To study the biochemical tests for starch, sucrose, glucose, fat and protein.

                                                                                                                                         (Biochemistry)

Principle:  Presence of the substances can be ascertained using some confirmatory tests.

Materials required: 5 test tubes, test tube holder, starch solution, glucose solution, sucrose solution, vegetable oil, protein solution, iodine solution, Fehling’s solutions A and B, paper, Sudan III, benzene, , Biuret solution, Xanthoproteic reagent, spirit lamp

 Procedure:  

STARCH

Sr no.	Test	Observation	Inference
1.	Iodine Test: Take about 2 ml of the sample solution in a test tube and add one or two drops of iodine solution in it.	Solution turns blue.	Starch is present.

Result: The given sample solution is starch.

 

 SUCROSE

Sr no.	Test	Observation	Inference
1.	Iodine Test: Take about 2 ml of the sample solution in a test tube and add one or two drops of iodine solution in it.	No blue colour.	Starch is absent.
2.	Fehling’s Test: Take about 2 ml of the sample solution in a test tube; and add some amount Fehling’s solution A and B (in equal amount) Heat the mixture of the test tube.	Red precipitate is not formed.	Monosaccharide (Glucose, fructose) is absent.
3.	Fehling’s Test: Take about 2 ml of the sample solution in a test tube; and add 2 or 3 drops of dil HCl. Stir it. Heat the mixture in a test tube. Now add some amount of Fehling’s solution A and B (in equal amount). Heat the mixture of the test tube.	Red coloured precipitate is formed.	Monosaccharide (Glucose or fructose) is present.  (On adding dil HCl, Sucrose hydrolyses into glucose and fructose.)

Result: The given sample solution is sucrose.

 

GLUCOSE

Sr no.	Test	Observation	Inference
1.	Iodine Test: Take about 2 ml of the sample solution in a test tube and add one or two drops of iodine solution in it.	No blue colour.	Starch is absent.
2.	Fehling’s Test: Take about 2 ml of the sample solution in a test tube; and add some amount of Fehling’s solution A and B (in equal amount) Heat the mixture of the test tube.	Red coloured precipitate is formed.	Monosaccharide (Glucose, fructose) is present.   Presence of glucose is confirmed.
3.	Benedict’s  Test: Take about 2 ml of the sample solution and add some amount of Benedict’s solution. Stir it. Heat the mixture of the test tube.	Red coloured precipitate is formed.	Presence of glucose is reconfirmed.

Result: The given sample solution is glucose. 

 

 

FAT

Sr no.	Test	Observation	Inference
1.	Paper Test: Put a drop of the sample on a paper.	Translucent area is formed on the paper. Or Some area is translucent.	Fat is confirmed. Or Some fat is present in the solution.
2.	Solubility Test: Take 2 ml of the sample in a test tube; and add 2 ml of water in it. Stir it.	Sample floats on water. Two layers are formed.	Fat is possible.
	Take 2 ml of the sample in a test tube; and add some benzene (or chloroform or ether) in it.	Sample is soluble in benzene (or chloroform or ether).	Fat is possible.
3.	Sudan III Test: Take 2 ml of the sample in a test tube; and add a little Sudan III in it. Stir it.	Pink droplets appear.	Fat is confirmed.

Result: The given sample is fat. 

 

PROTEIN

 

Sr no.	Test	Observation	Inference
1.	Biuret Test: Take 2 ml of the sample solution in a test tube; and add some Biuret solution. Stir it.	Blue-violet colour appears.	Presence of protein is confirmed.
2.	Xanthoproteic Test: Take 2 ml of the sample solution in a test tube; and add Xanthoproteic reagent in it. Stir it. Heat the mixture.	Yellow precipitate is formed.	Presence of protein is reconfirmed.

Result: The given sample solution has protein in it.

 

The structures of Morula, Blastula and Gastrula stages of embryonic development

I am giving here a very simplified version of the various stages of embryonic development of human and several other animals. The purpose is to clarify the concept, give only the basic main points and to differentiate between the three stages.

