Carbohydrates are widely distributed in nature and serve many functions. They can be classified based on their structure as monosaccharides, disaccharides, oligosaccharides, or polysaccharides. Monosaccharides are the simplest form and include important sugars like glucose and fructose. Multiple monosaccharides can link together to form larger carbohydrates. Many carbohydrates naturally exist as rings due to cyclization reactions between a carbonyl group and hydroxyl group. Carbohydrates play essential roles in energy storage, structure, and cellular processes in living organisms.
Enzymes mechanism of action, their specificity types, active center structure and action, inhibitor types, fisher and Koshlend theory are presented. Enzymes classification, a new class of enzymes discovered recently, detailed explanation of each class reaction types is presented as well
Conformational properties of polysaccharidesKAUSHAL SAHU
INTRODUCTION
CONCEPT AND TERMINOLOGIES ABOUT CONFORMATIONS
DIHEDRAL ANGLES AND A MAP OF FAVORED CONFORMATIONS
CLASSES OF CONFORMATIONS WITH EXAMPLES
ORDERED CONFORMATION
DISORDERED CONFORMATION
IMPORTANCE OF CONFORMATIONAL PROPERTIES
CONCLUSIONS
REFERENCES
This presentation is made for F.Y.Bsc. Students.
The presentation includes the General Properties of Carbohydrate and the classification of carbohydrates.
Introduction& Principle of Buffering
Buffer capacity
Types of Buffer
Henderson-Hesselbalch equation
Mechanism of Buffer action
Buffer system in body
Disturbance of Buffer balancing
Buffer Titration & curve
Application of Buffer
Conclusion
References
Resent reaserches
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.
Enzymes mechanism of action, their specificity types, active center structure and action, inhibitor types, fisher and Koshlend theory are presented. Enzymes classification, a new class of enzymes discovered recently, detailed explanation of each class reaction types is presented as well
Conformational properties of polysaccharidesKAUSHAL SAHU
INTRODUCTION
CONCEPT AND TERMINOLOGIES ABOUT CONFORMATIONS
DIHEDRAL ANGLES AND A MAP OF FAVORED CONFORMATIONS
CLASSES OF CONFORMATIONS WITH EXAMPLES
ORDERED CONFORMATION
DISORDERED CONFORMATION
IMPORTANCE OF CONFORMATIONAL PROPERTIES
CONCLUSIONS
REFERENCES
This presentation is made for F.Y.Bsc. Students.
The presentation includes the General Properties of Carbohydrate and the classification of carbohydrates.
Introduction& Principle of Buffering
Buffer capacity
Types of Buffer
Henderson-Hesselbalch equation
Mechanism of Buffer action
Buffer system in body
Disturbance of Buffer balancing
Buffer Titration & curve
Application of Buffer
Conclusion
References
Resent reaserches
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.
Introduction to Carbohydrates and its ChemistryDHANANJAY PATIL
A Comprehensive Introduction to Carbohydrates its chemistry, classification, qualitative tests an disorders related to its metabolism. This will give readers a overall insight to this topic. All types of queries and suggestions are most welcome
Carbohydrates And Monosaccharide Notes No# 1SidraMahmood15
full notes on carbohydrates and monosaccharide general aspects.
Carbohydrates, or carbs, are sugar molecules. Along with proteins and fats, carbohydrates are one of three main nutrients found in foods and drinks. Your body breaks down carbohydrates into glucose. Glucose, or blood sugar, is the main source of energy for your body's cells, tissues, and organ.
organic macromolecules that are made up of carbon, hydrogen, and oxygen atoms and are used for energy storage or as structural molecules.
Chemistry of life (Biochemistry) The study of chemical .docxbissacr
Chemistry of life (Biochemistry)
The study of chemical compounds that are vital for living organisms to sustain life is called biochemistry. The subject deals with the nature of these compounds and characteristic reactions they make inside the living organisms . We are not involved fundamentally with the study of biochemistry as a subject , but to give brief introduction to main classes of the organic compounds in this important field. It is beyond this discussion to present detailed explanation of these essential organic substances . We will give short introduction of the main classes and their active role in our body . Some of these groups are , carbohydrates , fats and proteins, etc..
· Carbohydrates.
Carbohydrates are classes of organic compounds that consist of carbon , hydrogen and oxygen with an empirical formula of Cm(H2O)n in most cases . The terms m and n can be the same as in the case of C6H12O6 (glucose) or different in the case of C12H22O11 (sucrose) . Another important feature of the carbohydrates is that oxygen and hydrogen are generally in ratio of 2:1 , so that it was historically called hydrates of carbon ; but not all compounds of carbohydrates necessarily maintain this hydrogen – oxygen ratio and not all compounds that fit this hydrogen-oxygen ratio are carbohydrates .
