Lipids-Introduction, properties and functions.
Classification-Simple lipids, complex lipids and derived lipids.
Lipids contain fatty acid and alcohol.
Saturated and Unsaturated fatty acids. Nomenclature of fatty acids, Cis-trans isomerism, essential fatty acids
Simple lipids-Fats, waxes
Compound lipids-Structure, function with examples of Phospholipids, Glycolipids, sulpholipids and lipoproteins.
Derived lipids: Structure, types, and functions of steroids, terpenes and carotenoids.
Lipoproteins-classified into chylomicrons, very low-density lipoproteins (VLDL), low density lipoproteins (LDL) and high-density lipoproteins (HDL) and their function.
Eicosanoids-prostanoids, leukotrienes (LTs), and lipoxins (LXs).
Functions of Eicosanoids
Lipids, micelles and liposomes.
A Comprehensive Introduction to Lipids and its chemistry, classification, qualitative tests and disorders related to its metabolism. This will give readers a overall insight to this topic. All types of queries and suggestions are most welcome
Polypeptides,peptides, types of peptides, structure of dipeptide, tripeptide...ShwetaMishra115
Descriptive notes on polypeptides
Polypeptides,peptides, types of peptides, structure of dipeptide, tripeptide and oligopeptide and different functions of peptide
A Comprehensive Introduction to Lipids and its chemistry, classification, qualitative tests and disorders related to its metabolism. This will give readers a overall insight to this topic. All types of queries and suggestions are most welcome
Polypeptides,peptides, types of peptides, structure of dipeptide, tripeptide...ShwetaMishra115
Descriptive notes on polypeptides
Polypeptides,peptides, types of peptides, structure of dipeptide, tripeptide and oligopeptide and different functions of peptide
Lipids Chemistry Structure & Function (More Detailed)hafizayyub
This presentation is for Medical students. It is more detailed explanation of Lipids including types and medical importance. It is made by Drs Charles Stephen and Dr Ayyub Patel
“These are the naturally Organic compounds, insoluble in water, soluble in organic solvents (alcohol, ether, etc.), which are potentially related to fatty acids & utilized by living cells."
Lipids are a heterogeneous group of compounds.
They are esters of fatty acids. Lipids occur widely in plants and animals. Lipids include fats, oils, waxes, and related compounds.
Lipids are a family of organic compounds, composed of fats and oils. These molecules yield high energy and are responsible for different functions within the human body.
Lipids Chemistry Structure & Function (More Detailed)hafizayyub
This presentation is for Medical students. It is more detailed explanation of Lipids including types and medical importance. It is made by Drs Charles Stephen and Dr Ayyub Patel
“These are the naturally Organic compounds, insoluble in water, soluble in organic solvents (alcohol, ether, etc.), which are potentially related to fatty acids & utilized by living cells."
Lipids are a heterogeneous group of compounds.
They are esters of fatty acids. Lipids occur widely in plants and animals. Lipids include fats, oils, waxes, and related compounds.
Lipids are a family of organic compounds, composed of fats and oils. These molecules yield high energy and are responsible for different functions within the human body.
3. Lipids.pptx topic for bsn and allied health sciencesitxshanzee4892
Lipids topic for bsn and allied health sciencesLipids topic for bsn and allied health sciencesLipids topic for bsn and allied health sciencesLipids topic for bsn and allied health sciencesLipids topic for bsn and allied health sciences
Fatty acids are obtained from the hydrolysis of fats.
Fatty acids that occur in natural fats usually contain an even number of carbon atoms (due to synthesis from 2-carbon units) and are straight chain derivatives.
The chain may be saturated (containing no double bonds) or unsaturated (containing one or more double bonds).
Lecture 11 - Lipids 1.pdf full introductionzaeemt91
Lipids are a diverse group of organic molecules that play essential roles in living organisms. They are characterized by their hydrophobic nature, meaning they are not soluble in water. The main classes of lipids include triglycerides (fats and oils), phospholipids, steroids, and waxes.
1. **Triglycerides:** These are the most common type of lipids and serve as a major energy storage form in cells. Triglycerides consist of glycerol and three fatty acid chains. Fatty acids can be saturated (no double bonds) or unsaturated (contain double bonds), influencing the physical properties of the lipid.
2. **Phospholipids:** These molecules are crucial components of cell membranes. Similar to triglycerides, they consist of glycerol and fatty acids, but one of the fatty acid chains is replaced by a phosphate group. The hydrophilic (water-attracting) phosphate head and hydrophobic (water-repelling) fatty acid tails contribute to the formation of the lipid bilayer in cell membranes.
3. **Steroids:** Steroids have a unique structure and play various roles in the body, including serving as structural components of cell membranes and acting as signaling molecules. Cholesterol is a common steroid and is a precursor to hormones like estrogen and testosterone.
4. **Waxes:** Waxes are esters of long-chain fatty acids and long-chain alcohols. They often function as protective coatings for plants and animals, helping to reduce water loss and prevent damage.
Lipids serve several vital functions in living organisms:
- **Energy Storage:** Triglycerides store energy in a concentrated form and can be broken down to release energy when needed.
- **Structural Role:** Phospholipids form the basis of cell membranes, providing structure and regulating the passage of substances into and out of cells.
- **Insulation and Protection:** Fats can act as insulators, helping organisms retain heat. Waxes form protective coatings on surfaces.
- **Cell Signaling:** Some lipids, such as certain steroids, serve as signaling molecules that regulate various physiological processes.
In summary, lipids are a diverse group of molecules with varied structures and functions, crucial for the structure, function, and energy balance of living organisms.
Herbal Drug Technology
Herbs as Raw Materials: Definition of herb, herbal medicine, herbal medicinal product and herbal drug preparation, source of herbs, selection, identification and authentication of herbal materials, processing of herbal raw material.
Herbal Excipients : Herbal Excipients – Significance of substances of natural origin as excipients, – colorants, sweeteners, binders, diluents, viscosity builders, dis-integrants, flavors & perfumes.
Herbal Formulations: Stages involved in herbal formulations, Orthodox formulations and methods of delivery of herbal extracts, Novel formulations of herbal extracts.
Introduction to proteomics, techniques to study proteomics such as protein electrophoresis, chromatography and mass spectrometry and protein database analysis, case studies derived from scientific literature including comparisons between healthy and diseased tissues, new approaches to analyse metabolic pathways, comprehensive analysis of protein-protein interactions in different cell types.
Metabolomics-Introduction, metabolism, intermediary metabolism, metabolic pathways, metabolites, metabolome, metabolic turnover, techniques used in metabolomics, metabolite profiling methods, data analysis, metabolomic resources, role of metabolomics in system biology.
Introduction to proteomics, techniques to study proteomics such as protein electrophoresis, chromatography and mass spectrometry and protein database analysis, case studies derived from scientific literature including comparisons between healthy and diseased tissues, new approaches to analyse metabolic pathways, comprehensive analysis of protein-protein interactions in different cell types.
