This document provides information on different types of complex lipids. It discusses glycolipids, gangliosides, phospholipids, steroids, sterols, and terpenes. Some key points include:
- Glycolipids are formed from a ceramide-sugar complex, with common examples being cerebrosides containing one sugar unit.
- Gangliosides have a core structure of ceramide-glucose-galactose and contain sialic acids. An important example is GM1.
- Phospholipids include sphingolipids and glycerophospholipids such as lecithins, cephalins, and plasmalogens.
- Steroids include cholesterol
Structure, Occurence and Reactions of Maltose, Lactose and Sucrose. Qualitative tests for disaacharides. Importance of Glycosides and Amino Sugars. Occurence and Structures of Homopolysaccharides such as Starch and Cellulose. Occurence and Structures of Heteropolysaccharides such as Hyaluronic acid and Chondroitin sulphates.
Introduction and defination
Classification
Reducing sugars
Non-reducing sugars
General properties
Common disaccharides
1) sucrose
Origin
Structure
Properties
Function
Structure, Occurence and Reactions of Maltose, Lactose and Sucrose. Qualitative tests for disaacharides. Importance of Glycosides and Amino Sugars. Occurence and Structures of Homopolysaccharides such as Starch and Cellulose. Occurence and Structures of Heteropolysaccharides such as Hyaluronic acid and Chondroitin sulphates.
Introduction and defination
Classification
Reducing sugars
Non-reducing sugars
General properties
Common disaccharides
1) sucrose
Origin
Structure
Properties
Function
Sugar derivatives and reactions of monosaccharidesNamrata Chhabra
Reactions of monosaccharides, osazone formation, reduction, oxidation, reaction with acids and alkalies, ester formation and formation of amino sugars, amino sugar acids and deoxy sugars.
WHAT IS CARBOHYDRATE? CLASSIFICATION OF CARBOHYDRATE? WHAT IS MONOSACCHARIDE? CLASSIFICATION OF MONOSACCHARIDE. PHYSICAL PROPERTY. CHEMICAL PROPERTY. ATRUCTURAL FORMULA. METABOLISM . IMPORTANCE OF MONOSACCHARIDE. IMPORTANT FACT RELATED TO MONOSACCHARIDE. DISORDER OF MONOSACCHARIDE CONCLUSION. REFRANCES
“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.
starch is an branched homo polysaccharide.
(contains same type of monomers)
It is the most common carbohydrate in human diet.
Starch is the storage form of glucose in plants. the plants utilize the glucose by using enzymes like amylase.
Sugar derivatives and reactions of monosaccharidesNamrata Chhabra
Reactions of monosaccharides, osazone formation, reduction, oxidation, reaction with acids and alkalies, ester formation and formation of amino sugars, amino sugar acids and deoxy sugars.
WHAT IS CARBOHYDRATE? CLASSIFICATION OF CARBOHYDRATE? WHAT IS MONOSACCHARIDE? CLASSIFICATION OF MONOSACCHARIDE. PHYSICAL PROPERTY. CHEMICAL PROPERTY. ATRUCTURAL FORMULA. METABOLISM . IMPORTANCE OF MONOSACCHARIDE. IMPORTANT FACT RELATED TO MONOSACCHARIDE. DISORDER OF MONOSACCHARIDE CONCLUSION. REFRANCES
“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.
starch is an branched homo polysaccharide.
(contains same type of monomers)
It is the most common carbohydrate in human diet.
Starch is the storage form of glucose in plants. the plants utilize the glucose by using enzymes like amylase.
Lipids-definition, functions.
Fatty acids- saturated and unsaturated fatty acids-definition, examples
Essential and non essential fatty acids, melting point of fatty acids.
Triacylglycerol and wax, phospholipids, glycolipids, Eicosanoids, plasma lipoproteins
Lipids may be regarded as organic substances which is insoluble in water, soluble in organic solvents (alcohol , ether etc.), Triacylglycerols (formerly triglycerides) are the esters of glycerol with fatty acids.
bio chemistry
كيمياء حيوية جامعة الملك سعود
chemistry
كيمياء جامعية
0503964728
محمد منير كيمياء
ابو يوسف
all branched of chemistry bio chemistry - organic chemistry - inorganic chemistry - analytically - spectra - d-block
It contains content about different types of biomolecules and their utilisation in our life. Cabohydtates are source of energy and obtained by various source. Fats and protein both are also essential for our life.
