Biomolecules- Carbohydrates, Proteins, Nucleic acids and Lipids

Biomolecules- Carbohydrates, Proteins, Nucleic acids and Lipids

Edited By Team Careers360 | Updated on Jul 02, 2025 05:30 PM IST

A biomolecule is a chemical compound found in living organisms or a molecule produced by a living organism. Biomolecules have a wide range of sizes and structures. Biomolecules are mainly classified into two types micromolecules and macromolecules. Instead of micromolecules and macromolecules, they are called small and large molecules, or organic and inorganic molecules. Macromolecules contain small-sized, low molecular weights between 18 and 800 daltons. Minerals, water, sugars, amino acids, and nucleotides will come under macromolecules. Macromolecules are large-sized and have a high molecular weight. These are above 10000 daltons. Carbohydrates, lipids (fats and oils), proteins, and nucleic acids will come under macromolecules. Macromolecules are formed by polymerizing subunits called monomers, except lipids. Macromolecules are alternatively called polyanions. A biomolecule is generally identified based on its molecular form, and a chemical equation usually represents a molecular form.

Macromolecules are organic compounds. They join together to form larger molecules. They have molecular weights of less than 1000 daltons.

Minerals

Minerals are the essential micromolecules that maintain the health of the body. Muscles, bones, hearts, and brains function correctly with the help of minerals. Minerals are found in many foods or as supplements.

Water

Water is an inorganic micromolecule. It is found in its free form. Two hydrogen atoms and one oxygen atom will combine to form water.

Sugar

Sugars are combined, forming carbohydrates. Sugars contain only carbon, oxygen, and hydrogen.

Amino acids

R-CH(NH2)COOH, where R represents the variable side chain group

Amino acid is a monomer that makes proteins. Amino acids are organic molecules that contain an amino group, a hydroxyl group, and a carbon side chain. There are 20 amino acids in micromolecules. Micromolecules of amino acids vary in terms of polarity, charge, molecular weight, and functions. Depending upon the relative position of the amino group with respect to a carboxyl group, amino acids are again divided into α, β, γ, δ and so on, and depending upon the relative number of amino and carboxyl groups in their molecule, amino acids can also be divided as acidic, basic, or neutral.

Nucleotide

It is the basic building block of nucleic acids. Each and every species of every generation resembles its ancestors in many ways, and the nucleus of a living cell is responsible for this transmission of inherent characteristics. The particles in the nucleus of the cell, responsible for heredity, are called chromosomes, and these are made up of proteins and another type of biomolecule called nucleic acids. Phosphate-sugar-base, where the base can be Adenine (A), Thymine (T), Guanine (G), or Cytosine (C).

Carbohydrates

Carbohydrates are also called polysaccharides. They are made up of simple sugars such as glucose, fructose, and galactose. Complex carbohydrates like starch and glycogen are made up of long chains of glucose molecules. Carbohydrates are also involved in the structural components of cells and organisms, such as the cell walls of plants and the exoskeletons of insects.

Cane sugar(sucrose), glucose [C6H12O6], starch, etc. are some examples of carbohydrates. Some of the carbohydrates, which are sweet in taste, are also called sugars. The general formula for carbohydrates is Cx(H2O)y, usually considered as carbon hydrates.


Based on their behaviour during hydrolysis, carbohydrates are classified into monosaccharides, oligosaccharides, and polysaccharides.

  • A carbohydrate which cannot be hydrolysed further to give a simpler unit of polyhydroxy aldehyde is called a monosaccharide.

Based on the number of carbon atoms and the functional group present in them Monosaccharides are further classified into different categories. For example, if a monosaccharide contains an aldehyde group, it is known as an aldose, and if it contains a keto group, it is known as a ketose.

  • Carbohydrate that yields two to ten monosaccharide units, on hydrolysis are called oligosaccharide

  • polysaccharides is the carbohydrates which yield a large number of monosaccharide units on hydrolysis.

Lipids

Lipids are another important class of biomolecules that play a crucial role in the structure and function of cell membranes. They are insoluble in water and include fats, oils, waxes, and steroids. Lipids with a higher melting point are usually solids at room temperature and are called fats or waxes; at a lower melting point, they are usually liquids at room temperature and are called oils. Lipids store energy in the body, insulate organs and tissues and act as signalling molecules. Fats and oils are made up of fatty acids and glycerol, while waxes are made up of long-chain fatty acids and alcohol.

