Class 10 Biology

MPBSE Class 10 Science Chapter 7 Coordination In Plants Question and Answers

Question 1. What are plant hormones?
Answer:

Plant hormones or phytohormones are non-nutrient diffusible chemical substances that control the activities of plants like growth, development, differentiation, movements, and other physiological processes.

Question 2. How is the movement of the leaves of a Sensitive Plant different from the movement of the shoot toward light?
Answer:

• Leaves of sensitive plant (Mimosa pudica) droop down on being touched or shaken. It is a harmonistic or seismonastic response where the direction of movement is predetermined by the presence of a turgor cell.
• The movement of the shoot toward light is a growth movement caused by the differential distribution of auxin.

Question 3. Give an example of a plant hormone that promotes growth.
Answer: Auxin (IAA)/Gibberellins (GA).

Question 4. How do auxins promote the growth of a tendril around a support?
Answer:

• In the region of contact, there is less availability of auxin as compared to the free side. Because of this, there is more growth on the free side.
• The tendril, therefore, bends over the support. The process continues and several coils are produced.

MPBSE Class 10 Science Chapter 7 Coordination In Plants Question and Answers

Question 5. Explain the cause of shoots of the plant bending towards light.
Answer:

• The bending of the shoot towards unilateral light is caused by the effect of light on auxin distribution.
• There is less auxin on the illuminated side and more auxin on the shaded side. Therefore, there is more growth on the shaded side and the shoot bends in the other direction.

Question 6. What are nastic and curvature movements? Give one example of each.
Answer:

• Nastic Movements. They are non-directional movements in which the direction of movements is determined by the structure of the responding organ, for example., the opening of flowers, haptonasty in the Sensitive Plant. Nastie movements can be due to growth or turgor changes.
• Curvature Movements. They are directional growth movements in which the response of the plant organ is determined by the direction of the stimulus, for example., positive phototropism of shoot.

Question 7.

1. What are plant hormones?
2. Write two functions of auxin.

Answer:

1. Plant Hormones. Plant hormones or phytohormones are non-nutrient diffusible chemical substances that can control various activities of plants like growth, differentiation, movements, development, and other physiological processes.
2. Functions of Auxin.
   1. Auxin induces cell enlargement.
   2. It prevents premature falling of leaves and fruits.

Question 8.

1. What is tropism?
2. How do auxins promote the growth of a tendril around a support?

Answer:

1. It is the directional curvature movement of generally cylindrical plant organs with the direction of stimulus determining the direction of movement.
2. More auxin is present on the side of the tendril away from the point of contact. Therefore, there is more growth on the free side as compared to the contact side. The more growth on the free side causes the tendril to coil around the support.

Question 9. How is the movement of leaves of sensitive plants different from the movement of a shoot towards light?
Answer:

MPBSE Class 10 Science Chapter 7 Coordination In Plants Question and Answers

Question 10. Which plant hormone

1. Inhibits the growth of plants
2. Increases yield
3. Controls cell division.

Answer:

1. Abscisic acid
2. Gibberellin
3. Cytokinin.

Question 11. What is phototropism?
Answer:

Phototropism. It is the directional growth movement of curvature that occurs in plant organs in response to unilateral light.

Question 12. What is hydrotropism?
Answer:

Hydrotropism. It is the tropic or directional movement of curvature that occurs due to unilateral exposure to water. Roots are positively hydrotropic.

Question 13. If you keep the potted plant horizontally for 2-3 days, what type of movements would be shown by the shoot and root after 2-3 days? Why?
Answer:

• The potted plant develops a geotropic response. It is different in shoot and root. The apical part of the shoot will bend upwardly.
• It is the negative geotropic response. The apical part of the root will bend downward. It is the positive geotropic response.

Question 14.

1. Which plant hormone is present in greater concentration in the areas of rapid cell division?
2. Give one example of a plant growth promoter and plant growth inhibitor.

