The NCERT Solutions for Class 11 Biology Chapter 9 Biomolecules explore complex biological compounds. It includes compounds such as carbohydrates, proteins, lipids, and nucleic acids. Biomolecules play an important role in various processes such as growth, development, and metabolism. With the help of the solutions, students can strengthen their understanding and identify the weak areas and work on them. The NCERT Solutions build a solid foundation in the subject of biology.
Biomolecules Class 11 question answer are written in simple and easy-to-understand language by subject experts. This helps learners improve their conceptual clarity and strengthen their skills. Biomolecules Class 11 questions and answers PDF explain complex topics step by step, making it easier to understand the structure and functions of different biomolecules. Regular practice with the NCERT Solutions for Class 11 improves problem-solving ability and builds confidence to score well in school exams and competitive exams like NEET.
Get Class 11 Biology Chapter 9 Biomolecules Question Answer (Exercise Questions)
The detailed solved explanations of all the questions given in the textbook are given below. Each question is answered step by step and follows the NCERT guidelines closely. Studying through the Class 11 Biology Chapter 9 Biomolecules question answer allows students to understand the structure clearly.
Q1. What are macromolecules? Give examples.
Answer:
The complex high molecular weight molecules separated in acid-insoluble fractions in the presence of trichloroacetic acid are referred to as macromolecules. They are polymers of a molecular weight of 10,000 daltons and above. Proteins, carbohydrates, nucleic acids, etc., are macromolecules. There are lipids in the acid-insoluble fraction, too, but they are not of high molecular weight.
Q2. What is meant by the tertiary structure of proteins?
Answer:
The three-dimensional configuration of a protein that arises from repeated coiling and folding of helical and pleated polypeptide chains is termed its tertiary structure. Through repeated folding and coiling, polar side chains remain exposed, whereas nonpolar amino acids are kept inside. The tertiary structure is bonded through weak bonds. The activity of a protein exists in tertiary structures.
Q4. Find out and make a list of proteins used as therapeutic agents. Find other applications of proteins (e.g., Cosmetics, etc.)
Answer:
Proteins with therapeutic uses are insulin, oxytocin, ADH, thrombin, fibrinogen, renin, immunoglobulin, diastase, streptokinase, etc.
Other applications of proteins are
1. As cosmetics- Proteins such as casein are used in beauty creams, shampoos, etc.
2. Sweeteners- Thaumatin and monellin are sweet proteins.
3. Dietary supplements- Proteins can be used as dietary supplements.
Q5. Explain the composition of triglycerides.
Answer:
A triglyceride is a chemical formed by the esterification of three molecules of fatty acids with one molecule of trihydric alcohol called glycerol. All three fatty acids of triglyceride can be similar, as in tripalmitin, or dissimilar, as in palmito-oleoistearin, dipalmitostearin, etc.
Answer:
The structure of the amino acid alanine is represented below:
Q8. What are gums made of? Is Fevicol different?
Answer:
Gums are made up of polysaccharides and pectins. These are the breakdown products of plant cell walls that are discharged from the wounds in the bark. Fevicol, on the other hand, is made of a sticky substance called resin. It is made of polyvinyl acetate. Gums are soluble in water, whereas resins are insoluble in water.
Q9. Find out a qualitative test for proteins, fats and oils, and amino acids, and test any fruit juice, saliva, sweat, and urine for them.
Answer:
One of the qualitative tests for proteins is the xanthoproteic test. When a qualitative test for protein in urine is done using the aid of the xanthoproteic test, if a yellow precipitate is formed, then it is guaranteed that there is protein in it. The qualitative test for fats is the emulsification test.
During the emulsification test, the experimental material is first treated with ethanol and then dissolved in water. The development of an emulsion proves the existence of fats. The qualitative analysis for oils is the translucent spot test. The material to be tested is placed on paper. The presence of oil is established when oil marks remain.
Q11. Describe the important properties of enzymes.
Answer:
Enzymes are proteinaceous substances that are capable of catalyzing chemical reactions of biological origin without themselves undergoing any change. They are commonly called biocatalysts. The properties of enzymes are as follows:
1. Enzymes are proteins by nature
2. Optimum temperature- An enzyme is active within a narrow range of temperature. The temperature at which an enzyme is most active is called the optimum temperature. The enzyme activity decreased above and below this temperature.
