eChapters

Introduction

Lipids (dietary or body reserve) serves as the major source of energy for the body at the time of carbohydrate depletion. Triacyl glycerol (TG) forms the major part of lipids alongwith phospholipids, cholesterol and fat-soluble vitamins. The different forms of lipids are utilised by the body for generation of energy in the form of ATP. In addition, it serves as the source of essential fattyacids and vitamins for different metabolic purpose.

Dietary triacylglycerols (TG) are digested by lipase group of enzymes (lingual, gastric, pancreatic and intestinal) secreted by the digestive tract into free fatty acids and 2-monoacylglycerols. The 2-monoacylglycerols are either absorbed as such or hydrolysed into glycerol and fatty acids which are then absorbed independently. The glycerol and fatty acids are distributed to different tissues through circulation and utilised in the following ways

i. Storage in fat cells of adipose tissue in the form of triacylglycerols.

ii. Oxidised in peripheral tissues for production of energy.

iii. converted to glucose in hepatic cells in the process of gluconeogenesis.

iv. Synthesis of other derived compounds like steroids and eicosanoids in gonadal and other tissues

v. Synthesis of phospholipids and cholesteryl esters.

Introduction

Lipids may be regarded as organic substances relatively insoluble in water, soluble in organic solvents (chloroform, ether, benzene, ethanol and other non-polar solvents, etc.), actually or potentially related to fatty acids and utilized by living cells. Lipids are a diverse group of hydrophobic or amphipathic biomolecules that play crucial roles in energy storage, cell membrane structure, and signaling. Unlike carbohydrates and proteins, lipids are not defined by a specific polymer structure but rather by their solubility in non-polar solvents. Broadly lipids are classified based on their function as ‘Storage lipids’ and ‘Structural lipids’. Some of them are co-factors, hormones, electron carriers, light-absorbing pigments and hydrophobic anchors of proteins.

Fatty Acids: Fatty acids are straight aliphatic chains with a methyl group at one end and a carboxyl group (-COOH) at the other end. They are the simplest form of lipids.

• Saturated Fatty Acids have no double bonds between carbon atoms, leading to straight chains (e.g., palmitic acid).

• Unsaturated Fatty Acids contain one or more double bonds, causing kinks in the chain (e.g., oleic acid). Fatty acids containing more than one double bond (polyunsaturated fatty acids/PUFA) are found in relatively minor amounts.

Introduction

According to the body needs, minerals may be divided into 2 groups like macrominerals and microminerals. Macrominerals are required in amounts greater than 100 mg/day. They include 6 elements like calcium, phosphorus, magnesium, sodium, potassium and chloride. Whereas microminerals are also known as trace elements and are required in amounts less than 100 mg/day. They include 10 elements like chromium, cobalt, copper, fluoride, iodine, iron, manganese, molybdenum, selenium, zinc and silicon. Some minerals are always required since small amounts of inorganic salts are always excreted Fruits, vegetables and cereals are the chief sources of the mineral elements in the diet. Milk products supply the majority of the calcium and phosphorus in the diet.

Milk and milk products are the richest source of calcium along with beans, leafy vegetables and egg yolk. It is absorbed from upper small intestine. Absorption of calcium is active process and requires calcium binding protein present in the intestinal mucosal cells. The absorption is regulated by vitamin D, parathyroid hormone, high protein diet, pH, high dietary lactate and citrate are the factors that promotes calcium absorption. Whereas high dietary phosphate, alkalinity and impaired fat absorption are the factors that inhibits calcium absorption. Of the total body calcium, 99 % present in bones and teeth in the form of hydroxyapatite and 1 % is present in body fluids and other tissues. Calcium in bones acts as a reservoir, which helps to stabilize calcium ions in plasma and extracellular f luid Parathyroid hormone and active vitamin D stimulate osteoblasts while estrogen hormone inhibits osteoclasts.