Answer:

1. Cytokinin hormone occurs in greater concentration in the areas of rapid cell division.
2. Growth Promoter – Auxin
   1. Growth Inhibitor – Abscisic acid (ABA).

MPBSE Class 10 Science Chapter 7 Coordination In Plants Question and Answers

Question 15. Why does the shoot of the plant bend towards light when it is kept inside a cardboard box with a small hole?
Answer:

• Light coming from the hole functions as a unilateral stimulus. It results in passing auxin formed on the illuminated side to the shaded side.
• The shaded side comes to have more auxin. Therefore, it shows more growth. Due to this, the shoot bends to the other side or source of light.

Question 16. What is geotropism? Describe an experiment to demonstrate positive and negative geotropism.
Answer:

Geotropism. It is a tropic or growth movement of curvature which occurs in response to the vector of gravity. The main stem is generally negatively geotropic while the main root is positively geotropic.

Question 17. List in tabular form three differences in the movement of leaves of Sensitive Plants when touched and the movement of tendrils towards the support.
Answer:

Question 18.

1. Name the property that causes a tendril to circle the object.
2. What is the benefit of it?
3. Fill in the blank_____

Answer:

1. Thigmotropism.
2. By circling the support, the tendril can hold the plant to support and allow it to climb further to exposing the leaves properly
3. Inhibits growth.
   1. Cytokinin.

Question 19. How does the sensitive plant detect the touch and how do the leaves move in response?
Answer:

• Touch is a stimulus that is converted into an electrochemical potential that reaches the bases of the leaflets and the leaf.
• The cells at the base show efflux of K+ and water. As a result, they shrink in size and cause the folding of leaflets and drooping of leaves.

Question 20. What are plant hormones? Name the plant hormones responsible for the following :

1. Growth of stem
2. Promotion of cell division
3. Inhibition of growth
4. Elongation of cells.

Answer: Plant hormones are non-nutrient, diffusible, chemical substances that control and coordinate growth, movements, and development.

1. Growth of Stem. Gibberellin
2. Promotion of Cell Division. Cytokinin.
3. Inhibition of Growth. Abscisic acid.
4. Elongation of Cells. Auxin.

MPBSE Class 10 Science Chapter 7 Coordination In Plants Question and Answers

Question 21.

1. Plants do not have any nervous system but yet if we touch a sensitive plant, some observable changes take place in its leaves. Explain how could this plant respond to external stimuli and how it is communicated.
2. Name the hormone that needs to be administered to
   1. Increase the height of a dwarf plant
   2. It causes rapid cell division in fruits and seeds.

Answer:

Touching the sensitive plant creates an electrochemical impulse that travels from cell to cell quickly and reaches the bases of leaflets and leaves.

Special cells present at these bases shrink and cause bending movement of leaves and leaflets. Recovery occurs in about ten minutes when basal cells regain turgidity.

1. Height of Dwarf Plant. Gibberellin.
2. Rapid Cell Division. Cytokinin.

MPBSE Class 10 Science Chapter 9 Heredity Question And Answers

Question 1. In a monohybrid cross between tall Pea plants TT and short Pea plants tt, a scientist obtained only tall Pea plants Tt in the F₁ generation. However, on selling the F₁ generation Pea plants he obtained both tall and short plants in the F₂ generation. Based on the above observations and with other angiosperms also, can the scientist arrive at a law? If yes, explain the law. If not, give a justification for your answer.
Answer:

There are two possibilities for the occurrence of tall plants in the F₁ generation :

• Only the factor for tallness passed into F₁ progeny. Both the alleles of tallness and shortness passed into F₁ progeny but only the allele of tallness is expressing itself.
• The second option is correct because the trait of shortness has appeared in the F₂ generation.
• Again this can happen only when the alleles for the two traits separate during gamete formation and randomly come together during fertilization.
• The scientist could, therefore, deduce the laws out of these observations : (1) Law of dominance. (2) Law of segregation.

Question 2.