In biochemistry the term carbohydrate denotes different compounds called saccharides . These compounds include sugars , starch and cellulose . Saccharides (Greek word meaning sugars) are generally classified into monosaccharides , disaccharides and polysaccharides .
Monosaccharides are the simple sugars which are either aldoses (aldehydes) like glucose or ketoses ( ketones) like fructose . These simple sugars are further classified on the base of the number of carbon atoms they contain like pentose (containing five carbon atoms) , or hexose (containing six carbon atoms) .
Carbohydrates are naturally formed in a process called photosynthesis in which plants combine CO2 from the air and water from the soil in the presence of chlorophyll , sunlight and certain enzymes producing simple sugars .
6 CO2 + 6H2O (sun light) C6H12O6 + 6O2
sugar(glucose)
This above reaction is not simple process as it looks , but extremely complicated reaction with different intermediate steps before it gives the final product . since the final product is a monosaccharide , plants have the ability to synthesize disaccharides by combining two molecules of monosaccharides .
2 C6H12O6 C12H1.
Lec 1 Carbohydrates-1.pptx the signs and symptoms of Kwashiorkor and Marasmus...phatimamohamett054
For security reasons why you think some students do the signs and symptoms of Kwashiorkor disease ppt biochemistry and Marasmus and Marasmus and Marasmus and Marasmus and Marasmus and Marasmus and the children are the signs of all that would have small mouth
This is for mscdfsm ,#medical #nursing #biology #neet #foodandnutrition #biochemistry and #related subjects .also it will help #dieticians to upgrade their skills
Title: Sense of Taste
Presenter: Dr. Faiza, Assistant Professor of Physiology
Qualifications:
MBBS (Best Graduate, AIMC Lahore)
FCPS Physiology
ICMT, CHPE, DHPE (STMU)
MPH (GC University, Faisalabad)
MBA (Virtual University of Pakistan)
Learning Objectives:
Describe the structure and function of taste buds.
Describe the relationship between the taste threshold and taste index of common substances.
Explain the chemical basis and signal transduction of taste perception for each type of primary taste sensation.
Recognize different abnormalities of taste perception and their causes.
Key Topics:
Significance of Taste Sensation:
Differentiation between pleasant and harmful food
Influence on behavior
Selection of food based on metabolic needs
Receptors of Taste:
Taste buds on the tongue
Influence of sense of smell, texture of food, and pain stimulation (e.g., by pepper)
Primary and Secondary Taste Sensations:
Primary taste sensations: Sweet, Sour, Salty, Bitter, Umami
Chemical basis and signal transduction mechanisms for each taste
Taste Threshold and Index:
Taste threshold values for Sweet (sucrose), Salty (NaCl), Sour (HCl), and Bitter (Quinine)
Taste index relationship: Inversely proportional to taste threshold
Taste Blindness:
Inability to taste certain substances, particularly thiourea compounds
Example: Phenylthiocarbamide
Structure and Function of Taste Buds:
Composition: Epithelial cells, Sustentacular/Supporting cells, Taste cells, Basal cells
Features: Taste pores, Taste hairs/microvilli, and Taste nerve fibers
Location of Taste Buds:
Found in papillae of the tongue (Fungiform, Circumvallate, Foliate)
Also present on the palate, tonsillar pillars, epiglottis, and proximal esophagus
Mechanism of Taste Stimulation:
Interaction of taste substances with receptors on microvilli
Signal transduction pathways for Umami, Sweet, Bitter, Sour, and Salty tastes
Taste Sensitivity and Adaptation:
Decrease in sensitivity with age
Rapid adaptation of taste sensation
Role of Saliva in Taste:
Dissolution of tastants to reach receptors
Washing away the stimulus
Taste Preferences and Aversions:
Mechanisms behind taste preference and aversion
Influence of receptors and neural pathways
Impact of Sensory Nerve Damage:
Degeneration of taste buds if the sensory nerve fiber is cut
Abnormalities of Taste Detection:
Conditions: Ageusia, Hypogeusia, Dysgeusia (parageusia)
Causes: Nerve damage, neurological disorders, infections, poor oral hygiene, adverse drug effects, deficiencies, aging, tobacco use, altered neurotransmitter levels
Neurotransmitters and Taste Threshold:
Effects of serotonin (5-HT) and norepinephrine (NE) on taste sensitivity
Supertasters:
25% of the population with heightened sensitivity to taste, especially bitterness
Increased number of fungiform papillae
These simplified slides by Dr. Sidra Arshad present an overview of the non-respiratory functions of the respiratory tract.