The analysis of global gene expression and transcription factor regulation, global approaches to alternative splicing and its regulation, long noncoding RNAs, gene expression models of signalling pathways, from gene expression to disease phenotypes, introduction to isoform sequencing, systematic and integrative analysis of gene expression to identify feature genes underlying human diseases.
Genome projects
Definition of genome, history of genome projects, whole genome sequencing, Maxam Gilbert sequencing, sanger sequencing, explanation on the first sequenced organisms (Bacteriophage, bacteria, archaeon, virus, bakers yeast, nematode.
Model organism-Arabidopsis thaliana, Mus musculus, Oryza sativa, Pan troglodyte etc.
Human genome project, milestones and significance.
Epigenetics studies stably heritable traits that cannot be explained by changes in DNA sequence.
Covalent modifications in chromatin
DNA- DNA methylation (CpG); hydroxymethylation
Histone - lysine acetylation, lysine and arginine methylation, serine and threonine phosphorylation, and lysine ubiquitination and sumoylation
Epigenetic mechanisms:
Modified histones as post translational modification
DNA methylation – 5mC the 5th base, methyl transferases; genetic imprinting.
Epigenomics: complete set of epigenetic modifications on the genetic material of a cell.
Specific epigenetic regulation
RNA interference
X inactivation (Lyonization)
Genomic imprinting
Epigenetics in development and diseases.
Comparative genomics: Genomic features are compared, evolutionary relationship
The major principle of comparative genomics is that common features of two organisms will often be encoded within the DNA that is evolutionarily conserved between them. orthologous sequences,
Started as soon as the whole genomes of two organisms became available (that is, the genomes of the bacteria Haemophilus influenzae and Mycoplasma genitalium) in 1995, comparative genomics is now a standard component of the analysis of every new genome sequence. comparative genomics studies of small model organisms (for example the model Caenorhabditis elegans and closely related Caenorhabditis briggsae) are of great importance to advance our understanding of general mechanisms of evolution
Computational tools for analyzing sequences and complete genomes. Application of comparative genomics in agriculture and medicine.
Mapping and sequencing genomes: Genetic and physical mapping, Sequencing genomes different strategies, High-throughput sequencing, next-generation sequencing technologies, comparative genomics, population genomics, epigenetics, Human genome project, pharmacogenomics, genomic medicine, applications of genomics to improve public health.
Disorders of liver and kidney, Nitrogen metabolism.pdfshinycthomas
Disorders of liver and kidney – Jaundice, fatty liver, normal and abnormal functions of liver and kidney. Inulin and urea clearance.
Abnormalities of nitrogen metabolism
Lipid metabolism and its disorders.pdfshinycthomas
Disorders of Lipids – Plasma lipoproteins, cholesterol, triglycerides and phospholipids in health and disease, hyperlipidemia, hyperlipoproteinemia, Gaucher’s disease, Tay-Sach’s and Niemann-Pick disease, ketone bodies.
a) Definition, classification, structure, stereochemistry and reactions of amino acids;
b) Classification of proteins on the basis of solubility and shape, structure, and biological functions. Primary structure - determination of amino acid sequences of proteins, the peptide bond, Ramachandran plot.
c) Secondary structure - weak interactions involved - alpha helix and beta sheet and beta turns structure, Pauling and Corey model for fibrous proteins, Collagen triple helix, and super secondary structures - helix-loop-helix.
d) Tertiary structure - alpha and beta domains. Quaternary structure - structure of haemoglobin, Solid state synthesis of peptides, Protein-Protein interactions, Concept of chaperones.
Nucleic acid-DNA and RNA
Gene-part of DNA
Functions of DNA
RNA-Functions, different types of RNA-Ribosomal RNAs (rRNAs), Messenger RNAs (mRNAs), Transfer RNAs (tRNAs)-Other RNA-Small nuclear RNA (snRNA), Micro RNA (miRNA), Small interfering RNA (siRNA), Heterogenous RNA (hnRNA).
Nucleic acid-nucleotides-nucleoside
Components of nucleotide-a nitrogenous (nitrogen-containing) base (pyrimidine and purine), (2) a pentose, and (3) a phosphate
Structure of pentose sugar, and 5 major bases (cytosine, thymine, uracil-pyrimidine bases and adenine, guanine-purine bases).
Deoxyribonucleotides and Ribo nucleotides-Molecular structure of deoxyadenosine monophosphate (dAMP), deoxyguanosine monophosphate (dGMP), deoxythymidine monophosphate (dTMP), deoxycytidine monophosphate (dCMP) and Adenosine monophosphate (AMP), Guanosine monophosphate (GMP), Cytosine monophosphate (CMP) and Uridine monophosphate (UMP), Watson crick base pairing, Hoogsteen base pairing,
Helical structure-Heterocylic N -Glycosides, Syn and Anti Conformers, detailed structure of single strand and double stranded DNA.
DNA Nucleotides and Tautomeric Form-Tautomers of Adenine, Cytosine, Guanine, and Thymine
Template strand, non coding strand and coding strand
Hydrogen bonds, phosphodiester linkage, hydrolysis of DNA and RNA.
Different forms of DNA-A, B, and Z forms.
Palindrome sequence, Linear DNA, Cruciform DNA, H DNA (Triplex DNA), Denaturation of DNA, Hyperchromicity, Tm, Renaturation of DNA, Tertiary structure of DNA, Difference of DNA and RNA, RNA structural elements, primary. secondary and tertiary structure of RNA. Detailed structure and functions of tRNA, mRNA, rRNA, miRNA, siRNA, hn RNA, snRNA.
Nucleic acid hybridization, C0t analysis, Buoyant density of DNA, Isopycnic centrifugation.
Vitamins-Introduction, Water soluble and fat soluble vitamins.
Water soluble vitamins-B complex vitamins: thiamin (vitamin B1), riboflavin (vitamin B2), niacin (vitamin B3), vitamin B6 (pyridoxine), folate (folic acid), vitamin B12, biotin and pantothenic acid-their source, structure, properties, metabolism, physiological significance, deficiency disease and human requirements.
Fat soluble vitamins: Fat soluble vitamins, Vitamin A, D, E and K and their their source, structure, properties, metabolism, physiological significance, deficiency disease and human requirements.
Vitamin A-Carotene in plants-α-carotenes, β-carotenes and γ-carotenes, 3 forms of vitamin A-Retinol, Retinal, Retinoic acid.
Vitamin D3-cholecalciferol,
Vitamin E -Tocopherol, Vitamin K-Phylloquinone or Anti hemorrhagic Vitamin or Coagulation Vitamin
A brief information about the SCOP protein database used in bioinformatics.
The Structural Classification of Proteins (SCOP) database is a comprehensive and authoritative resource for the structural and evolutionary relationships of proteins. It provides a detailed and curated classification of protein structures, grouping them into families, superfamilies, and folds based on their structural and sequence similarities.
