NIOS Class 12 Biology Chapter 14 Solution – Respiration and Elimination of Nitrogenous Wastes
NIOS Class 12 Biology Solution Chapter 14 Respiration and Elimination of Nitrogenous Wastes . NIOS Class 12 Biology Chapter 14 Question Answers Download PDF. NIOS Class 12 Biology Notes.
Board |
NIOS |
Class |
12th (Higher Secondary) |
Subject |
Biology |
Topic |
Question Answer, Solution, Notes |
INTEXT 14.1
1.) Define respiration
Ans: Respiration is the stepwise oxidation of glucose which results in the release of energy that is stored in the cytosol in the form of ATP (adenosine triphosphate)
2.) Name the two gases that are exchanged during respiration
Ans: O2, CO2 are the two gases that are exchanged during respiration
3.) What is cutaneous respiration? Name one animal that undertakes cutaneous respiration.
.. Ans: frogs show cutaneous respiration which is respiration through skin across their moist skin
4.) What is the colour of the blood of the earthworm? Name the pigment responsible
for the colour.
Ans: the color of the blood of earthworm is red due to the pigment responsible is haemoglobin.
5.) How is oxygen transported to the cells in the cockroach?
. Ans: The fine branches of tracheal trunks called tracheoles by which the oxygen is transported in which it penetrate the cells of the body and allow diffusion of respiratory gases directly into and from the cells.
6.) Name the group of animals in which blood is not involved in gaseous exchange.
. Ans: Insects are not involved in gaseous exchange.
7.) How does trachea communicate with the exterior in cockroach?
. Ans: The trachea communicate with the exterior in cockroach through spiracles.
8.) Trace the path of air from the nostrils to the lungs in the human body.
. Ans: The path of air from the nostrils to the lungs in the human body is as follow:
Nostrils → pharynx → bronchi → bronchioles → lungs
9.) Name the part of the respiratory system where air is filtered, moistened and warmed in humans
Ans:Air is filtered through nasal cavity where air is filtered, moistened and warmed in humans
10.) What is the function of the epiglottis in humans?
Ans: The epiglottis prevent food from entering the trachea or food pipe
INTEXT 14.2
1.) What is breathing?
Ans: It is a mechanical process of taking in atmospheric air into the lungs and giving out carbon dioxide. Breathing is an involuntary process but under special conditions it can become voluntary also.
It consist of two steps
(i) Inspiration or taking air in, and
(ii). Expiration or forcing air out
2.) What is the position of the diaphragm at the time of expiration?
Ans: Expiration is the step which involes relaxation. The diaphragm also relaxes and rises again into its original dome shaped condition
3.) What is the capacity of tidal volume?
Ans: The capacity of tidal volume 500 mL
4.) What is the maximum number of oxygen molecules with which haemoglobin can Plants and animals
combine?
Ans: The maximum number of oxygen molecules with which haemoglobin can Plants and animals Combine is four.
5.) Name the blood vessel that takes oxygenated blood from the lungs to the heart.
. Ans: Pulmonary vein takes oxygenated blood from the lungs to the heart.
6.) What are the three forms in which carbon dioxide is transported by the blood?
. Ans: (i) CO2 is physically dissolved in blood plasma – 5-7% of the total CO2
(ii) CO2 directly combines with haemoglobin of RBCs to form carbaminohaemoglobin – about 21-23%
(iii) As bicarbonate it is dissolved in plasma but produced in RBCs catalysed by the enzyme carbonic anhydrase and then diffuses into plasma – about 75% to 80%
7.) Name the vaccine used for prevention of TB.
Ans: Tuberculosis is a bacterial infection that spreads through droplets of infected persons .It can be prevented by Bacillus Calmette Guerin (BCG) vaccine.
8.) What is an occupational hazard.
Ans: Occupational hazard. caused by exposure to dangerous substances like silica, asbestos, dust, etc. that are present in the workplace environment
9.) What is the difference between bronchitis and asthma?
