CHAPTER -1 MAIN CONCEPTS OF LIFE SCIENCE
1.MAIN CONCEPTS OF LIFE SCIENCE
- Life science has many branches like botany, zoology etc
- Biology is a study of plants and animals
- Biology can be divided into two main branches
- Botany- study of plants
- Zoology- study of animals
- Some of the sub branches are
- Bacteriology- study of bacteria
- Virology- study of virus
- Phycology- study of algae
- Mycology- study of fungi
- Cytology- study of cell
Important terms coined by,
- Biology- Lamarck and Treriranus
- Cell- Robert Hooke
- Protoplasm- Purkinjee
- Genetics- W.Bateson
- Vaccine- Edward Jenner
Considered as father of
- Aristotle- Father of biology and zoology
- Theoprastus- Father of botany
- Gregor Johann Mandel- Father of Genetics
- Carl Linnaeus- Father of Modern Taxonomy
Micro Organisms
- Living organisms show a great degree of diversity in their size.
- They are measured in microns and milli microns. Example: Virus, bacteria, algae, fungi and protozoan.
Virus
- Virus is a Latin word which means poison. Viruses are the smallest and simplest of all living organisms.
- The study of viruses is called Virology.
- Based on their host, viruses are classified in to five types.
Bacteriophage |
Phytophage (Plant Virus) |
Phycophage (Algal Virus) |
VIRUS |
Zoophage (Animal virus) |
Mycophage (Fungal Virus) |
Bacteria
- The curd contains Lacto Bacillus bacteria which helps to change the milk into curd.
- Bacteria are unicellular and microscopic, belonging to the world microbes. The study of bacteria is called Bacteriology.
- Bacteria are measured in microns. 1 micron = 1/1000 millimeter.
- Four types of bacteria are recognized based on shape. They are
- Cocci (Spherical shaped)
- Bacilli (Rod shaped)
- Spirillum (Spiral or cork screw)
- Vibrio (Comma Shaped)
- On the basis of the number and arrangement of the flagella, bacteria are classified as
- Monotrichous (Single flagellum at one end)
- Amphitrichous (Tuft of flagella arising at both ends)
- Atrichous (without any flagella)
- Lophotrichous (Tuft of flagella at one ends) –
- Peritrichous (Flagella all around)
Algae
- Algae are a unicellular green algae. It is spherical or oval in shape.
- The cell wall may have a pectic sheath around it. There is a single large cup-shaped Chlamydomonas chloroplast
- There are narrow end of the cells which helps in locomotion.
- The study of algae is called phycology.
Fungi
- The conversion of sugar solution into alcohol and liberation of carbon dioxide is known as fermentation.
- Wine, alcohols are prepared from the molasses by the fermentation activity of the yeast. etc.
- Fungi do not ‘possess chlorophyll. Hence they are incapable of photosynthesis.
- The study of fungi is called Mycology.
Protozoa
- Protozoans are unicellular organisms.
- Protozoan’s show mainly two modes of life, free living and parasitic.
- Free living organisms inhabit fresh and salt water. Parasitic forms lives as ectoparasites or endoparasites. They cause diseases.
Use of Micro organisms in medicine agriculture, industry and daily living
Micro-organisms are used in the manufacturing of antibiotics, linen, bread, wine ,beer and other industries. Microorganisms are used to enrich the soil fertility
Name of the species | Antibiotic | |
Bacteria | Streptomyces riseus Bacillus subtils | Streptomycin Bacitracin |
Fungi | Penicillium notatum Penicillium chrysogenum | Penicillin |
Agriculture
- It may be defined as the science or practice of farming.
- The following bacteria are involved to enrich the soil fertility:
- Ammonifying bacteria: e. g. Bacillus ramosus
- Nitrifying bacteria: e.g., Nitrobacter
- Nitrogen-fixing bacteria: e.g., Azatobactor, Clostridium, Phizobium (Root nodules bacteria)
- The leaves of tea, tobacco, the beans of coffee and cocoa are fermented by the activity of Bacillus megaterium to impart the characteristic flavor. This is called curing.
- Streptococcus lactis (lactic acid bacteria) converts milk protein into curd. Vinegar is manufactured from sugar solution employing Acetobacter aceti.
- Oxalic acid is the fermentation product of fungi Aspergillus Niger. Yeast is the best source of vitamin B complex and vitamin Riboflavin
- Mushroom is also an edible (e.g.) Agaricus Morchella are edible and are cultivated
S.No | Micro Organisms | Name of the species | Diseases |
1 | Bacteria | Xanthomonas citri Pseudomonas Solanacearum Xanthomonas cryae | Citrus Canker Wilt of potato Bacterial blight in Rice |
2 | Fungi | Cercospora personata Cercospora arachidicola Pyricularia | Tikka disease of groundnut Blast disease of rice |
3 | Virus | Bunchy top virus Tobacco Mosaic virus Cucumber mosaic virus | Bunchy top of banana Tobacco Mosaic disease Cucumber Mosaic disease |
Pathogen | Diseases | Mode of Transmission |
Virus | Common cold,Polio,Hepatitis,Influenza,Jaundice AIDS | Air Water,direct contact Sexual contact |
Bacteria | Cholera,typhoid Tetanus Leptospirosis Leprosy | Contaminated water Cuts and wound Contact of animal’s urine (Rat and squirrel) Contact(vector) |
Fungi | Athlete’s feet | Spores in water and in ground |
Protozoan | Malaria | Vector example mosquito |
Bottling and Canning
- Pasteurization is used to preserve m.ilk. Milk is heated to 72°C forminutes and then suddenly cooled to 12°C
- Microbes are killed without causing damage to the taste, quality of milk for a longer time and packed in polythene pouches
The role of microbes in genetic engine
- Viruses are used in eradicating harmful pests like insects.
- Vaccines are produced to prevent serious viral infections.
- Their ability to move genetic information from one cell to another makes them useful for cloning DNA and could provide a way to deliver gene therapy(transformation)
- Viruses are very much used as biological research tools due totheir simplicity of structure and rapid multiplication.
- The cyclic movements of chemicals of Biospere between the organisms and the environment are referred as Bio – geo cycle.
- Algal bloom: Under certain conditions, algae produce “blooms” i.e. dense masses of materials that cover the water surface, thereby decrease oxygen content of water.
- This is followed by the death ofaquatic organisms.
- Algal bloom leads to loss of speciesdiversity which is known as Eutrophication.
- Pathology is a science which deals with diseases of plants, animals and human beings caused by viruses, bacteria and fungi.
- The cyclic movements of chemicals of Biosphere between the organisms and the environment are referred as Bio – geo cycle.
Algal bloom:
- Under certain conditions, algae produce “blooms” i.e. densemasses of materials that cover the water surface, thereby decrease the oxygen content of water.
- This is followed by the death of aquatic organisms. Algal bloom leads toloss of species diversity which is known as Eutrophication.
- Pathology is a science which deals with diseases of plants, animals and human beings caused by viruses, bacteria and fungi.