Observation of Io’s Resurfacing via Plume Deposition Using Ground-based Adapt...Sérgio Sacani
Since volcanic activity was first discovered on Io from Voyager images in 1979, changes
on Io’s surface have been monitored from both spacecraft and ground-based telescopes.
Here, we present the highest spatial resolution images of Io ever obtained from a groundbased telescope. These images, acquired by the SHARK-VIS instrument on the Large
Binocular Telescope, show evidence of a major resurfacing event on Io’s trailing hemisphere. When compared to the most recent spacecraft images, the SHARK-VIS images
show that a plume deposit from a powerful eruption at Pillan Patera has covered part
of the long-lived Pele plume deposit. Although this type of resurfacing event may be common on Io, few have been detected due to the rarity of spacecraft visits and the previously low spatial resolution available from Earth-based telescopes. The SHARK-VIS instrument ushers in a new era of high resolution imaging of Io’s surface using adaptive
optics at visible wavelengths.
(May 29th, 2024) Advancements in Intravital Microscopy- Insights for Preclini...Scintica Instrumentation
Intravital microscopy (IVM) is a powerful tool utilized to study cellular behavior over time and space in vivo. Much of our understanding of cell biology has been accomplished using various in vitro and ex vivo methods; however, these studies do not necessarily reflect the natural dynamics of biological processes. Unlike traditional cell culture or fixed tissue imaging, IVM allows for the ultra-fast high-resolution imaging of cellular processes over time and space and were studied in its natural environment. Real-time visualization of biological processes in the context of an intact organism helps maintain physiological relevance and provide insights into the progression of disease, response to treatments or developmental processes.
In this webinar we give an overview of advanced applications of the IVM system in preclinical research. IVIM technology is a provider of all-in-one intravital microscopy systems and solutions optimized for in vivo imaging of live animal models at sub-micron resolution. The system’s unique features and user-friendly software enables researchers to probe fast dynamic biological processes such as immune cell tracking, cell-cell interaction as well as vascularization and tumor metastasis with exceptional detail. This webinar will also give an overview of IVM being utilized in drug development, offering a view into the intricate interaction between drugs/nanoparticles and tissues in vivo and allows for the evaluation of therapeutic intervention in a variety of tissues and organs. This interdisciplinary collaboration continues to drive the advancements of novel therapeutic strategies.
The increased availability of biomedical data, particularly in the public domain, offers the opportunity to better understand human health and to develop effective therapeutics for a wide range of unmet medical needs. However, data scientists remain stymied by the fact that data remain hard to find and to productively reuse because data and their metadata i) are wholly inaccessible, ii) are in non-standard or incompatible representations, iii) do not conform to community standards, and iv) have unclear or highly restricted terms and conditions that preclude legitimate reuse. These limitations require a rethink on data can be made machine and AI-ready - the key motivation behind the FAIR Guiding Principles. Concurrently, while recent efforts have explored the use of deep learning to fuse disparate data into predictive models for a wide range of biomedical applications, these models often fail even when the correct answer is already known, and fail to explain individual predictions in terms that data scientists can appreciate. These limitations suggest that new methods to produce practical artificial intelligence are still needed.
In this talk, I will discuss our work in (1) building an integrative knowledge infrastructure to prepare FAIR and "AI-ready" data and services along with (2) neurosymbolic AI methods to improve the quality of predictions and to generate plausible explanations. Attention is given to standards, platforms, and methods to wrangle knowledge into simple, but effective semantic and latent representations, and to make these available into standards-compliant and discoverable interfaces that can be used in model building, validation, and explanation. Our work, and those of others in the field, creates a baseline for building trustworthy and easy to deploy AI models in biomedicine.
Bio
Dr. Michel Dumontier is the Distinguished Professor of Data Science at Maastricht University, founder and executive director of the Institute of Data Science, and co-founder of the FAIR (Findable, Accessible, Interoperable and Reusable) data principles. His research explores socio-technological approaches for responsible discovery science, which includes collaborative multi-modal knowledge graphs, privacy-preserving distributed data mining, and AI methods for drug discovery and personalized medicine. His work is supported through the Dutch National Research Agenda, the Netherlands Organisation for Scientific Research, Horizon Europe, the European Open Science Cloud, the US National Institutes of Health, and a Marie-Curie Innovative Training Network. He is the editor-in-chief for the journal Data Science and is internationally recognized for his contributions in bioinformatics, biomedical informatics, and semantic technologies including ontologies and linked data.
THE IMPORTANCE OF MARTIAN ATMOSPHERE SAMPLE RETURN.Sérgio Sacani
The return of a sample of near-surface atmosphere from Mars would facilitate answers to several first-order science questions surrounding the formation and evolution of the planet. One of the important aspects of terrestrial planet formation in general is the role that primary atmospheres played in influencing the chemistry and structure of the planets and their antecedents. Studies of the martian atmosphere can be used to investigate the role of a primary atmosphere in its history. Atmosphere samples would also inform our understanding of the near-surface chemistry of the planet, and ultimately the prospects for life. High-precision isotopic analyses of constituent gases are needed to address these questions, requiring that the analyses are made on returned samples rather than in situ.
Cancer cell metabolism: special Reference to Lactate PathwayAADYARAJPANDEY1
Normal Cell Metabolism:
Cellular respiration describes the series of steps that cells use to break down sugar and other chemicals to get the energy we need to function.
Energy is stored in the bonds of glucose and when glucose is broken down, much of that energy is released.
Cell utilize energy in the form of ATP.
The first step of respiration is called glycolysis. In a series of steps, glycolysis breaks glucose into two smaller molecules - a chemical called pyruvate. A small amount of ATP is formed during this process.
Most healthy cells continue the breakdown in a second process, called the Kreb's cycle. The Kreb's cycle allows cells to “burn” the pyruvates made in glycolysis to get more ATP.
The last step in the breakdown of glucose is called oxidative phosphorylation (Ox-Phos).
It takes place in specialized cell structures called mitochondria. This process produces a large amount of ATP. Importantly, cells need oxygen to complete oxidative phosphorylation.
If a cell completes only glycolysis, only 2 molecules of ATP are made per glucose. However, if the cell completes the entire respiration process (glycolysis - Kreb's - oxidative phosphorylation), about 36 molecules of ATP are created, giving it much more energy to use.
IN CANCER CELL:
Unlike healthy cells that "burn" the entire molecule of sugar to capture a large amount of energy as ATP, cancer cells are wasteful.
Cancer cells only partially break down sugar molecules. They overuse the first step of respiration, glycolysis. They frequently do not complete the second step, oxidative phosphorylation.
This results in only 2 molecules of ATP per each glucose molecule instead of the 36 or so ATPs healthy cells gain. As a result, cancer cells need to use a lot more sugar molecules to get enough energy to survive.