1. List two differences in tabular form between dominant and recessive traits.
2. What percentage or proportion of the plants in F₂ generation or progeny was round in Mendel’s cross between round and wrinkled seeded Pea plants?

Differences Between Dominant And Recessive Traits

Answer: (1)

2. 75% of plants had round seeds while 25% of plants had wrinkled seeds. The ratio is 3: 1.

MPBSE Class 10 Chapter 9 Heredity Question And Answers

Question 3. “A trait may be inherited but may not be expressed.” Justify the statement with the help of a suitable example.
Answer:

1. The trachea is a cylindrical conduit for air from the pharynx to the lungs.
2. The lining epithelium captures dust particles and bacteria, expelling them forth.
3. The trachea remains patent despite lower air pressure owing to the presence of C-shaped cartilaginous rings.

Question 4. Name the plant Mendel used for his experiment. What type of progeny was obtained by Mendel in F₁ and F₁ generations when he crossed tall and short plants? Write the ratios he obtained in F₂ generation plants.
Answer:

Garden Pea (Pisum sativum)

F₁ Generation. All tall.

F₂ Generation. 3 tall: 1 short or 3: 1

or 1 pure tall: 2 hybrid tall: 1 dwarf or 1: 2: 1.

Question 5.

1. Why did Mendel experiment to study the inheritance of two traits in garden peas?
2. What were his findings concerning the inheritance of traits in the F₁ and F₂ generations?
3. State the ratio obtained in the F₂ generation in the above-mentioned experiment.

Answer:

1. To study the independent inheritance of traits/factors of different characters.
2. F₁ Progeny. All dominant. F2 Progeny. Both parental traits as well as some new combinations or recombinants.
3. 9 : 3 : 3: 1 where 9/16 and 1/16 are parental types while two types of recombinants appear in the ratio of 3/16 and 3/16.

Class 10 Chapter 9 Heredity Question And Answers

Question 6. A green-stemmed rose plant denoted by GG and a brown-stemmed rose plant denoted by GG are allowed to undergo a cross with each other.

1. List your observations regarding (z) the Colour of the stem in the F₁ progeny and the Percentage of brown stemmed plants in F₂ progeny if F₁ plants are self-pollinated. The ratio of GG and Gg in F₂ progeny.

2. Based on the findings of this cross, what conclusion can be drawn?

Answer:

1. Colour in F₁ Progeny. Green
2. Percentage of Brown Stemmed Plants in F₂ Progeny. 25%
3. Ratio of GG and Gg in F₂ Progeny. 1: 2.

Conclusion: The trait which is expressed in whole F₁ progeny is dominant while the other trait which remains unexpressed in F₁ progeny but reappears in F₂ progeny is recessive.

Question 7.

1. Why is the F₁ progeny always of tall plants when a tall pea plant is crossed with a short pea plant?
2. How is F₂ progeny obtained by self-pollination of F₁ progeny different from F₁ progeny? Give a reason for this observation.
3. State a conclusion that can be drawn based on this observation.

Answer:

1. The trait or factor for tallness is dominant while the trait for shortness is recessive.
2. The recessive trait appears in the F₂ generation due to its segregation during gamete formation and the random coming together of the two traits or factors during fertilization. When two factors of shortness come together the recessive trait will appear.
3. The traits or factors are particulate structures which do not get destroyed or blend during inheritance.

Question 8. Mendel crossed two plants with visible contrasting characteristics and found that there were no halfway characteristics in the plants of F₁ progeny. Explain the reason for this observation of Mendel.
Answer:

Despite having inherited both the contrasting traits, F₁ progeny shows the trait of only one parent. This is because in the hybrid (F₁ plants) only one trait expresses its effect. The trait is dominant. The other trait which does not express its effect in the hybrid is called recessive.

