Everyday Biology Questions CBSE Class 9 Biology Worksheets Set 03

Questions with Answers

Question 1. What is meant by 'albino'?
Answer:
An albino is a person or animal with no pigment (melanin) in the skin, hair and eyes. The skin is pale, hair white, and the eyes look pink because blood shows through. It is a genetic condition.
In simple words: A living being lacking melanin pigment.

Teacher's Note:
1. Melanin gives colour to skin, hair and eyes.
2. Albinism is inherited.

Question 2. Is the common housefly dangerous to health? Why?
Answer:
Yes. The housefly sits on filth and rubbish and then on food, carrying germs on its legs and body. It spreads diseases such as cholera, typhoid and dysentery. Covering food and keeping surroundings clean controls flies.
In simple words: It carries germs from dirt to food.

Teacher's Note:
1. Flies breed in decaying matter.
2. Keep food covered.

Question 3. To which class of vertebrates does the animal echidna belong?
Answer:
Echidna belongs to the class Mammalia. It is an egg-laying mammal (monotreme) that feeds its young with milk. Along with the duck-billed platypus, it forms a connecting link between reptiles and mammals.
In simple words: Mammals, though it lays eggs.

Teacher's Note:
1. Monotremes lay eggs, marsupials carry young in a pouch.
2. Mammals have mammary glands.

Question 4. How can alligators be distinguished from crocodiles?
Answer:
An alligator has a broad, rounded U-shaped snout, and when its mouth is closed only the upper teeth are seen. A crocodile has a narrow, pointed V-shaped snout, and the large lower teeth also show when the mouth is closed.
In simple words: Alligators have a broad snout; crocodiles a narrow one with visible lower teeth.

Teacher's Note:
1. Both belong to the order Crocodilia.
2. Alligators generally live in fresh water.

Question 5. Who invented the electron microscope?
Answer:
Ernst Ruska and Max Knoll built the first electron microscope in 1931.
In simple words: Knoll and Ruska.

Teacher's Note:
1. It gives a much greater magnification than a light microscope.
2. It uses a beam of electrons instead of light.

Question 6. Who first reported lysosomes?
Answer:
Christian de Duve discovered lysosomes in 1955. They have digestive enzymes, and when a cell is damaged these enzymes can digest it, so lysosomes are called suicide bags.
In simple words: Christian de Duve.

Teacher's Note:
1. Lysosomes digest worn-out cell parts and germs.
2. Lysosomes are found mainly in animal cells.

Question 7. Which is the largest animal cell? Name a plant cell visible to the naked eye.
Answer:
The egg of an ostrich is the largest animal cell. A cotton fibre (a single long hair-like cell) and the fibre cells of ramie or flax are visible to the naked eye.
In simple words: Ostrich egg; cotton fibre.

Teacher's Note:
1. Most cells are microscopic.
2. Nerve cells are the longest cells in the human body.

Question 8. From which tree is the medicine for malaria extracted?
Answer:
Quinine is extracted from the bark of the cinchona tree.
In simple words: Cinchona.

Teacher's Note:
1. Quinine was long used to treat malaria.
2. Medicines from plants are called herbal drugs.

Question 9. Who proposed the name 'genes'?
Answer:
The Danish botanist Wilhelm Johannsen coined the word 'gene' in 1909.
In simple words: Wilhelm Johannsen.

Teacher's Note:
1. Mendel called them 'factors'.
2. Genes are units of heredity.

Question 10. To which phylum does the animal 'Portuguese man-of-war' belong?
Answer:
It belongs to the phylum Coelenterata (Cnidaria), the group with stinging cells (nematocysts) on tentacles. Jellyfish, hydra and sea anemone belong here.
In simple words: Coelenterata.

Teacher's Note:
1. Coelenterates have a body with two layers of cells.
2. Stinging cells are used for defence and capture of prey.

