Chapter 9 : Biomolecules

Class 11 Biology Chapter 9 Biomolecules Exercise Questions and Answers :

1. What are macromolecules? Give examples.

Answer : Macromolecules, also known as biomacromolecules, are large, complex organic compounds found in the acid-insoluble fraction of living organisms. They include proteins, nucleic acids (such as DNA and RNA), polysaccharides (like cellulose and chitin), and lipids (fats and phospholipids). These macromolecules have molecular weights typically exceeding ten thousand daltons. In contrast, micromolecules are smaller biomolecules with molecular weights below one thousand Daltons . Examples of macromolecules are essential components of life, responsible for various biological functions.

2. What is meant by tertiary structure of proteins?

Answer : The tertiary structure of proteins refers to the three-dimensional arrangement and folding of a protein's polypeptide chain into a complex and unique 3D shape. This structure is crucial for a protein's biological function as it determines its active sites and the specific interactions it can have with other molecules. It results from various chemical interactions like disulfide bonds, hydrogen bonds, hydrophobic interactions, and ionic bonds.

3. 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.

Answer :  The structures of 10 interesting small molecular weight biomolecules along with some information about industries that manufacture these compounds and their potential buyers are :

(i) Glucose () :

Structure :

Isolation Industry: Food and beverage, pharmaceutical, and biotechnology.

Buyers: Food and beverage companies, pharmaceuticals for drug formulation, and research institutions.

(ii) Ribose () :

Structure:

Isolation Industry: Biotechnology, pharmaceuticals, and research.

Buyers: Biotech firms for research and synthesis, pharmaceutical companies for drug development, and research institutions.

(iii) Glycine  () :

Structure:

Isolation Industry: Pharmaceutical, dietary supplement, and research.

Buyers: Pharmaceutical companies for drug formulation, dietary supplement manufacturers, and research institutions.

(iv) Alanine () :

Structure:

      

Isolation Industry: Pharmaceutical, biotechnology, and research.

Buyers: Pharmaceutical companies for drug development, biotech firms for research, and research institutions.

(v) Glycerol () :

Structure :

          

Isolation Industry: Chemical, cosmetic, and pharmaceutical.

Buyers: Chemical manufacturers, cosmetic companies for skin care products, and pharmaceutical companies for drug formulation.

(vi) Lecithin () :

Structure :

Isolation Industry: Food and beverage, pharmaceutical, and cosmetic.

Buyers: Food manufacturers, pharmaceutical companies, and cosmetic producers for various applications.

(vii) Adenine () :

Structure :

       

Isolation Industry: Pharmaceutical, biotechnology, and research.

Buyers: Pharmaceutical companies for drug development, biotech firms for research, and research institutions.

(viii) Uracil () :

Structure :

   

Isolation Industry: Pharmaceutical, biotechnology, and research.

Buyers: Pharmaceutical companies for drug development, biotech firms for research, and research institutions.

(ix) Adenosine () :

Structure :

Isolation Industry: Pharmaceutical and research.

Buyers: Pharmaceutical companies for drug development and research institutions.

(x) Adenylic Acid ()

Structure :

Isolation Industry: Pharmaceutical, biotechnology, and research.

Buyers: Pharmaceutical companies for drug development, biotech firms for research, and research institutions.

These biomolecules have various applications across industries, and their isolation and production cater to the needs of these sectors, including pharmaceuticals, food and beverage, cosmetics, and research institutions.

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

Answer : Proteins are used as therapeutic agents in various medical applications, including pharmaceuticals, and they have several other applications beyond therapeutics.

 Some proteins used as therapeutic agents :  Insulin, Oxytocin, Immunoglobin, Antidiuretic Hormone( ADH), Thrombin, Fibrinogen, Renin and streptokinases.

Some other Applications of Proteins:

(i) Cosmetics: Proteins like collagen and keratin are used in skincare and hair products for their moisturizing and strengthening properties.

(ii) Food Industry: Enzymes like proteases are used in food processing for meat tenderization and dairy production.

(iii) Biotechnology: Proteins are used in biotech research, including recombinant DNA technology for protein production.

(iv) Diagnostics: Proteins are used in diagnostic tests, such as enzyme-linked immunosorbent assays (ELISAs) and western blots.