Proteins

Proteins are the most important biomolecules in living organisms; milk, cheese, pulses, peanuts, fish, meat, etc. are a few examples of foods that contain protein. Proteins are polypeptide chains, which are generally made up of amino acids. Amino acids are further divided into two kinds.

  1. Essential amino acids

  2. Non-essential amino acids

Glycine, alanine, and serine are examples of amino acids. Proteins are mainly used to fight against infectious organisms and transport nutrients across the membrane. Based on the structure of the protein, it is classified into four types.

  1. Primary structure

  2. Secondary structure

  3. Tertiary structure

  4. Quaternary structure

The primary structure is the basic structure of the protein. Secondary structure protein threads form a helix. The tertiary structure is folded upon itself like a hollow woollen ball. In the quaternary structure, each polypeptide develops its tertiary structure and functions as a protein.

Basis of their molecular shape Proteins can be classified into two types

  1. Fibrous proteins: When the polypeptide chains run parallel and are held together by hydrogen and disulphide bonds, a fibre-like structure is formed which is called Fibrous protein.

  2. Globular proteins: When the chains of polypeptides coil around to give a spherical shape Globular proteins are formed.

Nucleic acid

Nucleic acids are large biomolecules. A significant function of nucleic acids is the storage and expression of genomic information. Nucleic acids are one of the most important macromolecules for life. They will carry the genetic blueprint of a cell and have instructions for the functioning of the cell. The two examples of nucleic acids are deoxyribonucleic acid and ribonucleic acid.

Deoxyribonucleic acid (DNA): C10H12N2O4, also written as (C5H5N5O)n where n is the number of nucleotide units in the DNA strand

Ribonucleic acid (RNA): C10H12N2O5P, also written as (C5H4O)n(C10H12N2O)nP where n is the number of nucleotide units in the RNA strand

ATP (Adenosine triphosphate)

ATP is a biomolecule that functions as the primary energy source for cellular processes in living organisms. It consists of a nucleotide base (adenine), a sugar molecule (ribose), and three phosphate groups. The high-energy phosphate bonds between the phosphate groups store energy that can be used by cells to power various processes, such as muscle contraction, nerve impulse transmission, and chemical synthesis. ATP is synthesized during cellular respiration and is used immediately, so it is constantly recycled in the cell. The chemical formula for ATP is C10H16N5O13P3.

Frequently Asked Questions (FAQs)

1. What is the alternate name of glycogen in a macro biomolecule?

Glycogen is called animal starch, the reserve food material for animals, bacteria, and fungi.

2. What are essential amino acids?

Living organisms obtain essential amino acids along with food.

3. What are the first and last amino acid sequences in a peptide chain?

The first amino acid of the sequence is called the N-terminal amino acid, and the last amino acid is called the C-terminal amino acid of a peptide chain.

4. Deoxyribonucleic acid and ribonucleic acid can be bitterly known as ___

Deoxyribonucleic acid is known as DNA, and ribonucleic acid is known as RNA.

5. What is the full form of ATP?

Adenosine Triphosphate.

6. What is a polypeptide chain in a biomolecule?

Amino acid micromolecules are joined together by peptide bonds to form polypeptide chains.