Introduction

A pentose sugar, one or more phosphate groups, and a nitrogenous base (purine or pyrimidine) make up a nucleotide. Phosphodiester bonds, which connect the 5’-hydroxyl group of one pentose to the 3’-hydroxyl group of the next, bind nucleic acids together as polymers of nucleotides. RNA and DNA are the two different forms of nucleic acids. RNA nucleotides contain ribose, while uracil and cytosine are typical pyrimidine bases. Thymine and cytosine are common pyrimidine bases, and DNA contains 2’-deoxyribose in its nucleotides. In both RNA and DNA, adenine and guanine are the main purines. There is ample evidence to suggest that genetic information is encoded in DNA The Avery MacLeod-McCarty experiment, in particular, demonstrated how DNA obtained from one bacterial strain may infiltrate and change the cells of another strain, giving it some of the genes from the donor. The Hershey-Chase experiment demonstrated that a bacterial virus’s DNA contains the genetic instructions needed for the virus to replicate in a host cell, but not its protein coat. Watson and Crick proposed that native DNA is made up of two antiparallel chains arranged in a right-handed double helical configuration based on a compilation of numerous published data points. A-T and G-C, two complementary base pairs, are created by hydrogen bonds inside the helix. 10.5 base pairs are stacked per turn, perpendicular to the double helix’s long axis, at a distance of 3.4 Å. There are various structural configurations for DNA A- and Z-DNA are two variants of the Watson-Crick form or B-DNA The DNA molecule bends as a result of certain sequence-dependent structural differences.

Introduction

Protein metabolism is a complex and multifaceted process that plays a crucial role in the overall health and function of living organisms. At the most fundamental level, protein metabolism involves the synthesis, breakdown, and utilization of proteins, which are essential macromolecules that serve a wide range of structural, functional, and regulatory roles within the body.

The process of protein synthesis, or translation, begins with the transcription of genetic information stored in DNA into messenger RNA (mRNA) molecules. These mRNA molecules then serve as templates for the assembly of specific sequences of amino acids into polypeptide chains, which ultimately fold into the three-dimensional structures of functional proteins. This highly regulated process is essential for the production of the diverse array of proteins required for cellular processes, tissue repair, immune function, and numerous other physiological activities. In contrast, protein degradation, or catabolism, refers to the breakdown of proteins into their constituent amino acids. This process is mediated by various proteolytic enzymes, such as endopeptidases, exopeptidases, and dipeptidases, which cleave the peptide bonds that hold the amino acid residues together Protein degradation serves important functions, such as the recycling of amino acids for energy production or the synthesis of new proteins, the removal of damaged or misfolded proteins, and the regulation of cellular signaling pathways.

Introduction

Proteins are complex biomolecules composed of amino acids, playing crucial roles in virtually all biological processes. They serve as enzymes, hormones, structural components, signaling molecules etc.

Structure/ Levels of Organization of Proteins

Generally, Proteins are polymers of L-alpha amino acids, linked by peptide bonds. The sequence and structure of these amino acids determine the protein’s function. Protein structure is hierarchically organized into four levels:

1. Primary Structure

• The linear sequence of amino acids in a polypeptide chain, determined by the genetic code.

2. Secondary Structure

• Local folding of the polypeptide chain into structures such as α-helices and β-pleated sheets, stabilized by hydrogen bonds.

Introduction

Human and animal body comprises of various tissues that are the functional unit of organ functioning and coordination. The tissues are further consisting of well differentiated cells that makes the tissue to behave in a special way for a particular purpose. The animal tissues are divided into epithelial, connective, muscular and nervous tissues. Epithelial tissues form the protective covering and inner lining of the body and organs. Connective tissues develop from the mesodermal cells of the embryo. they support and bind other tissues in the body. The muscular tissue develops from the mesoderm of the embryo and meant for movement and locomotion. Nervous tissue makes up the peripheral and the central nervous system and is responsible for initiation and transmission the nerve impulse. The tissues are biochemically composed of water, lipid, protein, ash, and carbohydrate along with other mineral and vitamins that are needed for its basic functioning. The extracellular matrix (ECM) forms a major component of connective tissue that forms layer and surrounds the cells or tissues meant for protection, signalling and communication. The protein component of ECM basically includes collagen, elastin, keratins, fibrillin, fibronectin, laminin and proteoglycans. Collagen is the major protein component of connective tissue that provides tensile strength, shape and fixes the organ in its position. Collagen is not homogenous rather consists of around 19 different types of proteins. There are around 30 variants of protein found in collagen. collagens type I and type II are respectively found in skin and bone. Collagen is triple helical polymer of highly elongated fibrils consisting of around 1000 amino acids majority of which consists of glycine along with proline and hydroxyproline. The forces like hydrogen bonds, covalent bonds, electrostatic, hydrophobic, and van der Waals are responsible for stabilizing the structure of collagen.

