Questions: What are diatoms? How they are helpful to us?
Ans: Diatoms are a single-celled alga which has a cell wall of silica called frustule. When diatoms die, they slowly sink to the sea floor and build up siliceous earths that are used to make glass, porcelain and ceramics. It is also used to make polishes and toothpaste.
Questions: Why diatoms are called chief producers in oceans?
Ans: Diatoms are autographs and synthesize food by photosynthesis.
(i) All the other creatures depend on the planktons in the ocean for food, as it completes the food chain. They play the vital role of primary producers.
(ii) They also maintain the ecological balance.
Questions: Why diatoms are called the jewels of plant kingdom?
Ans: The cell walls of diatoms are silicified i.e. impregnated with silica. On account of their delicately arranged ornamentation of cell walls diatoms have been regarded as jewels of plant kingdom.
Questions: How does the growth of algae harm water bodies?
Ans: some of the algae became poisonous after the die. Thus pollute water bodies. Bacteria feed on algae to multiply rapidly using up a lot of dissolve oxygen and prevent aquatic organism of their oxygen
Questions: Viruses are considered as being on the border line between living and non-living organisms, Why?
Ans: Viruses is nonliving outside living cells but grows and multiplies inside living cell so, viruses are considered as being on the border line between living and non-living organisms. The study of viruses is called Virology.
Questions: How are protozoan help in the bodies of termites and bacteria live in the intestine of human body?
Ans: Termites have protozoans living in their bodies that digest the cellulose in the wood eaten by termites and convert it into carbohydrates that the termites can use.
Bacteria live in the intestine of human body help absorption of food and prevent from many diseases. It helps with the production of some vitamins (B and K).
Questions: What we call the study of fungi?
Questions: What we call the study of virus?
Questions: What we call the study of bacteria and algae ?
Ans: The study of bacteria is called Bacteriology and the study of algae is called Phycology
Questions: How do viruses multiply within host cell?
Ans: Viruses when enters into the cell of host living body destroy the nuclear material and finely host cell burst out to release the viruses.
Ans: Paramecium swim in water by beating hair like structure called cilia against the water. The movement of cilia also direct food and water into gullet
Questions: Mention two ways in which fungi harm us?
Ans: Mould a kind of fungi spoil cooked food. Moulds and mildew grow on leather goods and cloths and furniture in monsoon and spoil them. Fungi cause diseases in plants and animals.
Questions: Mention three ways in which we use fungi?
Ans: Following are the three ways in which we use fungi
(i) Mushroom a kind of fungi eaten as a food.
(ii) Yeast is a kind of fungi used to prepare alcoholic drink, bakery product,
(iii) Penicillin and some other antibiotics are made from certain moulds
Questions: What does Sargasso Sea woe its name to?
Ans: Sargasso Sea woe its name to Sargassum, a particular sea weeds that grow abundantly in sea. Sailor avoids this sea as their boat stuck in the tangled mass of seaweeds.
Questions: What are the difference between the cell of bacteria and the cell of other living body?
Ans: The difference between the cell of bacteria and the cell of other living body are
(i) Cell wall is not made up of cell wall
(ii) Do not have nucleus
(iii)Does not have membrane bound organelles
Questions: Do red and brown algae have chlorophyll?
Ans: Yes, red and brown algae have pigment of colour which cover the colour of chlorophyll and make them appear red brown or yellowish
ï»¿Questions: Name a protozoon which can photosynthesize?
Ans: Euglena contain chlorophyll and can photosynthesise, lack of cell wall
Questions: How do bacteria reproduce?
Ans: Bacteria reproduce by binary fission