Body Fluids by Habeeb.

BODY FLUIDS:

Body is formed by solids & fluids. Fluid part is more than two third of the whole body, water forms most of the fluid part of the body. In human being, the total body water varies from 45% to 75%.

Composition of body fluids:

Body fluid contains water and solids , solids are organic and inorganic substances.

Organic Substances:

Glucose, amino_ acid & other proteins , fatty acids and other lipids , hormones and enzymes.

Inorganic Substances:

Inorganic Substances present in body fluids are Na+ , K+ , Ca++ Mg++ , Cl- , HCO3- , PO4-, SO4-.

ECF contains large quantity of Na+ , Cl- , HCO3- , glucose, fatty acids and oxygen.

ICF contains large quantity/ies of K+ , Mg++ , PO4- , SO4- , and  proteins.

The PH of ECF is  7.4

The PH of ICF is 7.0

Compartments And Distribution Of Body Fluids:

Total water in the body is about 40L distributed into two major compartments.

Intracellular Fluid:

Its volume is 22L and its forms 53% of the total body water.

Extracellular Fluid:

Its volume is 18L and it forms 45% of the total body water.

ECF is divided into 5 subunits:

1) Interstitial fluid and Lymph (20%) .

2) plasma 7.5% .

3) Fluid in bone (7.5%) .

4) Fluid in dense connective tissue like cartilage 7.5% .

5) Transcellular fluid 2.5% that include:

a . Cereberospinal fluid.

b . Intracellular Fluid.

c . Digestive juices.

d . Serous fluid , interpleural fluid , pericardial fluid , and peritoneal fluid.

e . Synovial fluid in joints.

f . Fluid in urinary tract.

Chart of distribution:

Water :

Water is the most abundantcomponent in living cell . Its amount varies app:  from 70 to 90% life activities occur in the cell due to the presence of water.

The ability of water to play its importance in biological systems is due to the basic chemistry of the molecule. The chemical formula of water is H2O which tell us that two atoms of hydrogen are joined to one atom of oxygen to make up each water molecule.

Water is a polar molecule. It means that it has a very slightly _ve end , _ the oxygen atom and a very slightly +ve end , _ the hydrogen atoms. The separation of electrical charge is called dipole. Which gives the water molecule its very important properties. One of the most important results of their charge separation is the tendency of H2O molecule to form hydrogen bonds.

Structure of water molecule:

Biologically important properties of water:

1) Behave as best solvent.

2) Slow to absorb and release heat ( high heat capacity)

3) High heat of vaporization.

4) An amphoteric molecule.

5) Cohesive forces in water molecule.

Function of Iron:

It play a vital role in cellular respiration.It forms the part of:

Hemoglobin=70%

Myoglobin=3-5%

Ferratin=2-5%

Body cells=3%

Heme-enzymes=0.1%

As xanthine oxidase, cytochromes catalase. Increase or decrease quantity of the iron.........

Macromineral (Sodium ):

Serum Level:      136 - 145 mEq/L .

Dietary Sources :  

Table salt orally or added to prepared food, bread , cheese, milk , whole grains..

Functions:

1 . Principal cation of extra cellular fluid.
2 . Regulates plasma volume.
3 .Regulates acid - base balance.
4 .Regulates osmotic pressure.
5 . Controls nerve and muscle functions as entry of sodium in a nerve or muscle fiber results in its depolarization.
6 . Help in glucose and amino acids absorption (Secondary active transport ).
7 .Regulates Na+  _ K+ ATPase activity.

Modes of Excretion:

 Mainly in :    1 ) sweat.

  POTASSIUM:-

 Serum level 3.5 - 5.5mEq/l.

Diatery sources:

       Citrus fruits , vegetables, meat, legumes, milk.

    FUNCTIONS:

          Principal cation of intracellular fluid.

          Causes repolarization.

          Act as vasodilator.

          Enhances the processes of 

           gluconeogenesis.

          Regulates Na+/k+ ATPase activity.

MODES OF EXCRETION:

       Feces:(10%).
     Urine:(90%).

CALCIUM:-

    Serum level: 4.2-5.2mEq/l

  Diatery sources: Milk and its production, beans, egg yolk, leafy vegetables, supplements like CaCO3.

DISTRIBUTION OF CALCIUM:
       Adult human body contains abut 1100gm of calcium and 99% of its is in skeleton.
The distribution of plasma calcium is as follows :

        DIFFUSIBLE:
 Occur as
        a)-Ionized calcium(50%).
        b)-Complexed to HCO3, Citrate etc.(10%).