Unlike healthy cells that "burn" the entire molecule of sugar to capture a large amount of energy as ATP, cancer cells are wasteful.
Cancer cells only partially break down sugar molecules. They overuse the first step of respiration, glycolysis. They frequently do not complete the second step, oxidative phosphorylation.
This results in only 2 molecules of ATP per each glucose molecule instead of the 36 or so ATPs healthy cells gain. As a result, cancer cells need to use a lot more sugar molecules to get enough energy to survive.
introduction to WARBERG PHENOMENA:
WARBURG EFFECT Usually, cancer cells are highly glycolytic (glucose addiction) and take up more glucose than do normal cells from outside.
Otto Heinrich Warburg (; 8 October 1883 – 1 August 1970) In 1931 was awarded the Nobel Prize in Physiology for his "discovery of the nature and mode of action of the respiratory enzyme.
WARNBURG EFFECT : cancer cells under aerobic (well-oxygenated) conditions to metabolize glucose to lactate (aerobic glycolysis) is known as the Warburg effect. Warburg made the observation that tumor slices consume glucose and secrete lactate at a higher rate than normal tissues.
Seminar of U.V. Spectroscopy by SAMIR PANDASAMIR PANDA
Spectroscopy is a branch of science dealing the study of interaction of electromagnetic radiation with matter.
Ultraviolet-visible spectroscopy refers to absorption spectroscopy or reflect spectroscopy in the UV-VIS spectral region.
Ultraviolet-visible spectroscopy is an analytical method that can measure the amount of light received by the analyte.
1. Module-3-Lipids
• The lipids are a heterogeneous group of compounds,
including fats, oils, steroids, waxes, and related
compounds, that are related more by their physical than
by their chemical properties.
• They have the common property of
being (1) relatively insoluble in water and (2) soluble in
nonpolar solvents such as ether and chloroform.
• They are important dietary constituents not only because
of their high energy value, but also because of the fat-
soluble vitamins and the essential fatty acids contained in
the fat of natural foods.
• Fat is stored in adipose tissue, where it also serves as a
thermal insula-tor in the subcutaneous tissues and
around certain organs. Dr. Shiny C Thomas, Biosciences, ADBU
2. Combinations of lipid and protein (lipoproteins) serve as the
means of transporting lipids in the blood.
LIPIDS ARE CLASSIFIED AS SIMPLE OR COMPLEX
1. Simple lipids: Esters of fatty acids with various alcohols.
a. Fats: Esters of fatty acids with glycerol. Oils are fats in the
liquid state.
b. Waxes: Esters of fatty acids with higher molecular weight
monohydric alcohols.
2.Complex lipids: Esters of fatty acids containing groups in
addition to an alcohol and a fatty acid.
a. Phospholipids: Lipids containing, in addition to fatty acids
and an alcohol, a phosphoric acid residue.
Dr. Shiny C Thomas, Biosciences, ADBU
3. They frequently have nitrogen containing bases and other
substituents, eg, in glycerophospholipids the alcohol is
glycerol and in sphingophospholipids the alcohol is
sphingosine.
b. Glycolipids (glycosphingolipids): Lipids containing a fatty
acid, sphingosine, and carbohydrate.
c. Lipoprteins: Macromolecular complexes of lipids with
proteins
d. Other complex lipids: Lipids such as sulfolipids and
aminolipids. Lipoproteins may also be placed in this category.
3. Precursor and derived lipids: These include fatty acids,
glycerol, steroids, other alcohols, fatty aldehydes, ketone
bodies, hydrocarbons, lipid-soluble vitamins, and hormones.
4. • Because they are uncharged, acylglycerols (glycerides),
cholesterol, and cholesteryl esters are termed neutral
lipids.
• Fatty acids occur in the body mainly as esters in natural
fats and oils, but are found in the unesterified form as
free fatty acids, a transport form in the plasma.
• Fatty acids that occur in natural fats usually contain an
even number of carbon atoms.
• The chain may be saturated (containing no double bonds)
or unsaturated (containing one or more double bonds).
5. Functions of lipids
Lipids perform several important functions
1. They are the concentrated fuel reserve of the body
(triacylglycerols).
2. Lipids are the constituents of membrane structure and
regulate the membrane permeability (phospholipids and
cholesterol ) .
3. They serve as a source of fat soluble vitamins (4, D, E and
K).
4. Lipids are important as cellular metabolic regulators
(steroid hormones and prostaglandins
5. Lipids protect the internal organs, serve as insulating
materials and give shape and smooth appearance to the
body.
6. • Other lipids, although present in relatively small
quantities, play crucial roles as:
• enzyme cofactors,
• electron carriers,
• light absorbing pigments,
• hydrophobic anchors for proteins,
• “chaperones” to help membrane proteins fold,
• emulsifying agents in the digestive tract,
• hormones,
• and intracellular messengers.
7. The fatty acids are hydrocarbon derivatives.
• Fatty acids are carboxylic acids with hydrocarbon chains
ranging from 4 to 36 carbons long (C4 to C36).
• In some fatty acids, this chain is unbranched and fully
saturated (contains no double bonds); in others the
chain contains one or more double bonds
8.
9. A simplified nomenclature for these compounds specifies
the chain length and number of double bonds, separated
by a colon;
for example, the 16-carbon saturated palmitic acid is
abbreviated 16:0, and the 18-carbon oleic acid, with one
double bond, is 18:1.
10. • The positions of any double bonds are specified by
superscript numbers following Δ (delta); a 20-carbon
fatty acid with one double bond between C-9 and C-10
(C-1 being the carboxyl carbon) and another between
C-12 and C-13 is designated Δ delta 20:2(Δ 9,12).
• There is also a common pattern in the location
of double bonds; in most monounsaturated fatty acids
the double bond is between C-9 and C-10 (Δ9), and
the other double bonds of polyunsaturated fatty acids
are generally Δ12 and Δ15 .
11. • The double bonds of polyunsaturated fatty acids are
almost never conjugated (alternating single and double
bonds, as in
• but are separated by a methylene group: .
Cis-trans isomerism
• Because of the double bonds, unsaturated fatty acids
exhibit cis-trans isomerism.
• In the cis isomer bulky groups are located on the same
side of double bond where as in trans isomer they are on
the opposite side of double bond (Fig. 6.9b).
• All the naturally occurring unsaturated fatty acids are cis-
isomers.
12.
13. Function
Cis and trans isomers are not interchangeable in cells. Only
cis isomers can fit into cell membrane because of bend at
double bond.
Nomenclature of Fatty Acids
Saturated fatty acids
Saturated fatty acids have both trivial names and systematic
names.
Systematic name
• Systematic name of a saturated fatty acid consist of two
parts. Name of hydrocarbon chain forms first part. ‘oic’
substituted in place of ‘e’ of hydrocarbon name forms
second part.