Learning objectives:
1. Enlist the non-respiratory functions of the respiratory tract
2. Briefly explain how these functions are carried out
3. Discuss the significance of dead space
4. Differentiate between minute ventilation and alveolar ventilation
5. Describe the cough and sneeze reflexes
Study Resources:
1. Chapter 39, Guyton and Hall Textbook of Medical Physiology, 14th edition
2. Chapter 34, Ganong’s Review of Medical Physiology, 26th edition
3. Chapter 17, Human Physiology by Lauralee Sherwood, 9th edition
4. Non-respiratory functions of the lungs https://academic.oup.com/bjaed/article/13/3/98/278874
- Video recording of this lecture in English language: https://youtu.be/lK81BzxMqdo
- Video recording of this lecture in Arabic language: https://youtu.be/Ve4P0COk9OI
- Link to download the book free: https://nephrotube.blogspot.com/p/nephrotube-nephrology-books.html
- Link to NephroTube website: www.NephroTube.com
- Link to NephroTube social media accounts: https://nephrotube.blogspot.com/p/join-nephrotube-on-social-media.html
Basavarajeeyam is an important text for ayurvedic physician belonging to andhra pradehs. It is a popular compendium in various parts of our country as well as in andhra pradesh. The content of the text was presented in sanskrit and telugu language (Bilingual). One of the most famous book in ayurvedic pharmaceutics and therapeutics. This book contains 25 chapters called as prakaranas. Many rasaoushadis were explained, pioneer of dhatu druti, nadi pareeksha, mutra pareeksha etc. Belongs to the period of 15-16 century. New diseases like upadamsha, phiranga rogas are explained.
Lung Cancer: Artificial Intelligence, Synergetics, Complex System Analysis, S...Oleg Kshivets
RESULTS: Overall life span (LS) was 2252.1±1742.5 days and cumulative 5-year survival (5YS) reached 73.2%, 10 years – 64.8%, 20 years – 42.5%. 513 LCP lived more than 5 years (LS=3124.6±1525.6 days), 148 LCP – more than 10 years (LS=5054.4±1504.1 days).199 LCP died because of LC (LS=562.7±374.5 days). 5YS of LCP after bi/lobectomies was significantly superior in comparison with LCP after pneumonectomies (78.1% vs.63.7%, P=0.00001 by log-rank test). AT significantly improved 5YS (66.3% vs. 34.8%) (P=0.00000 by log-rank test) only for LCP with N1-2. Cox modeling displayed that 5YS of LCP significantly depended on: phase transition (PT) early-invasive LC in terms of synergetics, PT N0—N12, cell ratio factors (ratio between cancer cells- CC and blood cells subpopulations), G1-3, histology, glucose, AT, blood cell circuit, prothrombin index, heparin tolerance, recalcification time (P=0.000-0.038). Neural networks, genetic algorithm selection and bootstrap simulation revealed relationships between 5YS and PT early-invasive LC (rank=1), PT N0—N12 (rank=2), thrombocytes/CC (3), erythrocytes/CC (4), eosinophils/CC (5), healthy cells/CC (6), lymphocytes/CC (7), segmented neutrophils/CC (8), stick neutrophils/CC (9), monocytes/CC (10); leucocytes/CC (11). Correct prediction of 5YS was 100% by neural networks computing (area under ROC curve=1.0; error=0.0).
CONCLUSIONS: 5YS of LCP after radical procedures significantly depended on: 1) PT early-invasive cancer; 2) PT N0--N12; 3) cell ratio factors; 4) blood cell circuit; 5) biochemical factors; 6) hemostasis system; 7) AT; 8) LC characteristics; 9) LC cell dynamics; 10) surgery type: lobectomy/pneumonectomy; 11) anthropometric data. Optimal diagnosis and treatment strategies for LC are: 1) screening and early detection of LC; 2) availability of experienced thoracic surgeons because of complexity of radical procedures; 3) aggressive en block surgery and adequate lymph node dissection for completeness; 4) precise prediction; 5) adjuvant chemoimmunoradiotherapy for LCP with unfavorable prognosis.
MANAGEMENT OF ATRIOVENTRICULAR CONDUCTION BLOCK.pdfJim Jacob Roy
Cardiac conduction defects can occur due to various causes.
Atrioventricular conduction blocks ( AV blocks ) are classified into 3 types.
