Friday, 5 January 2018

Points to Remember - biology

Robert Hooke discovered cells in cork and then in living plant tissue, using an early microscope.
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.
Bone marrow is fast affected by nuclear radiations.
The strongest muscle of the human body is the jaw muscle.
The largest muscle of the human body is Sartorius.
The smallest muscle of the human body is Stapedius.
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 microscopesTEMs 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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