Question 11. Which is the hardest material in the human body?
Answer:
Tooth enamel, the outer coating of the tooth, is the hardest substance in the body. It is made mainly of calcium phosphate.
In simple words: Tooth enamel.

Teacher's Note:
1. Enamel does not grow back once damaged.
2. Brush teeth to prevent decay of enamel.

Question 12. What is the 'Jaipur foot'?
Answer:
It is an artificial foot (limb) made of rubber and wood, developed in Jaipur by Dr P. K. Sethi and the craftsman Ram Chandra Sharma. It looks like a natural foot, is low in cost and lets a person squat, walk and climb.
In simple words: A low-cost artificial limb developed in Jaipur.

Teacher's Note:
1. Prosthetics replace missing body parts.
2. It is used in many countries.

Question 13. In which type of plants do you find dumb-bell shaped guard cells in leaves?
Answer:
In grasses (monocots such as wheat, maize and rice). In other plants guard cells are bean-shaped.
In simple words: In grasses and other monocots.

Teacher's Note:
1. Guard cells open and close stomata.
2. Stomata allow exchange of gases and water vapour.

Question 14. Who proposed binomial nomenclature for naming plants and animals?
Answer:
Carolus Linnaeus (Carl von Linne) in the eighteenth century. Each organism has two names, a generic and a specific name, such as Homo sapiens.
In simple words: Carolus Linnaeus.

Teacher's Note:
1. Names are written in italics or underlined separately.
2. Linnaeus is called the father of taxonomy.

Question 15. What type of venation is found in the leaves of monocots?
Answer:
Parallel venation, as in grass, wheat and maize. Dicot leaves usually have reticulate (net-like) venation.
In simple words: Parallel venation.

Teacher's Note:
1. Monocot seeds have one cotyledon.
2. Dicot leaves have net-like veins.

Question 16. What is meant by parthenogenesis?
Answer:
Parthenogenesis is a type of reproduction in which an egg develops into a new individual without fertilisation. In honeybees the males (drones) develop from unfertilised eggs, whereas queen and worker bees develop from fertilised eggs.
In simple words: Development of an egg without fertilisation.

Teacher's Note:
1. Parthenocarpy refers to fruit and parthenogenesis refers to animals.
2. Drones have half the number of chromosomes.

Question 17. Which country is the native place of coffee? What is the botanical name of rice?
Answer:
Coffee is native to Ethiopia. The botanical name of rice is Oryza sativa.
In simple words: Ethiopia; Oryza sativa.

Teacher's Note:
1. Botanical names are in Latin.
2. Rice is a staple food of many countries.

Question 18. Which organelle of the cell is termed 'suicide bag'?
Answer:
The lysosome. It contains powerful digestive enzymes. If the lysosome bursts inside the cell, the enzymes digest the cell itself.
In simple words: Lysosome.

Teacher's Note:
1. Lysosomes also destroy germs entering the cell.
2. Autolysis means self-digestion of the cell.

Question 19. Who discovered the nucleolus inside the nucleus?
Answer:
Fontana, in 1781, saw the nucleolus. Robert Brown discovered the nucleus in 1831.
In simple words: Felice Fontana.

Teacher's Note:
1. The nucleolus makes ribosomal RNA.
2. The nucleus controls all activities of the cell.

Question 20. What is a gene bank?
Answer:
A gene bank is a place where seeds, tissues or other genetic material of valuable plants and animals, especially those threatened with extinction, are stored in living condition for future use.
In simple words: A storehouse for preserving genetic material.

Teacher's Note:
1. Seed banks help to protect crop varieties.
2. Cryopreservation uses very low temperatures.

Question 21. From which part of the embryo of a seed does the root system arise?
Answer:
From the radicle. The plumule grows into the shoot (stem and leaves).
In simple words: The radicle.

Teacher's Note:
1. The embryo has radicle, plumule and cotyledons.
2. Cotyledons store food or become leaf-like.