     NON-DIFFUSIBLE:
       40% Calcium bound to:
        a)-Albumin.
        b)-Globulin.

CALCIUM IN THE BONES:
      Bone calcium is of two types:
1)- A ready exchangeable reservior (regulates plasma calcium level).
2)-A stable, larger and slowly exchangeable reservoir (concern with bone absorption and remodeling account for 95%of bone formation).

 CALCIUM ABSORPTION:-
    30% -80% of ingested calcium is absorbed ,primarily in the  upper small intestine by the active transport .Some calcium is also absorbed by passive diffusion.

ROLE OF KIDNEY:
    98%-99% of thr filtered calcium in kidney is absorbed,60% reabsorption is occur in proximal  tubules and remainder in the ascending loop of henle and distal tubules.
      FUNCTIONS OF CALCIUM:

     Important consitutents of bone and teeth.
     Regulates blood clotting.
     Regulates nerve and muscles function.
     Maintains the integrity of the capillary wall.
     Act as co-factors and activator for certain  enzymes like phospholipase A2.
     Act as vital second messenger.
     Involved in release of catecholamines in adrenal medulla in response to  cholergenic stimulation.
    Effect of adrenaline on liver cells (to increase guluconeolysis) is partly due to  an increase in calcium ion  within these cells (independent of cyclic AMP).

      MODE OF EXCRETION:
   1)-Feces(400 -800mEq/ day).
   2)- Urine(120- 200mEq/day).

    PHOSPHORUS:-
   Serum level:     In children:4-7 mg/dl.
                               In adults: 3-4.5mg/dl.

 DIATERY SOURCES:   Milk, beans, cereals,egg yolk, meat.

     DISTRIBUTION:
    Total body phosphorus is 500-800 gms of this 85-90% is  in skeleton.Total plasma phosphorus is  12ml/dl comprises of:
 
1. Inorganic phosphorus ( 4 mg / dl ) as PO4-3 , HPO4 - 2 , H2PO4 -1 .

2. Organic phosphorus ( 8 mg / dl ).

Absorption of phosphorus :

Phosphorus is absorbed in its inorganic form in the duodenum & small intestine by active transport and passive diffusion.

Role of kidney :

Inorganic phosphorus is filtered through the glomeruli & 80_ 90% is absorbed.

Modes of Excretion : 
1- feces ( 20 % ) .
2- Urine ( 80 % ) .

FUNCTIONS: 
1- Form  a part of the high energy compounds like ATP , UTP.
2- An important intracellular anion.
3- Bone and tooth development.
4- An important constituent of :

   a) Nucleic acids ( DNA & RNA ) .
   b) phospholipid .
   c) Cell membrane .


Magnesium : 

Serum level :
1.25 _ 2.5 mEq/ L .

Dietary sources :
Nuts, legumes, whole grains.

DISTRIBUTION :

About 21g of magnesium occurs in the body fluids , soft tissue, inorganic matter  of bones . Chiefly it exists as  in intracellular electrolytes.

FUNCTIONS :
1- constituent of bone and teeth.
2- Act as enzyme cofactor.
3- Decrease neuromuscular activity.

Chemistry Of Nucleic Acid by Saqib nayyar.

Nucleic Acids:

A 22-years old swiss phyician and chemist, Friedrich Miescher isolated substance from the nuclei of pus cells, which was quite different from other molecules and named it as 'nuclein' . Later , it was found that the nuclein had acidic properties and hence it was renamed as nucleic acid .

Nucleic acids are present in all organism , from virus to man .

The macromolecules are present either in the free-state or boun

d to proteins a nucleoproteins .Like proteins, the nucleic acids are biopolymer of high molecular weight with mononucleotide as their sub-units ( monomers ). The nucleic acids are the long chain of polynucleotide in which mononucleotides are linked with each other.      

There are two kinds of nucleic acids, deoxyribonucleic acid (DNA) and ribonucleic acid (RNA) . DNA is found mainly in the chromatin of the cell nucleus, whereas most of the RNA (90%) is present in the cell cytoplasm and a little (10%) in the nucleolus.

Nucleotide is a molecule which consists of following three parts.

   1) Pentose sugar (5 carbon).
   2) Phosphoric acid ( H3 PO4).
3) A nitrogenous base.

Pentose sugar found in nucleotide is either Ribose (C5 H 10 O5) or Deoxyribose (C5 H10 O4) .

