Class 11 Bio Practical

• Estimation of pyramids of numbers using simple techniques 
• Investigation of adaptive features of hydrophytes, halophytes, mesophytes and xerophytes from fresh material 
• Investigation of water content of soil samples 
• Sampling of a grass and community by quadrat method 
• Study of development of chick embryo 48 over 72 hours after incubation
• Study of ductless glands (pancreas, thyroid) using microscopic sections 
• Study of simple muscle twitch using frog's muscle 
• Study of skeleton of frog 
• Study of structure of hen's egg 
• The ketoses and aldoses react with phenylhydrazine to produce a phenylhydrazone which further reacts with another two molecules of phenylhydrazine to yield osazone. Needle-shaped yellow osazone crystals are produced by glucose, fructose and mannose, whereas lactosazone produces mushroom shaped crystals. Crystals of different shapes will be shown by different osazones. Flower-shaped crystals are produced by maltose.
• Procedure: To 0.5 g of phenylhydrazine hydrochloride add 0.1 gram of sodium acetate and ten drops of glacial acetic acid. Add 5 mL of test solution to this mixture and heat under boiling water bath for about half an hour. Cool the solution slowly and examine the crystals under a microscope.
• Chemically fats and oils are trimesters of glycerol and higher fatty acids. They are of animal or plant origin. Desi ghee is animal ghee while vanaspati ghee is vegetable ghee. Fats are solids whole oils are liquids at ordinary temperature. Fats and oils may be saturated or unsaturated.
• Saturated fat: Saturated fats contain only single bonds within the carbon chain. Saturated fats are of animal origin and are usually present in solid form. It increases the blood cholesterol level. Some examples are meat fat, butter etc. Coconut oil and palm oil also contain saturated fat.
• Unsaturated fat: Unsaturated fats contain double bonds within the carbon chain. Unsaturated fat is found in fish like salmon and tuna, nuts, seeds etc.
• The compound microscope is a very significant scientific tool for making biological studies. It is an instrument which is used to see and study such small objects which are otherwise invisible. Different types of microscopes with different magnifications are available but the most common one is the 'Monocular compound microscope' which magnifies upto 1,000 times. The most modern and the best available microscope is the "Electron microscope" which can magnify the objects upto 100,000 times. The power of a microscope to magnify the objects is known as its 'Magnification'.
• PARTS OF A MONOCULAR COMPOUND MICROSCOPE: Ocular (Eye-Piece):It is the part through which the observer looks at the specimen. It consists of a tube containing one lens which magnifies the image of the object being studied. The oculars may be of different powers such as 5X, 10X which means that different eyepieces can magnify the object to different extents. An eyepiece of 5X power (magnification) will magnify the image of an object 5 times and so on. The oculars of different magnifications can be used according to needs.
• Objectives: These are the metallic tubes containing lenses of different magnifications. These may be one, two or three in number. The magnifying power of each objective is engraved on it.
• The magnifying power of the microscope can be calculated for different sets of eyepieces and objectives by just multiplying the powers of the eyepiece and the objective, being used at the the eye time of study. For example, if the power of the eyepiece is 10X and that of the objective is 60X; the total magnification of the microscope shall be 10X 60X600X i.e., the microscope shall magnify the image 600 times the size of the object.
•  Stage: It is the horizontal circular or squarish platform on which the glass slide carrying the object is placed for study. It has a hole in the centre which admits light coming from the mirror. The light must pass through the object for distinct vision.
• Stage Clips: Two clips are movably fixed on the stage for holding the slide firmly in place and prevent it from slipping away when the object is being studied through the eyepiece.
• Diaphragm: It is attached below the stage-hole and serves to regulate the amount of light passing through the object. Some microscopes are provided with a condenser (with an adjustable iris diaphragm) while others have a round plate-like diaphragm with holes of different sizes to achieve the purpose.
• Mirror: A movable plano-concave mirror is fixed some distance below the stage. It can be moved sideways, upwards or downward to focus and reflect light upward through the diaphragm, stage hole, objective and then to the eyepiece.