This document describes the acute management of AV block.
Report Back from SGO 2024: What’s the Latest in Cervical Cancer?bkling
Are you curious about what’s new in cervical cancer research or unsure what the findings mean? Join Dr. Emily Ko, a gynecologic oncologist at Penn Medicine, to learn about the latest updates from the Society of Gynecologic Oncology (SGO) 2024 Annual Meeting on Women’s Cancer. Dr. Ko will discuss what the research presented at the conference means for you and answer your questions about the new developments.
Title: Sense of Smell
Presenter: Dr. Faiza, Assistant Professor of Physiology
Qualifications:
MBBS (Best Graduate, AIMC Lahore)
FCPS Physiology
ICMT, CHPE, DHPE (STMU)
MPH (GC University, Faisalabad)
MBA (Virtual University of Pakistan)
Learning Objectives:
Describe the primary categories of smells and the concept of odor blindness.
Explain the structure and location of the olfactory membrane and mucosa, including the types and roles of cells involved in olfaction.
Describe the pathway and mechanisms of olfactory signal transmission from the olfactory receptors to the brain.
Illustrate the biochemical cascade triggered by odorant binding to olfactory receptors, including the role of G-proteins and second messengers in generating an action potential.
Identify different types of olfactory disorders such as anosmia, hyposmia, hyperosmia, and dysosmia, including their potential causes.
Key Topics:
Olfactory Genes:
3% of the human genome accounts for olfactory genes.
400 genes for odorant receptors.
Olfactory Membrane:
Located in the superior part of the nasal cavity.
Medially: Folds downward along the superior septum.
Laterally: Folds over the superior turbinate and upper surface of the middle turbinate.
Total surface area: 5-10 square centimeters.
Olfactory Mucosa:
Olfactory Cells: Bipolar nerve cells derived from the CNS (100 million), with 4-25 olfactory cilia per cell.
Sustentacular Cells: Produce mucus and maintain ionic and molecular environment.
Basal Cells: Replace worn-out olfactory cells with an average lifespan of 1-2 months.
Bowman’s Gland: Secretes mucus.
Stimulation of Olfactory Cells:
Odorant dissolves in mucus and attaches to receptors on olfactory cilia.
Involves a cascade effect through G-proteins and second messengers, leading to depolarization and action potential generation in the olfactory nerve.
Quality of a Good Odorant:
Small (3-20 Carbon atoms), volatile, water-soluble, and lipid-soluble.
Facilitated by odorant-binding proteins in mucus.
Membrane Potential and Action Potential:
Resting membrane potential: -55mV.
Action potential frequency in the olfactory nerve increases with odorant strength.
Adaptation Towards the Sense of Smell:
Rapid adaptation within the first second, with further slow adaptation.
Psychological adaptation greater than receptor adaptation, involving feedback inhibition from the central nervous system.
Primary Sensations of Smell:
Camphoraceous, Musky, Floral, Pepperminty, Ethereal, Pungent, Putrid.
Odor Detection Threshold:
Examples: Hydrogen sulfide (0.0005 ppm), Methyl-mercaptan (0.002 ppm).
Some toxic substances are odorless at lethal concentrations.
Characteristics of Smell:
Odor blindness for single substances due to lack of appropriate receptor protein.
Behavioral and emotional influences of smell.
Transmission of Olfactory Signals:
From olfactory cells to glomeruli in the olfactory bulb, involving lateral inhibition.
Primitive, less old, and new olfactory systems with different path
Ozempic: Preoperative Management of Patients on GLP-1 Receptor Agonists Saeid Safari
Preoperative Management of Patients on GLP-1 Receptor Agonists like Ozempic and Semiglutide
ASA GUIDELINE
NYSORA Guideline
2 Case Reports of Gastric Ultrasound
NVBDCP.pptx Nation vector borne disease control programSapna Thakur
NVBDCP was launched in 2003-2004 . Vector-Borne Disease: Disease that results from an infection transmitted to humans and other animals by blood-feeding arthropods, such as mosquitoes, ticks, and fleas. Examples of vector-borne diseases include Dengue fever, West Nile Virus, Lyme disease, and malaria.
Recomendações da OMS sobre cuidados maternos e neonatais para uma experiência pós-natal positiva.
Em consonância com os ODS – Objetivos do Desenvolvimento Sustentável e a Estratégia Global para a Saúde das Mulheres, Crianças e Adolescentes, e aplicando uma abordagem baseada nos direitos humanos, os esforços de cuidados pós-natais devem expandir-se para além da cobertura e da simples sobrevivência, de modo a incluir cuidados de qualidade.
