancreatic juice from the following
(a) trypsin digests proteins and lipase carbohydrates
(b) trypsin digests emulsified fats and lipase proteins
(c) trypsin and lipase digest fats
(d) trypsin digests proteins and lipase emulsified fats
Answer: Answer is D. Pancreatic juice have ability to digest protein and fat due to presence of enzymes trypsin and lipase.
11.) When air is blown from mouth into a test-tube containing lime water, the lime water turned milky due to the presence of
(a) oxygen
(b) carbon dioxide
(c) nitrogen
(d) water vapour
Answer: Answer is B. Because humans exhale the carbon dioxide and when carbon dioxide come in contact with lime, the production of white colored fluid take place.
14.) Which of the following statement(s) is (are) true about respiration?
(i) During inhalation, ribs move inward and diaphragm is raised
(ii) In the alveoli, exchange of gases takes place i.e., oxygen from
alveolar air diffuses into blood and carbon dioxide from blood
into alveolar air
(iii) Haemoglobin has greater affinity for carbon dioxide thanoxygen
(iv) Alveoli increase surface area for exchange of gases
(a) (i) and (iv) (b) (ii) and (iii)
(c) (i) and (iii) (d) (ii) and (iv)
Answer: Answer is D.
15.) Which is the correct sequence of air passage during inhalation?
(a) Nostrils larynx pharynx trachea lungs
(b) Nasal passage trachea pharynx larynx alveoli
(c) larynx nostrils pharynx lungs
(d) Nostrils pharynx larynx trachea alveoli
Answer: Answer is D. Air enters the body through nasal cavity into pharynx, larynx, trachea and alveoli.
16.) During respiration exchange of gases take place in
(a) trachea and larynx
(b) alveoli of lungs
(c) alveoli and throat
(d) throat and larynx
Answer is B.During respiration exchange of gases take place in alveoli.
17.) Which of the following statement (s) is (are) true about heart?
(i) Left atrium receives oxygenated blood from different parts ofbody while right atrium receives deoxygenated blood from lungs
(ii) Left ventricle pumps oxygenated blood to different body partswhile right ventricle pumps deoxygenated blood to lungs
(iii) Left atrium transfers oxygenated blood to right ventricle whichsends it to different body parts
(iv) Right atrium receives deoxygenated blood from different partsof the body while left ventricle pumps oxygenated blood todifferent parts of the body
(a) (i)(b) (ii)(c) (ii) and (iv) (d) (i) and (iii)
Answer: Answer is C.
18.) What prevents backflow of blood inside the heart duringcontraction?
(a) Valves in heart
(b) Thick muscular walls of ventricles
(c) Thin walls of atria
(d) All of the above
Answer: Answer is A.
19.) Single circulation i.e., blood flows through the heart only onceduring one cycle of passage through the body, is exhibited by
(a) Labeo, Chameleon, Salamander
(b) Hippocampus, Exocoetus, Anabas
(c) Hyla, Rana, Draco
(d) Whale, Dolphin, Turtle
Answer: Answer is A.
20.) In which of the following vertebrate group/groups, heart doesnot pump oxygenated blood to different parts of the body?
(a) Pisces and amphibians
(b) Amphibians and reptiles
(c) Amphibians only
(d) Pisces only
Answer: D.
21.) Choose the correct statement that describes arteries.
(a) They have thick elastic walls, blood flows under high pressure;collect blood from different organs and bring it back to the heart.
(b) They have thin walls with valves inside, blood flows underlow pressure and carry blood away from the heart to variousorgans of the body
(c) They have thick elastic walls, blood flows under low pressure;carry blood from the heart to various organs of the body.
(d) They have thick elastic walls without valves inside, blood flowsunder high pressure and carry blood away from the heart todifferent parts of the body.
Answer: Answer is D.
22.) The filtration units of kidneys are called
(a) ureter
(b) urethra
(c) neurons
(d) nephrons
Answer: Answer is D. The filtration unit of kidney is nephron. Because neurons are present in brain and ureters and urethra are the parts of urinary system.
