A thorough understanding of Kerala Syllabus 9th Standard Biology Notes Pdf Chapter 3 Respiration and Excretion Extra Questions and Answers can improve academic performance.
Kerala Syllabus Std 9 Biology Chapter 3 Respiration and Excretion Extra Questions and Answers
Question 1.
What is the role of intercostal muscles in respiration and where they are found?
Answer:
Intercostal muscles are found in between the ribs. Their contraction and relaxation change the volume of the thoracic cavity so that air can enter and leave the lungs.
Question 2.
What do you mean by ventilation?
Answer:
Breathing is also known as ventilation, it involves two phases:
- Inspiration (Inhalation): The first phase, allows air to flow into the lungs.
- Expiration (Exhalation): The second phase, facilitates releasing of air from the lungs to the atmosphere.
Question 3.
What do you mean by alveolar exchange of gases?
Answer:
The exchange of oxygen from the air which has entered the alveolus, into the blood and the exchange of carbon dioxide into the alveolus from the blood. This is called the alveolar exchange of gases.
Question 4.
Differentiate between alveolar exchange and systemic exchange of gases.
Answer:
Alveolar exchange is the exchange of oxygen from the air which has entered the alveolus, into the blood and carbon dioxide exchange into the alveolus from the blood.
Systemic gas exchange is the movement of respiratory gases between blood in systemic capillaries and systemic cells.
Question 5.
How do the structure of alveoli and blood capillaries help in the exchange of gases?
Answer:
The walls of the alveoli are very thin, which makes it easier for oxygen and CO2 to pass between the alveoli and very small blood vessels (capillaries).
Question 6.
What do you mean by cellular respiration?
Answer:
Cellular respiration is the process of breaking down of glucose using oxygen and releasing energy, which occurs in cells.
Question 7.
List the two major stages involved in cellular respiration.
Answer:
- Glycolysis
- Krebs cycle
Question 8.
Mention the role of haemoglobin in respiration.
Answer:
Haemoglobin is an iron-containing proteinaceous pigment which imparts red colour to the red blood cells (RBCs). Structurally haemoglobin can bind with respiratory gases like O2 and CO2 and it helps in the transportation of these gases to and fro the cells.
Question 9.
How do amoeba and earthworms respire?
Answer:
Amoeba is a unicellular organism that respires through its cell membrane. Skin is the respiratory surface of earthworms.
Question 10.
Differentiate between stomata and lenticels.
Answer:
Stomata and lenticels are the specialized structures for gaseous exchange in plants. The small pores on the surface of leaves and young stems are called stomata. Stomata remain open in the daytime and close at night. Lenticels are the lens-shaped openings found on the surface of mature stems and roots.
Question 11.
List the differences between aerobic and anaerobic respiration.
Answer:
Aerobic respiration | Anaerobic respiration |
Respiration takes place in the presence of oxygen | Respiration takes place without the presence of oxygen |
Eg: All animals and plants | Eg: Yeast, Bacteria |
- Excretion is the process of removal of waste materials from the body.
- The organs that form the excretory system in human beings include the kidney, ureter, urethra, and urinary bladder.
- Synthesis of urea takes place in the liver.
- The kidneys are excretory organs that perform three main functions to produce urine, filtration, reabsorption, and secretion.
- Kidneys contain ultrafilters that filter waste from the blood. They are called nephrons (Structural and functional units of the kidney).
In all organisms, energy is produced from glucose. As a result of such metabolic activities, several byproducts are formed in the cells. If they become harmful to homeostasis, they are turned into waste. The process of removal of such waste materials from the body is called excretion.
The organs that form the excretory system in human beings include the kidney, ureter, urethra, and urinary bladder.
Carbon dioxide is utilized in various life processes. The process that converts the toxic substance like ammonia formed as a result of the metabolism of protein into less toxic urea is an important one among these.
Synthesis of urea takes place in the liver. Amino acids are formed by the breakdown of proteins. As a result of the metabolic activities of amino acids, several nitrogenous by-products are formed. The most harmful among these is ammonia. The ammonia formed in tissues diffuses into blood through tissue fluids and blood transports it to the liver. In liver with the help of certain enzymes, ammonia combines with carbon dioxide and water to form urea.
