Life Science Chapter – 3F : Excretion Oriental Book Company solution for Madhyamik Students Class 9
| Material | : Madhyamik Life Science Solution |
| Subject | : Life Science |
| Class | : 9 (Madhyamik) |
| Publisher | : Oriental Book Company Private Limited |
| Chapter Name | : Excretion |
Multiple Choice Questions (MCQs)
(Each question carries 1 mark)
Question 1
Elimination of Nitrogenous wastes is known as:
(a) Respiration
(b) Digestion
(c) Excretion
(d) Reproduction
Answer
(c) Excretion
Explanation: Excretion is the biological process by which nitrogenous metabolic waste products are removed from the body.
Question 2
What is the main excretory organ of earthworm?
(a) Flame cell
(b) Nephridia
(c) Green gland
(d) Malpighian tubes
Answer
(b) Nephridia
Explanation: Nephridia are tubular excretory structures in earthworms used for osmoregulation and waste elimination.
Question 3
Kidney is the excretory organ of:
(a) Invertebrates
(b) Prawns
(c) Vertebrates
(d) Cockroach
Answer
(c) Vertebrates
Explanation: Vertebrates have well-developed kidneys to eliminate nitrogenous wastes like urea from their bodies.
Question 4
Malpighian tubule is the excretory organ of:
(a) Prawn
(b) Earthworm
(c) Amoeba
(d) Cockroach
Answer
(d) Cockroach
Explanation: Malpighian tubules are the excretory organs found in insects like cockroaches, helping remove nitrogenous waste.
Question 5
What are sling excretory products of plant:
(a) Resin
(b) Gum
(c) Bak
(d) Leaf fall
Answer
(b) Gum
Explanation: Gums are non-nitrogenous excretory products of plants, commonly stored in dead cells and released naturally.
Question 6
Excretory organs of Trachia is:
(a) Malpighian tubule
(b) Flame cells
(c) Green gland
(d) Nephridia
Answer
(a) Malpighian tubule
Explanation: In tracheated insects like cockroaches, the Malpighian tubules are the primary excretory organs.
Fill in the Blanks
(Each question carries 1 mark)
Question 1
Kidney is the ______ organ of vertebrates.
Answer
main
Explanation: As per the text, “Kidney is regarded as the main excretory organ” in vertebrates, responsible for eliminating nitrogenous waste from the body.
Question 2
Resins are stored in special ______ ducts.
Answer
resin
Explanation: The OCR content says, “Resins are stored in special ducts, resin ducts, of plant body,” such as in Pinus Sp., confirming “resin” as the correct word.
Question 3
Alkaloids are ______ excretory products.
Answer
nitrogenous
Explanation: The section titled “Nitrogenous excretory products or Alkaloids” clearly states that alkaloids are nitrogenous waste substances formed by plants.
Question 4
Alkaloid morphine is found in unripe fruit of ______.
Answer
poppy
Explanation: According to the table of alkaloids, “Morphine” is listed with the source “Unripe fruit of Poppy,” making “poppy” the correct fill-in.
Question 5
Malpighian corpuscles are composed of two parts: Bowman’s capsule and ______.
Answer
glomerulus
Explanation: From the nephron structure section: “Each Malpighian corpuscle is 0.2 mm in diameter and is composed of two parts: Bowman’s capsule and glomerulus.”
State True or False
(Each question carries 1 mark)
Question 1
Flame cells are the excretory organs of flat worm.
Answer
True
Explanation: Flame cells are specialized excretory cells found in flatworms (Platyhelminthes). They help in osmoregulation and removal of nitrogenous waste, functioning like primitive kidneys.
Question 2
Alkaloid Emetine is found in root of Ipecac.
Answer
True
Explanation: Emetine is an alkaloid derived from the root of the Ipecac plant. It is used medically to induce vomiting and treat amoebic infections.
Question 3
Nephridia are the respiratory organ of Planaria.
Answer
False
Explanation: Nephridia are excretory organs, not respiratory. Planaria (a flatworm) actually uses flame cells for excretion and gas exchange occurs through the body surface, not via nephridia.
Question 4
Malpighian tubules are attached to the alimentary canal of insects.