For example, systematic name for a saturated fatty acid
containing 8 carbon atoms i.e., (octane + oic + acid) —→
octanoic acid.
14. • Usually saturated fatty acids end as anoic acids. Examples
of saturated fatty acids with systematic names, trivial
names and with sources are given in Table 6.1. The trivial
name for octanoic acid is caprylic acid.
Table 6.1 Sources, trivial and systematic names of saturated fatty acids
15. • In a fatty acid, the carbon atoms are numbered from the
carboxyl carbon.
• The carbon atom adjacent to the carboxyl carbon is
known as the α-carbon.
• Carbon atom adjacent to the α-carbon atom is known as β
carbon atom and so on.
• The end methyl carbon is called as ω-carbon (Fig. 6.9a).
Unsaturated fatty acids
They have trivial names, systematic names, ω-end names and
short hand forms.
16. Systematic name
• Like saturated fatty acids, the name of hydrocarbon forms
first part of systematic name of unsaturated fatty acids.
• But ‘enoic’ substituted in place of ‘ne’ of name of
hydrocarbon forms second part.
• Number of double bonds are written before ‘enoic’ and
symbol showing position of double bonds and isomerism
around double bond are written between two parts or in
the beginning.
17. • For example, systematic name for a mono unsaturated
fatty acid palmitoleic acid (trivial name) containing 16
carbon atoms and one double bond between 9 and 10
carbon atoms is monoenoic acid or cis-9-Hexadecaenoic
acid.
• Usually unsaturated fatty acids end as ‘enoic acids’.
18. Omega (Ѡ)-end series
• Unsaturated fatty acids are also named according to the
location of double bonds(s) from ω-end.
• For example, palmitoleic acid containing a double bond
between 9 and 10 carbon atoms is named as ω-7 fatty
acid.
Short hand forms
• Number of carbon atoms, number of double bonds and
location of double bonds of unsaturated fatty acid are
represented with short form.
• For example, palmitoleic acid is written as 16:1, Δ9 in
short hand form.
• First numeral indicates number of carbon atoms, later
number indicates number of double bonds and Δ9
indicates position of double bond.
19. • Example of unsaturated fatty acids with trivial names,
systematic names, ω-end names, short hand forms and
along with sources are given Table 6.2.
21. ESSENTIAL FATTY ACIDS
• They are not synthesized in the body. So they must be
obtained from diet.
• They are also called as poly unsaturated fatty acids
(PUFA).
• They are linoleic acid (LA), linolenic acid (LNA) and
arachidonic acid (AA).
Functions
1. They are essential for the synthesis of eicosanoids.
2. They are also required for membrane lipids.
22. Medical Importance
1. Dietary essential fatty acids has blood cholesterol
lowering effect.
2. Deficiency status of essential fatty acids are rare with
normal diet. However, deficiency of these in rats causes
poor growth, reproductive disorders and dermatitis.
3. Lipid transport may be impaired.
4. Infants consuming formula diets are susceptible to
deficiency of essential fatty acids. They may develop skin
abnormalities.
23. 1. A simple lipid is a fatty acid ester of different alcohols and
carries no other substance.
• These lipids are nonpolar compounds, mostly insoluble in
water, but soluble in nonpolar organic solvents such as
chloroform and benzene.
Simple lipids: esters of fatty acids with various alcohols.
a. Fats: esters of fatty acids with glycerol. Oils are fats in the
liquid state. Fats are also called triglycerides because all
the three hydroxyl groups of glycerol are esterified.
b. Waxes: Solid esters of long-chain fatty acids such as
palmitic acid with aliphatic or alicyclic higher molecular
weight monohydric alcohols. Waxes are water-insoluble due
to the weakly polar nature of the ester group. Eg:Cetyl alcohol.
24.
25. Compound Lipids or Heterolipids
Heterolipids are esters of fatty acids with alcohol and
possess additional groups also.
• Compound (conjugated) lipids are lipids conjugated with
other substances. They include:
1. Phospholipids formed of lipid, phosphoric acid and
nitrogenous base.
2. Glycolipids, formed of lipid part and carbohydrate part
3. Sulpholipids, lipids containing sulphate.
4. Lipoproteins formed of lipid part and protein part
26. Phospholipids or Phosphatids are compound containing
fatty acids and glycerol in addition to a phosphoric acid,
nitrogen bases and other substituents.
• They are a group of compound lipids formed of alcohol,
fatty acids, phosphoric acid and nitrogenous base.
• They usually possess one hydrophilic head and two non-
polar tails.
• They are called polar lipids and are amphipathic in
nautre.
27. The parts of a phospholipid molecule
This example is phosphatidylcholine, represented (A) schematically, (B) by a formula, (C) as a
space-filling model, and (D) as a symbol. The kink resulting from the cis-double bond is
exaggerated for emphasis.
28. They are classified according to the alcohol present into:
A) Phosphoglycerides
B) B) Sphingomyelin
A- Phosphoglycerides
• Phosphoglycerides are a group of phospholipids containing
glycerol with N/P ratio = 1
• They include phosphatidic, lecithin, cephalins,
phosphatidyl inositol, plasmalogen and cardiolipin.
29. 1- phosphatidic acid
It is phosphoric acid ester of diglycerides
Structure
It is formed of:
- Glycerol
-Saturated fatty, attached to α -carbon
of glycerol by ester bond.
-Unsaturated fatty acid , attached to
β- carbon of glycerol by ester bond.
-Phosphoric acid attached to α’ carbon
of glycerol by ester bond
Function of phosphatidic acid
It is an intermediate compound in biosynthesis of other
phosphoglycerides and triglycerides
30. 2- Lecithin
It is phosphatidyl choline
Structure
It is formed of:
- Glycerol
-Saturated fatty acid,
attached to α carbon
of glycerol by ester bond.
- Unsaturated fatty acid,
attached to β carbon of glycerol by ester bond.
- Phosphoric acid attached to α’ carbon of glycerol by
ester bond
- Choline attached to phosphoric acid by ester bond
31. Function of lecithin
1. It is the most abundant phospholipid in the cell
membrane
2. It acts as a lipotropic factor preventing accumulation of
lipids in the liver.
3. Dipalmityl lecithin acts as a surfactant in the lung alveoli
forming a layer at the interface of fluid lining the alveoli and
air in side alveoli preventing lung collapse
• In premature infants the lung alveoli do not secrete
lecithin in sufficient amount so the lungs collapse this is
called respiratory distress syndrome.
32. Lysolecithin
• Snake venom contains lecithinase enzyme, which
removes the unsaturated fatty acid from lecithin forming
lysolecithin.
• Lysolecithin is a strong surface-active substance that
has a marked haemolytic action causing haemolysis of the
red blood cells.
33. 3- Cephalins
They are phosphatidyl ethanolamine and phosphatidyl
serine
Structure
They are formed of:
- Glycerol
- Saturate d fatty acid, attached to α carbon of glycerol
by ester bond.