Class 10 Chapter 9 Heredity Question And Answers

Question 9. What are chromosomes? Explain stability of the DNA of the species is ensured in sexually reproducing organisms.
Answer:

• Chromosomes are thread-like entities based in the nucleus. Their DNA contains the genetic elements of the species. Every cell contains two copies of each chromosome.
• In germ cells, generated post-meiosis, just one chromosome of each kind is present.
• It may be either paternal or maternal. During fertilization, two gametes merge, reinstating the diploid state of chromosomes in the zygote and the subsequent cells of the organism derived from it.

Question 10.

1. Name the two types of gametes produced by men.
2. Does a male child inherit an X chromosome from his father? Justify.
3. How many types of gametes are produced by a human female?

Answer:

1. Men produce two types of sperms, X-carrying (gymnosperms) and Y-carrying (angiosperms) in equal proportion.
2. No. A male child inherits the X chromosome from his mother. From their father, he inherits the Y chromosome.
3. The female produces only one type of ova. They carry X chromosomes.

MPBSE Class 10 Science Life Processes Question and Answers

Question 1. (1) How many times does the blood go through the heart during one cycle in fish and why?

{2) List the respiratory pigment present in our body. Where is it present?

(3) Why are valves present in the heart and veins?
Answer:

1. Fish have a single circulation of blood in contrast to double circulation in humans. In fish, the heart pumps the blood into the gills for purification. From the gills, the purified blood goes to the body and then comes back to the heart for pumping.
2. Haemoglobin is the respiratory pigment. It is present in the red blood corpuscles.
3.  Valves are present in the heart and veins to prevent the backflow of blood.

Question 2. (1) Explain in brief the mechanism of circulation of blood in the human body.

(2) “Lymph is another type of fluid involved in transportation.” Justify the statement by explaining the process.
Answer:

(1) The right atrium receives deoxygenated blood from the heart (coronary sinus), upper part of the body (superior vena cava), and middle and lower part of the body (inferior vena cava). The left atrium receives oxygenated blood from the lungs.

• As the two atria get filled, they contract simultaneously and pour their blood into the ventricles of their side through auriculo-ventricular apertures.
• On getting filled, the ventricles undergo systole. The left ventricle sends oxygenated blood to all body parts through the systemic aorta. The right ventricle sends deoxygenated blood to the lungs through the pulmonary arch for oxygenation.

(2) Lymph is a transportation fluid formed from tissue fluid. It is specialised to collect large size secretions and excretions which cannot directly pass into the blood, For Example., proteins, hormones, and fat. The lymph picks them and pours their contents into the blood in the region of the subclavian vein.

MPBSE Class 10 Science Life Processes Question and Answers

Question 3. (1)(A) Receives deoxygenated blood from vena cava (B) Sends deoxygenated blood to the lung through the pulmonary artery (C) Receives oxygenated blood from lungs and (D) Sends oxygenated blood to all parts of the body through the aorta.

(2) What does the blood consist of?

(3) Name the respiratory pigment in human beings and discuss its role.
Answer:

1. (A) Right atrium (B) Right ventricle (C) Left atrium (D) Left ventricle.
2. Blood consists of blood plasma (55%) and blood cells (45%) of three types red blood corpuscles, white blood corpuscles and blood platelets.
3. Haemoglobin is the respiratory pigment that is found in red blood corpuscles. It carries oxygen as oxyhaemoglobin and a part of carbon dioxide as carbaminohaemoglobin.

Question 4. What is lymph? How is the composition of lymph different from blood plasma? What is the direction of its flow? List two functions of the lymphatic system.
Answer:

Lymph is a straw-coloured viscous fluid which is formed from tissue fluid and flows inside tubes called lymph vessels.

Lymph differs from blood plasma in having :

1. 94% water instead of 92% in plasma
2. 3.0 to 4.5 per cent protein instead of 6-8% protein in blood plasma
3. Globulin and fibrinogen contents are lower
4. Lymph receives a direct supply of secretion and excretion of tissues while blood obtains the same from lymph.

Direction of Flow. Unidirectional from tissues all over the body to subclavian veins.