7. What are biomolecules and why are they important?
Biomolecules are organic compounds that are essential for life processes. They include carbohydrates, proteins, nucleic acids, and lipids. These molecules are crucial because they form the structural and functional components of cells, carry out metabolic processes, store and transmit genetic information, and provide energy for organisms to survive and thrive.
8. How do carbohydrates, proteins, nucleic acids, and lipids differ in their basic building blocks?
Carbohydrates are made of simple sugars (monosaccharides), proteins are composed of amino acids, nucleic acids consist of nucleotides, and lipids are primarily built from fatty acids and glycerol. These different building blocks give each biomolecule unique properties and functions within living organisms.
9. What is the primary function of carbohydrates in living organisms?
The primary function of carbohydrates is to provide energy for cellular processes. They are easily broken down into glucose, which cells can use for immediate energy or store for later use. Additionally, carbohydrates play important roles in cell structure (e.g., cellulose in plant cell walls) and cellular recognition processes.
10. How do monosaccharides, disaccharides, and polysaccharides differ?
Monosaccharides are single sugar units (e.g., glucose, fructose). Disaccharides consist of two monosaccharides linked together (e.g., sucrose, lactose). Polysaccharides are long chains of many monosaccharides (e.g., starch, cellulose). The complexity increases from mono- to polysaccharides, affecting their properties and functions in organisms.
11. Why is glucose considered the most important monosaccharide?
Glucose is crucial because it's the primary energy source for most living cells. It's easily metabolized through cellular respiration to produce ATP, the energy currency of cells. Glucose is also a versatile building block for other carbohydrates and can be stored as glycogen in animals or starch in plants for future energy needs.
12. What is the difference between starch and cellulose, and why is this significant?
Starch and cellulose are both polysaccharides made of glucose units, but they differ in their bonding structure. Starch has α-1,4 glycosidic bonds, which can be broken down by human digestive enzymes, making it an important energy source. Cellulose has β-1,4 glycosidic bonds, which humans can't digest, making it useful for structural support in plants but indigestible for humans.
13. How do proteins differ from other biomolecules in terms of their diversity and functions?
Proteins are incredibly diverse due to the various combinations of 20 different amino acids. This diversity allows proteins to perform a wide range of functions, including enzymatic catalysis, structural support, transport, defense, regulation, and movement. Unlike carbohydrates and lipids, proteins can form complex three-dimensional structures that are crucial for their specific functions.
14. What is the significance of protein folding, and what happens if proteins misfold?
Protein folding is the process by which a protein assumes its three-dimensional structure, which is crucial for its function. The folded structure determines the protein's ability to interact with other molecules and perform its specific role. Misfolded proteins can lead to loss of function and sometimes aggregation, which is associated with various diseases such as Alzheimer's, Parkinson's, and certain types of cancer.
15. How do enzymes work, and why are they essential for life?
Enzymes are proteins that act as biological catalysts, speeding up chemical reactions in cells without being consumed. They work by lowering the activation energy required for reactions to occur. Enzymes are essential because they enable vital cellular processes to happen quickly enough to sustain life, from digestion to DNA replication.
16. What is the central dogma of molecular biology, and how do nucleic acids play a role in it?
The central dogma of molecular biology describes the flow of genetic information in cells: DNA is transcribed into RNA, which is then translated into proteins. Nucleic acids (DNA and RNA) are crucial in this process. DNA stores genetic information, RNA acts as a messenger carrying genetic instructions, and both are involved in protein synthesis, which is essential for cellular function and organism development.
17. How do DNA and RNA differ in structure and function?
DNA (deoxyribonucleic acid) is double-stranded, contains deoxyribose sugar, and uses thymine as a base. It primarily stores genetic information. RNA (ribonucleic acid) is usually single-stranded, contains ribose sugar, and uses uracil instead of thymine. RNA has various functions, including carrying genetic information (mRNA), assisting in protein synthesis (tRNA), and catalyzing biological reactions (rRNA).
18. Why is the complementary base pairing in DNA important?
Complementary base pairing in DNA (adenine with thymine, cytosine with guanine) is crucial for several reasons: it allows for accurate DNA replication, ensuring genetic information is faithfully passed to daughter cells; it enables the creation of RNA transcripts from DNA templates; and it's essential for DNA repair mechanisms, helping maintain genetic integrity.
19. What are the main types of RNA and their functions?
The main types of RNA are: 1) Messenger RNA (mRNA), which carries genetic information from DNA to ribosomes for protein synthesis; 2) Transfer RNA (tRNA), which brings specific amino acids to the ribosome during protein synthesis; 3) Ribosomal RNA (rRNA), which forms part of the ribosome structure and aids in protein synthesis. Other types include microRNA and small interfering RNA, which regulate gene expression.
20. How do lipids differ from carbohydrates and proteins in terms of their chemical structure?