Kidneys play a major role in the excretion of urine which contains waste materials including urea. The kidneys are excretory organs that perform three main functions to produce urine, filtration, reabsorption and secretion. Urea is made when foods containing protein (such as meat, poultry, and certain vegetables) are broken down in the body. Urea is carried in the blood to the kidneys. This is where it is removed, along with water and other wastes in the form of urine.
Kidney and related parts:
Human beings have a pair of kidneys. They are bean-shaped and are located in the abdominal cavity on either side of the vertebral column. Kidneys contain ultrafilters that filter waste from the blood. They are called nephrons. Nephrons are the basic structural and functional units of kidneys. Around 12 lakh nephrons are present in each kidney.
Question 12.
What do you mean by excretion?
Answer:
The process of removal of waste materials from the body is called excretion.
Question 13.
What is Urea?
Answer:
Urea is the main excretory material of human beings. In the liver with the help of certain enzymes, ammonia combines with carbon dioxide and water to form urea.
Question 14.
What is the role of the renal artery and renal vein in excretion?
Answer:
The renal artery is the blood vessel that carries blood to the kidneys. The renal vein carries blood away from the kidneys
Question 15.
Explain the structure of the human excretory system with a neat labelled diagram.
Answer:
The human excretory system consists of a pair of kidneys, a pair of ureters, a urinary bladder, and a urethra.
Renal arteries are the blood vessels that carry blood to the kidneys and the renal veins are the blood vessels that carry blood away from the kidneys. Pelvis is the initial part of ureter.
Question 16.
What are the three main steps for urine formation?
Answer:
- Glomerular filtration (Ultra filtration)
- Reabsorption
- Secretion
Question 17.
What is micturition? What are the major components of urine?
Answer:
Micturition is the process of urination. Water, urea, sodium chloride, potassium chloride, calcium salts, phosphate, uric acid, creatinine, etc. are the components of urine.
Question 18.
Name the diseases that may caused due to abnormal amounts of glucose and calcium oxalate crystals in urine.
Answer:
Abnormal amount of glucose – Diabetes
Abnormal amount of Calcium oxalate crystals – Kidney stone
Question 19.
What are nephrons? Mention their role in urine formation.
Answer:
A nephron is the basic structural and functional unit of the kidney. They are microscopic structures composed of a renal corpuscle and a renal tubule. There are about millions of nephrons in each human kidney.
Each nephron has a glomerulus to filter blood and a tubule that returns needed substances to blood and pulls out additional wastes. They process blood and create urine through a process of filtration, reabsorption, and secretion.
Question 20.
Name the membrane that covers the lungs.
Answer:
Pleura
Question 21.
Find the word pair relation and fill in the blank.
Intercostal muscles contracts: Inspiration
……….. : Expiration
Answer:
Intercostal muscles relaxes: Expiration
Question 22.
Explain the following terms.
a) Ventilation
b) Alveolus
Answer:
a) Ventilation
Breathing is also known as ventilation. Inspiration or inhalation and expiration or exhalation are the two phases of ventilation.
b) Alveolus
These are delicate air sacs that are elastic in nature and are seen at the tip of bronchioles. A network of numerous blood capillaries are found on their surface. They act as the respiratory surface for gaseous exchange.
Question 23.
Complete the table given below by including the information in the box.
- Volume of the thoracic cavity increases.
- Intercostal muscles relax.
- Diaphragm contracts.
- Pressure in the thoracic cavity increases.
Inspiration | Expiration |
Answer:
Inspiration | Expiration |
Volume of the thoracic cavity increases | intercostal muscies relax |
Diaphragm contracts | pressure in the thoracic cavity increases |
Question 24.
Observe the picture and answer the following questions.
a) Identify and write ‘X’ and ‘Y’
b) Write the functions of the delicate and elastic air sacs seen at the end of ‘Y’
c) How does the volume inside ‘Z’ reduce during expiration? How it is helpful?
Answer:
a) X= Trachea, Y= Bronchiole.
b) The exchange of respiratory gases takes place in these alveoli.
c) The intercostal muscles and diaphragm relaxes to lower the ribs. Thus the volume of the thoracic cavity decreases.