Functions of Lymphatic System.

1.  The lymphatic system functions as a middleman between tissue fluid and blood,
2. It picks up germs and takes them to lymph nodes for disposal.

Question 5. (A) What do the following transport: (1) Xylem (2) Phloem (3) Pulmonary vein (4) Vena Cava?

(B) Write two points of difference between the pulmonary artery and the pulmonary vein.
Answer:

1. (A) Xylem. Transports sap (water and mineral salts) from roots to aerial parts of the plant.
2. Phloem. It translocates food and other solutes from a place of manufacture or storage to a place of utilisation both in upward and downward directions.
3.  Pulmonary Vein. It carries oxygenated blood from the lungs to the left auricle.
4. Vena Cava. It carries deoxygenated blood from different parts of the body to the right auricle. Differences between Pulmonary Artery and Pulmonary Vein

MPBSE Class 10 Science Life Processes Question and Answers

Question 6. (1) The upward movement of water normally requires a pump in our houses but in tall trees, water rises up without any external support. Explain the mechanism.

(2) State three points of difference between the transport of materials in the xylem and phloem.
Answer:

(1) Water rises up the top of the tallest plants through the development of a negative pressure caused by loss of water in transpiration. Transpiration or loss of water in vapour form occurs from mesophyll and other cells of aerial parts.

1. As there are innumerable numbers of cells losing water, they develop a tremendous suction pressure and withdraw water from the nearby xylem channels. This puts the water present in the xylem channel under a negative pressure of 10-20 atm.
2. Negative pressure or pull caused by transpiration is unable to break the continuity of the water column due to the presence of cohesion force amongst water molecules and adhesion force between water and the wall of the xylem channel.
3. The negative pressure or transpiration pull reaches the root region and forces water to move upwards. It is just like upward pulling of a cold drink with the help of a straw pipe. The mechanism of the ascent of sap through transpiration pull and cohesion force was given by Dixon and Jolly (1894).

2. Force. It comes from the development of negative press- 2. It develops from the formation of turgor pressure, sure or transpiration pull.

3. Channel. The conducting channels are made of the conducting channels are formed of living sieves dead lignified elements, vessels and tracheids. tube elements.

Question 7. (1) Mention any two components of blood.

(2) Trace the movement of oxygenated blood in the body.

(3) Write the function of valves present in between atria and ventricles.

(4) Write one structural difference between artery and vein.
Answer:

1. Composition of Blood. Blood cells—45%. Plasma—55%. Blood cells arc of three types—red blood corpuscles, white blood corpuscles and blood platelets.
2. Movement of Oxygenated Blood. Blood is oxygenated in the lungs. Pulmonary veins carry the oxygenated blood from the lungs to the left atrium. The left atrium pours the oxygenated blood into the left ventricle. On contraction left ventricle pushes the oxygenated blood into the aorta for supply to various parts of the body.
3.  Function of Valves. A tricuspid valve lies over the right atrioventricular aperture. A bicuspid valve occurs over the left atrioventricular aperture. They are meant to prevent the backflow of blood into the atria when the ventricles contract.
4. Artery’ and Vein. An artery has a thicker elastic well and a narrower lumen while the vein has a thinner nonelastic wall with wider lumen and semilunar valves for preventing backflow of blood.

MPBSE Class 10 Science Life Processes Question and Answers

Question 8. (1) Write two water-conducting elements present in plants. How does water enter continuously into the root system?

(2) Explain why plants have low energy needs as compared to animals.
Answer:

1. The two water-conducting elements of plants are tracheids and vessels. Continuous Entry of Water.
2.  Plants have low energy requirements.

Question 9. List in tabular form three differences between blood and lymph.
Answer:

Question 10. “Blood circulation in fishes is different from the blood circulation in human beings.” Justify the statement.
Answer:

Fishes have two-chambered venous hearts with a single circulation. Human beings have four-chambered arterio¬venous hearts with double circulation.