Morula

1.      This is a solid mass of cells (blastomeres).

2.      It is formed 3 days after fertilisation

3.      It has 16 cells. All cells are totipotent.

4.      Its later stages have 32 cells and 64 cells.

5.      The outer cells form extra-embryonic parts and the inner cells form the future embryo proper.

Blastula

1.      This is formed 4-5 days after fertilisation.   

2.      This is a hollow sphere of cells with a cavity inside.

3.      The cavity is called blastocoel.

4.      Blastocoel has uterine fluid inside.

5.      Its later stage is called blastocyst with inner mass and outer trophoblast.

Gastrula

1.      It is an early multi-cellular embryo.

2.      It is formed after implantation.

3.      It is multi-layered. It has three germinal layers.

4.      It has an outer cavity called blastocoel.

5.      There is also a central cavity called archenteron.

Donation

Donation

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Cycas

This plant is Cycas. It looks similar to a palm tree. These trees are very rare in number. However, they are available for sale in nearby plant nurseries. It grows very slowly. So the plant is costly to buy. 

Cycas is a gymnosperm. The gymnosperms are the plants in which ovules are not enclosed by an ovary wall. After fertilisation the seeds remain exposed and therefore these plants are called naked-seeded plants. The gymnosperms produce microspores and megaspores which are produced in microsporangia and megasporangia borne on the sporophylls. 

Experiment: To demonstrate endosmosis in raisins

This is an experiment to show endosmosis in raisins (or in gram seeds). It is a part of Class 12 Biology Practical work. It is one of the major experiments. It comes under Plant Physiology.  It is also a part of Class 11 minor experiment or for Spotting. A simplified version of the experiment for your Practical file is given below:                                                          

                                                     Experiment

Aim: To demonstrate endosmosis in raisins and find the percentage of water absorption. 

Principle: Water moves from its higher concentration to lower concentration. It can pass through a selectively permeable membrane like the plasma membrane of cells (osmosis).

Materials Required: A few raisins, digital weighing scale, beaker, water, blotting paper. 

Procedure:

1.     Take three or four raisins and weigh it on a digital weighing scale. Note the weight W₁.

2.     Soak them by putting them in a beaker filled with pure water.

3.     After two hours, take out the raisins and wipe them dry using a blotting paper.

4.     Weigh the raisins on the digital weighing scale. Note the weight W₂.

Observation:

After a period of time, the raisins absorb water and get swollen because of endosmosis.

Initial weight of raisins = W₁ = _________

Weight of swollen raisins = W₂ = _________

Weight of absorbed water = W₃ = W₂ – W₁ = __________

Percentage of water absorbed by raisins = (W₃/W₁)  x 100 = ________ %

Result:

Raisins exhibit endosmosis and absorb water when soaked in it.

The percentage of water absorption of the given sample of raisin = _______%

Biological Classification Worksheet

 

Class 11 Biology Classification, Worksheet              Name: ____________________

1. Arrange these groups in hierarchy:  [order, family, kingdom, domain, phylum, species, class, genus]

2. Name any one animal and its trinomial name.

    __________________________________

3. Write the zoological names of:

            1. Lion _____________________

            2. Tiger _____________________

            3. Leopard __________________

            4. Cat ______________________

4. Name two organisms that show:

    a. Asymmetry: _____________________

    b. Radial symmetry: ___________________

    c. Bilateral symmetry: _________________

    d: diplobasty : _______________________

    e. triploblasty: ______________________

    f. Segmentation: _____________________

 

5. Father of Biology: __________________

6. Father of Botany: __________________

7. Father of Zoology: _________________

8. Father of Modern Taxonomy __________

 

9. Match the columns A with B

 

 

 

 

                                           

PTO

1. Protozoans  are called unicellular as well as _____________________ organisms.

2. ________________ is a connecting link between plants and animals.

3. _________________ have porous body wall.

4. _______________ is a living fossil.

5. Who coined the term protozoa? __________________

 

6. Match columns A and B

	A 1.     Ascaris 2.     Balanoglossus 3.     Hydra 4.     Neris 5.     Pila 6.     Planaria 7.     Scorpion 8.     Spongilla 9.     Star Fish 10.            Trypnosoma		B 1.     Annelida 2.     Arthropoda 3.     Coelenterata 4.     Echinodermata 5.     Hemichordata 6.     Mollusca 7.     Nematheminthes 8.     Platyhelminthes 9.     Porifera 10.            Protozoa