Learn biology online

Biology note A detailed insight on virus  A virus is a biological agent that reproduces inside the cells of living hosts. When infected by a virus, a host cell is forced to produce thousands of identical copies of the original virus an extraordinary rate .  There are various types of viruses in the world, As a representative of viruses, T2 Phage is itroduced here with its importance.  Test your self with these biology questions  biology question set 005 biology question set 004   Structure of virus: T2 Phage is a cellular. Its body is divided into two parts- head and tail; the head is a hexagonal and the tail is rod shaped, a protein shell surrounds the body. Inside the shell there is a' double-strand DNA in its head. At the upper end of the tail there is a collar, and at the lower end there is a base plate, some spikes and attachment fibres. In Viruses there is no nucleus, cell membrane, cytoplasm and other organelles. Multiplication of virus Viruses can multiply only inside som

              Biology question set 005 See  biology question set 004        Biology question set 003 Instructions: The set consist of section A and B. You can post the answers in comment box below.  Questions   SECTION A From which of the following region of the body would you find  vertebrae with less developed centra? A. Thoracic B. Lumbar C. Cervical D. Sacral 2.  If a microscope eye piece has a number ×10 written on itcand objective lens has a number ×45 written on it,  the magnification will be  A. 4.5          B. 10        C. 45      D. 450 2. Which one of the following statements is true ? A. Motor neurons transmit impulses from spinal cord to brain  B. Motor neurons transmit impulses from central nervous system to effectors of the body C. Motor neurons transmit impulses from effectors of the body to the central nervous system. D. Motor neurons are found only in the central nervous system.  3. Which one of these represents the route taken by urine in a mammal? A. Collecting tubu

ANSWERS TO QUESTIONS SET 004               SECTION A 1. C          2. D          3. B           4. B         5. B         6. C           7. A           8. B  9. C         10. D  See   question set 003 Answers to question set 003             SECTION B  11. Transpiration is the loss of water from the plants' leaves by evaporation. This  can also occur through stems and flowers (b). Environmental factors that affect the rate of transpiration are:- Temperature of the surrounding air  Humidity of the surrounding air  Pressure of wind  Light intensity  Experiment to show that a plant trqnspires  A large transparent polythene bag is tied around the shoot of a potted plant, and the plant is transferred to light. After a few hours, droplet are seen to form on the bag. This droplets are collected and tested to see if they are water. Example put the droplets in anhydrous copper sulphate which is white. This will turn to blue, and this confirms these to be drop of water. Therefore water is gi

  Biology question set 004 Instructions: This set comprises of two sections A and  B  Answer all the questions  Pick the correct option  See   question set 003    question set 002 Section A 1.  Ecological systems often have producers, consumers, predators, and preys. Which organisms maintain the balance of ecosystems ? A.  Preys             B. Consumers C. Producers      D. Predators 2. A student heated strongly a dry sample of soil to a constant mass.  The loss of mass in the soil is due to A. loss of mineral salts B. Loss if water C. Escape of air D. Destruction of humus 3. Which one of the following forms part if the insect respiratory system ? A. Trachea, tracheoles and branchioles B. Spiracle, trachea and tracheoles C. Spiracles, trachea and bronchioles D. Trachea, bronchus and bronchioles 4. The normal reproductive cycle of the human female involves the interaction of the A. Oviduct, thyroid gland and ovary B. Pituitary gland, ovary and vagina C. Adrenal gland, ovary and vagina D

Biology CLASSIFICATION OF PLANTS The Creator created the world with various types of diversified plants. There are such small plants, which cannot be seen with the naked eyes, again there are also such big plants that can be seen from a long distance. There are many plants. whcih do not have flowers. Again there ar e such plants which cannot be differentiated into root, stem and leaf. There are some plants, which have got no chlorophyll. They are not green and cannot prepare their own food. The number of plants in this diversified plant world is innumerable. They are in lacs not in thousands. How can we know this great plant world? For this there needs a well thought and well organized system. This is the system of plant classification. See Biology  question test Classification is a system of arrangement in which one can know the plant kingdom easily. Considering the characteristics of plants of the vast plant kingdom, plants having similar characteristics are arranged in groups, i.e.,

BIOLOGY  ANSWERS TO BIOLOGY QUESTION SET 003 1.C             2.A             3.B            4.D 5.C              6.B             7.B           8.C 9.C           .  10.D          11.B         12.A 13.A            14.C          15.C      16.N/A 17.B            18.D         19.A          20.A      Check the following   Biology  question set 003 Biology  question set 002