Question 11. (1) Write the correct sequence of steps followed during the journey of oxygen-rich blood from the lungs to various organs of the human body.

(2) What happens when the system of blood vessels develops a leak?
Answer:

1. Lungs → Pulmonary veins → Left atrium → Left atrial diastole followed by contraction → Left ventricle → Left ventricle diastole followed by contraction → Aorta → Various parts of body except lungs.

2. (A) Leakage will reduce blood quantity, blood pressure mid-efficiency of a pumping system,

(B) Blood coagulation at the site of length will plug the leakage

MPBSE Class 10 Science Life Processes Question and Answers

Question 13. Give Reasons

1. Ventricles have thicker muscular walls than atria
2. The transport system in plants is slow
3. The circulation of blood in aquatic vertebrates differs from that in terrestrial vertebrates.
4. During the daytime, water and minerals travel faster through the xylem as compared to the night.
5. Veins have valves whereas arteries do not.

Answer:

1. Thicker Walls of Ventricles.
2. Slow Transport in Plants. Plants have a lower requirement of energy.
3.  In aquatic vertebrates, like lush there is a single blood circulation while in terrestrial vertebrates there is double circulation.
4. The rate of water and mineral movement is higher during the daytime due to very high transpiration.
5. There is no forceful movement of blood in the veins. Veins possess valves to prevent backflow.

MPBSE Class 10 Science Excretion Question and Answers

Question 1. (1) Name the part that (A) Produces urine and (B) Releases urine to the outside.

(2) What is the main toxic waste kidney filters from blood?

(3) Name any two substances which are selectively reabsorbed from the tubules of a nephron.
Answer:

1.  (A) Kidney (B) Urethra
2.  Main Toxic Substance. Urea.
3.  Selectively Reabsorbed. Glucose, amino acids.

Question 2. (1) How is urine produced?

(2) Name two excretory products of plants other than Oxygen and Carbon dioxide.
Answer:

1. Production of Urine. It occurs through ultrafiltration of blood in renal or Malpighian capsules, reabsorption of useful substances (glucose, amino acids, salts, water) from the filtrate in PCT, tubular secretion of remaining wastes in DCT, and ADH-mediated concentration in collecting tubules.
2.  Alkaloids, tannins, resin, gum.

Question 3. (1) Write the important function of the structural and functional unit of the kidney.

(2) Write one function of an artificial kidney.
Answer:

1. Function of Nephron. It takes part in the ultrafiltration of blood, reabsorption of useful materials in PCT, and selective secretion of remaining wastes in the area of the DCT.
2. Artificial Kidney. It is specialized in removing toxins, urea, uric acid, and other wastes from the body of a person suffering from a damaged kidney.

MPBSE Class 10 Biology The Excretory System Question And Answers

Question 4. (1) Explain the excretory system in human beings.

(2) List four strategies used by plants for excretion.
Answer:

(1) The human excretory system consists of a pair of kidneys, a pair of ureters, a urinary bladder, and a urethra.

• Kidneys are reddish-brown bean-shaped structures present in the lower abdomen, one on each side of the vertebral column. In the concave hilum part of the kidney enters a waste-laden renal artery. The renal vein and ureter come out of the same.
• Each kidney has about a million nephrons. They are the structural and functional units of the kidney. Each nephron has a renal or Malpighian capsule and a renal tubule. Blood is filtered in the region of the Malpighian capsule.
• It produces primary urine. Useful substances present in the primary urinary are reabsorbed in the PCT part of the uriniferous tubule. Residual waste products are poured into the urine in the DCT part of the nephron. Nephrons pour the urine into the collecting tubule where it may be further concentrated.
• Ureters are narrow distensible tubes that carry urine from the kidneys into the urinary bladder. The urinary bladder is a pear-shaped distensible sac that stores urine. It has the capacity to store urine up to 700 to 800 ml.
• As the urinary bladder reaches the halfway mark, an urge for micturition begins to appear. The urethra carries the urine from the urinary bladder to the outside.