Introduction

Vitamins are the organic derived accessory food factors apart from carbohydrate, lipid and proteins meant for specific biological functions, optimum growth and health of an organism. These factors are are required in minute amount in the diet for proper functioning of biological enzymes. The term accessory factors were given by Hopkins to the essential nutrients present in the natural foods. Funk (1913) coined the term vitamine to the active principal present in rice polishings. Vitamins are classified into two categories like fat soluble A and water-soluble b Vitamins A, D, E, K are fat soluble whereas Vitamins B and C are water soluble. The B group of vitamins include vitamin B1, B2, B6, biotin folic acid, B12 etcall the fat-soluble vitamins are isoprenoid in nature consisting of repeating isoprenoid units. And meant for diversified functions. The water-soluble vitamins are heterogenous group of compounds generally not stored in the body and readily excreted in urine. These are mostly act as coenzymes for the vital biological enzymes deficiency of which reflects in the form of various deceases.

Vitamin A, include retinoid group of compounds like retinol, retinal and retinoic acid Retinol is a primary alcohol containing β-ionone ring with isoprenoid units, double bonds and hydroxyl group. Naturally it exists as ester of long chain fatty acids. Retinal is the aldehyde form whereas Retinoic acid is the acid form. Carotene is provitamin A normally found in plant origin foods that in the intestine gives rise to two moles of retinal by enzyme carotene 15-15-dioxygenase. Diet contains retinol esters and p-carotene. Retinol esters are hydrolyzed into fatty acids and retinol that absorbed into intestinal mucosal cells. p-carotene Is absorbed and converted into retinal by p-carotene dioxygenase. Retinal then converted into retinol. In the intestinal mucosal cells, retinol re-esterifies with fatty acid to form retinol ester.

Bioenergetics is a branch of Biochemistry that focuses on the study of energy transformation and utilization in living organisms. It primarily deals with how cells capture, store, and utilize energy to drive various biological processes essential for sustaining life. The flow of energy in biological systems operates in accordance with the principles of thermodynamics, which govern the conversion of energy from one form to another. In living cells, energy is typically obtained through biochemical reactions involving the breakdown of organic compounds such as carbohydrates, fats, and proteins. This energy is then utilized for various physiological processes like the synthesis of biomolecules, active transport of ions, muscle contraction, and nerve conduction, enabling the cell to maintain its structural and functional integrity. Thermodynamics, a branch of physical chemistry, plays a crucial role in bioenergetics as it explains the changes in energy associated with biochemical reactions. In biochemical thermodynamics, also referred to as bioenergetics, the primary focus is on how energy released from one reaction can be utilized to drive another reaction that requires energy input. This is achieved through

ABSTRACT

Bats: A colony of 500 insectivorous bats of Hipposideros speoris inhabited a natural cave in Madurai (9^O58’ N. lat; 78^O10’ E long). At a depth of 40 m, the cave experiences a constant temperature of 27 + 0.1^OC, 95 % relative humidity and absolute and perpetual darkness. Therefore there were no day/night cues. Yet all the members of the bat colony flew out 10 to 15 min. after sunset as though they knew the time of sunset. Recorded flight and rest experiments in flight activity cages and a hand-wound Thermohygrograph drum 40 m from the cave mouth over periods of 50 days revealed that the free-flying conspecific bats were socially synchronizing the activity patterns of the three captive bats. Bats were telling other bats time.

Mice : In the field mouse, Mus booduga the mother conveys information of day and night to her pups by means of her presence and absence (PA) cycles. Her presence meant day and absence denoted night. We named this phenomenon maternal entrainment. Such entrainment of the time sense of the pups was possible if in every cycle the mother was presented for a minimum of 8 hr but not exceeding 16 hr. Therefore 8 hr and 16 hr describe the limits of maternal entrainment.

COMMON FEATURES OF BIOLOGICAL MEMBRANES

Membranes are sheetlike, just a few molecules thick and form closed boundaries between cell compartments.

Membranes contain lipids and proteins, with small amounts of carbohydrayes linked to the lipids and proteins.

Lipids in membranes are small with hydrophobic and hydrophilic portions. Lipid bilayers provide a barrier to the diffusion of polar molecules.

Characteristic functions of membranes are mediated by specific proteins, serving as pumps, channels, receptors, energy transducers and enzymes.

Membrane components associate through noncovalent interactions.

Membranes are asymmetrical, with two sides of the membrane differing from each other.

Lipid and protein molecules often diffuse rapidly in the plane of the membrane.

Central transport of ions and molecules into and out of the cell.

Generate proton gradients for ATP production by oxidative phosphorylation.