Ribose is found in RNA nucleotides which Deoxyribosome sugar is found in DNA nucleotides, both of them are distinguished primarily on the basis of this pentose sugar.
This sugar behave as basic skeleton.

Phosphoric acid is common in all nucleotides. It is attached with 5th carbon of pentose sugar in each nucleotide

There are two basic types of nitrogenous bases I.e. Purine and 
pyrrimidin. Purine includes two nitrogenous bases named Adenine (A) and Guanine (G) pyrimidine includes three nitrogenous bases cytosine (C), thymine (T) and uracil (U) . The nucleotides differ on the basis of their nitrogenous bases.

Formation of nucleotide takes place in two steps. At first step the nitrogenous base combines with pentose sugar at its first carbon to form a nucleoside . At the second step the phosphoric acid combines with the 5th carbon of pentose sugar to form a nucleotide.

1 .  Mononucliotide:

Generally,nucleotides are found in the nucleic acid as polynucleotide but they also found as mononucleotide and dinucleotide. Mononucleotides exist singly in the cell or as a part of other molecules. These are not the part of DNA or RNA . Some of these have extra phosphate groups e.g ATP (Adenosine triphosphate).

An unstable molecule and carries energy from place to place within a cell. It is synthesized from ADP (Adenosine diphosphate) and inorganic phosphate by capturing energy during photosynthesis.

Energy is utilized to derive energy demanding reactions such as in synthesis of proteins, lipids, carbohydrates, mechanical energy for cyclosis, contractility , cell-division , movement of flagella, active transport etc.

ATP consists of Adenosine ( Adenosine and ribose sugar ) and three phosphate ; among them two are energy rich phosphate bond.
During conversion of  ATP into ADP , the free energy releases which is considerable large i.e.  31.81Kj or 7.3K. Cal / mole energy.

2 . Dinucleotide :

Sometimes two nucleotides are covalently bounded together, to form compounds are called dinucleotide . One of the well-known dinucleotide is Nicotinamide adenine dinucleotide ( NAD ).

Nicotineamide is a vitamin constituent.

NAD is a co-enzyme ( co-enzymes are the organic molecules ( non protein ) which bind to enzyme ( protein ) and serve as a carries for chemical groups or electrons ) that carries electron and work with dehydrogenase enzyme. It removes two hydrogen atom ( e- + 2H+ ) from its substrate, both electrons, but only one hydrogen ion is passed to NAD which reduces it to NADH.
3 . Polynucleotide ( Nucleic acids as informational macromolecules ) :

Nucleic acids are the polynucleotides . They have a variety of role

in living organisms. They make it possible for cells to function according to specific patterns and give rise to new cells that either function similarly or develop new function, according to plans encoded in encoded in the nucleic acid .

LIFE FATE MATERIAL

DNA

Genetic information is encoded in a nucleic acid molecule. Four different nucleotides make up each informational nucleic acid molecules . The cell interpretes the information present many nucleic acid molecules as sequence of amino acid in protein and peptide molecules. The synthesis of proteins with definite sequences of amino acid as controlled amounts of protein is observed as the expression of heredity of an organism which generally give the physical appearance of that particular characters.

DNA as hereditary material:

Transformation of the one type of bacteria in to another type and infection of bacteria by bacteriophage provides first evidence that DNA is the hereditary material. Griffith discovered that living bacteria can acquire genetics material from dead bacteria and transform live bacteria from non-virulent to virulent . Avery and his colleagues showed that the genes taken up living bacteria during transformation were composed of DNA.

DNA AS A HEREDITY MATERIAL

A bacteriophage consists solely of DNA & protein. When it infects a bacterium, the phage injects its DNA only into the bacterium, where it directs the synthesis of more phages Hershey and Chase thus experimentally confirmed that DNA must be the genetic material. DNA has specific sequences of nitrogenous bases . These sequences of bases in DNA can which encode vast amount of information. Since the nitrogenous bases are of four type, it is amazing that how just four  different types of bases in DNA encode all of the information needed to 20 amino acids. Each sequence represents a unique set of genetic institutions encode a huge amount of information in the form of genetic codes.

RNA as a carries of information :

In Eukaryotic cells DNA is located in the nucleus while most of the synthesis and metabolic functions occur in the cytoplasm under the instruction of DNA. Therefore, DNA requires some intermediate molecules that carry informations from DNA to the cytoplasm. These molecules are ribonucleic acids or  RNA 's .

