Carbohydrate Flashcards
Examples of monosacharide are?
Ribose, glucose, fructose, ribulose
Monosacharide can either have ___ or____ fictional group?
Aldose(aldehyde) or ketone
The lowest monosacharide in aldose and ketone form is?
TRIOSE–Glyceraldehyde and dihydroxyacetone
Xylose and Ribose has how many C atom?
5C atoms
What’s Fisher projection?
method of representing the three-dimensional structures of molecules on a page
By using lines
How do you identify D and L Isomers?
If the OH on the last carbon points left it’s an L Isomers
And right a D Isomer
Aldotetrose has how many sterioisomers?
Using 2^n
n=2
Ans= 4
Aldohexose has how many sterioisomers?
Ans= 16
2^4
The human body only functions with ____ Isomers of carbohydrates?
D Isomers
What are Haworth structures?
There are chemical structures depicted without C or H only lines
What’s Isomerism?
This is when a compound has the same molecular weight and formula but had different properties
What’s structural Isomerism?
Has the same molecular formula by different structure
What’s stereo Isomerism?
See structural formula bt different spacial configuration
Stereo Isomer can be divided into?
Geometric (cis and trans) and
Optical (D and L)
What’s a racemic mixsture?
Racemic mixture is when a mixture contains equal amount of d and l Isomers therefore having no optical activity due to them cancelling each other out
What’s enantiomer?
When two Isomers rotates the plane-polatized light in a quality and opposite direction
What’s Diasterioisomer?
And Mesotype Diasterioisomer
When the amount of rotation is not equal
When the isomer does not rotate at all
Glucose is also referred to as?
Dextrose because it’s a D isomer
What’s empimerism?
When Isomers are different only in the configuration of a single C other than the reference C
1–Glucose and ____ are empimers which only differ at ___
2–Glucose and ____ are empimers which only differ at ___
Mannose at C2
Galactose at C4
The mutarotaion of Fisher projection gives?
Haworth projection
What’s mutarotaion?
Mutarotation is the change in the optical rotation because of the change in the equilibrium between two anomers.
What the importance of mutarotaion?
Glucose test with glucose oxidase
What’s tautomerism?
Is a condition in which two Isomers are converted into another and are United in equilibrium
Glucose in mild alkaline solution is converted into?
And the transformation is called?
Fructose qnd mannose
Lobry de bruyn vanEkensein transformation
Why does glycosides not reduce Benedict reagnts?
And how can it be solved?
Because the sugar group is masked
It can be hydrolyzed by boiling with dilute acid so the sugar can be free and reduce Cu in Benedict reagnt
Which monosacharide doesn’t reduce Benedict reagent?
Sucrose
What’s the biomedical importance of (deoxy sugar— removing O2 from the OH group of sugar)
Deoxy sugar like L- fructose is present in blood group antigens and many other glycoprotein
Deoxy ribosomes is present in nucleic acid
In an alkaline medium sugar is oxidized to ______ and Cu^2 is reduced to Cu^+
With what color change?
Enediol
From blue to brick red
Aldehyde group are oxidized to_____ while cyclic hemiacetal to ______ by SIlver AMmonia(Tollens Reagent)
Aldoric acid and lactose
Silver reagent
_____ is used to differentiate sugars in biological fluid? Eg Urine
OSAZONE
Sugar (except sucrose) + EXCESS phenylthydrazine and high temp= osazone
Dehydration of monosacharide( heated with strong acid) leads to the formation of?
Molish’s test
Furfural derivatives
When glucose undergoes molish’s test it forms?
Hydroxyl Methyl furfural
Honey contains inverted sugar
And inverted sugar is sweeter than sucrase
Polysacharide usually have _____ taste?
Tasteless
Examples of Homopolysacharide and Hetero are?
I, G, Dex, Cellu, strach, Chitin
Agar(agon😂), Proteoglycan
Starch is composed of ____&_____
Amylose (soluble in water)
amd Amylopectin (insoluble in water) and forms gell
What’s the difference between amylose and Amylopectin?