Question 25.
Observe the figure related to breathing and answer the questions.
a) Identify the step of breathing.
b) Name the parts indicated as X and Y
c) How does the combined action of X and Y help in this process?
Answer:
a) Inspiration
b) X – Intercostal muscles, Y – Diaphragm
c) During inspiration, air enters the lungs by the contraction of both the intercostal muscles and the diaphragm.
Question 26.
The exchange of gases occurs between the alveoli and blood capillaries by $\qquad$
Answer:
By Simple diffusion.
Question 27.
What is oxyhaemoglobin?
Answer:
When oxygen combines with haemoglobin in the blood to forms oxyhaemoglobin to facilitate the transport of oxygen.
Question 28.
Observe the figure and answer the questions
a. Identify and write X and Y.
b.The peculiarities of X and Y are suitable for performing its functions effectively. Substantiate.
Answer:
(a) X = Alveolus, Y=Blood capillary.
(b) The inner wall of the alveoli is always kept moist. The walls of the alveoli and capillaries are made up of a single layer of cells.
Question 29.
Write down any two features that make the Alveoli suitable for gas exchange.
Answer:
- The walls of the alveoli and capillaries are made up of a single layer of cells
- The inner wall of the alveolus is always kept moist
Question 30.
Briefly explain the parts of the Human respiratory system and prepare a flowchart to illustrate the path of atmospheric air, entering the nostrils till it reaches the alveoli.
Answer:
The human respiratory system consists of a group of organs and tissues that help us to breathe. The major parts include:
- A pair of external nostrils: To inhale and exhale air.
- Nasal chamber: This is lined with hair and mucus to filter the air from dust and dirt.
- Pharynx: It is a passage behind the nasal chamber and serves as the common passage for both air and food.
- Larynx: It is the sound box
- Trachea: A long tube passing through the mid-thoracic cavity also known as a windpipe. The walls of the trachea comprise C -shaped cartilaginous rings which give hardness to the trachea and maintain it by completely expanding. The trachea extends further down into the breastbone and splits into two bronchi, one for each lung.
- Bronchi: The trachea divides into left and right bronchi.
- Bronchioles: Each bronchus is further divided into finer channels known as bronchioles.
- Alveoli: The bronchioles terminate in balloon-like or sac-like structures known as the alveoli, Through which gaseous exchange takes place.
- Lungs: Humans have a pair of lungs, which are sac-like structures and covered by a double layered membrane known as pleura.
Question 31.
Name the phase of cellular respiration that takes place in the cytoplasm.
Answer:
Glycolysis.
Question 32.
Give a chemical equation for respiration.
Answer:
Question 33.
Observe the illustration and complete it suitably.
Answer:
i) Lactic acid.
Question 34.
“The toxic substances produced and reached inside the human body are changed into harmless substances.”
a) Name the organ responsible for this activity.
b) Complete the illustration, showing the chemical reaction taking place in this organ suitably.
Answer:
a) Liver.
b) Ammonia +CO2
Question 35.
Analyze the word pair relation and fill it accordingly.
a. Bacteria: Lactic acid
b. Yeast:……………..
Answer:
b. Yeast: Alcohol, CO2
Question 36.
Anaerobic respiration takes place in human muscles under certain circumstances.
a. Give reason for this.
b. Name the product of this process.
Answer:
a) When oxygen availability decreases due to strenuous exercise or work, anaerobic respiration takes place in muscle cells.
b) Lactic acid.
Question 37.
Analyze the given picture carefully and state the role of haemoglobin in oxygen transport.
Answer:
Haemoglobin carries oxygen as oxyhaemoglobin and it is diffused into the cells through tissue fluid and supplies oxygen to all cells.
Question 38.
Analyse the illustration of anaerobic respiration and answer the following questions.
a) Identify (i) and (ii).
b) In which circumstance, the formation of (i) takes place in the human body?
Answer:
a) (i) Lactic acid
(ii) Alcohol
b) When we are doing strenuous exercises or something like that, our muscle cells lack oxygen. In such situations, muscle cells respire without oxygen which results in the production of lactic acid in cells.
Question 39.