Genetic information in cell from DNA to RNA than to cytoplasm in a two step process for the synthesis of proteins.

Transcription :

In this step information contained in a specific segments of DNA is copied into RNA.  The RNA which perform this process is called transcription.

 FORMATION OF PROTEIN  BY THE PROCESS OF TRNASCRIPTION AND TRANSLATION AND 

Chemistry of Lipids by Rakhi Goswami.

LIPIDS: 

Lipids are important constituent of of the diet because they are a source of high energy value. Lipids are also important because of the fat-soluble vitamins,  and essential fatty acids found in the fat of the natural food stuffs. Body fat serves as a very good source of energy, it is stored in adipose tissues. They also act as insulating material in the subcutaneous tissues and are also seen around certain organs. Lipids combined with proteins are important constituents of the cell membranes and mitochondria of the cell. Lipids are not generally macromolecules. Lipids are naturally occurring organic compounds, commonly known as oils and fats. Lipids occur through out the living world in  microorganisms, higher plants and animals and also in all cell types. Lipids contribute to cell structure, provide stored fuel and also take part in many biological processes.

Lipids Definition

Lipids are naturally occurring hydrophobic molecules. They are heterogenous group of compounds related to fatty acids. They include fats, oils, waxes, phospholipids, etc. They make up about 70% of the dry weight of the nervous system. Lipids are crucial for the healthy functioning of the nerve cells. Lipids are greasy or oily organic substances; lipids are sparingly soluble in water and are soluble in organic solvents like chloroform, ether and benzene.

CHARACTERISTICS OF LIPID

• Lipids are relatively insoluble in water.
• They are soluble in non-polar solvents, like ether, chloroform, methanol.
• Lipids also act as electrical insulators, they insulate nerve axons.
• Lipids have high energy content and are metabolized to release calories.
• Fats contain saturated fatty acids, they are solid at room temperatures. Example, animal fats.
• Plant fats are unsaturated and are liquid at room temperatures. 
• Pure fats are colorless, they have extremely bland taste. 
• The fats are sparingly soluble in water and hence are described are hydrophobic substances. 
• They are freely soluble in organic solvents like ether, acetone and benzene. 
• The melting point of fats depends on the length of the chain of the constituent fatty acid and the degree of unsaturation. 
• Geometric isomerism, the presence of double bond in the unsaturated fatty acid of the lipid molecule produces geometric or cis-trans isomerism. 
• Fats have insulating capacity, they are bad conductors of heat. 
• Emulsification is the process by which a lipid mass is converted to a number of small lipid droplets. The process of emulsification happens before the fats can be absorbed by the intestinal walls. 
• The fats are hydrolyzed by the enzyme lipases to yield fatty acids and glycerol. 
• The hydrolysis of fats by alkali is called saponification. This reaction results in the formation of glycerol and salts of fatty acids called soaps.
• Hydrolytic rancidity is caused by the growth of microorganisms which secrete enzymes like lipases. These split fats into glycerol and free fatty acids. 

• Types of Lipids

• 

General characters of lipids are 

General characters of lipids;

Simple Lipids or Homolipids

Simple lipids are the esters of fatty acids with various alcohols. 

Fats and Oils (triglycerides and triacylglycerols) - These are esters of fatty acids with a trihydroxy alcohol, glycerol. A fat is solid at ordinary room temperature, an oil is liquid. 

Mixed Triglycerides are one in which the three fatty acids radicles are different from each other. Example: distearo-olein, dioleo-palmitin. 

Waxes:

  Are the esters of fatty acids with high molecular weight monohydroxy alcohols. Example: Beeswax, Carnauba wax. 

Compound Lipids or Heterolipids

Heterolipids are esters of fatty acids with alcohol and possess additional groups also.

 Phospholipids or Phosphatids are compound containing fatty acids and glycerol in addition to a phosphoric acid, nitrogen bases and other substituents. They usually possess one hydrophilic head and tow non-polar tails. They are called polar lipids and are amphipathic in nautre. 

Phosphoinositides are said to occur in phospholipids of brain tissue and soybeans. The ply important role in transport processes in cells.

Phosphosphingosides are commonly found in nerve tissue. Example: sphingomyelins. 

Glycolipids are the compounds of fatty acids with carbohydrates and contain nitrogen but no phosphoric acid. The glycolipids also include certain structurally related compounds comprising the groups gangliosides, sulpholipids and sulfatids. 

