Sri Raghavendra Educational Institutions Society (R)

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Sri Krishna Institute of Technology

www.skit.org.in

Subject: BIOLOGY FOR ENGINEERS

Presented by: Lavanya

Department: AIML

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Sri Krishna Institute of Technology

Module 1: Introduction to Biology

SYLLABUS:

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The cell: The basic unit of life, Structure and functions of a cell. The Plant Cell and animal cell, Prokaryotic and Eukaryotic cell, Stem cells and their application. Biomolecules: Properties and functions of Carbohydrates, Nucleic acids, proteins, lipids. Importance of special biomolecules; Enzymes (Classification (with one example each),Properties and functions), vitamins and hormones.

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People can think of cells as tiny packages that contain minute factories, warehouses,

transport systems, and power plants.

They function on their own, creating their own energy and self-replicating — the cell is the

smallest unit of life that can replicate.

Cells are the basic units of life.

Prokaryotic Cell:

Prokaryotic cells are single-celled microorganisms known to be the earliest on earth.

Prokaryotes include Bacteria and Archaea. The photosynthetic prokaryotes include

cyanobacteria that perform photosynthesis.

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Eukaryotic cell:

Eukaryotic cells are common to all multicellular (more than one cell) organisms.

Eukaryotes have DNA in a centralized nucleus and membrane-bound organelles, such as mitochondria and chloroplasts, carrying specialized functions. Specialized structure and functions of a eukaryotic cell aid in regulating proper tissues and body functioning

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Prokariyotic Cell Structure

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Prokaryotic Cell Structure

A prokaryotic cell does not have a nuclear membrane. However, the genetic material is present in a region in the cytoplasm known as the nucleoid. They may be spherical, rod-shaped, or spiral.

A prokaryotic cell structure is as follows:

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Capsule– It is an outer protective covering found in the bacterial cells, in addition to the cell wall.

It helps in moisture retention, protects the cell when engulfed, and helps in the attachment of cells to nutrients and surfaces.

Cell Wall– It is the outermost layer of the cell which gives shape to the cell.

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Cytoplasm– The cytoplasm is mainly composed of enzymes, salts, cell organelles and is a gel-like component.

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Cell Membrane– This layer surrounds the cytoplasm and regulates the entry and exit of substances in the cells.

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Pili– These are hair-like outgrowths that attach to the surface of other bacterial cells.

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Flagella– These are long structures in the form of a whip, that help in the locomotion of a cell.

Ribosomes– These are involved in protein synthesis.

Plasmids– Plasmids are non-chromosomal DNA structures. These are not involved in reproduction.

Nucleoid Region– It is the region in the cytoplasm where the genetic material is present.

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Short functions of components of a Eukaryotic Cell:

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Cell membrane – Controls entry and exit of substances.

Cytoplasm – Jelly-like medium where cell reactions occur.

Nucleus – Controls cell activities; contains DNA.

Nuclear envelope – Protects the nucleus and regulates transport.

Chromatin – Genetic material responsible for heredity.

Nucleolus – Produces ribosomes.

Ribosome – Site of protein synthesis.

Rough ER – Synthesizes and transports proteins.

Smooth ER – Synthesizes lipids and detoxifies chemicals.

Golgi apparatus – Modifies and packages proteins.

Mitochondria – Produces energy (ATP).

Lysosome – Digests waste and damaged cell parts.

Peroxisome – Detoxifies harmful substances.

Vacuole – Stores water, nutrients, and waste.

Microtubules – Provide support and help in cell division.

Microfilaments – Help maintain cell shape and movement.

Intermediate filaments – Give mechanical strength to the cell.

• Eukaryotic cells have a nucleus enclosed within the nuclear membrane and form large and complex organisms. Protozoa, fungi, plants, and animals all have eukaryotic cells. They are classified under the kingdom Eukaryota.
• They can maintain different environments in a single cell that allows them to carry out various metabolic reactions. This helps them grow many times larger than the prokaryotic cells.