Cellular respiration is the process of releasing energy from glucose inside the cells.
a) What are the two stages of cellular respiration?
b) Name the cell organelle in which the second phase of cellular respiration takes place.
c) What are the end products of cellular respiration?
Answer:
a) Glycolysis and Kreb’s cycle.
b) Mitochondrion.
c) CO2 and water
Question 40.
Complete the following table related to cellular respiration suitably.
Indicator | Glycolysis | Kreb’s cycle |
Location | (i) ………. | (ii)………… |
Need of oxygen | (iii) ………. | (iv)………… |
Process | (v) ………. is converted into Pyruvic acid | (vi) ………… |
Answer:
(i) Cytoplasm (ii) Mitochondna (iii) No need of Oxygen (iv) Oxygen required (v) Glucose (vi) Carbon dioxide, water and 28 ATP
Question 41.
What are lenticels?
Answer:
Small pores on the surface of mature stems and roots.
Question 42.
Name the respiratory surface of fish.
Answer:
Gills
Question 43.
Which among the given animals is the odd one in connection with their excretory organ? Write the common features of others.
(Snake, Earthworm, Fish, Frog)
Answer:
Earthworms, others possess kidneys.
Question 44.
Respiratory surfaces are different in various organisms. Mention the respiratory surfaces of the given organisms.
a) Fish
b) Earthworm
Answer:
a) Fish – Gills
b) Earthworm – Skin (Cutaneous respiration)
Question 45.
“Stomata remain open in the daytime and closed at night.” Give the reason.
Answer:
Photosynthesis occurs during the day and thus stomata are open to supply the carbon dioxide required for the process. The stomatal openings remain closed at night as photosynthesis is not conducted without sunlight. They are closed to prevent water loss via the stomatal pores.
Question 46.
Does bacteria need oxygen for their respiration? Compare the respiratory mechanisms in bacteria and yeast.
Answer:
No. Bacteria follow anaerobic respiration. So they do not need oxygen for their respiration.
Both in bacteria and yeast anaerobic respiration happens in the cell cytoplasm. In bacteria, lactic acid is formed as the result of anaerobic respiration while in yeast alcohol and CO2 are formed as products.
Question 47.
Correct mistakes if any in the underlined parts.
a) Lungs expel CO2
b) Urea is formed in the kidneys.
c) Water and salts are expelled through skin.
Answer:
b) Urea formed in the Liver.
Question 48.
How does ammonia is converted into urea in liver?
Answer:
Synthesis of urea takes place in the liver. Amino acids are formed by the breakdown of proteins.
As a result of the metabolic activities of amino acids, several nitrogenous by-products are formed. The most harmful among these is ammonia. The ammonia formed in tissues diffuses into blood through tissue fluids and blood transports it to the liver. In the liver with the help of certain enzymes, ammonia combines with carbon dioxide and water to form urea.
Question 49.
What are Nephrons? Explain the structure of a nephron with a neat labelled diagram.
Answer:
Nephrons are the basic structural and functional units of kidneys. Around 12 lakh nephrons are present in each kidney
Question 50.
Name the parts related to the human excretory system using the following hints.
a) Ultra filters present in the kidneys
b) Network of minute capillaries present in the Bowman’s capsule
c) Blood vessel which carries blood away from the kidneys
d) Part that carries urine to the urinary bladder.
Answer:
a) Nephrons
b) Glomerulus
c) Renal vein
d) Ureters
Question 51.
Give reasons for each of the following.
a) Glucose and amino acids are not present in urine.
b) Difference in the diameters of afferent vessel and efferent vessel help in ultrafiltration.
Answer:
a) Essential materials such as glucose, amino acids, etc. formed after ultrafiltration are reabsorbed.
So that they are not present in urine.
b) The afferent arteriole is larger in diameter than the efferent arteriole; This is to provide for the increased blood pressure in the glomerulus for ultrafiltration to take place.
Question 52.
Analyze the illustration and answer the following questions
a) Name the process of urine formation that takes place in the part labelled ‘X’
b) What are the features of ‘X’ that help in this process?
c) Does the fluid form as a result of this process turn into urine completely? Why?
Answer:
a) Ultrafiltration of blood.
b) The glomerulus wall is very thin and porous. The difference in the diameter of afferent and efferent vessels increases the pressure there.
c) No, most of the essential components are reabsorbed.