Derived Lipids

Derived lipids are the substances derived from simple and compound lipids by hydrolysis. These includes fatty acids, alcohols, monoglycerides and diglycerides, steroids, terpenes, carotenoids.

The most common derived lipids are steroids, terpenes and carotenoids.

Steroids do not contain fatty acids, they are nonsaponifiable, and are not hydrolyzed on heating. They are widely distributed in animals, where they are associated with physiological processes. Example: Estranes, androstranes, etc.

Terpenes in majority are found in plants. Example: Natural rubber. gernoil, etc.

Carotenoids are tetraterpenes. They are widely distributed in both plants and animals. They are exclusively of plant origin. Due to the presence of many conjugated double bonds, they are colored red or yellow. Example: Lycopreene, carotenes, Xanthophylls. 

Essential fatty acids are those that cannot be constructed through any chemical pathways, known to happen in humans. They must be obtained from the diet. Linoleic acid and linolenic acid are the essential fatty acids.

Non-essential fatty acids are those which are not necessary to be taken through diet, they are synthesized through chemical pathways. 

Unsaturated fatty acids have one or more double bonds between carbon atoLipids has no single common structure.. The tow carbon atoms are bound to each other through double bonds and can occur in cis or trans configuration. 

Saturated fatty acids are long chain carboxylic acids and do not have double bonds. Example: Arachidic acid, Palmitic acid, etc.

Structure of Lipids

Lipids has no single common structure. The most commonly occurring lipids are triglycerides and phospholipids. 

Triglycerides are fats and oils. Triglycerides have a glycerol backbone bonded to three fatty acids. If the three fatty are similar then the triglyceride is known as simple triglyceride. If the fatty acids are not similar then the fatty acids are known as mixed triglyceride. 

The second most common class of lipids are phospholipids. They are found in membranes of animal and plants. Phospholipids contains glycerol and fatty acids, they also contain phosphoric acids and a low-molecular weight alcohol. Common phospholipids are lecithins and cephalins. 

Function of Lipids

• 
  

Lipids perform several biological functions: 

• Lipids are storage compounds, triglycerides serve as reserve energy of the body. 
• Lipids are important component of cell membranes structure in eukaryotic cells. 
• Lipids regulate membrane permeability. 
• They serve as source for fat soluble vitamins like A, D, E, K.
• They act electrical  insulators to the nerve fibres, where the myelin sheath contains lipids. 
• Lipids are components of some enzyme systems. 
• Some lipids like prostaglandins and steroid hormones act as cellular metabolic regulators. 
• Cholesterol is found in cell membranes, blood, and bile of many organisms. 
• As lipids are small molecules and are insoluble in water, they act as signalling molecules. 
• Layers of fat in the subcutaneous layer, provides insulation and protection from cold. Body temperature maintenance is done by brown fat. 
• Polyunsaturated phospholipids are important constituents of phospholipids, they provide fluidity and flexibility to the cell membranes. 
• Lipoproteins that are complexes of lipids and proteins, occur in blood as plasma lipoprotein, they enable transport of lipids in aqueous environment, and their transport throughout the body. 
• Cholesterol maintains fluidity of membranes by interacting with lipid complexes. 
• Cholesterol is the precursor of bile acids, Vitamin D and steroids. 
• Essential fatty acids like linoleic and linolenic acids are precursors of many different types of ecosanoids including prostaglandins, thromboxanes. These play a important role in pain, fever, inflammation and blood clotting. 
  
  

List of Lipids

Lipids are a diverse group of naturally occurring organic compounds. Below are the list of lipids:

Examples of Lipids

Few well known examples of lipids are as follows:

Fatty acids - Oleic acid, Linoleic acid, Palmitoleic acid, Arachidonic acid. 

Fats and Oils - Animal fats -  Butter, Lard, Human fat, Herring oil. Plant oils - Coconut oil, Corn, Palm, Peanut, Sunflower oil

Waxes - Spermacti, Beeswax, Carnauba wax. 

.Phospholipids - Lecithins, Cephalins, Plasmoalogens, Phosphatidyl inositols, Sphingomyelins.

Glycolipids - Kerasin, Phrenosin, Nervon, Oxynervon. 

Steroids - C 29, C 28, C 27, C 24, C 21 steroids. 

Terpenes - Monoterpenes, Sesquiterpenes, Diterpenes, Triterpenes.

Carotenoids - Lycopene, Carotenes, Xanthophylls.