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The features of eukaryotic cells are as follows:

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• Eukaryotic cells have the nucleus enclosed within the nuclear membrane.
• The cell has mitochondria.
• Flagella and cilia are the locomotory organs in a eukaryotic cell.
• A cell wall is the outermost layer of the eukaryotic cells.
• The cells divide by a process called mitosis.
• The eukaryotic cells contain a cytoskeletal structure.
• The nucleus contains a single, linear DNA, which carries all the genetic information.

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Stem Cells and its Applications

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Stem cells are special human cells that can develop into many different types of cells,

from muscle cells to brain cells.”

What are Stem Cells?

Stem cells also have the ability to repair damaged cells. These cells have strong healing power.

They can evolve into any type of cell. Research on stem cells is going on, and it is believed that

stem cell therapies can cure ailments like paralysis and Alzheimer’s as well. Let us have a

detailed look at stem cells, their types and their functions.

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Types of cells

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• Stem cells are of the following different types:
• Embryonic Stem Cells
• Adult Stem Cells
• Induced Pluripotent Stem Cells
• Mesenchyme stem cells

Embryonic Stem Cells

The fertilized egg begins to divide immediately. All the cells in the young embryo are totipotent cells. These cells form a hollow structure within a few days. Cells in one region group together to form the inner cell mass. This contains pluripotent cells that make up the developing foetus.

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Adult Stem Cells

These stem cells are obtained from developed organs and tissues. They can repair and replace the damaged tissues in the region where they are located. For eg., hematopoietic stem cells are found in the bone marrow. These stem cells are used in bone marrow transplants to treat specific types of cancers.

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Induced Pluripotent Stem Cells

These cells have been tested and arranged by converting tissue-specific cells into embryonic cells in the lab. These cells are accepted as an important tool to learn about the normal development, onset and progression of the disease and are also helpful in testing various drugs. These stem cells share the same characteristics as embryonic cells do. They also have the potential to give rise to all the different types of cells in the human body.

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The characteristics of mesenchymal stem cells depend on the organ from where they originate.

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Mesenchymal Stem Cells :

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These cells are mainly formed from the connective tissues surrounding other tissues and organs, known as the stroma. These mesenchymal stem cells are accurately called stromal cells.

The first mesenchymal stem cells were found in the bone marrow that is capable of developing bones, fat cells, and cartilage.

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There are different mesenchymal stem cells that are used to treat various diseases as they have been developed from different tissues of the human body.

The characteristics of mesenchymal stem cells depend on the organ from where they originate.

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Applications of Stem Cells

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Following are the important applications of stem cells:

Tissue Regeneration

This is the most important application of stem cells. The stem cells can be used to grow a specific type of tissue or organ. This can be helpful in kidney and liver transplants. The doctors have already used the stem cells from beneath the epidermis to develop skin tissue that can repair severe burns or other injuries by tissue grafting.

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Treatment of Cardiovascular Disease

A team of researchers have developed blood vessels in mice using human stem cells. Within two weeks of implantation, the blood vessels formed their network and were as efficient as the natural vessels.

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Treatment of Brain Diseases

Stem cells can also treat diseases such as Parkinson’s disease and Alzheimer’s. These can help to replenish the damaged brain cells. Researchers have tried to differentiate embryonic stem cells into these types of cells and make it possible to treat diseases.

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Blood Disease Treatment

The adult hematopoietic stem cells are used to treat cancers, sickle cell anaemia, and other immunodeficiency diseases. These stem cells can be used to produce red blood cells and white blood cells in the body

What are Biomolecules?

• Biomolecules are the most essential organic molecules, which are involved in the maintenance and metabolic processes of living organisms.
• They are substances produced by Living organisms
• These non-living molecules are the actual foot-soldiers of the battle of sustenance of life.
• They range from small molecules such as primary and secondary metabolites and hormones to large macromolecules like proteins, nucleic acids, carbohydrates, lipids etc.