Estas diretrizes visam melhorar a qualidade dos cuidados pós-natais essenciais e de rotina prestados às mulheres e aos recém-nascidos, com o objetivo final de melhorar a saúde e o bem-estar materno e neonatal.
Uma “experiência pós-natal positiva” é um resultado importante para todas as mulheres que dão à luz e para os seus recém-nascidos, estabelecendo as bases para a melhoria da saúde e do bem-estar a curto e longo prazo. Uma experiência pós-natal positiva é definida como aquela em que as mulheres, pessoas que gestam, os recém-nascidos, os casais, os pais, os cuidadores e as famílias recebem informação consistente, garantia e apoio de profissionais de saúde motivados; e onde um sistema de saúde flexível e com recursos reconheça as necessidades das mulheres e dos bebês e respeite o seu contexto cultural.
Estas diretrizes consolidadas apresentam algumas recomendações novas e já bem fundamentadas sobre cuidados pós-natais de rotina para mulheres e neonatos que recebem cuidados no pós-parto em unidades de saúde ou na comunidade, independentemente dos recursos disponíveis.
É fornecido um conjunto abrangente de recomendações para cuidados durante o período puerperal, com ênfase nos cuidados essenciais que todas as mulheres e recém-nascidos devem receber, e com a devida atenção à qualidade dos cuidados; isto é, a entrega e a experiência do cuidado recebido. Estas diretrizes atualizam e ampliam as recomendações da OMS de 2014 sobre cuidados pós-natais da mãe e do recém-nascido e complementam as atuais diretrizes da OMS sobre a gestão de complicações pós-natais.
O estabelecimento da amamentação e o manejo das principais intercorrências é contemplada.
Recomendamos muito.
Vamos discutir essas recomendações no nosso curso de pós-graduação em Aleitamento no Instituto Ciclos.
Esta publicação só está disponível em inglês até o momento.
Prof. Marcus Renato de Carvalho
www.agostodourado.com
micro teaching on communication m.sc nursing.pdfAnurag Sharma
Microteaching is a unique model of practice teaching. It is a viable instrument for the. desired change in the teaching behavior or the behavior potential which, in specified types of real. classroom situations, tends to facilitate the achievement of specified types of objectives.
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Pharynx and Clinical Correlations BY Dr.Rabia Inam Gandapore.pptx
Carbohydrates.pdf
1. CARBOHYDRATES
• Introduction:
• Carbohydrates are widely distributed in nature. They are found
abundantly in plants and in animals. In plants, carbohydrates may be
found as sucrose, cellulose, starch and the like. In animals, they are
very important sources of food. They may be transformed to simpler
forms in the animal digestive tract. In the liver they are transformed
into glycogen also known as animal starch. When broken down to
glucose, they provide the main source of energy for living organisms.
Carbohydrates are likewise found in the connective tissues of animals
where they serve as lubricants in joints.
2. • The simplest form of carbohydrates are the monosaccharides. When
2 of these are linked together the resulting carbohydrate is called a
disaccharide. Both monosaccharides and disaccharides are called
sugars .Linking together of many thousands of monosaccharides lead
to the formation of larger carbohydrates known as polysaccharides.
3. CHEMISTRY OF CARBOHYDRATES
1. Definition
Carbohydrates – also known as saccharides, are polyhydroxy aldehydes or
ketones and their derivatives with at least three carbon atoms that possess a
carbonyl group.
- most abundant organic molecules
- represented by the simple stoichiometric formula (CH2O)n hence
used to be known as “hydrated carbon”.
- functions: provide significant fraction of the energy in the diet
of most organisms
storage form of energy in the body; used as a primary cellular
fuel
serve as cell membrane components that mediate some forms of
intercellular communication
serve as structural components of many organisms
4. 2. CLASSIFICATION
Classification of carbohydrates is based on their ability to be hydrolyzed
to smaller compounds, by the number of carbon atoms, by the direction
of rotation of polarized light, and by the structural relationships to the
three-carbon sugar glyceraldehyde.
2.1 Monosaccharides are simple, monomeric sugars that can no longer
be hydrolyzed to smaller compounds. They consist of a single poly-
hydroxy aldehyde or ketone unit.
2.1.1 They may be further classified, depending on the number of
carbon atoms present into:
5. - Trioses: the smallest molecules composed of 3 carbon atoms. There
are two trioses, the glyceraldehyde (aldose) and the
dihydroxyacetone (ketose), which have the same atomic composition
but differ in the location of their hydrogen and double bonds
(tautomers).