Comparing Evolved Extractive Text Summary Scores of Bidirectional Encoder Rep...University of Maribor
Slides from:
11th International Conference on Electrical, Electronics and Computer Engineering (IcETRAN), Niš, 3-6 June 2024
Track: Artificial Intelligence
https://www.etran.rs/2024/en/home-english/
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.
Professional air quality monitoring systems provide immediate, on-site data for analysis, compliance, and decision-making.
Monitor common gases, weather parameters, particulates.
Introduction:
RNA interference (RNAi) or Post-Transcriptional Gene Silencing (PTGS) is an important biological process for modulating eukaryotic gene expression.
It is highly conserved process of posttranscriptional gene silencing by which double stranded RNA (dsRNA) causes sequence-specific degradation of mRNA sequences.
dsRNA-induced gene silencing (RNAi) is reported in a wide range of eukaryotes ranging from worms, insects, mammals and plants.
This process mediates resistance to both endogenous parasitic and exogenous pathogenic nucleic acids, and regulates the expression of protein-coding genes.
What are small ncRNAs?
micro RNA (miRNA)
short interfering RNA (siRNA)
Properties of small non-coding RNA:
Involved in silencing mRNA transcripts.
Called “small” because they are usually only about 21-24 nucleotides long.
Synthesized by first cutting up longer precursor sequences (like the 61nt one that Lee discovered).
Silence an mRNA by base pairing with some sequence on the mRNA.
Discovery of siRNA?
The first small RNA:
In 1993 Rosalind Lee (Victor Ambros lab) was studying a non- coding gene in C. elegans, lin-4, that was involved in silencing of another gene, lin-14, at the appropriate time in the
development of the worm C. elegans.
Two small transcripts of lin-4 (22nt and 61nt) were found to be complementary to a sequence in the 3' UTR of lin-14.
Because lin-4 encoded no protein, she deduced that it must be these transcripts that are causing the silencing by RNA-RNA interactions.
Types of RNAi ( non coding RNA)
MiRNA
Length (23-25 nt)
Trans acting
Binds with target MRNA in mismatch
Translation inhibition
Si RNA
Length 21 nt.
Cis acting
Bind with target Mrna in perfect complementary sequence
Piwi-RNA
Length ; 25 to 36 nt.
Expressed in Germ Cells
Regulates trnasposomes activity
MECHANISM OF RNAI:
First the double-stranded RNA teams up with a protein complex named Dicer, which cuts the long RNA into short pieces.
Then another protein complex called RISC (RNA-induced silencing complex) discards one of the two RNA strands.
The RISC-docked, single-stranded RNA then pairs with the homologous mRNA and destroys it.
THE RISC COMPLEX:
RISC is large(>500kD) RNA multi- protein Binding complex which triggers MRNA degradation in response to MRNA
Unwinding of double stranded Si RNA by ATP independent Helicase
Active component of RISC is Ago proteins( ENDONUCLEASE) which cleave target MRNA.
DICER: endonuclease (RNase Family III)
Argonaute: Central Component of the RNA-Induced Silencing Complex (RISC)
One strand of the dsRNA produced by Dicer is retained in the RISC complex in association with Argonaute
ARGONAUTE PROTEIN :
1.PAZ(PIWI/Argonaute/ Zwille)- Recognition of target MRNA
2.PIWI (p-element induced wimpy Testis)- breaks Phosphodiester bond of mRNA.)RNAse H activity.
MiRNA:
The Double-stranded RNAs are naturally produced in eukaryotic cells during development, and they have a key role in regulating gene expression .
Richard's entangled aventures in wonderlandRichard Gill
Since the loophole-free Bell experiments of 2020 and the Nobel prizes in physics of 2022, critics of Bell's work have retreated to the fortress of super-determinism. Now, super-determinism is a derogatory word - it just means "determinism". Palmer, Hance and Hossenfelder argue that quantum mechanics and determinism are not incompatible, using a sophisticated mathematical construction based on a subtle thinning of allowed states and measurements in quantum mechanics, such that what is left appears to make Bell's argument fail, without altering the empirical predictions of quantum mechanics. I think however that it is a smoke screen, and the slogan "lost in math" comes to my mind. I will discuss some other recent disproofs of Bell's theorem using the language of causality based on causal graphs. Causal thinking is also central to law and justice. I will mention surprising connections to my work on serial killer nurse cases, in particular the Dutch case of Lucia de Berk and the current UK case of Lucy Letby.