23.) Oxygen liberated during photosynthesis comes from
(a) water
(b) chlorophyll
(c) carbon dioxide
(d) glucose
Answer: Answer is A. When water molecules break down into OH and H, then oxygen releases from water.
24.) The blood leaving the tissues becomes richer in
(a) carbon dioxide
(b) water
(c) heamoglobin
(d) oxygen
Answer: Answer is A.
25.) Which of the following is an incorrect statement?
(a) Organisms grow with time
(b) Organisms must repair and maintain their structure
(c) Movement of molecules does not take place among cells
(d) Energy is essential for life processes
Answer: Answer is C.
26.) The internal (cellular) energy reserve in autotrophs is
(a) glycogen
(b) protein
(c) starch
(d) fatty acid
Answer is C.
27.) Which of the following equations is the summary ofphotosynthesis?
(a) 6CO2 + 12H2O –> C6H12O6 + 6O2+ 6H2O
(b) 6CO2 + H2O + Sunlight –> C6H12O6 + O2+ 6H2O
(c) 6CO2 + 12H2O + Chlorophyll + Sunlight –> C6H12O6 + 6O2+ 6H2O
(d) 6CO2 + 12H2O + Chlorophyll + Sunlight –> C6H12O6 + 6CO2+ 6H2O
Answer: Answer is C.
28.) Choose the event that does not occur in photosynthesis
(a) Absorption of light energy by chlorophyll
(b) Reduction of carbon dioxide to carbohydrates
(c) Oxidation of carbon to carbon dioxide
(d) Conversion of light energy to chemical energy
Answer: Answer is C.
29.) The opening and closing of the stomatal pore depends upon
(a) oxygen
(b) temperature
(c) water in guard cells
(d) concentration of CO2 in stomata
Answer : Answer is C. It depends upon concentration of water in guard cells.
30.) Choose the forms in which most plants absorb nitrogen
(i) Proteins
(ii) Nitrates and Nitrites
(iii) Urea
(iv) Atmospheric nitrogen
(a) (i) and (ii) (b) (ii) and (iii)
(c) (iii) and (iv) (d) (i) and (iv)
Answer: Answer is B.
31.) Which is the first enzyme to mix with food in the digestive tract?
(a) Pepsin
(b) Cellulase
(c) Amylase
(d) Trypsin
Answer: Answer is C.
32.) Which of the following statement(s) is (are) correct?
(i) Pyruvate can be converted into ethanol and carbon dioxideby yeast
(ii) Fermentation takes place in aerobic bacteria
(iii) Fermentation takes place in mitochondria
(iv) Fermentation is a form of anaerobic respiration
(a) (i) and (iii) (b) (ii) and (iv)
(c) (i) and (iv) (d) (ii) and (iii)
Answer: Answer is A.
33.) Lack of oxygen in muscles often leads to cramps among cricketers.This results due to
(a) conversion of pyruvate to ethanol
(b) conversion of pyruvate to glucose
(c) non conversion of glucose to pyruvate
(d) conversion of pyruvate to lactic acid
Answer: Answer is D.
34.) Choose the correct path of urine in our body
(a) kidney ureter urethra urinary bladder
(b) kidney urinary bladder urethra ureter
(c) kidney ureters urinary bladder urethra
(d) urinary bladder kidney ureter urethra
Answer: Answer is C.
35.) During deficiency of oxygen in tissues of human beings, pyruvicacid is converted into lactic acid in the
(a) cytoplasm
(b) chloroplast
(c) mitochondria
(d) golgi body
Answer: Answer is A.
Short Answer Questions
36.) Name the following
(a) The process in plants that links light energy with chemical energy
(b) Organisms that can prepare their own food
(c) The cell organelle where photosynthesis occurs
(d) Cells that surround a stomatal pore
(e) Organisms that cannot prepare their own food
(f) An enzyme secreted from gastric glands in stomach that actson proteins.
Answer:
(a) The process in plant that that links light energy with chemical energy called as photosynthesis.
(b) Organisms that can prepare their own food are called as autotrophs.
(c) The cell organelle where photosynthesis occurs is called as chloroplast.
