Friday, 5 January 2018

Points to Remember - biology

Robert Hooke discovered cells in cork and then in living plant tissue, using an early microscope.
l Hippocrates is called the father of medicine.
l Euglena is an organism which exhibits the characteristics of plants and animals both and has been kept in Protista kingdom.
l The fungi born on cowdung are called corporphilous fungi.
l A single centrosome is present in animal cells. It is also found in some fungi and algae cells.
l Bone marrow is fast affected by nuclear radiations.
l The strongest muscle of the human body is the jaw muscle.
l The largest muscle of the human body is Sartorius.
l The smallest muscle of the human body is Stapedius.
l The horns of the rhinoceros are formed of keratin protein.
l The largest bone of the body — Femur
l The smallest bone of the body — Stapes or Stirrup (a bone in ear)
l Algae like microcysts, chrococcus and oscillaleria are deadly poisons (toxic) that coexist in ponds, rivers, seas
etc and due to their presence fishes and other aquatic living beings die.
l The smallest chromosome among all the micro-organisms is that of algae.
l The algae chlorella can be used in spacecraft to take proteineous food, water and oxygen.
l The moss plant sphagnum is used as fuel and is called peat energy.
l The plants of mosses are also used as antiseptics.
l Cycas plant is also called Sago Palm.
l Pine nuts, which are extracted from pine tree, is also used as edible substance.
l An alkalide ephedrine is obtained from the juice of ephedra and is utilised as medicine for people suffering from asthma.
l Tannin is utilized in making leather and ink, while resin is extracted from some coniferous trees and utilised in making burnish, shoe polish, plastic, paints etc.
l There are various gymnosperms which seem to appear extremely beautiful and which are utilized for decorative purposes. They are planted in gardens, in parks, on roofs etc.
l The largest ovule is that of the plant cycas, which is a gymnosperm.
l Fungi do not contain chlorophyll and cannot produce their own food. They must rely on other organisms to get their food.
l Some fungi feed on decaying organic matter, while some are parasites of plants and animals.
l Fungi reproduce by means of spores. These can be produced sexually or asexually (without another fungus).
l Different types of microscopes are light microscopes, TEMs and SEMs. TEM shows the details of the inside of a cell. SEM shows the details of the surface of a cell.
l Haemoglobinometer is an instrument for recording the haemoglobin content of blood.
l Fat cells can be stained with Sudan III, Scharlach R and osmic acid.
l The keratinized cells with degenarated nuclei are constantly in the process of flaking off the surface of the skin in the form of dandruff.
l Hassall's cells are phagocytes found in the thymus.
l Deficiency of ATP in muscle causes rigor mortis.
l Normovolemia refers to normal blood volume. Decreased blood volume is called hypovolemia and increased blood volume is called hypervolemia.
l Normal cholesterol level of human blood is 50-180 mg per 100 ml of blood. High level of cholesterol may lead to heart attack.
l Pneumatic bones contain air centers and are found in birds.
l Sneezing: The spasmodic contraction of muscles of expiration forcefully expels air through the nose of mouth. Its stimulus may be an irritation of nasal mucosa.
l Yawning: A deep inspiration through widely opened mouth producing an exaggerated depression of the lower jaw. May be stimulated by drowsiness or fatigue, but precise stimulus-receptor cause is unknown.
l Philip Drinker, an American engineer, invented a tank respirator or iron lung in 1929.
l Cyanosis is the dark-bluish discoloration of the skin and mucous membrane due to deficiency of oxygen in blood.
l Soil fertility can be enhanced by the use of organic material such as blue-green algae. This technique is largely used
for growing rice crop.
l Amphibians live on land and water both. They are coldblooded or poikilothermal.
l Amphibians do not have nails. Fertilization and embryonic development always takes place in water in their case.
l The common examples of amphibians are frog, toad, hyla and salamander.
l Snakes are limbless and lack ears but have a keen sense of smell.
l Turtles and tortoises have bony shells, into which they can retract their head and limbs. Turtles are the most long-lived animals.
l Crocodiles and alligators live in water or close to it (moist climate) and are generally fish-eaters.
l The gharial is a unique reptile of Indian species with a thin snout.
l The hearts of most of the reptiles are three-chambered but the crocodile has a four-chambered heart.
l The Ostrich is the only living member of the genus Struthio, while Kiwi belongs to the genus Apteryx.
l The largest living bird is Ostrich and the smallest living bird is Humming bird. Among the Indian birds, the Sun bird is the smallest.
l The fastest flying bird all over the world is Swift, while the fastest running bird is Ostrich.
l At present the bird Dodo, which was found in Mauritius, has become completely extinct .
l Whales and Dolphins are aquatic mammals. Their forelimbs are modified as flippers and they lack hindlimbs.
l Blue whale is the largest animal among all, while Dolphin is a highly intelligent mammal.
l Macropus, commonly knonw as kangaroo, is abundantly found in Australia.
l The metal magnesium is found in the chlorophyll of plant leaves.
l The chemical substance chloroplast is also called the nucleus of photosynthesis.

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