3. Optimum pH- Every enzyme has an optimum pH at which it is maximally active. Most of the intracellular enzymes work at neutral pH.
4. Enzymes are substrate specific, i.e., one enzyme catalyzes only a particular substrate. Every enzyme has specific sites called active sites for the binding of substrate.
5. Only a small quantity of the enzyme is capable of forming the desired product
6. Enzyme activity is sensitive to certain chemicals called inhibitors or modulators.
Check the NCERT Books and NCERT Syllabus here:
Important Questions of NCERT Class 11 Biology Chapter 9 Biomolecules
This chapter explains the structure and functions of biomolecules like carbohydrates, proteins, and nucleic acids. Given below are some of the important questions from this chapter, along with the answer. To score well, it is important to practice the questions given in the NCERT Solutions for Class 11 Biology Chapter 9 Biomolecules.
Question 1: What type of bond joins monosaccharides in polysaccharides?
a. Peptide bond
b. Glycosidic bond
c. Phosphodiester bond
d. Hydrogen bond
Answer: The correct answer is option (b), Glycosidic bond
Explanation: Glycosidic bonds are the chemical connections between monosaccharide units in polysaccharides. Peptide bonds connect amino acids in proteins, phosphodiester bonds connect nucleotides in DNA and RNA, and hydrogen bonds are weaker interactions that stabilize the structure of molecules.
Question 2: In the zwitterionic form of tryptophan, which functional groups are present?
a. Ketonic and Aldehydic group
b. Only the Carboxylic group
c. Carboxylic and Amino group
d. Aldehyde and Amino group
Answer: The correct answer is option (c), Carboxylic and Amino group
Explanation: In the zwitterionic form of tryptophan, both the amino group and the carboxylic group are ionized. This form exists when the amino acid is in an aqueous solution at physiological pH. The molecule carries both positive and negative charges but remains electrically neutral overall.
Question 3: Identify the option that represents a typical instance of 'feedback inhibition':
a. The reaction between Cyanide and cytochrome.
b. The interaction between sulpha drugs and bacteria involved in Folic acid synthesis.
c. Allosteric inhibition of Hexokinase by Glucose 6-phosphate.
d. The reaction involves Succinic dehydrogenase and Succinic acid.
Answer: The correct answer is option (c), Allosteric inhibition of Hexokinase by Glucose 6-phosphate.
Explanation: Feedback inhibition occurs when the end product of a metabolic pathway inhibits the enzyme involved in its own synthesis. In this case, Glucose 6-phosphate inhibits Hexokinase, the enzyme that catalyzes the first step of glycolysis. This regulation prevents the unnecessary breakdown of glucose when sufficient product is already formed.
Question 4: The primary structure of a protein molecule has
a. Two ends
b. One end
c. Three ends
d. No ends
Answer: The correct answer is option (a), Two ends
Explanation: The primary structure of a protein molecule consists of a specific sequence of amino acids linked by peptide bonds. This sequence is determined by the gene encoding the protein and dictates its overall structure and function. Any change or mutation in the sequence can alter the protein's properties, potentially affecting its biological activity. The primary structure serves as the foundation for the protein's higher-order structures, including secondary, tertiary, and quaternary forms.
Question 5: Glycogen is a homopolymer made of
a. Glucose units
b. Galactose units
c. Ribose units
d. Amino acids
Answer: The correct answer is option (a), Glucose units
Explanation: Glycogen is indeed a homopolymer made of glucose units. The term "glycogen" comes from the Greek words "glyco" (meaning sweet, referring to glucose) and "gen" (meaning to produce), so it essentially means "a substance that produces glucose."
Why Class 11 Biology Chapter 9 Biomolecules NCERT Solutions are Important?
The chapter Biomolecules allows students to understand the chemical composition of all living organisms and the importance of various biomolecules that are present in the human body. Different biomolecules, such as carbohydrates, proteins, lipids, and nucleic acids, are included, along with their functions and structures.
- Class 11 Biology Chapter 9 Biomolecules NCERT Solutions are important because they provide explanations of concepts like enzymes, metabolism, and catalytic activity.
- The solutions also help students understand the difference between different biomolecules based on their structure, function, and composition.
- Different biomolecules, such as carbohydrates, proteins, lipids, and nucleic acids, are included in the solutions, along with well-labeled diagrams.
- Topics of biomolecules are mainly useful for the NEET aspirants, as many questions are directly based on the biomolecules chapter in the competitive exams.