- Unsaturated fatty acid, attached to β carbon of
glycerol by ester bond.
- Phosphoric acid attached to α’ carbon of glycerol by
ester bond
- Ethanolamine or serine.
34. Functions of cephalins
- They have a role in blood coagulation.
- They accelerate blood clotting because they enter in
the structure of thromboplastine, which is essential for
blood clotting.
35. 4- Phosphatidyl inositol
It is also called lipoinositol
Structure
It is formed of:
- Glycerol
-Saturate d fatty, attached to
α carbon of glycerol
by ester bond.
-Unsaturated fatty acid , attached to β carbon of glycerol by
ester bond.
- Phosphoric acid attached to α’ carbon of glycerol by ester
bond
- Inositol, which is a cyclic alcohol derived from glucose
36. Function of phosphatidyl inositol
• It is found in brain tissue.
• It has a role in mechanism of hormone action. On
hydrolysis by phospholipase C enzyme, it gives
compounds, which act as second messengers in hormone
action
e.g. diacyl glycerol (DAG) and inositol triphosphate (IP3).
37. 5- Plasmalogens
They are lecithin or cephalin in which the fatty acid
attached to α carbon is replaced by fatty aldehyde in
the enol form.
Structure
It is formed of:
- Glycerol
- Fatty aldehyde, enol form
(unsaturated alcohol)
- Unsaturated fatty acid
- Phosphoric acid
- Nitrogenous bas e, which may be choline, ethanolamine or
serine
Function of plasmalogens
They are present in cardiac muscle, skeletal muscles and brain.
38. 6- Cardiolipin
It is a diphosphatidyl glycerol formed of 2 phosphatidic acids
attached together by glycerol.
Structure
It is formed of:
- 3 glycerol molecules.
- 2 saturated fatty acid s.
- 2 unsaturated fatty acids.
- 2 molecules of phosphoric acid.
Functions of cardiolipin
• Important component of the inner mitochondrial membrane, where it
constitutes about 20% of the total lipid composition. Also found in the
membranes of most bacteria
• Cardiolipin is present in heart muscle.
• It is used as antigen for detection of syphilis.(bacterial infection-
painless sore on genitals, rectum or mouth, spread by sexual
contact)
39. B- Sphingomyelins
• Sphingomyelin is a phospholipid with N/P ratio = 2.
In this type of phospholipids the alcohol is sphingol alcohol
which is also called sphingosine base i.e. sphingomyelin
contains sphingosine base instead of glycerol.
• Sphingosine base contains 18 carbon atoms:
• The first carbon contains hydroxyl group (- OH).
• The second carbon contains amino group (-NH2)
• The third carbon contains hydroxyl group.
• There is a double bond between C4 and C5
40. Structure of sphingomyelin
Sphingomyelin is formed of:
• Sphingosine base
• Unsaturated fatty acid attached to the amino group of
sphingosine
• Phosphoric acid attached to the first carbon of
sphingosine.
• Choline base attached to phosphoric acid.
41. Function of sphingomyelin
• It is abundant in the nervous system in the myelin sheath
also it is present to lesser extent in liver, spleen and bone
marrow.
N.B: Ceramide
• It is formed of sphingosine base to which fatty acid is
attached by amide linkage.
• It differs from sphingomyelin, as it does not contain
phosphoric acid or choline.
42. N.B: Nimann Pick disease
• It is a disease caused by deficiency of sphingomyelinase
enzyme, which catabolizes sphingomyelin.
• This leads to accumulation of large amounts of
sphingomyelin in liver, spleen and brain.
43. 2- Glycolipids
• They are compound lipids that contain carbohydrates.
They also contain sphingosine base
They include cerebrosides and gangliosides
1- Cerebrosides
• These are compound lipids formed of lipids and
carbohydrates.
• They are called cerebrosides because they are present
mainly in the brain and nerves.
44. Structure
It is formed of:
- Sphingosine base.
- Long chain fatty acid attached to the amino group of the
sphingosine base by amide linkage.
-Carbohydrate usually galactose but may be glucose.
Functions of cerebrosides
• They are present mainly in the nervous tissues i.e. brain
and nerves.
• They act as electric insulators of nerve impulses.
Also, they are present in spleen, liver , adrenal gland, kidney
and lungs.
45. 2- Gangliosides
These are the most complex glycolipids.
Structure
- Sphingosine base.
- Long chain fatty acid
- One glucose molecule .
- 2 galactose molecules.
- N-acetyl galactosamine .
*- N-acetyl neuraminic acid (siailic acid; NANA).
Function
Gangliosides are present in high concentration in brain.
They act as receptors at cell membrane.
46. 3- Sulpholipids
They are cerebrosides containing sulphate group attached to
C3 of galactose.
Structure of sulpholipids
It is formed of:
- Sphingosine base.
- Long chain fatty ac id attached to the amino group of the
sphingosine base by amide linkage.
- Carbohydrate usually galactose but may be glucose.
- Sulphate group attached to carbon number 3 of galactose.
Function of sulpholipids
They are present in brain and nervous tissues.
47. 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
Steroids are complex molecules containing four fused rings.
The four fused rings makeup
‘cyclopentanoperhydrophenanthrene’ or ‘sterane’ ring.
Sterane ring is also called as steroid nucleus.
48. • The steroid nucleus, consisting of four fused rings, three
with six carbons and one with five.
• Steroids are called as non-saponifiable lipids because they
contain no fatty acids and they can not form soaps.
• The most abundant steroids are sterols which are steroid
alcohols.
49. Sterols are structural lipids present in the membranes
of most eukaryotic cells.
1. CHOLESTEROL
Structure
Cholesterol, 3-hydroxy-5,6-cholestene
50. • In animal tissue, cholesterol is the major sterol.
Cholesterol is 3-hydroxy-5, 6-cholestene. It is found in bile
(chol-bile).
• In a normal 65 Kg adult, 200 gm of cholesterol is present.
• Brain is rich in cholesterol. It is also present in spinal cord
and neurons.
• It is amphipathic, with a polar head group (the hydroxyl
group at C-3) and a nonpolar hydrocarbon body (the
steroid nucleus and the hydrocarbon side chain at C-17),
about as long as a 16- carbon fatty acid in its extended
form.
51. Other Noteworthy Steroids
1. Ergosterol Provitamin of vitamin D found in yeast and
plants.
2. Sitosterol Present in plants.
3. Cardiac glycosides like quabain and streptomycin an
antibiotic.
4. Coprostanol found in feces is derived from cholesterol.
5. Wool fat sterols like agnosterol and lanosterol.
52. 2. Ergosterol Is a Precursor of Vitamin D
Ergosterol occurs in plants and yeast and is important as a
precursor of vitamin D
53. Derived lipids
They are compounds derived from simple and compound
lipids by hydrolysis e.g. fatty acids glycerol glycerol.
Also; the include substances related to lipids as steroids and
isoprenoids.