Lipids are primarily hydrophobic molecules, unlike the generally hydrophilic carbohydrates and proteins. They're not polymers but instead consist of fatty acids, often attached to a glycerol backbone. This hydrophobic nature allows lipids to form cell membranes, store energy efficiently, and act as signaling molecules.
21. What are the main functions of lipids in living organisms?
Lipids serve several crucial functions: 1) Energy storage, particularly in the form of triglycerides; 2) Cell membrane formation, providing a barrier between the cell and its environment; 3) Insulation, helping maintain body temperature in animals; 4) Hormone production, as many hormones are lipid-based; 5) Vitamin absorption, as some vitamins are fat-soluble; 6) Cell signaling, playing a role in communication between cells.
22. How do phospholipids contribute to the formation of cell membranes?
Phospholipids have a hydrophilic (water-loving) head and two hydrophobic (water-fearing) tails. In water, they spontaneously form a bilayer with the hydrophilic heads facing the water on both sides and the hydrophobic tails facing each other in the middle. This structure forms the basis of cell membranes, creating a selective barrier that controls what enters and exits the cell.
23. What is the difference between saturated and unsaturated fatty acids, and why is this important?
Saturated fatty acids have no double bonds between carbon atoms, while unsaturated fatty acids have one or more double bonds. This difference affects their physical properties: saturated fats are typically solid at room temperature, while unsaturated fats are liquid (oils). Nutritionally, unsaturated fats are generally considered healthier, as high intake of saturated fats is associated with increased risk of cardiovascular disease.
24. How do steroids differ from other lipids, and what are their main functions?
Steroids are lipids with a distinctive ring structure, unlike the linear structure of fatty acids. They include cholesterol, sex hormones (e.g., testosterone, estrogen), and corticosteroids. Steroids function as components of cell membranes (cholesterol), regulate metabolism and immune responses (corticosteroids), and control sexual characteristics and reproduction (sex hormones).
25. What is the role of cholesterol in cell membranes?
Cholesterol is a crucial component of animal cell membranes. It helps regulate membrane fluidity, making the membrane less fluid at higher temperatures and more fluid at lower temperatures. This maintains the membrane's integrity and function across a range of temperatures. Cholesterol also plays a role in membrane permeability and the formation of lipid rafts, which are important for cell signaling.
26. How do biomolecules interact with each other in living systems?
Biomolecules interact in complex ways to support life processes. For example, proteins (enzymes) catalyze reactions involving carbohydrates and lipids; nucleic acids direct the synthesis of proteins; lipids form membranes that house proteins and carbohydrates; and carbohydrates can be attached to proteins and lipids, modifying their functions. These interactions form the basis of metabolism, cellular structure, and genetic processes.
27. What is the importance of hydrogen bonds in biomolecules?
Hydrogen bonds are crucial in biomolecules for several reasons: 1) They stabilize the double helix structure of DNA; 2) They contribute to the secondary and tertiary structures of proteins (e.g., alpha helices and beta sheets); 3) They allow water to have unique properties essential for life; 4) They enable recognition between biomolecules, crucial for processes like enzyme-substrate interactions and DNA replication.
28. How do post-translational modifications affect protein function?
Post-translational modifications are chemical changes made to proteins after they're synthesized. These can include phosphorylation, glycosylation, ubiquitination, and others. They can alter a protein's function, localization, stability, or interactions with other molecules. For example, phosphorylation often activates or deactivates enzymes, playing a crucial role in cell signaling pathways.
29. What is the significance of the peptide bond in proteins?
The peptide bond is the covalent link between amino acids in proteins. It's formed by a condensation reaction between the carboxyl group of one amino acid and the amino group of another. The peptide bond is strong and resistant to hydrolysis, providing stability to the protein structure. Its planar nature and ability to form hydrogen bonds are crucial for the formation of secondary structures like alpha helices and beta sheets.
30. How do chaperone proteins assist in protein folding?
Chaperone proteins help other proteins fold into their correct three-dimensional structures. They do this by: 1) Preventing newly synthesized proteins from aggregating; 2) Assisting in the folding process by providing a protected environment; 3) Helping to refold proteins that have been denatured by stress; 4) In some cases, marking misfolded proteins for degradation. Chaperones are crucial for maintaining cellular health and preventing protein misfolding diseases.
31. What is the role of non-coding RNA in cellular processes?
Non-coding RNAs are functional RNA molecules that are transcribed from DNA but not translated into proteins. They play various roles: 1) Regulatory functions, such as microRNAs that control gene expression; 2) Structural roles, like rRNA in ribosomes; 3) Catalytic functions, such as ribozymes; 4) Guide RNAs in processes like RNA editing. The discovery of non-coding RNAs has revolutionized our understanding of gene regulation and cellular complexity.
32. How do carbohydrates contribute to cellular recognition processes?
Carbohydrates play a crucial role in cellular recognition through glycoproteins and glycolipids on cell surfaces. These carbohydrate chains act as "markers" that can be recognized by other cells or molecules. This is important for processes like immune system function (recognizing foreign cells), cell-cell adhesion, and signaling between cells. The specific arrangement of sugars creates a "glycan code" that cells use for identification and communication.