. Ans: In contrast to bronchial asthma, which is an allergic reaction, bronchitis is an infection of the airways and is treatable with medications.
10.) The alveoli of a heavy smoker were damaged, their surface area was reduced and elasticity was lost. What is the technical term for this condition.
Ans: Emphysema is a respiratory condition brought on by heavy cigarette smoking andcrecurrent bronchitis
INTECT 14.3
1.) Name the organ where urea is produced and the organ from where urea is excreted.
Ans: Urea is produced in liver and excreted through kidney
2.) Which is the most toxic form of nitrogenous waste? Name an organism that Excretes
Ans: Ammonia is the most toxic form of nitrogenous waste and amoeba and fresh water fishes excretes it.
INTEXT 14.4
1.) In what form the cockroaches excrete their nitrogenous waste? What is its advantage for cockroach?
Ans: The cockroaches excrete their nitrogenous waste in the form of Uric acid ,this is to prevent water loss as these animals need to conserve water
2.) Where do Malpighian tubules of cockroach open?
Ans: The malpighian tubules are long, blind ended tubules attached to the alimentary canal opens at the junction of mid and hindgut.
3.) List the parts of human excretory system and their functions.
Ans: (i)Kidney- It filters nitrogenous wastes, excess of water and salt
(ii) Ureters- It transport urine to the bladder
(iii) Urinary bladder-It store of urine temporally
(iv)Urethra- It drains urine outside the body
4.) Name the functional unit of kidney and its parts.
Ans: The functional unit of kidney is nephron which are large number of minute tubular structures. It consist of Bowman’s capsules and glomerulus, PCT, loop of Henle, DCT, collecting duct
5.) List the substances that are filtered out during ultrafiltration
Ans: The substances that are filtered out during ultrafiltration are water, amino acid, glucose, urea, uric acid, minerals, vitamins.
6.) What are the substances reabsorbed by the nephron?
Ans: Water, glucose, some salts, amino acid and small quantity of urea and uric acid are reabsorbed by the nephron
7.) What is the importance of tubular secretion?
Ans: By tubular secretion direct elimination of certain minerals can take place such as ammonia and potassium can occur.
8.) Under which situation are the following present?
(a) Glucose in the urine .- Diabetes mellitus
(b) Uric acid crystals –Gout
9.) What is the normal volume of urine excreted per day?
Ans: The normal volume of urine excreted per day is 1200 to 1500 mL.
10.) What will happen if JGA (juxtaglomerular apparatus) stops secreting the enzyme renin?
Ans: Renin converts a plasma protein called angiotensinogen into angiotensin II. . Angiotensin II also stimulates adrenal gland to release the hormone Aldosterone which makes distal tubules of nephron to reabsorb sodium and water. This also increases blood volume and blood pressure, if renin gets stop secreting then blood Pressure will remain abnormally low
11.) Name a hormone, which is a polypeptide in nature and secreted by the heart muscles and is also a vasodilator
Ans: Antinatriuretic factor is also a vasodialator.
INTEXT 14.5
1.) Name the organ where urea is formed.
Ans: Urea is formed in liver
2.) Why is cellophane used in haemodialysis?
Ans: Cellphane is permeable to micro molecules such as urea, uric acid and mineral ions. It is not permeable to macromolecules such as plasma proteins, therefore it is used in haemodialysis.
3.) What is the composition of dialyzing fluid?
Ans: Dialyzing fluid, content solutes like those in blood plasma but no nitrogenous molecules like urea, and uric acid.
4.) From which type of blood vessel artery or vein, is the blood taken out for dialysis?
Ans: The blood is taken out for dialysis Artery.
5.) When is kidney transplantation advised?
Ans: Renal transplantation is suggested if other treatment options for renal failure are unsuccessful.
6.) How is bile pigment removed from our body?
Ans: The bile pigments are excreted along with bile, which flows into the small intestine and from there these get removed with the faeces.