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Biomolecules range from small molecules (metabolites and hormones) to large macromolecules (proteins, nucleic acids, carbohydrates, lipids) that perform essential functions in living organisms.

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1. Primary Metabolites

Small molecules produced during normal cell metabolism.

Essential for growth and development.

Examples: amino acids, sugars, organic acids.

2. Secondary Metabolites

Compounds not directly required for growth but help in defense and survival.

Often produced by plants and microorganisms.

Examples: antibiotics, pigments, alkaloids.

3. Hormones

Chemical messengers that regulate body functions.

Control growth, metabolism, and reproduction.

Example: insulin.

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Carbohydrates:

Organic molecules that provide energy and structural support.

Function: Provide energy to the body.

Examples: glucose, starch, cellulose.

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Proteins

Large biomolecules made of amino acids.

Function: Build and repair tissues; act as enzymes, structural support, transport, and regulation.

Examples: Hemoglobin, enzymes.

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Nucleic Acids

Function:Store and transmit genetic information.

Examples: DNA and RNA.

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Lipids

Hydrophobic molecules such as fats and oils.

Function: Energy storage , insulation, and cell membrane formation.

Examples: Fats, oils, phospholipids.

Carbohydrates

• Carbohydrates are a class of organic compounds and are an important source of energy for living organisms.
• They are composed of carbon (C), hydrogen (H), and oxygen (O) atoms and are classified based on their molecular structure and function.
• General formula is Cn(H2O)n.

Properties:

• Carbohydrates act as energy reserves, also stores fuels and metabolic intermediates
• Ribose and Deoxyribose sugars forms the structural frame of the genetic material, RNA and DNA
• Polysaccharaides like cellulose are the structural elements in the cell walls of bacteria and plants
• Carbohydrates are linked to proteins and lipids that play important roles in cell interactions
• Carbohydrates are organic compounds which are aldehydes or ketones with many hydorxyl groups

Monosaccharides

These are the simplest form of carbohydrates and include glucose and fructose. They are

easily soluble in water and serve as the primary source of energy for the body.

Figure: Structural formula of glucose

Figure: Ring

Disaccharides

These are formed by the condensation of two monosaccharides and include sucrose,

lactose, and maltose. They are commonly found in sugar and are broken down into

monosaccharides during digestion

Polysaccharides

• These are long chains of mono-saccharides linked together.

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• They serve as storage molecules for energy, such as glycogen in animals and starch in plants, and Also provide structure and support, such as cellulose in plant cell walls.

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• In addition to their role as energy sources, carbohydrates also play important roles in cellular processes, such as cellular signaling and recognition, and in regulating gene expression.

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Functions of Carbohydrates

Carbohydrates are important biomolecules that provide energy and perform several essential functions in living organisms.

1. Energy Source ⚡

The primary function of carbohydrates is to provide energy for the body.

Cells break down carbohydrates (like glucose) to produce energy for metabolic activities.

2. Energy Storage 🧪

Carbohydrates are stored for future energy needs.

In plants, energy is stored as Starch.

In animals, energy is stored as Glycogen.

3. Structural Function 🌿

Some carbohydrates form structural components of cells.

Example: Cellulose forms the cell wall of plants and provides rigidity and support.

4. Component of Biomolecules 🧬

Carbohydrates are part of important biological molecules.

Example: Ribose in RNA and Deoxyribose in DNA.

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5. Cell Communication and Recognition 🔬

Carbohydrates on the cell surface help in cell recognition and signaling.

They form glycoproteins and glycolipids which help cells interact with each other.

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6. Protective Function 🛡️

Carbohydrates help in lubrication and protection of tissues.

Example: muco-polysaccharides present in connective tissues and joints.

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7. Regulation of Metabolism ⚙️

Carbohydrates help regulate fat and protein metabolism in the body.

Proteins

Proteins are macromolecules made up of monomers called amino acids. Amino acids are the building block of all proteins.