This pdf is about the Schizophrenia.
For more details visit on YouTube; @SELF-EXPLANATORY;
https://www.youtube.com/channel/UCAiarMZDNhe1A3Rnpr_WkzA/videos
Thanks...!
(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 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.
Nutraceutical market, scope and growth: Herbal drug technologyLokesh Patil
As consumer awareness of health and wellness rises, the nutraceutical market—which includes goods like functional meals, drinks, and dietary supplements that provide health advantages beyond basic nutrition—is growing significantly. As healthcare expenses rise, the population ages, and people want natural and preventative health solutions more and more, this industry is increasing quickly. Further driving market expansion are product formulation innovations and the use of cutting-edge technology for customized nutrition. With its worldwide reach, the nutraceutical industry is expected to keep growing and provide significant chances for research and investment in a number of categories, including vitamins, minerals, probiotics, and herbal supplements.
Deep Behavioral Phenotyping in Systems Neuroscience for Functional Atlasing a...Ana Luísa Pinho
Functional Magnetic Resonance Imaging (fMRI) provides means to characterize brain activations in response to behavior. However, cognitive neuroscience has been limited to group-level effects referring to the performance of specific tasks. To obtain the functional profile of elementary cognitive mechanisms, the combination of brain responses to many tasks is required. Yet, to date, both structural atlases and parcellation-based activations do not fully account for cognitive function and still present several limitations. Further, they do not adapt overall to individual characteristics. In this talk, I will give an account of deep-behavioral phenotyping strategies, namely data-driven methods in large task-fMRI datasets, to optimize functional brain-data collection and improve inference of effects-of-interest related to mental processes. Key to this approach is the employment of fast multi-functional paradigms rich on features that can be well parametrized and, consequently, facilitate the creation of psycho-physiological constructs to be modelled with imaging data. Particular emphasis will be given to music stimuli when studying high-order cognitive mechanisms, due to their ecological nature and quality to enable complex behavior compounded by discrete entities. I will also discuss how deep-behavioral phenotyping and individualized models applied to neuroimaging data can better account for the subject-specific organization of domain-general cognitive systems in the human brain. Finally, the accumulation of functional brain signatures brings the possibility to clarify relationships among tasks and create a univocal link between brain systems and mental functions through: (1) the development of ontologies proposing an organization of cognitive processes; and (2) brain-network taxonomies describing functional specialization. To this end, tools to improve commensurability in cognitive science are necessary, such as public repositories, ontology-based platforms and automated meta-analysis tools. I will thus discuss some brain-atlasing resources currently under development, and their applicability in cognitive as well as clinical neuroscience.
4. COMPOUND OR COMPLEX LIPIDS:
This term includes:
1. Glycolipids
2. Gangliosides
3. Phospholipids
5.
6. Types of complex lipids:
Glycolipids
Gangliosides
Phospholidids
Streroids and sterols
Terpenes (isoprene complexes)
7. 1.Glycolipids (Glycosphingolipids)
These are ceramide-sugar(s).
Ceramide (sphingosine-fatty acid complex) and
glycolipids can be represented as below:
Ceramide+one more hexoses=glycolipids
8. Sphingosine :
Sphingosine is an 18-carbon monosaturated alcohol
containing:
An amino(-NH2) group.
A long chain fatty acid(22-26)is attach to sphingosine
at its( –NH2) group forming what is called ceramide.
Thus ceramide is sphingosine-fatty acid complex.
9.
10. Formation of glycolipids:
Glycolipids are formed when one or more sugars are
attached to ceramide at its terminal –OH group.
Glycolipids can be represented as ceramide sugars.
In certain cases dihydrosphingosine replaces
sphingosine.
11. Occurence:
Glycolipids occur mostly in white matter of the brain
and in the myelin sheaths of nerve fibers.
Various glycolipids such as cerebron, nervon,
oxynervon and kerasin differ from each other in the
type of fatty acid and the type of sugar present in their
molecules.