Answer
True
Explanation: Malpighian tubules open into the junction between the midgut and hindgut of insects. They collect metabolic waste from the hemolymph and empty it into the alimentary canal for excretion.
Question 5
Distal convoluted tubules reabsorb water.
Answer
True
Explanation: The distal convoluted tubule in the nephron reabsorbs water and other substances like sodium ions, especially under the influence of antidiuretic hormone (ADH), contributing to urine concentration.
Columns Matching
(Each question carries 1 mark)
| Column I | Column II | Correct Match | Explanation |
|---|---|---|---|
| (a) Atropine | (d) Belladona | (a) → (d) | Atropine is an alkaloid derived from the leaves of the Belladona plant. It is used to dilate pupils in ophthalmology. |
| (b) Flame cell | (c) Planaria | (b) → (c) | Flame cells are excretory organs in flatworms like Planaria, functioning in waste removal and osmoregulation. |
| (c) Resin | (e) Pinus | (c) → (e) | Resin is a plant excretory product found in resin ducts of Pinus species (pine trees). |
| (d) Contractile Vacuole | (b) Paramoecium | (d) → (b) | The contractile vacuole in Paramoecium (a unicellular protozoan) expels excess water to maintain osmotic balance. |
| (e) Reserpine | (a) Rauwolfia | (e) → (a) | Reserpine is an alkaloid extracted from the root of Rauwolfia serpentina, used in treating high blood pressure and mental disorders. |
Choose the odd one and write it
Question (a)
Quinine, Morphine, Nicotene, Latex
Answer
Latex
Explanation: Quinine, Morphine, and Nicotine are all alkaloids — nitrogenous excretory products of plants. Latex, however, is a non-nitrogenous product (a milky emulsion), making it the odd one.
Question (b)
Gum, Resins, Tanins, Thein
Answer
Thein
Explanation: Gum, Resins, and Tanins are non-nitrogenous excretory products. Thein is a nitrogenous alkaloid (caffeine-like stimulant), hence it does not belong in the group.
Question (c)
Flame cell, Nephridia, Malpighian tubules, Urethra
Answer
Urethra
Explanation: Flame cell, Nephridia, and Malpighian tubules are excretory organs of invertebrates. Urethra is part of the human urinary tract but not an excretory organ by itself — it is only a passage.
Very Short Answer Type Questions
(Each question carries 1 mark)
Question 1
What is the primary organ of excretion in human beings?
Answer
Kidney
Explanation: The kidneys are the main excretory organs in humans responsible for filtering blood and removing nitrogenous waste.
Question 2
What is latex? Name a plant where it is found.
Answer
Latex is a milky excretory substance composed of water, resins, alkaloids, etc. It is found in Hevea brasiliensis (rubber plant).
Question 3
Write down the name of an alkaloid and mention its source.
Answer
Quinine – obtained from the bark of the Cinchona tree.
Question 4
Name the processes by which plants remove excretory products.
Answer
Leaf fall, bark shedding, fruit/flower shedding, diffusion, and storage in dead tissues.
Question 5
Which organ in man maintains water balance?
Answer
Kidney
Explanation: Kidneys regulate water balance through filtration and selective reabsorption under the influence of hormones like ADH.
Question 6
What are the sources of quinine and rubber?
Answer
Quinine: Bark of Cinchona
Rubber: Latex from Hevea brasiliensis
Long Answer Type Questions
(Each question carries 5 marks)
Question 1
What is excretion? Name the main excretory substances of plants and animals.
Answer
Excretion is the physiological process by which living organisms remove toxic metabolic waste products from their body in order to maintain internal chemical stability, known as homeostasis.
In Animals:
- Urea: Formed in the liver through the ornithine cycle by conversion of toxic ammonia; excreted by kidneys (ureotelic animals like humans).
- Uric Acid: Excreted by insects, reptiles, and birds (uricotelic animals); conserves water.
In Plants:
- Alkaloids (Nitrogenous): e.g., Quinine (from Cinchona), Morphine (from Poppy), Thein (from Tea).
- Non-Nitrogenous Products: e.g., Gum, Resin, Latex, Tannins.