• Proteins are highly complex macromolecules consisting of one or more long chains of amino acids linked together by peptide bonds.
• They play a vital role in the structure, function, and regulation of cells,tissues, and organs.

Properties of Proteins

Functions of Proteins

1. Catalyzing Chemical reactions
2. Transporting Molecules
3. Providing Mechanical support
4. Regulating Cell Behaviour

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Catalyzing chemical reactions

Amylase: An enzyme that breaks down starch into simple sugars like glucose and maltose. It

is found in saliva and pancreatic juice.

Lipase: An enzyme that breaks down fats into fatty acids and glycerol. It is found in the

pancreas and small intestine.

Catalase: An enzyme that converts hydrogen peroxide into water and oxygen. It is found in

most cells of the body.

Transporting Molecules

• Hemoglobin: Hemoglobin is a protein found in red blood cells that transports oxygen from

the lungs to the tissues in the body.

• Albumin: Albumin is a protein found in blood plasma that helps transport various substances

such as hormones, fatty acids, and drugs throughout the body.

• Transferrin: Transferrin is a protein that transports iron in the blood from the site of

absorption in the gut to the bone marrow, liver, and other tissues that require it.

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Providing Mechanical Support

• Collagen: Collagen is the main structural protein in the body and provides support to tissues

such as skin, tendons, cartilage, bone, and teeth.

• Elastin: Elastin is a protein that provides elasticity and stretchability to tissues such as skin,

lungs, arteries, and ligaments.

• Keratin: Keratin is a protein that forms the structural basis of hair, nails, and the outer layer

of skin.

• Actin and Myosin: Actin and myosin are proteins that are involved in muscle contraction

and provide the mechanical force required for movement.

Regulating Cell Behaviour

Receptor proteins: Receptor proteins are proteins that are located on the surface of cells and bind to specific signaling molecules such as hormones, growth factors, and

neurotransmitters.

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Enzymes: Enzymes are proteins that catalyze specific chemical reactions in the body. Many

enzymes are involved in regulating cellular behavior, such as kinases and phosphatases that regulate protein phosphorylation and dephosphorylation, respectively

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Cytoskeleton proteins: Cytoskeleton proteins, such as actin and tubulin, play a critical role in regulating cell shape, movement, and division.

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Transcription factors: Transcription factors are proteins that bind to DNA and regulate gene expression. They play a critical role in regulating cellular differentiation, proliferation, and apoptosis.

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Lipids:

Lipids are a group of organic compounds that include fats, oils, waxes, and some hormones.

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Properties of Lipids

• Energy storage: Lipids are a major source of stored energy in the body, and they can be broken down to release energy when it is needed.

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• Insulation: Lipids help to insulate the body, helping to regulate temperature and protect

against heat loss.

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• Cell membrane structure: Lipids are a major component of cell membranes, helping to

maintain their fluidity and stability.

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• Hormone synthesis: Some lipids, such as cholesterol, are precursors to hormones, and are

necessary for their production

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• Transport: Lipids are soluble in fat, but not in water. This makes them ideal for carrying fat soluble vitamins and other lipophilic compounds through the bloodstream.

Functions of Lipids

Functions of Lipids

Energy storage:�Lipids store energy in the body in the form of fats.

Structural component of cell membranes:�Lipids such as Phospholipid and Cholesterol are important components of cell membranes.

Insulation and protection:�Lipids help maintain body temperature and protect internal organs.

Hormone production:�Some lipids are involved in the formation of steroid hormones such as Testosterone.

Transport of fat-soluble vitamins:�Lipids help absorb vitamins A, D, E, and K.

Waterproofing:�Waxes protect plant leaves and animal skin from water loss.

Nucleic Acids:

Nucleic acids are biopolymers that play a crucial role in the storage and transfer of

genetic information in all living organisms.

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There are two types of nucleic acids:

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Deoxyribonucleic acid (DNA): DNA is the genetic material that carries the instructions for

the development, functioning, and reproduction of all living organisms. DNA is a doublestranded helix structure composed of nucleotides, which consist of a sugar(deoxyribose), a phosphate group, and a nitrogenous base (adenine, guanine, cytosine, or thymine).