33. What is the significance of the genetic code being universal?
The universality of the genetic code means that the same codons (three-nucleotide sequences) specify the same amino acids in almost all organisms. This universality suggests a common evolutionary origin for all life on Earth. It also has practical implications, allowing genes from one organism to be expressed in another (the basis of genetic engineering), and enabling the study of one organism's genes to provide insights into others, including humans.
34. How do intrinsically disordered proteins challenge the traditional structure-function paradigm?
Intrinsically disordered proteins (IDPs) lack a fixed three-dimensional structure under physiological conditions. This challenges the traditional view that a protein's function is determined by its stable 3D structure. IDPs can adopt different conformations depending on their environment or binding partners, allowing them to interact with multiple targets and participate in various cellular processes. They're particularly important in signaling and regulation, where flexibility and adaptability are advantageous.
35. What is the role of lipid rafts in cell membranes?
Lipid rafts are dynamic, cholesterol- and sphingolipid-rich microdomains in cell membranes. They play important roles in: 1) Cell signaling, by concentrating certain proteins and lipids to facilitate their interaction; 2) Membrane trafficking, including endocytosis and exocytosis; 3) Protein sorting within the membrane; 4) Serving as entry points for some pathogens. The concept of lipid rafts has significantly impacted our understanding of membrane organization and function.
36. How do epigenetic modifications of DNA affect gene expression?
Epigenetic modifications are chemical changes to DNA or associated proteins that don't alter the DNA sequence but can affect gene expression. Common modifications include DNA methylation and histone modifications. These can activate or repress genes by changing the accessibility of DNA to transcription machinery. Epigenetic modifications are influenced by environmental factors and can be inherited, providing a mechanism for gene regulation that goes beyond the DNA sequence itself.
37. What is the importance of alternative splicing in increasing protein diversity?
Alternative splicing is a process where a single gene can produce multiple mRNA transcripts, and consequently, multiple protein isoforms. This greatly increases the diversity of proteins that can be produced from a limited number of genes. It allows for: 1) Tissue-specific protein expression; 2) Developmental stage-specific protein production; 3) Rapid adaptation to changing cellular needs; 4) Evolution of new protein functions without the need for new genes. Alternative splicing is a key factor in the complexity of higher organisms.
38. How do prions challenge our understanding of protein function and disease?
Prions are misfolded proteins that can induce normal proteins of the same type to also misfold, leading to neurodegenerative diseases. They challenge our understanding because: 1) They can cause disease without genetic material (DNA/RNA), contradicting the central dogma; 2) They demonstrate how protein shape, not just sequence, is crucial for function; 3) They can transmit biological information through protein folding patterns; 4) They suggest that some traits can be inherited through proteins alone, not just genes.
39. What is the significance of the various levels of protein structure?
Proteins have four levels of structure, each building upon the previous: 1) Primary structure is the sequence of amino acids, determining the protein's basic properties; 2) Secondary structure involves local folding patterns like alpha helices and beta sheets, stabilized by hydrogen bonds; 3) Tertiary structure is the overall 3D shape of a single protein molecule, crucial for its function; 4) Quaternary structure involves the association of multiple protein subunits. Each level contributes to the protein's final shape and function, highlighting the importance of structure in determining protein behavior.
40. How do membrane transport proteins facilitate the movement of molecules across cell membranes?
Membrane transport proteins allow specific molecules to cross the hydrophobic barrier of the cell membrane. They work in several ways: 1) Channel proteins form pores for passive diffusion of specific ions or small molecules; 2) Carrier proteins undergo conformational changes to move substances across the membrane, either passively (facilitated diffusion) or actively (using energy); 3) Pump proteins use energy (usually from ATP) to move substances against their concentration gradient. These proteins are crucial for maintaining cellular homeostasis, nutrient uptake, and waste removal.
41. What is the role of nucleotides beyond their function in nucleic acids?
While nucleotides are best known as the building blocks of DNA and RNA, they have several other important functions: 1) Energy currency (e.g., ATP in cellular energy transfer); 2) Signaling molecules (e.g., cAMP in intracellular signaling); 3) Coenzymes (e.g., NAD+ in redox reactions); 4) Regulators of enzyme activity; 5) Components of other biomolecules (e.g., UDP-glucose in glycogen synthesis). This versatility makes nucleotides crucial players in various cellular processes beyond genetic information storage and transfer.
42. How do carbohydrates contribute to the extracellular matrix?
Carbohydrates are key components of the extracellular matrix (ECM), particularly in the form of glycosaminoglycans (GAGs) and proteoglycans. They contribute by: 1) Providing structural support and cushioning for cells; 2

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