- Tetroses: composed of 4 carbon atoms, (CH2O)4, include threose,
erythrose, and ketose.
- Pentoses: of major biological importance consisting of 5 carbon
atoms. Examples are ribose, xylose, arabinose and rhamnose
- Hexoses: 6 carbon atoms like glucose, fructose, mannose and
galactose
TEK
Gly-Di
AXRR
GGFM
6. 2.1.2 Depending on the kind of functional group present,
monosaccharides can be classified into:
a. Aldoses - contain the aldehyde group, -(H)C=O
b. Ketoses - possess the ketone group, - C=O
c. Derived monosaccharides contain functional groups other than
carbonyl or hydroxyl
2.2 Disaccharides are groups of carbohydrates which on hydrolysis yield
two monosaccharides which may be the same, or different from each
other .Examples are sucrose, lactose, maltose and iso-maltose.
SuMaLI
7. They may be distinguished from one another from:
a. the two specific sugar monomers involved, and their
stereo configurations
b. the carbons involved in the linkage
c. the order of 2 monomer units, if they are of different kinds
d. anomeric configuration of the hydroxyl group on carbon 1 of
each residue
2.3 Oligosaccharides contain three to twelve units of monosaccharides
joined by glycosidic linkage. Maltotriose and raffinose belong to
this group.
2.4 Polysaccharides are polymers of more than 12 monosaccharide
units joined in long linear or branched chains. Of interest and
importance in this group are starch, glycogen and cellulose.
Malto3-Raff
SGC
8. 3. MONOSACCHARIDES
3.1 These are polyhydroxy aldehydes and polyhydroxy ketones or their
derivatives which have the empirical formula (CH2O)n where n=3
or some large number. A characteristic of the simple sugar is the
presence of the carbonyl ketone group (-C=O), or the carbonyl
aldehyde group (-CHO).
- If the carbonyl group is at the end of the chain, the monosaccharide
is an aldehyde derivative and called an aldose.
The simplest aldose is glyceraldehyde or glycerose.
- If the carbonyl group is at any other position, it is a ketone derivative
and called a ketose, the simplest of which is dihydroxy acetone.
9. 3.2 Monosaccharides are represented using the Fischer projection
formulas given below:
H-C=O CH2-OH
H-C-OH C=O
CH2OH CH2-OH
Glyceraldehyde Dihydroxyacetone
The carbon atoms are identified by corresponding numbers, with
carbon 1(C1) being the carbon of the carbonyl group (functional group)
in glyceraldehyde and C2 in dihydroxyacetone.
10. 3.3 Isomerism
Isomers are compounds that have the same structural or
chemical formula but differ in spatial configuration. The presence of
asymmetric carbon atoms to which four different groups or radicals are
joined allows the formation of isomers. The number of possible
isomers of a sugar depends upon the number of asymmetric carbon in
the molecule, expressed as 2n where n is the number of asymmetric
carbon.
3.3.1 D and L configuration. It the OH group on the asymmetric
carbon farthest from the carbonyl group points to the right (dextro),
the sugar is the D isomer. If the OH group points to the left (levo), it is
the L isomer.
11. The D and L isomers are mirror images of each other and are known
as enantiomers. Most simple sugars that occur in mammals are of the
D configuration.
H-C=O H-C=O
H-C-OH HO-C-H
CH2OH CH2OH
D-Glyceraldehyde L-Glyceraldehyde
3.3.2 Epimers. These are isomers that differ only in the configuration
around one specific carbon atom. Glucose and mannose are
epimers with respect to carbon atom 2, while glucose and
galactose are epimers with respect to carbon 4.
12. 3.3.3 Optical activity. When a beam of polarized light is allowed to pass
through a solution of an optical isomer, it will be rotated either to the
right, dextrorotatory (+), or to the left, levorotatory (-), D and L- sugars
are not necessarily d-or l-, respectively.
3.3.4 Cyclization of monosaccharides (the ring structure). Most
monosaccharides with five or more carbon atoms in the chains give
these compounds the potential to form very stable ring structures.
Where the aldehyde or ketone group reacts with an alcohol group on
the same sugar, they form a hemiacetal or hemiketal ring, respectively.
The hydrogen of the hydroxyl group on the penultimate carbon shifts to
the carbonyl group with the formation of an oxygen (O). If the resulting
ring has six members (5 carbons and 1 oxygen), it is a pyranose ring, and
if five-membered (4 carbons and 1 oxygen), it is called a furanose ring.