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Ribonucleic acid (RNA): RNA is involved in the expression of the genetic information

stored in DNA by carrying the message from the DNA to the ribosome, where it is used to

build proteins. RNA is a single-stranded molecule composed of nucleotides, which consist

of a sugar (ribose), a phosphate group, and a nitrogenous base (adenine, guanine, cytosine,

or uracil).

There are Three Established Types of RNA:

Transfer RNA (tRNA): Works as the transmitter molecule for amino acids to be employed in protein synthesis and is accountable for decoding the mRNA.

Messenger RNA (mRNA): Transfers genetic sequence data between DNA and ribosomes, regulating protein synthesis and carrying directions from DNA (deoxyribonucleic acid) in the nucleus to the ribosome.

Ribosomal RNA (rRNA): Studies the Deoxyribonucleic acid sequence and catalyses peptide bond formation

Functions of Nucleic Acids

• Nucleic Acid is responsible for the synthesis of protein in our body
• RNA is a vital component of protein synthesis.
• Loss of DNA content is linked to many diseases.
• DNA is an essential component required for transferring genes from parents to offspring.
• All the information of a cell is stored in DNA.
• DNA fingerprinting is a method used by forensic experts to determine paternity. It is also used for the identification of criminals. It has also played a major role in studies regarding biological evolution and genetics.

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Properties Nucleic Acids

Enzymes

CLASSIFICATION OF ENZYMES

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Enzymes are another important biomolecule, which are proteins that help speed up metabolism, or the chemical reactions in our bodies.

They build some substances and break others down. All living things have enzymes. Our bodies naturally produce enzymes.

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Oxidoreductases

These catalyze oxidation and reduction reactions, e.g. pyruvate dehydrogenase, catalysing the oxidation of pyruvate to acetyl coenzyme A.

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Transferases

These catalyze transferring of the chemical group from one to another compound. An example is a transaminase, which transfers an amino group from one molecule to another.

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Hydrolases

They catalyze the hydrolysis of a bond. For example, the enzyme pepsin hydrolyzes peptide bonds in proteins.

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Lyases

These catalyze the breakage of bonds without catalysis, e.g. aldolase (an enzyme in glycolysis) catalyzes the splitting of fructose-1, 6-bisphosphate to glyceraldehyde-3-phosphate and dihydroxyacetone phosphate.

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Ligases

Ligases catalyze the association of two molecules. For example, DNA ligase catalyzes the joining of two fragments of DNA by forming a phosphodiester bond.

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Isomerases

They catalyze the formation of an isomer of a compound. Example: phosphoglucomutase catalyzes the conversion of glucose-1-phosphate to glucose-6-phosphate (phosphate group is transferred from one to another position in the same compound) in glycogenolysis (glycogen is converted to glucose for energy to be released quickly).

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Properties of Enzymes for Engineering Applications

Enzymes have several properties that make them ideal for engineering applications,

including:

• Specificity: Enzymes have a high level of specificity for the substrates they bind and there actions they catalyze, making them highly efficient at performing specific tasks.

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• Reactivity: Enzymes increase the rate of chemical reactions without being consumed in the process, allowing them to perform multiple cycles of the same reaction.

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• Stability: Enzymes are generally stable at a wide range of temperatures and pH values, making them useful in a variety of industrial processes.

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• Renewability: Enzymes are biodegradable and can be produced from renewable resources, making them an environmentally friendly alternative to traditional chemical catalysts.

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• Cost-effectiveness: Enzymes can be produced in large quantities through fermentation, making them a cost-effective alternative to synthetic catalysts in many applications.

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These properties make enzymes ideal for use in various industrial and engineering applications, from bioremediation and biofuel production to food and beverage processing and textile production.

Functions of Enzymes

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Digestion of food: Enzymes break down carbohydrates, proteins, and fats during digestion.