Receptors bind extracellular signals and transduce the signal to cell interior.

Animals experience the effects of force in everyday life. For example, the animal body exerts a force on the body and to the objects during various agricultural operations. Furthermore, the gravitational force exerts continuously, for instance while sitting, walking, etc. All parts of the body in one way or the other are loaded by forces. The bones provide rigidity to the body and can sustain high loads. The skin is resistant to force. The cardiovascular system is continuously loaded dynamically owing to the pulsating blood pressure. The bladder is loaded and stretched when it fills up. The intervertebral discs serve as flexible force- transmitting media that give the spine its flexibility. Beside force, animals are using levers all the time in their daily life to increase the ‘force’ that is applied to some object.
Animal soft tissues are complex materials that can exhibit nonlinear, time dependent, inhomogeneous, and anisotropic behaviors. The mechanical responses are reflected in all levels of organism (molecules, organelle and body levels). Several biological activities are under the action of forces, which even govern the gene expression. The study dealing with the forces and their effects on living systems is the Biomechanics.
Biomechanics applies the laws and the techniques of mechanics in the study of biological systems and phenomena. Indeed, mechanics provides the tools for:

Biometry is the measurement of various grossly visible dimensions of organs and their application in statistical analysis to generate biological data.
Various biometrical parameters used for different organs
The biometry of different organs is conducted with the help of non-stretchable thread, Vernier callipers, measuring scale, protector, glass beaker of various sizes, calibrated measuring cylinders, etc. While conducting biometry, it should be kept in mind that the way or the procedure for conducting biometry of different organs varies due to variation in shapes of the same and their positions. Some of the biometrical parameters of different organs and bones are summarized below.
1. Length: May be used to measure the distance between the highest points along the length of any bone or organ. Usually expressed in cm. Non-stretchable thread, Vernier callipers and measuring scale are used for this purpose.
2. Breadth: May be used to measure the distance between the highest points along the breadth of any bone or organ. Usually expressed in cm. Non-stretchable thread, Vernier callipers and measuring scale are used for this purpose.
3. Thickness: May be used to measure the distance between the highest points in regard to the thickness of any bone or organ. Usually expressed in cm. Non-stretchable thread, Vernier callipers and measuring scale are used for this purpose.
4. Volume: It is measures by water displacement of any organ. Usually smaller organs are used. The fresh organ is dipped into a calibrated

Biochemistry: An Overview of Biomolecules Biochemistry is a branch of science that delves into the chemical composition and interactions of cells and organisms. It focuses on the molecular structures found within biological systems, their chemical characteristics, functions, and the reactions they undergo. By studying these molecules, biochemists gain insights into the fundamental processes that sustain life. Properties of Biomolecules General Characteristics Biomolecules are fundamentally organic compounds, sharing similar properties with typical organic molecules. They obey the same physical and chemical principles, undergo similar reactions, and adhere to universal physical laws. However, their complexity and biological specificity distinguish them from simpler organic compounds. Composition and Structural Features The backbone of biomolecules is predominantly composed of carbon, which forms four covalent bonds, often exhibiting a tetrahedral geometry. Carbon skeletons can exist in diverse forms like linear,

Introduction

Several hazardous chemicals, microbes, and techniques like recombinant DNA technology are used for research and development work in research Institutes and universities. Therefore, the researchers, technical, helping and supporting staffs as well as the laboratory outputs must be kept free from contaminations. Thus, biosafety is necessary to prevent unintentional exposure/ release of hazardous chemicals, microbes/pathogens, and toxins to the laboratory staff and environment. Following the biosafety guidelines and ethical considerations are essential to maintain safety standards for the researchers as well as the environment. This chapter deals with various biosafety measures and ethical issues to be strictly followed while working in a research laboratory. The required safety level needs to be determined as per the chemical/biological materials are used in the laboratory to keep the researcher/environment safe for sustainable research and developmental activities.

Biosafety

The term biosafety is used to describe the procedure and policies needed to ensure environmental and personal safety. Biosafety refers to the containment principles, technologies and practices that are implemented to prevent unintentional exposure to pathogens, toxins, or their accidental release into the environment. A fundamental objective of any biosafety program is the containment of potentially harmful chemical/biological agents as precautionary safety measures.

Why Biosafety?