(d) Cells that surround a stomatal pore are called as guard cells.
(e) Organisms that cannot prepare their own food are called as heterotrophs.
(f) An enzyme secreted from gastric glands in stomach that actson proteins is called as pepsin.
37.) “All plants give out oxygen during day and carbon dioxide duringnight”. Do you agree with this statement? Give reason.
Answer : The photosynthesis process takes place during day in presence of light and therefore during respiration it release oxygen but during night there is no photosynthesis so no release of oxygen so due to respiration mechanism plants release carbon dioxide.
38.) How do the guard cells regulate opening and closing of stomatalpores?
Answer: The guard cells regulate opening and closing of stomatalporesdue to water concentration. When water enters in the guard cells due to presence of water guard cells swells and ultimately opens. Whereas when water loses from guard cells, due to empty space in guard cells they get closed.
39.) Two green plants are kept separately in oxygen free containers,one in the dark and the other in continuous light. Which one willlive longer? Give reasons.
Answer: Two green plants are kept separately in oxygen free containers,one in the dark and the other in continuous light. The plant which is kept in continuous light will live longer because in presence of light plants will perform photosynthesis that means they will make food.
40.) If a plant is releasing carbon dioxide and taking in oxygen duringthe day, does it mean that there is no photosynthesis occurring?
Justify your answer.
Answer: If a plant is releasing carbon dioxide and taking in oxygen duringthe day, it does not mean that there is no photosynthesis occurring, because respiration and photosynthesis both are completely independent process. The respiration it occurs continuously. Whereas photosynthesis occur only during day.
41.) Why do fishes die when taken out of water?
Answer: Fishes respire by exchanging oxygen and carbon dioxide in water. The major respiratory organ of fish are gills. The gills have ability to absorb the oxygen from the water. But when fishes are taken out of water, they cannot absorb oxygen from air therefore fishes die.
42.) Differentiate between an autotroph and a heterotroph.
Answer:
Autotrophs | Heterotrophs |
Autotrophs are those living organisms which can prepare their own food. | Heterotrophs are those who cannot prepare their own food but instead depend on others. |
These are called as producers. | These are called as consumers. |
For example: Plants and algae. | For example : Animals. |
43.) Is ‘nutrition’ a necessity for an organism? Discuss.
Answer: Yes, nutrition is necessary for all the living organisms, to perform daily functions such as exercise, weight lifting, work etc. The nutrition provides us the nutrients which are required to maintain a healthy life style. The lack of nutrients will cause variety of diseases. The nutrients include carbohydrates, protein, fats, minerals and vitamins. These nutrients are help to keep body in working condition. These required in small quantity but the presence of nutrients is important.
44.) What would happen if green plants disappear from earth?
Answer: If the green plants disappear from earth, then the amount of oxygen will reduce day by dat. Because plants are major source of oxygen. Plants gives us food and many of the animals depend only on grass for food. Under such conditions, the food chain will disturb. There will be low amount of water on earth, and the complete earth environment will disturbed.
45.) Leaves of a healthy potted plant were coated with vaseline. Willthis plant remain healthy for long? Give reasons for your answer.
Answer: If leaves of a healthy potted plant were coated with Vaseline then plant will not remain healthy for a longer period of time because the Vaseline will completely block the carbon dioxide path. In the leaves stomata is present, stomata will unable to receive the carbon dioxide. Therefore the plant will die soon.
46.) How does aerobic respiration differ from anaerobic respiration?
Answer: Aerobic respiration can be defined as the process which takes place in presence of oxygen and the end product is water and carbon dioxide. Those an anerobic respiration can be defined as the process which occurs in absence of oxygen, end product of anaerobic respiration is called as lactic acid and alcohol.
47.) Match the words of Column (A) with that of Column (B)
Answer:
Column A | Column B |
Phloem | Excretion |
Nephron | Translocation of food |
Veins | Clotting of blood |
Platelets | Deoxygenated blood |
Answer:
Column A | Answer |
Phloem | Translocation of food |
Nephron | Excretion |
Veins | Deoxygenated blood |
Platelets | Clotting of blood |
48.) Differentiate between an artery and a vein.