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Metabolism regulation: They control metabolic pathways in cells.

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Energy production: Enzymes participate in cellular respiration and ATP production.

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DNA replication and repair: Enzymes help in copying and repairing genetic material.

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Biosynthesis of molecules: They help synthesize proteins, hormones, and other biomolecules.

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Industrial applications: Used in food processing, medicine, and biotechnology.

VITAMINS

Vitamins are chemical compounds that are required in small amounts with our regular diet in order to carry out certain biological functions and for the maintenance of our growth.

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Classification of Vitamins

Vitamins are generally classified as water-soluble vitamins and fat-soluble vitamins.

1. Fat-Soluble Vitamins

Vitamin A, D, E and K are fat-soluble. These are stored in adipose tissues and hence are called fat-soluble vitamins.

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2. Water-Soluble Vitamins

Vitamins in B-group and vitamin C are water-soluble and cannot be stored in our bodies as they pass with the water in urine. These vitamins must be supplied to our bodies with regular diets.

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Functions of Vitamins

Based on their role in biological processes and their effect different vitamins have different functions, their function can be best understood by knowing about their deficiency diseases. Given below is the list of vitamins and their deficiency diseases:

Vitamin A – Hardening of the cornea in the eye, night blindness.

Vitamin B1 – Deficiency may cause beriberi and dwarfism.

Vitamin B2 – Deficiency can cause disorders in the digestive system, skin burning sensations, and cheilosis.

Vitamin B6 – Deficiency of B6 causes convulsions, conjunctivitis, and sometimes neurological disorders.

Vitamin B12 – Its deficiency can cause pernicious anaemia and a decrease in red blood cells in haemoglobin.

Vitamin C – It is a water-soluble vitamin, its deficiency causes bleeding in gums and scurvy.

Vitamin D – It is obtained by our body when exposed to sunlight. Its deficiency causes improper growth of bones, soft bones in kids, and rickets.

Vitamin E – Deficiency of vitamin E leads to weakness in muscles and increases the fragility of red blood cells.

Vitamin K – It plays an important role in blood clotting. The deficiency of vitamin K increases the time taken by the blood to clot. Severe deficiency may cause death due to excessive blood loss in case of a cut or an injury

Harmones

What are Hormones?

• Hormones are chemicals that essentially function as messengers of the body. These chemicals are secreted by special glands known as the endocrine glands.
• These endocrine glands are distributed throughout the body.
• These messengers control many physiological functions as well as psychological health.
• They are also quite important in maintaining homeostasis in the body.

Types of Hormones

To regulate various functions, different types of hormones are produced in the body. They are classified as follows:

Peptide Hormones

Steroid Hormones

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Peptide Hormones

Peptide hormones are composed of amino acids and are soluble in water. Peptide hormones are unable to pass through the cell membrane as it contains a phospholipid bilayer that stops any fat-insoluble molecules from diffusing into the cell. Insulin is an important peptide hormone produced by the pancreas.

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Steroid Hormones

Unlike peptide hormones, steroid hormones are fat-soluble and are able to pass through a cell membrane. Hormones such as testosterone, estrogen and progesterone are examples of steroid hormones.

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Functions of Hormones

Following are some important functions of hormones:

Food metabolism.

Growth and development.

Controlling thirst and hunger.

Maintaining body temperature.

Regulating mood and cognitive functions.

Initiating and maintaining sexual development and reproduction.

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The significant properties of hormones are –

They have a low molecular weight; thus, they can easily pass through capillaries.

Hormones always act in low concentration.

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They are soluble in water so that they can be transported via blood.

The importance of hormones is that they are non-antigenic. They are organic catalysts. Hormones act as coenzymes of other enzymes in the human body.

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Hormones, in their first action, cause a limited number of reactions and do not influence any metabolic activities of a cell directly.

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A significant characteristic of hormones is that, after their function is over, they are readily destroyed, excreted or inactivated.

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Hormonal activities are not hereditary.