(v) Textiles: Proteins are used in textiles for their properties like elasticity and moisture-wicking.

(vi) Enzymes in Detergents: Proteases and amylases are used in laundry detergents to break down stains.

(vii) Regenerative Medicine: Proteins are used in tissue engineering and regenerative therapies to promote cell growth and repair.

(viii) Research: Proteins are essential tools in scientific research for studying biological processes and drug development .

5. Explain the composition of triglyceride.

Answer :  A triglyceride consists of three fatty acid molecules attached to a glycerol molecule. The glycerol molecule has three carbon atoms, each with a hydroxyl group to which a fatty acid binds. The type and number of fatty acids determine the triglyceride's characteristics, with saturated and unsaturated fatty acids being common constituents.

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

Answer : Answer : To construct a ball-and-stick model of D-glucose using commercially available atomic models, create a hexagonal ring using carbon (C) atoms as balls. Attach hydrogen (H) and oxygen (O) atoms as sticks to represent chemical bonds, ensuring correct bond angles and lengths. Highlight the chiral carbon to show glucose's 3D structure. This model provides a visual representation of D-glucose.

           

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

Answer : The structure of the  alanine :

               

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

Answer : Gums, in various applications, can be natural or synthetic substances. Natural gums are often plant-derived and contain polysaccharides.

In contrast, Fevicol, a synthetic adhesive, primarily consists of polyvinyl acetate (PVA) and other synthetic polymers, which are different from the natural gums found in nature and the biomacromolecules in living systems like proteins, nucleic acids, and polysaccharides.

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

Answer :  Qualitative tests for proteins, fats and oils, and amino acids can be conducted using chemical reagents.

(a) Biuret Test for Proteins :

Procedure : Add a few drops of a 10% sodium hydroxide (NaOH) solution to the test solution to make it alkaline. Then, add a few drops of 1% copper sulfate () solution.

Result : Purple coloration indicates the presence of proteins.

(b) Sudan Red Test for Fats and Oils :

Procedure : Add a few drops of Sudan Red solution to the test solution.

Result : If fats and oils are present, they will turn a red color.

(c) Ninhydrin Test for Amino Acids :

Procedure : Add a few drops of a ninhydrin solution to the test solution and heat it.

Result : The presence of amino acids is indicated by the appearance of a purple or bluish color.

To test various substances:

Fruit Juice: Perform the Biuret test. A purple color indicates the presence of proteins.

Saliva: Use the Ninhydrin test. A purple or bluish color suggests the presence of amino acids.

Sweat: You can use the Biuret test or the Ninhydrin test for amino acids. A positive result may indicate the presence of proteins or amino acids in sweat.

Urine: Perform both the Biuret test for proteins and the Ninhydrin test for amino acids. A positive result in the Biuret test indicates the presence of proteins, while a purple or bluish color in the Ninhydrin test suggests the presence of amino acids.

10. 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!

Answer :  Estimating the exact amount of cellulose produced by all plants in the biosphere is challenging due to the vast and diverse ecosystems worldwide, but it is estimated to be in the range of hundreds of gigatons (billions of metric tons) annually. In contrast, humans produce around 400 million metric tons of paper each year. This comparison highlights the significant consumption of plant material by humans, emphasizing the impact on global vegetation and ecosystems. It underscores the importance of sustainable practices to mitigate the loss of vegetation and its environmental consequences.

11. Describe the important properties of enzymes.

Answer : The important properties of enzymes are :

(i) Composition: Enzymes are usually proteins, but some can be RNA molecules called ribozymes.

(ii) Structure: Enzymes have primary, secondary, and tertiary structures, with a specific "active site."

(iii) Catalytic Activity: They speed up chemical reactions by lowering the energy needed for the reactions to occur.

(iv) Specificity: Enzymes are highly specific, each one working with a particular substrate.

(v) Temperature Sensitivity: Enzymes function best within a specific temperature range, often near body temperature (37°C).

(vi) Thermal Stability: Some enzymes from extremophiles can work at very high temperatures.

(vii) Difference from Inorganic Catalysts: Enzymes are sensitive to high temperatures, unlike inorganic catalysts.