Terminal Exercise
1.) List the major steps that are involved with respiration in humans.
Ans : Respiration is the gradual oxidation of glucose (and other foods), which releases energy that has been stored in the cytosol as ATP (adenosine triphosphate). When our body needs energy, ATP is destroyed, releasing a significant amount of energy.
Respiration is completed in following steps :
Step-1 Gaseous exchange
Step 2 Cellular Respiration
2.) How is oxygen transported in earthworm?
Ans : The respiratory system is absent in earthworms. The earthworm’s entire body is covered in skin, which serves as the respiratory surface. The skin’s capillaries absorb oxygen that is dissolved in water (in skin moisture) and release carbon dioxide into the atmosphere.
3.) Name the respiratory pigment in earthworm
Ans: Pigment haemoglobin is present in earthworn
. 4.) What is the role of carbonic anhydrase in the transport of carbon dioxide in our body?
Ans : Carbonic anhydrase converts the carbondioxide inti carbonic acid and bicarbonate ions
5.)) Which part of our respiratory system is known as the voice box?
Ans : Larynx is known as the voice box.
6.) Where are respiratory centres situated in our brain?
Ans : The medulla oblongata and pons of the brain contain three clusters of neurons referred to as respiratory centres. As follows: (a) Dorsal respiratory group, (b) Ventral respiratory group , (c) Pneumotaxis center
7.) Name one nitrogenous waste removed by the kidney
Ans: Urea is removed by the kidney. The liver breaks down extra nucleic acids and amino acids to create it. The kidneys’ ability to filter and eliminate urea through the production of urine is facilitated by blood.
8.) Name the hormone the absence of which will result in excretion of hypotonic urine
Ans : Anti diuretic harmone will result in excretion of hypotonic urine
9.) What is the role of cellophane in dialysis?
Ans : Cellphane is permeable to micro molecules such as urea, uric acid and mineral ions. It is not permeable to macromolecules such as plasma proteins, therefore it is used in haemodialysis.
10.) Why is inspiration said to be an active phase and expiration as passive phase?
Ans: As a result of contractions, the chest cavity expands, the air pressure in the lungs is lowered, and atmospheric air rushes in to fill the lungs with fresh air. So, inspiration is a respiratory phase that is in motion , while Passive phase refers to the period during which the volume of the chest cavity decreases, raising the air pressure inside the lungs and forcing CO2-filled air out of the body during expiration.
11.) Differentiate between (a) Breathing and respiration
Breathing | Respiration |
Breathing is a physical process. | Respiration is a Bio-chemical process involving enzymes |
It exclusively occurs in mammals, birds, and reptiles. | It Occurs in all organisms |
It involves gaseous exchange between the animal and its external environment | It involves the enzymatic breakdown of glucose to provide energy whether oxygen is present or not. |
(b) Inspiration and expiration
Inspiration | Expiration |
Inspiration is an active phase | Expiration is an passive phae |
The volume of lungs increases | The volume of lungs decreases. |
12.) List the special features of alveoli that enable easy gaseous exchange
Ans : The two bronchi widely branch into bronchioles, terminal bronchioles, and finally, the air sacs known as alveoli.
Alveoli are the organs where the actual gaseous exchange occurs
O2 from the alveoli diffuses into the capillaries, whereas the removal of CO2 from other capillaries also occurs in the alveoli.
The alveolar membrane is incredibly delicate, wet, and densely packed with blood capillaries.
13.) What is vital capacity, tidal volume and residual volume?
Ans : Vital capacity : Maximum amount of air that can be exhaled following a maximum inhalation
Tidal volume : It is the volume of air that is effortlessly inhaled and expelled (normal breathing)
Residual volume : It is the Volume of air that, even during forced expiration, cannot be forced out. This is the air that is still present in the lungs and airways.
14.) Give reasons for the following : (a) Exchange of gases at the alveolar surface continues even during expiration.
Ans: Even during the expiration , exchange of gases at the alveolar surface continues because after exhalation there is still some gases which can be then get exchange.
