NCERT Class 11 Biology BioMolecules

Read and download NCERT Class 11 Biology BioMolecules in NCERT book for Class 11 Biology. You can download latest NCERT eBooks chapter wise in PDF format free from Studiestoday.com. This Biology textbook for Class 11 is designed by NCERT and is very useful for students. Please also refer to the NCERT solutions for Class 11 Biology to understand the answers of the exercise questions given at the end of this chapter

NCERT Book for Class 11 Biology Chapter 9 Biomolecules

Class 11 Biology students should refer to the following NCERT Book Chapter 9 Biomolecules in Class 11. This NCERT Book for Class 11 Biology will be very useful for exams and help you to score good marks

Chapter 9 Biomolecules NCERT Book Class 11

BIOMOLECULES

9.1 HOW TO ANALYSE CHEMICAL COMPOSITION?

We can continue asking in the same way, what type of organic compounds are found in living organisms? How does one go about finding the answer? To get an answer, one has to perform a chemical analysis. We can take any living tissue (a vegetable or a piece of liver, etc.) and grind it in trichloroacetic acid (Cl3CCOOH) using a mortar and a pestle. We obtain a thick slurry. If we were to strain this through a cheesecloth or cotton we would obtain twofractions. One is called the filtrate or more technically, the acid-soluble pool, and the second, the retentate or the acid-insoluble fraction. Scientists have found thousands of organic compounds in the acid-soluble pool. In higher classes you will learn about how to analyse a living tissue sample and identify a particular organic compound. It will suffice to say here that one extracts the compounds, then subjects the extract to various separation techniques till one has separated a compound from all other compounds. In other words, one isolates and purifies a compound. Analytical techniques, when applied to the compound give us an idea of the molecular formula and the probable structure of the compound. All the carbon compounds that we get from living tissues can be called ‘biomolecules’. However, living organisms have also got inorganic elements and compounds in them.

How do we know this? A slightly different but destructive experiment has to be done. One weighs a small amount of a living tissue (say a leaf or liver and this is called wet weight) and dry it. All the water, evaporates. The remaining material gives dry weight. Now if the tissue is fully burnt, all the carbon compounds are oxidised to gaseous form (CO2, water vapour) and are removed. What is remaining is called ‘ash’. This ash contains inorganic elements (like calcium, magnesium etc). Inorganic compounds like sulphate, phosphate, etc., are also seen in the acid-soluble fraction. Therefore elemental analysis gives elemental composition of living tissues in th form of hydrogen, oxygen, chlorine, carbon etc. while analysis for compounds gives an idea of Element % Weight of

* Adapted from CNR Rao, Understanding Chemistry, Universities Press, Hyderabad. TABLE 9.1 A Comparison of Elements Present in Non-living and Living Matter* Component Formula Sodium Na+ Potassium K+  Calcium Ca++ Magnesium Mg++ Water H2OTABLE 9.2 A List of Representative Inorganic

Constituents of Living Tissues

the kind of organic (Figure 9.1) and inorganic constituents (Table 9.2) present in living tissues. From a chemistry point of view, one can identify functional groups like aldehydes, ketones, aromatic compounds, etc. But from a biological point of view, we shall classify them into amino acids, nucleotide bases, fatty acids etc. Amino acids are organic compounds containing an amino group and an acidic group as substituents on the same carbon i.e., the α-carbon. Hence, they are called α-amino acids. They are substituted methanes. There are four substituent groups occupying the four valency positions. These are hydrogen, carboxyl group, amino group and a variable group designated as R group. 

EXERCISES

1. What are macromolecules? Give examples.

2. Illustrate a glycosidic, peptide and a phospho-diester bond.

3. What is meant by tertiary structure of proteins?

4. Find and write down structures of 10 interesting small molecular weight biomolecules. Find if there is any industry which manufactures the compounds by isolation. Find out who are the buyers.

5. Proteins have primary structure. If you are given a method to know which amino acid is at either of the two termini (ends) of a protein, can you connect this information to purity or homogeneity of a protein?

6. Find out and make a list of proteins used as therapeutic agents. Find other applications of proteins (e.g., Cosmetics etc.)

7. Explain the composition of triglyceride.

8. Can you describe what happens when milk is converted into curd or yoghurt, from your understanding of proteins.

9. Can you attempt building models of biomolecules using commercially available atomic models (Ball and Stick models).

10. Attempt titrating an amino acid against a weak base and discover the number of dissociating ( ionizable ) functional groups in the amino acid.

11. Draw the structure of the amino acid, alanine.

12. What are gums made of? Is Fevicol different?

13. Find out a qualitative test for proteins, fats and oils, amino acids and test any fruit juice, saliva, sweat and urine for them.

14. Find out how much cellulose is made by all the plants in the biosphere and compare it with how much of paper is manufactured by man and hence what is the consumption of plant material by man annually. What a loss of vegetation!

15. Describe the important properties of enzymes.


Please refer to attached file for NCERT Class 11 Biology - BioMolecules

Chapter 17 Breathing and Exchange of Gases
NCERT Class 11 Biology Breathing and Exchange of Gases

NCERT Book Class 11 Biology Chapter 9 Biomolecules

The above NCERT Books for Class 11 Biology Chapter 9 Biomolecules have been published by NCERT for latest academic session. The textbook by NCERT for Chapter 9 Biomolecules Biology Class 11 is being used by various schools and almost all education boards in India. Teachers have always recommended students to refer to Chapter 9 Biomolecules NCERT etextbooks as the exams for Class 11 Biology are always asked as per the syllabus defined in these ebooks. These Class 11 Chapter 9 Biomolecules book for Biology also includes collection of question. Along with Biology Class 11 NCERT Book in Pdf for Chapter 9 Biomolecules we have provided all NCERT Books in English Medium for Class 11 which will be really helpful for students who have opted for english language as a medium. Class 11 students will need their books in English so we have provided them here for all subjects in Class 11.

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