Steroids are a class of lipids found in eukaryotic cell membranes and rarely in some bacteria. Cholesterol is a type of steroid or modified steroid that is an essential structural component of animal cell membranes. It is required to maintain membrane integrity and fluidity. Cholesterol also serves as a precursor for the biosynthesis of steroid hormones, bile acids, and vitamin D. Within cells, cholesterol is converted to bile salts which help to emulsify and absorb dietary fats in the small intestine. Bile salts are then reabsorbed and recycled through enterohepatic circulation.
cholesterol introduction , synthesis , degradation and functions.
different intermediate products , biochemical importance, fate of cholesterol: synthesis of bile acids (primary and secondary ) , synthesis of vitamin D and different steroid hormones
clinical significance of cholesterol: Hypercholesterolemia ANd hypocholesterolemia normal ranges and so on
structure of proteins
definition of Digestion
sources of Proteins --> EXOGENEOUS SOURCES 50-100g/day and ENDOGENEOUS SOURCES 30-100g/day
Proteins DEGRADED BY --> HYDROLASES specifically PEPTIDASES(ENDOPEPTIDASES & EXOPEPTIDASES)
1. Gastric Digestion of Proteins
2. Pancreatic Digestion of Proteins
3. Digestion of Proteins by Small Intestine Enzymes
Absorption of Amino ACids by Na+Dependent, Na+ Independent, Meister Cycle or gama-glutamyl cycle
Cholesterol is a waxy substance found in your blood. Your body needs cholesterol to build healthy cells, but high levels of cholesterol can increase your risk of heart disease.
cholesterol introduction , synthesis , degradation and functions.
different intermediate products , biochemical importance, fate of cholesterol: synthesis of bile acids (primary and secondary ) , synthesis of vitamin D and different steroid hormones
clinical significance of cholesterol: Hypercholesterolemia ANd hypocholesterolemia normal ranges and so on
structure of proteins
definition of Digestion
sources of Proteins --> EXOGENEOUS SOURCES 50-100g/day and ENDOGENEOUS SOURCES 30-100g/day
Proteins DEGRADED BY --> HYDROLASES specifically PEPTIDASES(ENDOPEPTIDASES & EXOPEPTIDASES)
1. Gastric Digestion of Proteins
2. Pancreatic Digestion of Proteins
3. Digestion of Proteins by Small Intestine Enzymes
Absorption of Amino ACids by Na+Dependent, Na+ Independent, Meister Cycle or gama-glutamyl cycle
Cholesterol is a waxy substance found in your blood. Your body needs cholesterol to build healthy cells, but high levels of cholesterol can increase your risk of heart disease.
Subject : Nutrition, Unit- VI
This topic provides brief knowledge about lipid metabolism and it is prepared according to INC syllabus for first year BSc Nursing Students.
Lipids are fatty substances that play an important role in a number of body functions. Apart from being structural components of the cells, Lipids also act as a source and mode of storage of energy for the body. The Lipid Profile Test measures the levels of specific types of lipids in the blood.
For more details, visit:
https://www.1mg.com/labs/test/lipid-profile-1909
Subject : Nutrition, Unit- VI
This topic provides brief knowledge about lipid metabolism and it is prepared according to INC syllabus for first year BSc Nursing Students.
Lipids are fatty substances that play an important role in a number of body functions. Apart from being structural components of the cells, Lipids also act as a source and mode of storage of energy for the body. The Lipid Profile Test measures the levels of specific types of lipids in the blood.
For more details, visit:
https://www.1mg.com/labs/test/lipid-profile-1909
Omega-6 is essential to the body and the main omega-6 acid required by the body is Linoleic acid.
To know more email us : support@nirogam.com
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Omega -3 & Omega -6 Fatty acids and their Health EffectsZahir Khan
Omega-3 fatty acids are essential fatty acids, a class of nutrients needed for our body to function normally.
These are the fats of life which help our cells to function properly.
Omega-3 cannot be produced be our body and should be supplied through the diet
There are 3 very important types of Omega 3 acids
1.Alpha-linolenic acid (ALA)
2.Eicosapentaenoic acid (EPA)
3.Docosahexaenoic acid (DHA)
which have amazing health benefits
Omega 3 plays a major role in a number of functions in our body. Here are they:-
Relaxation and contraction of muscles
Blood clotting
Digestion
Fertility
Cell division
Growth
Movement of calcium and other substances in and out of cells.
Cholesterol (from the Ancient Greek chole- (bile) and stereos (solid), followed by the chemical sufffix -ol for an alcohol) is an organic molecule. It is a sterol (or modified steroid), a type of lipid. Cholesterol is biosynthesized by all animal cells and is an essential structural component of animal cell membranes.