14. 3.3.5 Anomeric carbon. With the ring formation, the first carbon
becomes asymmetric resulting in the creation of an anomeric
carbon designated as alpha (ɑ) or beta (ß) anomer. When the OH
group on the new asymmetric carbon (anomeric carbon ) is on
the same side of the oxygen ring, the sugar is an alpha anomer,
and ß anomer if on the opposite side of the oxygen ring. The
cyclic alpha or ß anomers of sugars in solution are in equilibrium
with each other, and can readily undergo spontaneous
interconversion using the open-chain structure leading to the
process of mutarotation.
15. 3.3.6 Pyranose and furanose ring structures. (Haworth projection). The
stable ring structure of monosaccharides resemble the ring structures
of either pyran or furan, hence glucopyranose, glucofuranose,
fructopyranose and fructofuranose.
CH2OH
HO-C-H H O OH
H-C-OH H
HO H H
HO-C-H O OH
H-C-OH H OH
H-C
CH2OH
ß-D-Glucopyranose ß-D-Glucopyranose
17. In the Haworth projection, the alpha (ɑ) designation is used if the
OH group of the anomeric carbon is below the plane of the ring and ß if
the OH group is above the plane of the ring.
3.3.7 Chair and boat conformation. The actual conformation of the
pyranose and furanose rings are not planar. Instead, the pyranose
ring exists in the more stable “chair” and the less favored “boat” forms.
The OH groups exist in either axial (vertical) or equatorial (non-vertical)
position depending on whether they are approximately parallel or
perpendicular to the axial, which can be defined perpendicular to the
central plane of the molecule.
19. 4. BIOLOGICALLY IMPORTANT SUGARS (Derivatives of Monosaccharides)
4.1 Glycosides- asymmetric mixed acetals formed by the reaction of the
anomeric carbon atom of the intermolecular hemiacetal or pyranose form
of the aldohexose with a hydroxyl group furnished by an alcohol. The
anomeric carbon in glycosides do not interconvert by mutarotation in the
absence of an acid catalyst.
The glycosidic linkage is also formed by the reaction of the
anomeric carbon of the monosaccharide with a hydroxyl group of another
monosaccharide to yield a disaccharide.
They are also hydrolyzed by enzymes called glycosidase which
differ in their specificity according to the type of glycosidic bond (ɑ or ß ),
structure of the monosaccharide unit (s); and the structure of the alcohol.
20. 4.2 Neutral Sugars
CH2OH
H O H HOCH2 O
H CH2OH
OH H H HO
HO OH H OH
H OH HO H
ɑ-D-Galactopyranose ɑ-D-Fructofuranose
21. CH2OH CH2OH
HO O H H O H
H H
OH H OH HO
H OH HO OH
H OH H H
ɑ-D-Galactopyranose ɑ-D-Mannopyranose
22. 4.3 Sugar Acids
The oxidation of the terminal group/s (either the aldehyde group
or the alcohol group, or both) to carboxylic group /s produces three
different acid derivatives of the aldoses.
4.3.1 Aldonic acid is formed from the oxidation of the aldehyde
group.
4.3.2 Uronic acid is produced by oxidation of the terminal carbon
(primary alcohol group) to a carboxyl group.
4.3.3 Aldaric acid results from the oxidation of both aldehyde group
and the terminal carbon (primary hydroxyl group) to carboxyl group,
also called saccharic acids.
23. COOH CHO COOH
(CHOH)n (CHOH)n (CHOH)n
CH2OH COOH COOH
Aldonic acid Uronic acid Aldaric acid
4.4 Amino Sugars
Hexosamines are formed through substitution of a hydroxyl group
by an amino group on the sugar ring. The amino group is usually
acetylated (N-acetylglucosamine and N-acetylgalactosamine) or may
also be sulfated (heparin). Sialic acid is a ketose that is an acetylated
derivative of neuraminic acid. Other examples are muramic acid and N-
glycolyl derivaties of hexosamines.
24. CH2OH CH2OH
H O H H O H
H H
OH H OH H
HO OH HO CH
O
H NH2 H H-N C-ON
alpha-D-Glucosamine N-acetyl-alpha-D-glucosamine
26. 4.5 Pentoses
The major pentoses are D- ribose, L-arabinose, D-xylose and
L-xylulose.
O CHO
HOCH2 OH HO-C-H
H-C-OH
H H O H-C-OH
H CH2OH
OH OH
ß-D-Ribofuranose D-Arabinose
27. 4.6 Deoxysugars
These are formed thru selective reduction, when a hydroxyl group
attached to the ring structure has been replaced by a hydrogen atom.