With the increasing number of countries adopting molecular biology tools and techniques in life science research and development activities, especially in the areas of agriculture and medicine, the biosafety issues are gaining importance to ensure biological safety for the public and the environment. Conducting research in safe and sustainable manner is not only a personal requirement but essential collective efforts to ensure biological safety for a clean and safe environment. This requires rules, regulations, monitoring bodies, and awareness among the workers as well as the public. Therefore, biosafety per se is an integral part of laboratory research and requires awareness among the researchers so that biological safety can be well taken care from the grassroot level.

Precautions to be taken while working in the laboratory for personal safety and to prevent any hazards.
    1.    Be vaccinated against dangerous viruses viz., rabies and hepatitis B as persons can contract infection while working with these organisms.
    2.    Use eye protection viz., goggles, spectacles etc to avoid splashing microbes into the eyes. 
    3.    Do not rub eyes with contaminated hands or objects.
    4.    Do not eat or drink anything in the microbiology laboratory as it will contaminate the laboratory.

Biotechnology is being harnessed in various aspects of the livestock industry to hasten breed development for improved animal health and welfare, enhanced reproduction, and improved nutritional quality and safety of animal-derived foods. Various biotechnology methods are used in improving the breeding stock of animals. These include artificial insemination (AI), embryo transfer (ET), in-vitro fertilization (IVF), sexing of semen and embryos, micromanipulation of oocytes/ embryos, transgenesis, somatic cell nuclear transfer and the emerging technology on genomics and marker-assisted selection (MAS). Artificial Insemination: One of the earliest perfected technology is artificial insemination (AI) where new breeds of animals are produced through the introduction of the male sperm from one superior male to the female reproductive tract without mating. AI reduces transmission of venereal disease, lessens the need of farms to maintain breeding males, facilitates more accurate recording of pedigrees, and minimizes the cost of introducing improved genetics. Various technologies have evolved that led to the efficient use of AI in developing desired livestock, including the methods of freezing semen or cryopreservation and sperm sexing.

Whenever we get a cut, a red fluid comes out of the wound. This red fluid is called blood. Blood is very important for the body as is evident from the fact that the loss of blood from the body makes it weak and may even cause death. Physiologically the blood is a red tissue composed of cells suspended in a pale yellow fluid, plasma. Unicellular organisms that live in immediate contact with the external environment obtain nutrients directly from that environment and eliminate unused or unwanted materials. Blood and lymph are important connecting fluids among the diverse anatomical structures of the mammalian organisms. Thus blood is the liquid vehicle by which the major organic nutrients are transported from the intestine where they are absorbed, to the liver where they are processed and thence to other organs. Similarly blood is the liquid vehicle for the transport of waste materials from various organs to the kidney and gastrointestinal tract from where they are eliminated. Thus the blood is the major transport carrier of nutrients, metabolites, oxygen, hormones, waste products etc. inside the body. Blood is an important medium to maintain homeostasis of various electrolytes in the body. Besides blood provides the army against any external attack on the body by harmful microorganisms. This army is in the form of cells, called white blood or corpuscles or leucocytes.

In a normal adult human being, about 5 to 6 litre of blood is present which is about 8 percent of the body weight. In domestic animals generally 5 to 8 per cent of the body weight is blood (say 30-40 litre in a cow). The blood is composed of two parts, the cells and the fluid part or plasma. The cellular constituents of blood include erythrocytes or red blood corpuscles, leucocytes or white blood corpuscles and thrombocytes or platelets. The cellular constituents of blood varies with the species as well as with the age and physiological stage of the animal.

The extracellular constituents or plasma is composed of water, electrolytes, proteins, lipids, glucose, enzymes and hormones etc. The blood undergoes coagulation on exposure to air leaving clear watery fluid, called serum. The serum is nothing but plasma minus fibrinogen and other clotting factors. The serum is a clear yellowish fluid. The yellow colour is due to the presence of small quantities of bilirubin, a bile pigment and of carotenoids. The blood serum of cattle is yellow due to presence of more of carotenoids whereas that of buffalo is white due to the absence of carotenoids. The blood clot consists of a network of fibrous strands of fibrin in which are enmeshed the cellular elements of the blood. Blood clotting is a protective mechanism against excessive loss of blood from the body. The lymph also clots, although, somewhat more slowly than blood.

Blood is the fluid pumped by the heart that circulates throughout the body via the arteries, veins, and capillaries . Blood is a body fluid in animals and human beings that delivers necessary substances such as nutrients and oxygen to the cells and transports metabolic waste products away from those same cells. Hematology is the science or study of blood, blood-forming organs and blood diseases.