Cholesterol also serves as a precursor for the biosynthesis of steroid hormones, bile acid and vitamin D. Cholesterol is the principal sterol synthesized by all animals. In vertebrates, hepatic cells typically produce the greatest amounts. It is absent among prokaryotes (bacteria and archaea), although there are some exceptions, such as Mycoplasma, which require cholesterol for growth.
cholesterol is essential because it is involved in synthesis of
1. steroidal hormone
2.vitamin-d
3.bile acids
4. it is also structural component of cell membrane
IN PLASMA MEMBRANE
Cholesterol is important in the membrane as it helps to maintain cell membrane stability at varying temperatures. Cholesterol is bound to neighbouring phospholipid molecules via hydrogen bonds and therefore at low temperatures, reduces their packing.
2. TRANSPORTATION
Cholesteryl ester, a dietary lipid, is an ester of cholesterol. The ester bond is formed between the carboxylate group of a fatty acid and the hydroxyl group of cholesterol. Cholesteryl esters have a lower solubility in water due to their increased hydrophobicity. Esters are formed by replacing at least one –OH (hydroxyl) group with an –O–alkyl (alkoxy) group. They are hydrolyzed by pancreatic enzymes, cholesterol esterase, to produce cholesterol and free fatty acids
cholesterol is also important to maintain structure of lipoprotein
Cholesterol travels through the blood on proteins called “lipoproteins.” Two types of lipoproteins carry cholesterol throughout the body:
1.LDL (low-density lipoprotein), sometimes called “bad” cholesterol, makes up most of your body's cholesterol.
2.HDL (high-density lipoprotein) called “good cholesterol” makes a less part of your body’s cholesterol
the slides aim at providing explanations on cholesterol biosynthesis, regulations, functions of cholesterol, and their consequences. facts about lipoproteins have also been included. enjoy the reading
prepared by Asangalwisye Deo
St. john's University of Tanzania
Operation “Blue Star” is the only event in the history of Independent India where the state went into war with its own people. Even after about 40 years it is not clear if it was culmination of states anger over people of the region, a political game of power or start of dictatorial chapter in the democratic setup.
The people of Punjab felt alienated from main stream due to denial of their just demands during a long democratic struggle since independence. As it happen all over the word, it led to militant struggle with great loss of lives of military, police and civilian personnel. Killing of Indira Gandhi and massacre of innocent Sikhs in Delhi and other India cities was also associated with this movement.
Francesca Gottschalk - How can education support child empowerment.pptxEduSkills OECD
Francesca Gottschalk from the OECD’s Centre for Educational Research and Innovation presents at the Ask an Expert Webinar: How can education support child empowerment?
2024.06.01 Introducing a competency framework for languag learning materials ...Sandy Millin
http://sandymillin.wordpress.com/iateflwebinar2024
Published classroom materials form the basis of syllabuses, drive teacher professional development, and have a potentially huge influence on learners, teachers and education systems. All teachers also create their own materials, whether a few sentences on a blackboard, a highly-structured fully-realised online course, or anything in between. Despite this, the knowledge and skills needed to create effective language learning materials are rarely part of teacher training, and are mostly learnt by trial and error.
Knowledge and skills frameworks, generally called competency frameworks, for ELT teachers, trainers and managers have existed for a few years now. However, until I created one for my MA dissertation, there wasn’t one drawing together what we need to know and do to be able to effectively produce language learning materials.
This webinar will introduce you to my framework, highlighting the key competencies I identified from my research. It will also show how anybody involved in language teaching (any language, not just English!), teacher training, managing schools or developing language learning materials can benefit from using the framework.
Read| The latest issue of The Challenger is here! We are thrilled to announce that our school paper has qualified for the NATIONAL SCHOOLS PRESS CONFERENCE (NSPC) 2024. Thank you for your unwavering support and trust. Dive into the stories that made us stand out!
How to Make a Field invisible in Odoo 17Celine George
It is possible to hide or invisible some fields in odoo. Commonly using “invisible” attribute in the field definition to invisible the fields. This slide will show how to make a field invisible in odoo 17.
Unit 8 - Information and Communication Technology (Paper I).pdfThiyagu K
This slides describes the basic concepts of ICT, basics of Email, Emerging Technology and Digital Initiatives in Education. This presentations aligns with the UGC Paper I syllabus.
2. Steroids are a third class of lipids found
in the membranes of eukaryotes, and,
very rarely, in bacteria.
Steroids, along with lipid vitamins and
terpenes, are classified as isoprenoids
because their structures are related to
the five carbon molecule isoprene.
Steroids contain four fused rings: three
six-carbon rings designated A, B, and C
and a five-carbon D ring.
4. Cholesterol, is derived from the
Ancient Greek word Chole - bile
and stereos - solid
Followed by the chemical
suffix - ol for an alcohol, is an
organic molecule.