Answer:
Artery | Vein |
1.) Takes the blood away from heart. | 1.) It gives the blood back to the heart. |
2.) The diameter is more and thick blood vessels. | 2.) The diameter is less and thin blood vessel. |
3.) Flow of blood is fast as compared to vein. | 3.) Flow of blood is slow as compared to artery. |
4.) The major function is to carry the oxygenated blood. | 4.) The major function is to carry the deoxygenated blood. |
49.) What are the adaptations of leaf for photosynthesis?
Answer: The leaves are adapted for photosynthesis, because eaves are the major part of plant for photosynthesis. The surface area of leaves is more larger for the gaseous exchange. Along with it the leaves contain stomata for photosynthesis.
50.) Why is small intestine in herbivores longer than in carnivores?
Answer: The small intestine in herbivores longer than in carnivores because herbivores eat plant parts whereas carnivores eat the meat and animal parts. Therefore the plant contains cellulose and for complete digestion of cellulose, much time is required. Therefore the small intestine in herbivores longer than in carnivores.
51.) What will happen if mucus is not secreted by the gastric glands?
Answer: The mucus secretion by the gastric gland is much needed process for digestion. The stomach usually have acidic ph. The walls of stomach is protected by mucus from the acid and more specifically HCl. If mucus will absent then complete damage of stomach will takes place.
52.) What is the significance of emulsification of fats?
Answer: The emulsification of fats can be defined as digestion of fats and oils. So that they can be converted into more simpler form and will be easy to digest and undigested fats can be excrete out.
53.) What causes movement of food inside the alimentary canal?
Answer: The movement of food inside the alimentary canal occurs due to peristalsis mechanism. In this type of mechanisms wall of intestine contains the food and these muscles contract and relax for pushing the food into next part of the body.
54.) Why does absorption of digested food occur mainly in the smallintestine?
Answer: The absorption of digested food occur mainly in the smallintestine because the walls of small intestine contains the blood vessels and these blood vessels will helpful in absorption of food material.
55.) Match Group (A) with Group (B)
Group (A) | Group (B) |
(a) Autotrophic nutrition | Leech |
(b) Heterotrophic nutrition | Paramoecium |
(c) Parasitic nutrition | Deer |
(d) Digestion in food vacuoles | Green plant |
Answer:
Group (A) | Answer |
(a) Autotrophic nutrition | LeechGreen plant |
(b) Heterotrophic nutrition | Deer |
(c) Parasitic nutrition | Leech |
(d) Digestion in food vacuoles | Paramoecium |
56.) Why is the rate of breathing in aquatic organisms much fasterthan in terrestrial organisms?
Answer: The aquatic organisms take oxygen from water. In the water, the oxygen is present in dissolved form and the fishes can respire through gills, as compared to terrestrial organisms oxygen is present in air and it is not in dissolved form, therefore the rate of breathing in aquatic organisms much fasterthan in terrestrial organisms.
57.) Why is blood circulation in human heart called double circulation?
Answer: Blood circulation in human heart called double circulation because in the human body the circulation is of two types such as systemic circulation and pulmonary circulation. It transports oxygenated and deoxygenated blood.
58.) What is the advantage of having four chambered heart?
Answer:The 4 chambers are present in heart, in which 2 auricles and 2 ventricles are present. The left and right part of the heart is separated by valves, therefore the blood cannot mixed in between two parts. The right part of heart contains deoxygenated blood and left part of heart contains oxygenated blood.
59.) Mention the major events during photosynthesis.
Answer :
- Absorption of sunlight (Light energy) by chlorophyll of the leaf.
- Conversion of light energy into chemical energy.
- Breakdown of water molecule and CO2 into glucose (sugar).
- Formation of O2 as a by product.
60.) In each of the following situations what happens to the rate ofphotosynthesis?
(a) Cloudy days
(b) No rainfall in the area
(c) Good manuring in the area
(d) Stomata get blocked due to dust
Answer:
(a) Cloudy days: In the cloudy days, there will be less sunlight and therefore the photosynthesis rate will be declines.