(b) Trachea and bronchi do not collapse when air pressure decreases inside them
Ans: Trachea and bronchi have structure of cartilage which provide them from getting collapse even air pressure decrease inside them.
15.) Draw the excretory system of human and label the parts
16.) Draw the structure of a nephron and label the parts
17.) What is the cause and symptoms of pneumonia and TB?
Ans : Pneumonia is a acute inflammation brought on by a lung’s alveoli being infected with diplococcus. It results in a fever, discomfort, and a violent cough.The majority of the air is filled with fluid and dead W.B.C.
TB is a bacterial infection that spreads via droplets from affected individuals. The most frequent kind is pulmonary T.B., but it can also affect many other organs.
A typical sign is weight loss and coughing. Low-grade fever goes along with it. The act of coughing may, in rare circumstances, result in blood.
18.) What is the role of liver in excretion?
Ans : It eliminates medicines, certain vitamins, cholesterol, and bile pigments.It eliminates all of the compounds in bile, which travels to the small intestine and is thereafter eliminated in faeces. Additionally, the liver is where urea and uric acid are formed (from ammonia). The kidneys flush them out of the body.
19.) Explain how nitrogenous wastes are removed from the body of cockroach.
Ans : The cockroaches excrete their nitrogenous waste in the form of Uric acid ,this is to prevent water loss as these animals need to conserve water. In cockroaches, malpighian tubules transport uric acid from the body cavity to the digestive system for elimination.
20.) How does ultrafiltration and reabsorption occur in nephrons?
Ans : Ultrafilteration : The capillary walls filter every small molecule from the blood plasma into the Bowman’s capsule, including water, glucose, minerals, amino acids, urea, and uric acid. The glomerular blood still contains proteins. As a result, the lumen of the Bowman’s capsule fills with a filtrate free of protein. Pressure for filtration is provided by the hydrostatic pressure of the moving blood. There is continuous process of ultra filtration
Reabsorption : REabsorption maintain the balance of salt and water are reabsorbed through the renal tubule walls. The Proximal Convoluted Tubule (PCT) reabsorbes between 65 and 85 percent of the filtrate.It contains salts, water, glucose, and amino acids. The descending limb reabsorbs around 5% of the water that is lost. Since the ascending limb is water-impermeable, only salts are reabsorbed here.
21.) Explain how gaseous exchange takes place in the lungs
Ans : Carbon dioxide is transported from tissues to the lungs and oxygen is transported from the lungs to the various tissues through the blood. By splitting into tiny capillaries that round alveoli, the pulmonary artery, which transports deoxygenated blood to the lungs, does so. Alveolar air has more oxygen, while capillary air contains more carbon dioxide. The oxygen diffuses from alveolar air into the blood as a result of the difference in pressure between oxygen and carbon dioxide in the alveoli and blood capillaries. At the same time, blood capillaries release carbon dioxide into the alveolar air. The pulmonary vein transports oxygenated blood from the lungs to the heart.
23.) How is
(a)Water balance :
(b) Salt balance maintained by kidney :
24.) List the parts of human respiratory system in correct sequence and state their functions
Ans: (i) Nostril: It filter the unwanted particles.
(ii) Nasal cavity: Traps the dust, bacteria .
(iii) Pharynx : the same pathway by which food and breathing gas enter the digestive tract
(iv) Larynx : Connects the pharynx to trachea .
(v) Trachea : Passage for air upto bronchi
(vi) Bronchus : splits when it enters the lungs to become secondary bronchi, tertiary bronchioles, and finally terminal bronchioles. They combine to form the bronchial tree.
(vii) Alveoli : Exchange of Gases.
25.) List three characteristics of our lungs which make them suitable as respiratory surface.
Ans: Lungs consist of bronchus which further dovides.
It contains small capillaries which allow the exchange of gases.
It have large surface area which is helpfull in gas exchange.
Also See: Next Chapter No. 15 Question answer