(2) Strategies for Excretion in Plants

• Oxygen during the daytime and carbon dioxide at night pass out of the plants through diffusion.
• Secondary metabolites like alkaloids, organic acids, and tannins collect in old dying leaves which later fall off.
• Waste products such as tannins, resins, and others pass into the bark which is peeled off periodically.
• Resins, gums, and tannins are also deposited in old non-functional xylem.

MPBSE Class 10 Biology The Excretory System Question And Answers

Question 5. State the function of the renal artery, kidney, ureter, and urinary bladder In Hum, an Excretory System
Answer:

Renal Artery. It brings oxygenated blood laden with waste products into the kidney.

Kidney. Separation and elimination of nitrogenous and other waste products, regulation of water balance, regulation of blood pressure and pH.

Ureter. Carrying of urine from the kidney to the urinary bladder.

Urinary Bladder. Temporary storage of urine and helping in voiding the same.

Question 6. (1) Define excretion. (2) Name the basic filtration unit in the kidney. (3) Draw the excretory system in human beings and label the organs that perform the following function : (A) Forms urine, (B) Is a long tube that collects urine from the kidney
Answer:

1. Excretion. It is the removal of metabolic wastes, toxins, and excess salts from the body.
2. Basic filtration Unit Nephrons or uriniferous tubule.

Question 7. Name the organs that form the excretory system in human beings.
Answer:

A pair of kidneys, a pair of ureters, a urinary bladder, and a urethra.

Question 8. (1) Describe the structure and function of the basic unit of the kidney.

(2) List two factors on which the reabsorption of water from urine depends.
Answer:

1. Nephron.
2. (A) Amount of excess water and wastes (B) Antidiuretic hormone (ADH).

MPBSE Class 10 Biology The Excretory System Question And Answers

Question 9. Write one main function for each of the labeled parts.
Answer:

1. Kidney. Urine formation. Ureter. Transport of urine from the kidney to the urinary bladder.
2. Urinary Bladder. Stores urine. Urethra. Throws out urine or micturition.

Question 10. (1) How do the leaves of plants help in excretion? Explain briefly.

(2) Describe the structure and function of the nephron.
Answer:

(1) (A) Passage of O₂ during daytime

(B) Transpiration of excess water

(C) Passage of CO₂ during night

(D) Storage of secondary metabolites and waste products which are disposed of when the old leaves fall off.

(2) Nephron

Important Questions For Class 10 Biology Respiration  Respiration

Question 1. What is the function of the trachea? Why do the walls not collapse even when there is less air in them?
Answer:

• The trachea is a cylindrical conduit for air from the pharynx to the lungs
• The lining epithelium captures dust particles and bacteria, expelling them forth.
• The trachea remains patent despite lower air pressure owing to the presence of C-shaped cartilaginous rings.

Question 2. Give reason:

1. Fine hair and mucus are present in the nasal passage.
2. Rings of cartilage are present in the throat.

Answer:

1. Fine hair and mucus present in nasal passages trap dust particles and microbes from inspired air.
2. Rings of cartilage prevent the collapsing of the trachea when air pressure is low.

Question 3. Mention the shape of guard cells and write their constituents.
Answer:

In most plants, guard cells are bean-shaped in outline. They are joined at their ends but are free on inner thick-walled regions. The outer walls are thin-walled. Guard cells are nucleated. They have several small chloroplasts and small-sized vacuoles.

Question 4. Why is diffusion not sufficient to meet the oxygen requirement of all the cells in multicellular organisms?
Answer:

Diffusion may transpire if each cell in the body is encased by intercellular gaps that are linked to the atmosphere via pores. This is not possible in mammals. Consequently, they possess a transport system to deliver oxygen to all body cells.

Class 10 Respiration Life processes Important questions

Question 5.

1. Why are cramps caused in our muscles during sudden excess activity?
2. Name the type of respiration that takes place in Yeast during fermentation.