A common fatty acid present in these compounds is a
24-carbon containing fatty acid namely cerebronic
acid.
12. Glycolipids containing one sugar unit are called
cerebrosides.
Examples of cerebrosides:
Ceramide-glucose
Ceramide- galactose
Occurance:
these occur in plasma membranes of non-neural and
neural tissues respectively.
13. A more complex glycolipid is ceramide- trihexoside;
Its composition is ceramide-glucose-galactose-
galactose.
It can be converted to ceramide
dihexoside(ceramide-glucose-galactose).
Glycolipids have been found to be the determinants of
blood group antigens, A and B.
14. Note :
The sugar molecules present in glycolipids may be
sulfated forming sulfatides also called sulfolipids.
15. 2.Gangliosides:
In this the basic core structure is mostly ceramide-
glucose-galactose-N- acetylgalactosamine and N-
acetyleneuraminic acid.
Neuraminic acid is one of the sialic acids.
16. Occurance:
Ganglioside occur in brain, spleen,
RBCs and nerve cells.
In the brain gangliosides contribute
about 6% of the membrane lipids in
gray matter.
17. Examples:
One important example of ganglioside is GM1.
It occurs in the intestinal cell membrane and act as the
site of attachment to cholera toxin.
Molecular Formula: C73H131N3O31
Its structure is ceramide-glucose- glactose-N-
acetylegalactosamine -galactose
18. GM2 has structure ceramide-glucose-N-
acetylneuraminic acid
Galactose –N-acetylegalactosamine.
Symbol M in these gangliosides means they contain
only one molecule of sialic acid; more complex
gangliosides can have several of these acids.
19. Globosides:
Closely related to glycolipids are compounds called
globosides, said to be mucolipids.
The core structure of globosides is ceramide-glucose-
galactose-galactose-N- acetygalactosamine.
22. Occurance:
Sphingomyelins are present in large amounts in
brain and nerve tissues and in smaller amount in
other tissues and blood.
Because sphingomyelins contain
phosphocholine or phosphoethanolamine,
therefore they possess polar groups resembling
glycerophospholipids.
Sphingomyelin are more stable molecules than
glycerophospholipids.
23. B.Glycerophospholipids:
These are also called phosphoglycerides or glycerol
phosphatides;
These are the phospholipids containing
Glycerol
Fatty acid
H3PO4
And in many cases nitrogenous bases as well
24. Occurance:
They occur in all cells, plant as well as animals.
They are very important as constituent of cellular
structure is shown by the fact that they do not undergo
rapid mobilization during starvation as happens to
neutral fats.
These compounds are not freely soluble in water but
are water- miscible; they do not make true solutions in
water but they disperse forming micelles.
They are good emulsifying agents.
25. Types of glycerophospholipids:
There are various types of glycerophospholipids:
Phosphatidic acids
Lecithins
Cephalins
Plasmalogens
phosphatidylglycerol
26. Phosphatidic acid:
In these acids, one of the fatty acids
of a triacylglycerol is replaced by
H3PO4.
Occurance:
These are parent compounds of all
glycerophospholipids.
They are present in cells in small
amounts only.
27. Lecithins:
These are derivatives of L- phosphatidic acid in which
choline (a nitrogenous base) is joined to
H3PO4(phosphatidic acid+ choline + lecithine);in other
words they are phosphatidyl- cholines.
Choline is trimethylethanolamine and is a quaternary
ammonium compound which is as NaOH.
Depending upon the type of fatty acids R’ and R’’ , there
are many types of lecithins.
Both of its fatty acids may be saturated , both may be
unsaturated or one may be saturated, while the other is
unsaturated.
28. Properties of lecithins:
Lecithins are soluble in all fat- solvents except acetone.
They are white waxy materials.
They are the most abundant of the phospholipids in
cell membranes, serum and bile.
They are good emulsifying agents for fats.
Lecithins are convertible to lysolecithins by the
enzymatic removal of one of a fatty acid group
attached to either carbon No.1 or 2: the latter
compounds cause hemolysis of erythrocytes.
29. The enzyme catalyzing the conversion of lecithin
lysolecithin is called phospholipase A and is found
in snake venoms .
Lecithins containing two molecules of palmatic acid,
i.e. dipalmitoyl lecithin occur in surfactant, a
substance has secreted by type- 2 cells of the lung
alveoli.