(b) No rainfall in the area: If there is no rainfall in the area then again photosynthesis rate will decrease because water is essential component for photosynthesis.
(c) Good manuring in the area: Under such conditions all the nutrients will be present in sufficient amount, so rate of photosynthesis will ultimately increase.
(d) Stomata get blocked due to dust: Stomata is the main organelle for photosynthesis and if it gets block photosynthesis will stop.
61.) Name the energy currency in the living organisms. When and where is it produced?
Answer: The energy currency present in humans is ATP. (Adenosine Tri Phosphate). Humans gets energy in the form of ATP. The ATP is formed during the cellular respiration process such as glycolysis, krebs cycle and electron transport chain. It is formed in the mitochondria.
62.) What is common for cuscuta, ticks and leeches?
Answer: All 3 cuscuta, ticks and leeches are the parasites. The parasites are those organisms which lives on another organisms for the purpose of feeding, they get nutrition from the host and complete their life cycle.
63.) Explain the role of mouth in digestion of food.
All the humans intake variety of food, according to their habitat, taste and health. To digest this food humans have digestive system, this digestive system helps to digest, absorb the food and excrete undigested food material. To perform these functions, digestive system contains two main parts : 1. Digestive tract 2. Digestive glands
Digestive tract :It includes mouth, pharynx, esophagus, stomach, intestine, rectum and anus. The digestive tract starts with mouth and ends on anus.
Mouth : Taking substances into body via mouth. The mouth contains teeth and tongue.
- Teeth : They cut and chewing the food into a soft pulp that means it will be easy to swallow. Mixing the food with saliva.
- Tongue : Moves the food into mouth and helps to swallow.
64.) What are the functions of gastric glands present in the wall of theStomach?
Answer :They produce the chemical secretion needed to breakdown the food material. It includes gastric gland. These glands which produces chemicals which are required to swallow and breakdown food material.
65.) Match the terms in Column (A) with those in Column (B)
Column (A) | Column (B) |
Trypsin | Pancreas |
Amylase | Liver |
Bile | Gastric glands |
Pepsin | Saliva |
Answer:
Column (A) | Answer |
Trypsin | Pancreas |
Amylase | Saliva |
Bile | Liver |
Pepsin | Gastric glands |
66.) Name the correct substrates for the following enzymes
(a) Trypsin (b) Amylase
(c) Pepsin (d) Lipase
Answer:
(a) Trypsin: Protein
(b) Amylase: Starch
(c) Pepsin: Protein
(d) Lipase: Lipid
67.) Why do veins have thin walls as compared to arteries?
Answer: veins have thin walls as compared to arteries because artery transport the blood from the heart to various organs with high pressure, therefore its thickness is more as compared to veins.
68.) What will happen if platelets were absent in the blood?
Answer: If platelets was absent in blood then there is no coagulation reaction, even after the injury blood will fail to clot. Because the function of platelets is blood clotting.
69.) Plants have low energy needs as compared to animals. Explain.
Answer:Plants have low energy needs as compared to animals because plants are unable to move from one location to another and plants have ability to prepare their own food. Those animals move from one location to another and they are not autotrophs.
70.) Why and how does water enter continuously into the root xylem?
Answer: The water enters continuously into root xylem because of transpiration force. The xylem cells maintain contact with soil and therefore water concentration is maintained in plant.
71.) Why is transpiration important for plants?
Answer: It is the biological process in which water is losing through the pores which are present on leaf of the plant. This is called as transpiration.
Plants do transpiration because plants need small amount of water and when plants have excess water then plants start loses water through leaf called transpiration.
The process of transpiration occurs through leaves because leaves have specialized structure called stomata. The stomata have pores in their structure so that water lost from the stomata takes place. For example : we can observe the droplets on leaf, this is due to process of transpiration.
72.) How do leaves of plants help in excretion?
Answer: Leaves take part in excretion, but along with excretion leaves are part of photosynthesis and respiration. Plants exchanges two type of gases oxygen and carbon dioxide. Through the stomatal pores these gases can be exchanged and from the leaf water also excretes.