BIOLOGY QUESTION SET 003 INSTRUCTIONS: Pick the correct answer. Answer all the questions.  1. There were many termites in leaf litter layer decomposing it while ant-eaters fed on the termites faster.  This relationship can best be illustrated using  A. Pyramid of biomass  B. Food web C. Food chain  D. Pyramid of energy 2. Epiphytes are not regarded as parasites because  A. They do not at any time derive their nutritional requirements from the trees on which they grow  B. They have roots and leaves and so can make their own food  C. They never harm the trees on which they grow  D. Both the epiphytes and the trees on which they grow mutually benefit from on another 3. Secondary thicknening in flowering plants is brought about by division of the  A. Phloem cells  B. Cambium cells  C. Xylem cells  D. Cortex cells 4. The term used to describe the process in changes in types of organisms in a given location is known as  A. Competition  B. Habitat C. Food chain  D. Succession 5. Which one of

ANSWERSTOQUESTIONSET002 1.B      2.D        3.B         4.A 5.C      6.D        7.D         8.C 9.C      10.A      11.B      12.D 13.C    14.D     15.C SEE  QUESTION SET 002 Also check ANSWERS TO QUESTION SET 002 question set 003 Answers to question set 003

Are you a brilliant biology student? try this question set 002 BIOLOGY QUESTION SET 002 Multichoice questions instructions: Pick the most correct answers 1 .Which one of the following sets contains only insect possessing halters? A . Moths, butterfly, preying mantis B . Mosquito, Tsetse fly, house fly. C . Cockroach, grasshopper, beetle. D . Bees, Wasp, Dragon fly. 2 . The best way of finding out the number of rats in an abandoned farmland is by A . direct counting. B . quadrat method. C . line transect method. D . capture-recapture method. 3 . Which one of the following will reduce the nitrate content in the soil most rapidly? A. Deforestation. B. Water logging C. Mono cropping. D. Over grazing. 4. When the environmental temperature reduces, the rate of gaseous exchange in a well illuminated plant decreases. This is mainly due to reduction in stomata aperture. the rate of transpiration. the rate of photosynthesis. the rate of tissue respiration 5. Which of the following is likely

Structural, Characteristics, Functions and Location of Connective Tissue . Structural Characteristics: The. amount of matrix is more in connective tissue but the number of cells is comparatively less. Matrix may be jelly like, soft or hard and fragile. One or more than one type of fibre and materials like calcium carbonate may remain present in matrix (Fig-5.6): Functions : Connective tissue connects muscle with muscle and bone with bone. Connective tissue may transform into skeletal tissue, fibrous tissue and. fluid connective tissue. On the basis of structure and function connective tissue is mainly of three types. As: A . Films Connective Tissue: This type of connective tissue lies below the body-integument and sparsely in muscles. In their matrix numerous fibres are present. B. Skeletal Tissue: Internal structural building tissue of the body is called the skeletal tissue. Functions : 1. This tissue forms the internal structure of the body, e.g. skeletal system. 2. It gives the b

ANIMAL TISSUE, ORGAN AND ORGAN SYSTEM There is only one cell in the body of the animals of the phylum Protozoa. Animals of the Phylum Porifera are simplest multi-cellular animals. Their cells do not form actual tissue. Though tissues, organs and systems are not formed in members of the phylum Cnidaria (previously known as Coelenterata), their body cells are, however, arranged in two layers. In the animals from phylum Platyhelminthes to Chordata, tissues, organs and organ systems are seen. Members of those phyla are three layered. From there three embryonic cell layers (namely ectoderm, mesoderm and endoderm), tissues, organs and systems are formed. Tissue : In the body of multi-cellular animals some cells remain together and performa particular function. These cells are either formed from the ectoderm, mesoderm or endoderm of the embryo and remain close together. Inter-cellular materials or matrix are present between these cells. These cells may be similar or of different types. Arisin

ANSWERS TO QUESTION SET 001 1. C       2. A       3. A          4. A   5. A       6. A       7. C           8. B 9. B       10. B You want to check the questions che here  Question set 001

INSTRUCTIONS. a). Answer all the questions. b). Check your answers by clicking on the link answer. 1.  The breaking down of organic compounds from complex to simpler with liberation of energy     is called ? A.catabolism. B. hydrolysis C. metabolism D. Anabolism. 2. In which of the following organs does mucus play a protective role A. Stomach B. Oesophagus C. Duodenum D. Colon. 3. Which one of the following fruits is an example of a drupe? A. Avocado. B. Passion C. Tomato D. Orange 4. At neutral pH the enzyme pepsin may be A. In activated B. Denatured C. Inhibited D. Destroyed 5. A fruit with several sutures along which it splits when ripe is called a A. Berry B. Legume C. Capsule D. Drupe 6. A microscope with a X5 eyepiece and a X20 objective lens will magnify an object by. A. X100 B. X25 C. X250 D. X4 7. Which part of the microscope is used for regulating the amount of light? A. Diaghram B. lense C. mirror D. eye piece 8. Which of the following parts of a cell is responsible for ener