It is a derived lipid molecule –
a sterol or modified steroid
7. PROPERTIES
Molecular formula C27H46O
Molar mass 386.65 g/mol
Appearance white crystalline powder[2]
Density 1.052 g/cm3
Melting point 148–150 °C[2]
Boiling point 360 °C (decomposes)
Solubility in water 0.095 mg/L (30 °C)
Solubility
soluble in acetone, benzene,
chloroform, ethanol, ether, hexane,
isopropyl myristate, methanol
8.
9. PRODUCTION OF CHOLESTEROL IN
VERTEBRATES
In vertebrates the hepatic cells
typically produce greater
amounts of Cholesterol than
other cells.
It is almost completely absent
among prokaryotes (bacteria and
archaea), although there are
some exceptions such as
Mycoplasma, which require
cholesterol for growth.
10. BODY CHOLESTEROL CONTENT
For a man of about 68 kg (150 lb), typical
total body-cholesterol synthesis is
approximately 1 g (1,000 mg) per day,
Total body content of Cholesterol is
approximately 35 g, primarily located
within the membranes of all the cells of
the body.
Typical daily dietary intake of additional
cholesterol, is 200–300 mg.
11. INGESTED CHOLESTEROL
Most ingested cholesterol is esterified, and
esterified cholesterol is poorly absorbed
. The body also compensates for any
absorption of additional cholesterol by
reducing cholesterol synthesis.
For these reasons, seven to ten hours after
ingestion of cholesterol, blood levels will
show little if any effect on total body
cholesterol content or concentrations of
cholesterol in the blood.
12. However, during the first seven hours
after ingestion of cholesterol, the levels
significantly increase
Cholesterol is recycled.
The liver excretes it in a non-esterified
form (via bile) into the digestive tract
.
Typically about 50% of the excreted
cholesterol is reabsorbed by the small
bowel back into the bloodstream.
14. CHOLESTEROL IS REQUIRED
TO BUILD AND MAINTAIN
MEMBRANES
It modulates membrane
fluidity over the range of
physiological temperatures.
15. Cholesterol serves as a precursor
for the biosynthesis of steroids
hormones, bile acids, and vitamin D
Cholesterol is the principal sterol
synthesized by animals. All kinds of
cells in animals can produce it.
Recent studies show that vitamin D
is a potent antioxidant, helping to
detox the body and protect arteries
too.
16. CELL MEMBRAIN INTEGRITY
It is biosynthesized by all
animal cells because it is an
essential structural component
of animal cell membranes
It is required to maintain both
the structural integrity and
fluidity of the cell membrane
17. (a) To protect membrane
integrity/cell-viability cholesterol
enables animal cells not to need a
cell wall like plants & bacteria
And thus animal cells are able to
(b) change shape and
(c) move about (unlike bacteria and
plant cells which are restricted by
their cell walls).
18.
19. The hydroxyl group on cholesterol interacts
with the polar head groups of the membrane
phospholipids and sphingolipids
While the bulky steroid and the
hydrocarbon chain are embedded in the
membrane, alongside the nonpolar fatty-
acid chain of the other lipids.
Through the interaction with the
phospholipid fatty-acid chains, cholesterol
increases membrane packing, which
reduces membrane fluidity.
20.
21. o The structure of the tetracyclic ring of
cholesterol contributes to the decreased
fluidity of the cell membrane as the
molecule is in a trans conformation
making all but the side chain of
cholesterol rigid and planar.
o In this structural role, cholesterol reduces
the permeability of the plasma membrane
to neutral solutes, hydrogen ions, and
sodium ions.
22. Within the cell membrane, cholesterol also
functions in intracellular transport, cell
signalling and nerve conduction.
Cholesterol is essential for the structure and
function of invaginated caveolae and clathrin-
coated pits, including caveolae-dependent
and clathrin-dependent endocytosis
The role of cholesterol in such endocytosis
can be investigated by using methyl beta
cyclodextrin (MβCD) to remove cholesterol
from the plasma membrane.
23.
24. Recently, cholesterol has also been
implicated in cell signalling processes,
assisting in the formation of lipid rafts in
the plasma membrane.
Lipid raft formation brings receptor
proteins in close proximity with high
concentrations of second messenger
molecules.]
In many neurons, a myelin sheath, rich in
cholesterol, since it is derived from
compacted layers of Schwann cell
membrane, provides insulation for more
efficient conduction of impulses.
25. Cholesterol inserts itself into the bilayer and keeps the
chains of the phospholipids from becoming entangled.
They also work with the proteins to allow for movement
around the cell surface.
26. On the top you can see how the cholesterol
(yellow) breaks up the monotony of the
phospholipids.