Surfactant has a surface tension lowering effect and is
of great help in facilitating lung expansion at birth
and later.
30. The potentiality of the lungs to expand after birth can
be predicted by a chemical analysis of the amniotic
fluid.
If the ratio of lecithin to sphingomyelin in this fluid is
high , it means normal condition.
If the ratio of lecithin to sphingomyelin in this fluid is
high , it means normal condition.
31. Cephalin:
These are structurally identical with lecithins except
the base choline is replaced by either of ethanolamine,
serine , inosite ( occuring as myoinositol) or threonine,
forming phosphatidylethanolamine ,
phosphatidylinositol or threonine respectively.
32. Occurance:
Some authors prefer to reserve the term cephalins for
phosphatidylethanolamine only.
Cephalins are so named because they occur in high
concentration in brain tissue.
Cephalins have properties generally similar to lecithins
and occur associations with them; however , they are
more acidic than lecithins.
They also take part in clotting of blood.
33. Plasmalogens:
The plasmalogens resemble lecithin and cephalin in
structure, but instead of containing a fatty acid the
contain a vinyl ethyl substituent at carbon No.1 of
glycerol and on hydrolysis liberate a high fatty
aldehyde instead of a fatty acid.
In most plasmalogens the base ethanolamine though
choline, serine or inositol may be present.
34. Occurance:
Plasmalogens are chiefly found in skeletal muscle,
heart , brain , liver , platelets.
Plasmalogens appear to be resistant to phospholipases.
Only of the related compounds is the platelet
activating factor which is released from basophils; it
stimulates the aggregation of platelets and release
serotonin from them.
35. Phosphatidylglycerol:
In this case a glycerol molecule is attached to the
phosphoric acid part of the phosphatidic acid.
This substance gives rise to diphosphatidylglycerol also
called cardiolipin.
Occurance:
They occur in mitochondria.
36. 4.Steroids And Sterols:
A large number of compounds found in nature in the
non- saponifiable fraction of lipid belong to the class
of compounds called steroid.
In most of the natural steroids a methyl group is
present at carbon No. 13 and one is usually present at
carbon No 10 .
A subgroup of steroid is sterols which contain one or
more hydroxyl groups and carbonyle or carboxyl
group; there names end in –ol.
37. Some of the natural compounds belonging to the
steroids are cholestrol , ergosterol, bile acids, male and
female sex hormones and the hormones of the adrenal
cortex.
Cardiac glycosides and some alkaloids also have
steroid components.
38. Cholesterol:
It is the most abundant animal sterol.
It was first isolated in 1784 from gall stones
(cholesterol=solid bile).
39. Occurance:
It occur in all animal tissues.
It is most abundant in the adrenal cortex(10%) where it
acts as the precursor of steroid hormones, followed by
nervous system(2%).
Normal plasma level ranges from 150 to 220 mg/dl but
level of 200 mg/dl is at present considered to be the
maximum desirable.
Some 140 grams of cholesterol may be present in an
adult human body.
40. Cholesterol occurs in all animals but only in few higher
plants.
It generally crystallizes in the form of white rhombic
plates.
It is without taste and odor .
• It is insoluble in water but soluble In chloroform ,
ether and acetone(fat solvents).
• It is also very soluble in liquid fat and in solution of
bile salts.
• It is precipitated by digitonin which is a glycoside
present in the leaves and seeds of digitalss.
41. It is solid at room temperature and melts at 150C .
Cholesterol forms esters due to the presence of –OH
group in its molecule.
Cholesterol occurs in tissues in free as well as bound
form, i.e. as esterified with fatty acid.
Cholesterol occur in plasma membrane of tissue cells
and in the plasma lipoproteins.
42. Dehydrocholesterol:
This sterol occur in many tissues but that which is
present in the skin has the special role.
It is converted to vitamin D3 , I.e. cholecalciferol when
the skin is exposed to ultraviolet rays.
Exposure to sunlight is also the results in the
formation of vitamin D3 in the skin because sunlight
contains some u.v. rays; for this reason, vitamin D3 is
also called sunlight vitamin.
43. Ergosterol:
It is the main sterol of fungi and yeast .