BIOLOGY complex plant tissues Tracheids : Cells are dead, long with transverse ends, containing large vacuole. Cell walls are hard, strong. and lignified. Their main functions are to give mechanical strength and to supply water and dissolved minerals from root to the leaves.Complex tissue is composed of more than one kind of cells. They are two types, namely Xylem tissue and Phloem tissue.  Tracheid  Xylem tissue : Xylem tissue consists of four types of cells, namely: Tracheids, Vessels or Trachaea, Xylem fibre and Xylem Parenchyma.  Vessel  Vessels or Trachaea: Cells are broad and short, placed end to end to form a continuous hollow tube. Water and waterdissolved minerals are conducted from root to leaf by these cells.   �Xylem fibre: These are sclerenchymatous cells. Their main function is to give mechanical strength to the plant. Xylem parenchyma: These are parenchymatous . cells. Functions of these cells are storage and conduction of food materials. Functions of xylem tissue:

Male-Female determining chromosome: @@@$ IMPORTANT@@@ READ THIS Every living being has a definite number of chromosomes. In human beings there are 23 pairs of chromosome. Among them 22. pairs are similar in both male and female, these are Autosomes, AA. Members of the remaining pair of chromosome are different in male and female. This pair of chromosome determines the sex of human beings. As they determine the sex, so they are called X and y sex chromosome or sex determining chromosome. One of the sex chromosomes is X chromosome and the other is Y chromosome. If the sex chromosome pair is XY, the child will be male (son), and if it is XX, the child will be female (daughter). In Drosophylla (a fly) also XX indicate female and XY male. So in case of determining the sex, the role of X and Y chromosome is vital. Whether the child will be a son or daughter: Now we will discuss whether the father or mother is responsible for the birth of a son or daughter. Both male and female have 44 autos

Division Of Labour In Multicellular Plants : Tissue and Tissue System Tissue : In unicellular organisms a single cell does all the functions. There is no chance of division of labour on the basis of cell. In contrast, this kind of division is found in multicellular living body. In this case, it is observed that a group of cells performs the duty of manufacturing food; another group stores it, while the other group conducts the transport of food materials. There is further a group of cells that gives mechanical strenght to some organs. In many cases it is observed that a group of cells originating from a single origin remain closely attached in a place and collectively perform a similar type of function. This type of cells in a group is called tissue. In multicellular organisms division of labour is the main cause of formation of tissue. Types of Tissue : Cells of all tissues do not have the power of cell division but some of them have. Therefore tissues are of two types in terms of t

CLASSIFICATION OF LIVING THINGS 2. KINGDOM PROTOCTISTA This kingdom consist of three groups of organisms:- the protozoa, algae and the slime mould. They are a diverse group with some formally classified in plant and animal kingdom. CHARACTERISTICS OF PROTOCTISTA. They are single celled or simple multicellular eukaryotic organisms. Live in moist or aquatic environment. They have heterotrophic nutrition and feed by ingesting food like animals. They are microscopic in their size. Move by pseudopodia (amoeba), cilia (paramecium) or flagella (Euglena) Fig. Some protozoan AMOEBA Paramecium Paramecium ALGAE Characteristics of Algae. Single celled, conical or filamentous in form. It poses chlorophyll and have autotropic nutrition. Most of the algae are aquatic in habitat living in both fresh water and marine environment. Their bodies are thallus i.e without differentiation into roots, stem or leaves. They contain variety of pigments. i.e Brown, yellow, green, red, and are distinguished by thos

CLASSIFICATION OF LIVING THINGS.  3. KINGDOM PLANTAE.   Kingdom plantae  Plants are organisms which have chlorophyll in the and are able to manufacture their own food in the presence of sunlight, using carbondioxide and water. CHARACTERISTICS OF PLANTAE   They are multicellular and eucaryotic (nuclei are surrounded by nuclear membranes).   They contain chlorophyll and hence hence carry out autotrophic nutrition.   They store food in the form of starch.   Their cells have rigid cellulose cell walls.   They do not carry out locomotion and have limited movement. The major divisions of plants BRYOPHYTA example ( liverworts,mosses ). Characteristics   they are multicellular, non-flowering and non-vascular plants.   Their body is a thallus i.e have no true roots, stems and leaves but have structures resembling them.   They roproduce sexually by gamete formation and asexually by spores and also vegetatively.   Live in moist terrestrial environments. TRACHEOPHYTA (Vascular plants)