Steroids
They are a large group of biologically important compounds.
All of them contain a steroid nucleus, which is
cyclopentano-perhydrophenanthrene nucleus.
56. 1- Sterols
They are complex alcohols that contain hydroxyl group and
do not contain carbonyl or carboxyl groups e.g. cholesterol
and ergosterol.
They are present in animal and plant tissues; cholesterol is
present in animals and ergosterol in plants.
A- Cholesterol
It is the best-known sterol.
It is the most abundant animal sterol
57. Properties of cholesterol
1- Cholesterol is insolubl e in water but soluble in fat
solvents.
2- It is present in every animal cell but mainly in adrenal
cortex, liver, kidney, brain and nervous tissues.
3- It is present in human blood in concentration of 150 - 270
mg /dl
4- Reduction by intestinal bacteria converts cholesterol into
dihydrocholesterol (coprastanol) by saturation of the double
bond between C5 and C6.
Coprastanol is present in faces.
58. Structure
It is forme d of 27 carbon atoms. It is formed of:
- Cyclopentano-perhydrophenanthrene (steroid)
nucleus.
- Alcoholic hydroxyl group (-OH) at C3.
- Double bond between C5 and C6.
- Side chain of 8 carbon atoms at C 17.
59. Functions of cholesterol
1. Cholesterol enters in the structure of all body cells
2. Cholesterol is the precursor of all steroid hormones.
3. It is oxidized in the liver to give bile acids.
4. It is oxidized to 7 dehydrocholesterol by introduction of
double bond between C7 and C8.
N.B. 7 dehydrocholesterol is provitamin D3 because it is
converted to vitamin D3 when the skin is exposed to
ultraviolet rays.
60. Colour reactions of cholesterol
1. Lieberman-Burchard test, on addition of acetic anhydride
and concentrated sulphuric acid to cholesterol, it gives bluish
green colour.
2. Salkowski test, on addition of chloroform and
concentrated sulphuric acid to cholesterol it gives bluish red
to purple colour.
61. B- Ergosterol
It is plant sterol, which is poorly absorbed from small
intestine.
Structure
It is forme d of 28 carbon atoms and contains:
- Cyclopentano-perhydrophenanthrene nucleus .
- Alcoholic hydroxyl group (-OH) at C3.
- 2 double bonds, one between C5 and C6 and the other
between C7 and C8.
- Side chain of 9 carbon atoms at C17. It contains double
bond between C22 and C23.
- There is an extra methyl group at C24 in the side chain of
ergosterol.
62. Function of ergosterol
Ergosterol is provitam in D2 because it is converted to
vitamin D2 when the skin is exposed to ultraviolet rays.
63. 2- Steroid Hormones
These are hormones that contain steroid nucleus. They
include:
A- Male sex hormones: The main male sex hormone is called
testosterone.
B- Female sex hormon es: The female sex hormones in clude
estrogens and progesterone
C- Adrenal cortex hormones: They are secreted from the adre
nal cortex. They are classified into: glucocorticoids,
mineralocorticoids and aldosterone.
D- Active forms of vitamin D: 1,25 dihydroxy vitamin D3
(calcitriol) and 1,25 dihydroxy vitamin D2 are the active forms
of vitamin D.
64. • They are considered hormones as they are synthesized in
an organ (skin), activated in other organs (liver and
kidney) and exert function on other organs ( small
intestine and bones).
3- Steroid vitamins
These are vitamin D2 and vitamin D3.
Structure
Vitamin D 3 is derived from 7 dehydrocholesterol by rupture
(opening) of ring B by ultraviolet rays
Vitamin D2 is derived from ergosterol by rupture (opening) of
ring B by ultraviolet rays.
65. 4- Bile acids
These are acid s that contain 24 carbon atoms. They are
formed from cholesterol in the liver by oxidation of the side
chain.
There are 4 bile acids:
A- Cholic acid
• It is the main bile acid in humans.
• It is 3,7,12-trihydroxy cholanic acid.
B- Deoxycholic acid
• It is 3,12 dihydroxy cholanic acid.
C- Chenodeoxycholic acid
• It is 3,7 dihydroxy cholanic acid.
D- Lithocholic acid
• It is 3 hydroxy cholanic acid.
66. • Bile acids unite with glycine t o form glycocholic acid. Or
they may unite with taurine (derived from amino acid
cysteine) to form taurocholic acid.
• Glyco cholic acid unites with sodium or potassium to form
sodium glycocholate or potassium glycocholate.
• Also, taurocholic acid forms sodium taurocholate and
potassium taurocholate.
• Sodium glycocholate, potassium glycocholate, sodium
taurocholate and potassium taurocholate are bile salts.
• Bile salts have a role in lipid digestion and absorption.
67. Isoprenoids
They are unsaturated hydrocarbons.
They are formed of repeated units of 5 carbon atoms called
isoprene units.
They include:
1. Ubiquinone, which is a member of the respiratory chain in
mitochondria.
2. Dolichol, which is a long chain unsaturated alcohol which
chairs in glycoprotein synthesis.
3. Carotenes, which are provitamin A.
4. Rubber
5. Camphor
68. Carotenes
They are unsaturated hydrocarbons formed of 40 carbon
atoms with the general formula C40H56.
They are formed of repeated units of 5 carbon atoms called
isoprene units.
They are orange in colour.
Sources of carotenes
Carotenes are obtained from plant sources as carrots and
plant leaves.
Importance of carotenes
• They are precursors of vitamin A.
Types of carotenes
There are 3 types o f carotenes α, β and γ
70. Lipoproteins
These are compound lipids formed of lipid part (which may be
triglycerides, cholesterol or phospholipids) and
protein part (which may be or globulin).
Function of lipoproteins:-
1. They enter in the structure of cell membrane.
2. They are important for lipid transport in the blood. Lipids
are insoluble in water so they cannot be transported alone.
• Lipids bind to protein to make lipoproteins are water-
soluble and can be transported in the blood.
• The protein part of lipoprotein is called as apolipoprotein
or apoprotein. The apoprotein and lipids are held together
by non-covalent forces.
71. Classification of lipoproteins
Lipoproteins are classified into 4 types according to the rate
of floatation in sodium chloride solution after
ultracentrifugation.
• These types are chylomicrons, very low-density
lipoproteins (VLDL), low density lipoproteins (LDL) and
high-density lipoproteins (HDL)
72. Apoproteins of lipoproteins
The proportion of protein part differs in various lipoproteins.
Further the composition of apoprotein part also differs
among various lipoproteins.
There are five types of apoproteins.
They are apoprotein A, apo B, apo C, apo D, and apo E.
Some of the apoproteins have subtypes also.
73. Functions of Lipoproteins
Lipoproteins are involved in the transportation of lipids in
the body.
1. Chylomicrons They transport dietary or exogenous
triglycerides from intestine to liver.