Answer:

1. Muscles get fatigued during sudden excess activity due to the accumulation of lactic acid caused by anaerobic respiration. This causes cramps.
2. Anaerobic respiration yields ethyl alcohol and carbon dioxide.

Question 6. Write two different ways in which glucose is oxidised to provide energy in the human body. Write the products formed in each case.
Answer:

The two ways in which glucose is oxidised are aerobic and anaerobic. In aerobic respiration, oxygen functions as a terminal oxidant. It produces CO₂ and water.

In anaerobic respiration that occurs in skeletal muscles, oxygen is not used. Glucose is broken down to produce lactic acid.

Question 7. Give a reason for the following:

1. The glottis is covered by epiglottis.
2. Lung alveoli are covered with blood capillaries.
3. The wall of the trachea is supported by cartilage rings.

Answer:

1. The epiglottis covers the glottis during swallowing to prevent entry of food and water into the trachea.
2. Lung alveoli are covered by blood capillaries because they function as the respiratory surface of the lungs. There is a gaseous exchange between blood and alveolar air with oxygen entering blood and carbon dioxide entering alveolar air.
3. Cartilage rings provide support to the trachea and keep it open for free passage of air.

Question 8. List three characteristics of lungs which make them an efficient respiratory surface.
Answer:

1. Lungs have a large number of microscopic alveoli which create a huge respiratory surface area of about 80 m².
2. Alveoli are invested with blood capillaries for rapid exchange of gases.
3. The passageway of air is non-collapsible being supported by cartilaginous rings in broader branches and surfactant in narrow areas.
4. Airtight location of lungs in the thoracic cavity where rise or fall in pressure causes exhalation and inhalation respectively.

Important Question for Class 10 Science Life Processes

Question 9.

1. The breathing cycle is rhythmic whereas the exchange of gases is continuous. Justify the statement.
2. Why is breathing through the mouth harmful?

Answer:

1. The whole of the air is not drained out during exhalation. A large amount of air remains in the lungs. The same is called residual volume. It allows the continued exchange of gases.
2. Breathing through the mouth is harmful as:
   1. It allows dust particles and microbes to enter the buccal cavity and lungs causing irritation and infection,
   2. Dry, hot or cold air produces irritation to the whole respiratory system.

Question 10. Mention the special features of nasal breathing that make it a safer process.
Answer:

• Filtration of particulate matter by nasal cilia.
• Elimination of dust and microorganisms by the mucus in the nasal cavities.
• Expelling trapped dust and germs by ciliary action.
• Destruction of microorganisms by lysosome in the nasal epithelium.
• Humidification of breathed air by the moist nasal epithelium.
• Air conditioning refers to the process of adjusting the temperature of inhaled air to match that of the body, facilitated by the blood capillaries located in the nasal passage

Question 11. Explain how glucose is broken down in the absence or shortage of oxygen.
Answer:

Glucose is first broken down to form two molecules of pyruvate, two molecules each of NADH₂ and ATP.

1. In the absence or shortage of oxygen, pyruvate is reduced by NADH₂ by two methods
2. Formation of ethyl alcohol and evolution of CO₂ as in yeast.
3. Formation of lactic acid as in skeletal muscles and lactic acid bacteria.

In both cases, a molecule of glucose yields a small amount of energy (2ATP molecules) as compared to aerobic respiration (38 ATP molecules).

Class 10 Biology Chapter 2 Respiration

Question 12.

1. In the process of respiration, state the functions of alveoli.
2. The rate of breathing in aquatic organisms is much faster than that in terrestrial organisms. Give reasons.
3. Complete the following pathway showing the breakdown of glucose

Answer:

1. Alveoli. Exchange of gases.
2. Aquatic Organisms. The rate of breathing is faster in aquatic organisms in order to obtain required oxygen from water which is very low as compared to air.
3. Pyruvate
4. Carbon dioxide.