Question 53.
Make suitable pairs using the information given in the boxes A and B, based on the model given.
Model: Region where urine from the filters flows into – Pelvis
A | B |
Dark coloured inner part of the kidney | Renal tubule |
Reabsorption and secretion takes place | Medulla |
The blood vessel that comes out of the Bowmanns capsule | Pelvis |
Region where urine from the filters flows into. | Effective Vessel |
Cortex |
Answer:
- Dark coloured inner part of the kidney – Medulla
- Reabsorption and secretion takes place – Renal tubule
- The blood vessel that comes out of the Bowman’s capsule – Efferent vessel.
Question 54.
“Drinking a lot of water and urinating timely helps to avoid urinary infections.” Do you agree with this statement? Why?
Answer:
Yes, agree. Timely urination washes out the disease-causing germs from the urinary tract.
Question 55.
“In case of kidney failure, blood is purified by passing through artificial kidneys”.
a. What is the name of this process?
b. Name the chemical substance used in this process.
c. Write the importance of this chemical substance.
Answer:
a) Haemodialysis
b) Heparin
c) Heparin prevents the clotting of blood.
Question 56.
Observe the figure and answer the questions.
i) Which is the method of treatment indicated in the figure?
ii) When is this treatment needed?
iii) Write the stages of this treatment in correct order
Answer:
i) Haemodialysis
ii) Haemodialysis is the process proposed by modern medicine for the removal of wastes from blood when both the kidneys become non-functional
iii)
- Blood which contains wastes from the artery is pumped into the dialysis unit. Heparin is added to prevent coagulation.
- Wastes from the blood are diffused into the dialysing fluid when it flows through the cellophane tube.
- Purified blood is pumped back to the veins through another tube
Question 57.
Name the pores present at the tip of the grass leaves to eliminate excess water.
Answer:
Hydathodes.
Question 58.
Mention the main excretory organs and the excretory products respectively of the following organisms.
a) Insects
b) Reptiles
c) Earthworms
d) Birds
Answer:
a) Insects – Malpighian tubules – Uric acid
b) Reptiles – Kidney – Uric acid
c) Earthworms – Nephridia – Urea
d) Birds – Kidney – Uric acid
Question 59.
Observe the figure related to excretion in plants and answer the questions.
i) Identify A and B.
ii) How do A and B help in excretion?
iii) Write any other two excretory mechanisms in plants.
Answer:
i) A-Hydathodes, B-Formation of heartwood
ii) Excess water is eliminated through small pores (hydathodes) present at the tip of leaves in certain shrubs and grasses. Some waste products accumulate in the older xylem cells at the centre and play a major role in heartwood formation.
iii) Stomata-excrete O2, CO2 and H2O Abscission of leaves
Question 60.
Complete the following table related to the excretory process in different organisms suitably.
Organism | Excretory organ | Excretory material |
Amoeba | (i) …………… | (ii) ………………. |
Fish | (iii) …………… | Ammonia |
Frog | Kidney | (iv) ……………….. |
Earthworm | (v) …………… | (vi) ………………… |
Answer:
i) Contractile vacuole
ii) Ammonia
iii) kidneys
(iv) Urea
(v) Nephridia
(vi) urea, ammonia, water
Question 61.
Complete the given flow chart related to homeostasis suitably.
Answer:
A- Disruption of homeostasis.
B- Water balance.
C- Salt balance.
D- Regulation of pH.
Question 62.
How lungs help in maintaining the body’s homeostasis?
Answer:
Lungs act as an excretory organ in our body. CO2 accumulates in the body as a waste product during respiration eliminated through the lungs. Regulation of O2 level, Regulation of pH , etc. are the other roles played by lungs in our body.
Question 63.
Mention the factors that disturb the homeostasis of the body.
Answer:
Internal as well as external factors disturb the homeostasis. Some of them are:
- Wrong food habits
- Over-nutrition and under-nutrition,
- Lack of exercise
- Mental stress
- Alcoholism
- Smoking and the use of addictive drugs
- Pollution
- Lack of hygiene
- The abundance of pathogens
- Improper use of medicines, and contact with toxic substances.