The most important is 2-deoxy-D-ribofuranose.
O
HOCH2 OH
H H O
H
OH H
2-deoxy ß-D-Ribofuranose
28. 4.7 Phosphoric Acid Esters of Monosaccharides
These are formed by the reaction of the sugar with a phosphate group which usually comes
from a high-energy compound such as adenosine triphosphate (ATP).
O
CH2OH CH2-C-P-OH
O
O O
H H H H
O
HO OH H O-P-OH HO OH H OH
O
H OH H OH
Glucose-1-phosphate D Glucose-6-phosphate
29. 4.8 Sugar Alcohols
Polyols result from the reduction of the carbonyl group of the sugar
to alcohol.
glyceraldehyde – glycerol
glucose – sorbitol or glucitol
mannose- mannitol
galactose – dulcitol or galactitol
ribose – ribitol
31. 5. OLIIGOSACCHARIDES
5.1 Homo-oligosaccharides yield only one kind of sugar upon
hydrolysis.
Maltose (D-glucopyranosyl-ɑ-1,4-ɑ-D-glucopyranose)
CH2OH CH2OH
H O H H O H -formed as an intermediate
OH H O OH product of the action of
HO OH amylase on starch
H OH H OH - contains 2-D- glucose
residues
Ma-Is- Cell
34. 5.2 Hetero-oligosaccharides yield more than one kind of sugar units
upon hydrolysis.
5.2.1 Lactose (D-galactopyranosyl-ß-1, 4-ɑ-D-glucopyranose)
CH2OH CH2OH
HO O O -has a free anomeric carbon
on the glucose residue
O hence in reducing sugar
OH OH OH
OH OH
35. 5.2.2 Sucrose (D-glucopyranosyl-ɑ-1, 2- D –fructofuranose)
H O HOCH2 O H
OH H
HO O CH2OH
H OH 1, 2 OH
- cane sugar or table sugar
- no free anomeric carbon hence
does not undergo mutarotation
- hydrolysis-inversion
36. 5.2.3 Glycoproteins are carbohydrates linked to protein by covalent
combination. Protein linkage may either be N-linked or O-linked.
N-acetylglucosamine-asparagine linkage
CH2OH O
H O H N NH
N - C - CH2 - CH
C=O N-linked
OH
HO
O
NH - C - CH3
38. Galactose - hydroxylysine linkage
CH2OH NH2
HO O CH2
OH H O CH
H H CH2 O-linked
H OH CH2
CH-NH2
C=O
Xylose-serine linkage
(Glycans), on complete hydrolysis with acid or specific enzymes
monosaccharides and/or simple monosaccharide derivatives.
39. 6. POLYSACCHARIDES
5.1 Homoglycans are polysaccharides that consist of only one type
of repeating monosaccharide unit.
- Amylose is a linear chain of alpha-D glucose units linked via
alpha-1, 4 glycosidic bonds. The repeating disaccharide of
this unbranched polymer is maltose.
- Amylopectin is a homoglycan consisting of a branched chain
structure composed of alpha-D-glucose units in
40. alpha-1, 4 linkages and alpha-1, 6 linkages at branching points.
• - Starch is a mixture of amylose and amylopectin.
• - Glycogen resembls amylopectin in having alpha-1, 6 branches from
an alpha-1, 4 chain, although it is more branched.
- Cellulose consists of a long, unbranched chain of D-glucose units with
B-1, 4 linkages. The repeating unit is B-cellobiose.
6.2 Heteroglycans are composed of two or more different mono-
saccharide residues.
- Pectins consist of D-galacturonic acid units with alpha-1, 4
glycosidic linkages, with some of the carboxyl groups present as
methyl esters.
41. • - Mucopolysaccharides are built up from more than one type of
monosaccharide units. These components may be aminated,
sulfated, or N-acetylated.
- Hyaluronic acid is an acidic mucopolysaccharide made up of
repeating disaccharide units of glucuronic acid joined to
N-acetylglucosamine.
- Heparin is a sulfated, acidic mucopolysaccharide that consists
of an O-sulfated glucuronic acid bound to an N-sulfated
glucosamine that has a second O-sulfate group.
- Chondroitin sulfate contains the repeating disaccharide unit of
glucuronic acid joined to N-acetylgalactosamine sulfate.
42. References:
Biochemistry by: Campbell
Harper’s Illustrated Biochemistry by: Murray, Robert K., et al.
Lehninger’s Principles of Biochemistry by: Cox, et al.
UPOU Manual in Biochemistry
On-Line references