The space makes it easy for proteins and lipids
to flow – hence the fluid mosaic model.
The Figure shows a lipid raft, made with
phospholipids with longer tails, and similar
proteins to do similar functions.
These rafts can move around to where they are
needed on the surface, break up and reform
later, all because the elements of them are
fluid.
Thank you cholesterol.
31. PRECURSOR OF STEROID
HORMONES
Cholesterol is the precursor to all steroid
hormones, which account for numerous
physiological functions your body needs to maintain
a normal, healthy state
Cholesterol is similar to a band aid used to repair
wounds and irritations on the arteries.
Pregnenolone is also a precursor to all other
steroid hormones.
32. Cholesterol is an important precursor
molecule for the synthesis of
Steroid hormones
Including the adrenal gland hormones
cortisol and aldosterone,
As well as the sex hormones
progesterone, estrogens, and
testosterone, and their derivatives.
Some research indicates cholesterol may
act as an antioxidant
33.
34. Glucocorticoids are necessary for blood sugar
regulation, being extremely important for your power
houses, the mitochondria.
Mineralocorticoids are the key to balancing your
minerals, maintaining a perfect and very sensitive
homeostasis. This in turn adjust blood pressure quickly
and counteracts a loss of minerals e.g. through sweating.
Sex Hormones -All your sex hormones are made from
cholesterol. If you are male, testosterone (an androgen)
Ladies fight with estrogens and progesterone on a
monthly basis.
36. Within cells, cholesterol is the precursor
molecule in several biochemical pathways.
In the liver, cholesterol is converted to bile,
which is then stored in the gallbladder.
Bile contains bile salts, which solubilize
fats in the digestive tract and aid in the
intestinal absorption of fat molecules as
well as the fat-soluble vitamins, A, D, E,
and K.
37. WHAT ARE BILE SALTS ?
The bile salts are conjugates of cholic
acid and chenodeoxycholic acid with
glycine and taurine. Normally the ratio
of glycine : taurine conjugates is about
3 : 1.
They are synthesised in the liver by
hydroxylation and side-chain oxidation
of cholesterol, followed by conjugation
with glycine or taurine.
38. conjugated bilirubin 5.1
cholesterol 16.0
lecithin and other
phospholipids
3.9
bile salts 145.0
What are the main constituents of bile?
Apart from electrolytes, the main constituents of gall bladder bile
are as follows (mmol /L )
39. WHAT IS THE FUNCTION OF THE BILE SALTS ?
The function of the bile
salts in the small intestine is
to emulsify dietary lipids into
mixed micelles that are
small enough to be
absorbed across the
intestinal mucosa.
.
40. The bile salts are amphiphilic
molecules, with a hydrophobic
planar hydrocarbon ring and a
hydrophilic region provided by
the hydroxyl groups and the
glycine or taurine conjugated
to the carboxylic acid group
above the plane of the ring.
41.
42. In an aqueous medium the bile
salts will form micelles on their
own.
In bile they also emulsify the
cholesterol that is secreted in the
bile, so keeping it in solution.
The phospholipids in bile also
help to emulsify the cholesterol
43. REABSORPTION OF BILE SALTS
It seems likely that bile salts are reabsorbed
from the small intestine and recycled.
Interestingly, they are not absorbed from the
micelles that contain monoacylglycerol, non-
esterified fatty acids, phospholipids and
cholesterol.
Instead, as the other lipids are absorbed into
intestinal epithelial cells from the micelles, the
remnants for micelles that consist more or less
completely of bile salt conjugates.
These are absorbed in the terminal ileum.
44. BILE ACIDS
Analysis of bile shows the presence of four
bile acids, conjugated with glycine and
taurine:
Chenodeoxycholic and Cholic acids, which
are synthesised from cholesterol by isolated
hepatocytes,
And Deoxycholic acid, as well as a small
amount of Lithocholic acid, neither of which
is synthesised by isolated hepatocytes.
45. When the glycine and taurine
conjugates of chenodeoxycholic
acid and cholic acid were
incubated with a mixed culture of
faecal bacteria,
Free chenodeoxycholic acid and
cholic acid were found in the
incubation medium, together with
two new compounds: lithocholic
acid and deoxycholic acid.
46.
47.
48. Intestinal bacteria seem to be able to
deconjugate the conjugated bile acids, and
metabolise them further, to lithocholic and
deoxycholic acids.
Although some 75 mmol of bile salts are
secreted each day, the total body pool is only
about 7.5 - 12.5 mmol; each molecule is
secreted and reabsorbed some 6 - 10 time daily.
Chenodeoxycholic and cholic acid are generally
referred to as primary bile salts, because they
are synthesised in the liver; lithocholic and
deoxycholic acids are referred to as secondary
bile salts.