Long Answer Questions
73.) Explain the process of nutrition in Amoeba.
Answer: According to the diagram of nutrition in amoeba (single cell microorganism)
Diagram of amoeba nutrition
If any food particle is present near the amoeba, then with the help of finger like projection present on their body that is pseudopodia. With the help of this pseudopodia, these amoeba can attract or engulf their food. This is the mechanism of nutrition in amoeba.
74.) Describe the alimentary canal of man.
Answer: It includes mouth, pharynx, esophagus, stomach, intestine, rectum and anus. The digestive tract starts with mouth and ends on anus.
- Mouth : Taking substances into body via mouth. The mouth contains teeth and tongue.
- Teeth : They cut and chewing the food into a soft pulp that means it will be easy to swallow. Mixing the food with saliva.
- Tongue : Moves the food into mouth and helps to swallow.
Pharynx : It is also known as throat. It receives the food from mouth and passes to esophagus.
- Esophagus : It is the passage between pharynx and stomach, to pass the food and drink to next part.
- Stomach : It acts as blender and mixing of food takes place in stomach. It also mix the acid with food.
- Intestine : It is the site for digestion and absorption of food material
- Rectum and anus : All the undigested food material is excrete out through the anus.
75.) Explain the process of breathing in man.
Answer : Every living organism take breathing that means take air from the nose and exit it out through the nose. Respiration can be termed as gaseous exchange, basically two types of gases are exchanged such as Oxygen and Carbon dioxide. If person is breathing that means 2 basic processes are carried out.
1.) Inhalation : Inhalation means taking air more specifically oxygen from the surrounding.
2.) Exhalation : Exhalation means give the Carbon dioxide to external environment.
As we can see in diagram, in inhaled air 78 % of nitrogen is present, we breath air so it contains all types of gases and not single oxygen, after breathing humans exhale the air. Within the body oxygen and carbon dioxide exchange occurs so in the next diagram of exhalation we can observe that the amount of carbon dioxide has been increased. The nitrogen amount is same in inhalation and exhalation that is 78 %. So the question why nitrogen amount remains same ? The answer is human body does not require nitrogen gas during respiration, not required in processing, so the amount of nitrogen remains same.
To carry out respiration, humans have respiratory system. The respiratory organs required for respiration, all the organs carry help in respiration that is gaseous exchange. Ventilation is the term used for proper amount of oxygen in the lungs.
The respiratory system includes nasal cavity, pharynx, lungs, alveoli, diaphragm (dome shaped organ) and trachea
Process of respiration as follows :
- Humans inhale the air through the nasal cavity.
- The inhaled air enters in the pharynx into trachea.
- The oxygen will enters into lungs through bronchioles.
- Within the bronchioles air passes from primary to secondary bronchioles and then lungs filled up with air and due to air within the lungs, the lungs expands in size.
- As the lungs expands, that means volume of lungs increase leads to contraction of diaphragm which is dome shaped organ that is situated below the lungs.
- Then air enters into alveoli, the alveoli provides actual area for gaseous exchange.
- Within the alveoli the oxygen exchange with carbon dioxide.
- Again during the exhalation process, the lungs contracts that means volume of lungs decreases and it leads to expansion of diaphragm.
- Then air leaves the lungs and through the nasal cavity the air exhaled outside.
76.) Explain the importance of soil for plant growth.
Answer: The soil is important for growth of plant because the roots of plant are completely connected with soil, so the soil must contain nutrients which are essential for plant growth. It should contain minerals, which provide supplement to all parts of the plant. The soil shold be of good quality because it must have water holding capacity.77.) Draw the diagram of alimentary canal of man and label the following parts.
Mouth, esophagus, Stomach, Intestine
Answer:
78.) How do carbohydrates, proteins and fats get digested in humanbeings?
Answer: carbohydrates, proteins and fats get digested in human beings with the help of enzymes and breakdown cycle such as protein get degraded by enzyme protease, pepsin and trypsin. Fats are also called as lipids they digested with the help of enzyme lipase and for digestion of carbohydrates the major pathways carried out in body such glycolysis, krebs cycle and electron transport chain.