Question 2
What is latex? What is its utility in human beings?
Answer
Latex is a milky white or yellowish fluid secreted by specialized plant cells called laticiferous ducts. It is a complex emulsion composed of water, rubber particles, proteins, starches, oils, alkaloids, sugars, enzymes, and resins.
Utilities in Humans:
- Rubber Production: Latex from rubber trees is the primary source of natural rubber used in tires, gloves, boots, balloons, and elastic products.
- Enzymes: Papain (from papaya) is used in digestive medicine, tenderizing meat, and cosmetics.
- Medicinal Uses: Some latex components have antimicrobial and anti-inflammatory properties.
Question 3
What are the differences between the excretory agents of plants and animals?
Answer
| Feature | Plants | Animals |
|---|---|---|
| Excretory Organs | No specialized organs; use passive methods | Well-developed organs like kidneys, lungs, skin, liver |
| Types of Excretory Products | Alkaloids, gums, resins, latex, tannins, CO₂, water vapour | Urea, uric acid, ammonia, CO₂, water, creatinine, bile pigments |
| Excretion Mechanism | Passive: via diffusion, shedding of parts (leaves, bark, fruits) | Active: via filtration, secretion, reabsorption (urination, sweating) |
| Waste Storage | Wastes may be stored in vacuoles or dead tissues | Not stored; must be eliminated regularly |
| Toxicity of Wastes | Usually less toxic or converted to harmless compounds | Often toxic and need rapid elimination |
| Regulation | Lacks hormonal regulation of excretion | Regulated by hormones like ADH, aldosterone |
Question 4
Give the names and functions of excretory products of plants useful to human beings.
Answer
Plants produce various waste products that are actually useful to humans in medicine, industry, and agriculture. These are called valuable excretory products.
| Excretory Product | Source Plant | Function / Use |
|---|---|---|
| Quinine | Cinchona bark | Anti-malarial medicine |
| Morphine | Papaver somniferum (Poppy) | Painkiller, sedative |
| Caffeine (Thein) | Camellia sinensis (Tea) | Central nervous system stimulant |
| Resins | Pinus, Cedrus | Used in varnishes, perfumes, and incense |
| Gums | Acacia, Albizia | Used in adhesives, printing, medicine as laxative |
| Tannins | Oak, Amlaki, Tea leaves | Leather tanning, ink making, dyes, and medicinal applications |
| Latex | Hevea brasiliensis | Natural rubber for industrial and commercial products |
| Papain | Carica papaya | Digestive enzyme, meat tenderizer, used in pharmaceuticals |
Question 5
Draw and describe a typical nephron.
Answer
A nephron is the microscopic structural and functional unit of the kidney responsible for urine formation. Each kidney contains about 1 million nephrons.
Structure of a Nephron:
1. Malpighian Corpuscle: Located in the renal cortex
- Bowman’s Capsule: A cup-shaped sac that receives filtrate.
- Glomerulus: A tuft of capillaries that filters blood under pressure.
2. Renal Tubule:
- Proximal Convoluted Tubule (PCT): Site of selective reabsorption of water, glucose, salts, etc.
- Loop of Henle: Forms a hairpin turn in the medulla; reabsorbs water and salts.
- Distal Convoluted Tubule (DCT): Performs fine-tuning of reabsorption, affected by hormones.
- Collecting Duct: Collects urine from multiple nephrons and transports it to the renal pelvis.
Question 6
Describe very briefly the structure of human Kidney in a section.
Answer
The human kidney is a bean-shaped organ about 11 cm long and 150 g in weight. It is retroperitoneal, located behind the abdomen on either side of the vertebral column.
Main parts in longitudinal section:
- Renal Capsule: Tough fibrous outer membrane protecting the kidney.
- Cortex: Outer dark brown layer containing most nephrons and blood vessels.
- Medulla: Inner lighter region divided into cone-shaped structures called renal pyramids.
- Renal Pelvis: Funnel-shaped cavity that collects urine from pyramids and connects to the ureter.
- Calyces (Major and Minor): Cup-like extensions of the pelvis where urine collects from pyramids.