2. Very low density lipoproteins (VLDL) They are involved
in the transport of endogenous triglycerides from liver to
extra hepatic tissues.
3. Low density lipoproteins (LDL) LDL is the major vehicle
for the transport of cholesterol from liver to extra hepatic
tissues.
4. High density lipoproteins (HDL) HDL is the major vehicle
for the transport of cholesterol from extra hepatic tissues to
the liver.
74. EICOSANOIDS
• These compounds, derived from eicosa (20-carbon)
polyenoic fatty acids, comprise the prostanoids,
leukotrienes (LTs), and lipoxins (LXs).
• Prostanoids include prostaglandins (PGs),
prostacyclins (PGIs), and thromboxanes (TXs). Often word
prostaglandins is used to indicate all prostanoids.
75. Prostaglandins
• Since they are initially found in prostate gland they are
named as prostaglandins.
• But later they are identified in all cells and tissues except
erythrocytes.
Structures
• Chemically prostaglandins are derivatives of a 20 carbon
prostanoic acid.
• Prostanoic acid is a cyclic compound with two side
chains
• The cyclic ring present in prostanoic acid is a
cyclopentane ring.
• There are some six or more types of prostaglandins.
76. • They are prostaglandin A(PGA), PGB, PGC, PGD,
PGE, PGF, PGG and PGH
• Most widely distributed prostaglandins are PGA1, PGA2,
PGE1, PGE2, PGE3, PGF1, PGF2, PGF3.
Prostaglandin E2 (PGE2 )
77.
78. Prostacylins
Structure
They contain a second five-numbered ring in addition to the
one common to all prostaglandins.
Thromboxane
Structure
They are so named because they are identified first in
thrombocytes. They contain a six numbered heterocyclic
oxane ring
79. Leukotriens and Lipoxins
Structure
• They are found in leukocytes. They are derivatives of
arachidonic acid and contain no cyclic ring.
• HPETE (5-hydroperoxy eicosa tetra enoic acid) derived
from arachidonic acid serves as precursor for leukotriens
and lipoxins.
• They are characterized by the presence of three or four
conjugated double bonds, respectively.
• Leukotrienes cause bronchoconstriction as well as being
potent proinflammatory agents, and play a part in
asthma.
80. FUNCTIONS OF EICOSANOIDS
They function as local hormones. They act on several organs
and produce physiological as well as pharmacological
effects.
1. Heart PGE class prostaglandins increases cardiac output
and myocardial contraction.
2. Blood vessels Prostaglandins (PGE) maintain blood vessel
tone and arterial pressure.
3. Blood pressure PGA and PGE class prostaglandins lower
blood pressure. So they may be useful as anti hypertensive
agents.
4. Brain PGE class prostaglandins produce sedation and
tranquilizing effect in cerebral cortex.
81. 5. Kidney PGA and PGE class prostaglandins increases
excretion of Na+, K+ and CI-. They may increase urine volume
by increasing plasma flow.
6. Lungs Prostaglandins dilate bronchi, so they are useful in
the treatment of asthma.
8. Stomach Prostaglandins decreases acid secretion in
stomach. So they are useful in the treatment of peptic ulcers.
9. Uterus. Prostaglandins induces contraction of uterine
muscle. So they are used in the termination of pregnancy.
Prostaglandins also has role in fertility.
10. Metabolism Prostaglandins influences several metabolism
by altering cAMP level. For example, they inhibit lipolysis in
adipocyte by increasing cAMP level.
11. PGE class prostaglandins are involved in inflammation.
82. 12. Prostacylins inhibit platelet aggregation.
13. Thromboxanes causes platelet aggregation and clot
formation.
14. Leukotreins are involved in the regulation of neutrophil
and eosinophil function. They act as mediators of
immediate hyper sensitivity reaction. The slow reacting
substance of anaphylaxis (SRS-A) is a leukotriene. Some
leukotriens act as chemotactic agents. Lipoxins are
vasoactive and immuno regulatory substances.
15. Thromboxane A2 regulates acquired immunity. It causes
construction of smooth muscle cells. It is a mitogen.
83. LIPID LAYERS, MICELLES AND LIPOSOMES
• In general, lipids are insoluble in water since they contain a
predominance of nonpolar (hydrocarbon) groups.
• However, fatty acids, phospholipids, sphingolipids, bile
salts, and, to a lesser extent, cholesterol contain polar
groups.
• Therefore, part of the molecule is hydrophobic, or water-
insoluble; and part is hydrophilic, or water soluble.
Such molecules are described as amphipathic
84. • They become oriented at oil:water interfaces with the
polar group in the water phase and the nonpolar group in
the oil phase.
• A bilayer of such amphipathic lipids is the basic structure
in biologic membranes
85. Lipid monolayer
• When amphipathic molecules like phospholipids are
present in water, their polar head groups orient towards
water phase and hydrophobic tails towards air.
• As a result, a unimolecular lipid layer is formed at water
air interphase.
86. Micelles
• When amphipathic lipids are present beyond a critical
concentration in aqueons medium, they aggregate into
spheres.
• The sphere aggregates of amphipathic lipids are known as
micelles
• In the sphere shaped micelles
polar head groups of
amphipathic lipids are on the
exterior whereas non-polar
tails are in the interior.
• Bile salts can form micelles.
87. Lipid Bilayer
Structure
• When phospholipids are present in water oil mixture,
their polar head groups orient towards water and non-
polar tails towards oil.
• As result, a lipid bilayer is formed. Lipid bilayer is formed
even in the absence of oil phase because of hydrophobic
attraction.
Function
Lipid bilayer is the
basic structure of cell membrane.
88. Liposomes
Structure
When a lipid bilayer closes on itself a spherical vesicle called
as ‘liposome’ is formed. Liposomes may be formed by
sonicating an amphipathic lipid in an aqueous medium.
Functions
1. Liposomes are used as a carrier of certain drugs to
specific site of body where they act.
They can deliver drugs directly into cell because they easily
fuses with cell membranes.
2. They are used in cancer therapy to deliver drugs only to
cancer cells.
3. In gene therapy also they are used as vehicles for genes.
89.
90. Emulsions are much larger particles, formed usually by
nonpolar lipids in an aqueous medium.
• These are stabilized by emulsifying agents such as
amphipathic lipids (eg, lecithin), which form a surface
layer separating the main bulk of the nonpolar material
from the aqueous phase.
Emulsification: It is the process by which a lipid mass is
converted into a number of small lipid droplets.
• The fats may be emulsified by shaking either with water
or with emulsifying agents like soaps, gums, proteins etc.
91. Packing arrangements of lipid molecules in an aqueous environment
(A) Wedge-shaped lipid molecules (above) form micelles, whereas cylinder-
shaped phospholipid molecules (below) form bilayers. (B) A lipid micelle and a lipid
bilayer seen in cross section. Lipid molecules spontaneously form one or other of these
structures in water, depending on their shape.