79.) Explain the mechanism of photosynthesis.
Answer: Plants have ability to produce their own food material with the help of sunlight and this process is called as photosynthesis. [ Photo = Light, synthesis = to put together or produce ]. For formation of food in plants, they need adequate amount of sunlight, water and air [ Oxygen and Carbon dioxide ].
Photosynthesis is formation or synthesis of food in presence of light by the green tissues (green leaf) in plants.
Photosynthesis reaction can be carried out in following way :
Plant gets light energy from the sun that is received by chlorophyll which is present in leaf of the plant and using this light energy plants convert carbon dioxide and water into glucose (sugar) and as a by product oxygen formation takes place. Now the glucose will be used as energy to carry out the functions of the plant.
Steps of photosynthesis
- Absorption of sunlight (Light energy) by chlorophyll of the leaf.
- Conversion of light energy into chemical energy.
- Breakdown of water molecule and CO2 into glucose (sugar).
- Formation of O2 as a by product.
80) Explain the three pathways of breakdown in living organisms.
Answer :
As we seen in diagram the glucose can be broken down in 3 ways on the basis of presence or absence of oxygen. The first step takes place in cytoplasm that is breakdown of glucose into 2 molecules of pyruvate. This pyruvate in the presence of oxygen will convert into water and carbon dioxide whereas the in absence of oxygen that is fermentation will convert the pyruvate into ethanol or lactic acid on the basis of conditions.
81.) Describe the flow of blood through the heart of human beings.
Answer :
- The circulatory system in humans have 2 types of circulation. Namely,
- Pulmonary circulation
- Systemic circulation
- Pulmonary circulation of blood is transport from heart to lungs and then lungs to heart.
- Systemic circulation of blood circulated from heart to other parts of the body.
- Deoxygenated blood enters the heart through superior vena cava and it will enter into the right atrium or right auricle.
- The blood in the right atrium will enter into right ventricle, through the valve present in between them is tricuspid valve.
- From the right atrium 70 % of the blood will enter into right ventricle.
- Through the right ventricle deoxygenated blood will enter into pulmonary artery as we can see in the above diagram.
- The blood enters into pulmonary artery, now will transport into lungs. This process is called as pulmonary circulation.
- From the lungs the oxygenated blood through the pulmonary veins will enter into left atrium.
- The valve present in between left atrium and left ventricle is called bicuspid valve.
- Through the bicuspid valve the oxygenated blood will enter into left ventricle.
The oxygenated blood present in left ventricle will enter into aorta and through this aorta oxygenated blood will be transported to all the parts of the body. This is called systemic circulation.
82.) Describe the process of urine formation in kidneys.
Answer :
- There are 2 kidneys present in the healthy normal individual. Kidneys are part of the excretory system.
- Kidneys situated below the abdomen and it is a bean shaped organ.
- The measurement of adult kidney is about 12 cm long, 6 cm wide and 3cm thick.
- Each kidney weigh about 150 -170 gm in weight.
- The kidney contains renal artery and renal veins.
- The area in the kidney where renal artery, renal vein and ureter meet called renal hilum.
- The structural unit of kidney is called as nephron.
Ureters :
- The ureters are part of urinary system, which are attached to kidney from one side and to urinary bladder on other side.
- These ureters are made up of smooth muscles.
- Ureters are usually 20-30 cm long and 3-4 mm in diameter.
- These thin tubes carry urine from kidney to urinary bladder.
Urinary bladder :
- Urinary bladder also called as bladder. It is present beneath the ureters.
- The urinary bladder is muscular organ which temporarily stores the urine.
- The normal capacity of urinary bladder to store the urine is 400- 600 ml.
- The urinary bladder wall will expand to store urine and relax during urination.
Urethra :
- Urethra is a thin muscular tube to pass the urine outside the body.
- Inborn have involuntary muscles of urethra. Involuntary means the muscles cannot be controlled by own.
- Adults have voluntary muscles of urethra.
- When brain signals to urethra, at that time urination occurs.