Its name originates from the fact that it was first
isolated from ergot , a fungus which grows on plants
specially rye.
when irradiated with u.v. rays it is converted to
ergocalciferol which is the same as vitaminD2.
44. 5.Terpenes(isoprene complexes):
These are hydrocarbons containing carbon and
hydrogen in the ratio of 10: 16; these compounds
contain multiple units of the five carbon containing
hydrocarbon, namely isoprene.
Isoprene has the following structure:
45. The number of isoprene units greatly varies in
different terpenes.
Terpenes may be either
Linear
Or cyclic molecules
Some substances have both linear and cyclic terpenes
in their molecules.
Terpene includes vitamins A, E and K; coenzyme Q
also belong to these compounds.
46. Dolichol is a 17 to 21 isoprene unit containing alcohol
that act as sugar carrier.
During the addition of polysaccharides units to certain
proteins and lipids (forming glycoproteins and
glycolipids respectively) the sugar unit to be anchored
on cell membranes are chemically activated by
attachment to dolichol.
47. Other compound related to terpenes are
Camphor
Menthol
Limolene
Which are present in oil of camphor , mint and lemon
respectively.
48. Functions of lipids:
1) They are good sources of energy, as they provide
9Kcal=approximately 38KJ(1 cal =4.184 J)/g fat utilize
in the body.
2) Lipids in food also act as carriers of fat soluble
vitamins and nutritionally essential fatty acids
(linoleic acid and alpha linolenic acid).these two
fatty acids are needed by the body, but they cannot
be synthesized in the body.
3) Lipids also make the food more palatable and serve
to decrease its mass.
49. 4) The dietary lipids decrease gastric motility and
secretions and have a high satiety value.
5) Body fat provides contour to the body and also
gives anatomical stability to organs like kidneys.
6) Fats are good energy reservoirs in the body.
Adipose tissue is best suited for this purpose due to
its very little water content and high energy content.
7) Lipids act as electrical insulators in the nervous
tissue allowing rapid propagation of action potential,
i.e. depolarization waves or nerve impulses along
myelinated nerve fibers.
50. 8) Lipids are an integral part of cell protoplasm and
cell membranes. Glycolipids occur particularly in the
outer face of plasma membrane and contribute to the
carbohydrate of cell surface.
9) Some lipids act as precursors of very important
physiological compounds. For example,
cholesterol is the precursor of steroid hormones; 7-
dehydrocholesterol and ergosterol are the precursors
of vitamins D3 and D2 respectively.
10) Presence of lipids like cholesterol and others in skin
makes it highly resistant to the absorption of
water-soluble substances and also to the action of
many chemical agents.
51. 11) The sphingosine-containing lipids have a role in the
transmission of the nerve impulses across
synapses as they form part of the post synaptic
membrane receptors.
12) Eicosanoides which include prostanoids, likotriens
and lipoxins possess very important physiological
compounds.
13) In certain cases derivatives of lipids act as
intracellular messengers after they are released.
14) The terpene called dolichol helps in adding sugars to
proteins and lipids in the cell membrane.
52. 15) The platelet-activating factor is a lipid(
plasmalogen); it aggregates platelets and has many
other functions.
16) Ceramide is an important 2nd messenger regulating
pathways such as the cell cycle, aging and
apoptosis(programmed cell death).
17) Cardiolipin occurs in the inner membrane of
mitochondria where it plays a vital role in
mitochondrial functions; it is also believed to be
concerned with apoptosis.
53. Relationship with diseases:
I. Lipids along with proteins form lipoproteins that act
as transporters of various lipids from one tissue to
another. Abnormalities of lipoproteins are
responsible for diseases such as atherosclerosis
causing ischemic diseases.
II. Storage of abnormally high levels of certain lipids
occur due to lack of lysosomal acid hydrolases
resulting in lipid storage diseases.
54. III. One of the lecithins, dipalmitoyl lecithin, is
produced by the alveolar type II cells of the lungs;
the substance called surfactant has detergent- like
surface tension lowering properties preventing
collapse of pulmonary alveoli during expiration; it
also facilitates inspiration by the same property. Its
absence in the new born may prove fatal by
producing the infant respiratory distress
syndrome(IRDS).
IV. Gangliosides M1 present in the intestinal mucosa
acts as the receptor for cholera toxin.