Amylose– has glucose of 1,4 gly Bond and are unbranded, soluble in H2O
Amylopectin– has glucose of 2,6 gly Bond and are branched, insoluble in H2O
Starch forms ____ coloured complex with_____(sensitive test)
Blue
Iodine
Why is strach not a reducing agent?
Because the free sugar group are negligible in number
Salivary and pancreatic amylase breaks down 1,4 gly Bond in starch until it stops at?
Maltose
What’s limit dextrin or residual dextrin?
This is what’s left when Beta amylase of plants act on starch breaking bown the 1,4gly Bond in amylose and stopping and leaving the 1-6 gly Bond in Amylopectin
Innermost core of glycogen is_____&
Glycogenin
Btw glycogen and Amylopectin which is more branched and compact?
Glycogen
Cellulose is made up of glucose linked together by ____ bond
Beta 1,4 glycosidic Bond
With no branching
Inulin is composed of _____ linked together by_____ and is used for?
D-Fructose
Beta 1,2 linkage
It’s used for renal clearance value and glumerular filtartion Rate
Dextran is composed of ____ which are linked by______
And it’s uses
Glucose
1,6—1,4—1,3 links
To treat hypovolumic shock
Chitin os composed of linked by_____
N-acetyl-glucosamine with Beta-1, 4 gly Bond
Agar a hetero polysacharide is composed of?
Agarose and agaropectin
Mucopolysacharide or GAG Glucoaminoglycan is composed of?
Uronic acid(sugar acid) and animo dugar
Or repeating disacharide
And are -vely charged
GAG is found in?
Mucos secretion making it slippery
Vitreous honor of eye
How does GAG make mucos slippery?
GAG is negatively charged therefore attracts water
Which example of GAG(hetero polysacharide) helps clear the bell around the ovum for better penetration?
Hyaluronidase
Keratan sulfate ( only GAG without Uronic acid) is composed of?
And functions?
Repeating unit of galactose and n-acetyl-glucosamine
It helps keep them cornea transparent
What are the examples of GAG?
Keratan sulphate
Heparin
Hyaluronic acid
Heparin is composed of?
Sulphate glucosine and glucuronic acid (iduronic acid)
Proteoglycan that has less than 10% C is called?
Glycoprotein
Proteoglycan that has more than 10% C is called?
Mucoprotein
Galactose, glucose, fructose and mannose has how many C atom?
6C
Glycogen is a branched____ madeup of ___&____ linkage
homopolysaccharide with glucose units linked in alpha-1, 4 linkages
(straight line) and alpha-1, 6 linkages (branching point).
Branching makes the molecule more
globular and less space-consuming
mainly stored in liver and muscles
The liver can store up to 150–200 grams, which amounts to 10% of the organ’s wet weight.
Skeletal muscle
contains glycogen at much lower concentration than the liver, however, its much larger
overall mass means that the absolute amount of glycogen stored there is approximately twice
higher than in the liver.
Glycogen Metabolism consists of
A. Synthetic phase: Formation of glycogen
B. Catabolic phase: Breakdown of glycogen
Glycogenin is a small bifunctional protein that serves both as the starter substrate and the
polymerase that synthesizes the initial linear strand of glucose residues
HEXOSE MONOPHOSPHATE SHUNT (HMP)
Is primarily a ____ pathway that utilizes
is primarily an anabolic pathway that utilizes
the 6 carbons of glucose to generate 5 carbon sugars and reducing equivalents.
HEXOSE MONOPHOSPHATE SHUNT (HMP)
However, this
pathway does oxidize glucose and under certain conditions can completely oxidize glucose to
CO2 and water, it is not meant for energy generation.
Biomedical Importance of HMP
It provides reducing equivalents, in the form of NADPH (electron donor)
It provides the cell with pentoses (ribose-5-phosphate) for the synthesis of the
nucleotides and nucleic acids.
(PPP) can help break down pentose sugars that come from the digestion of nucleic acids in our diet.
Additionally, it can rearrange the carbon structures of the carbohydrates we consume into substances that are used in the processes of glycolysis nd gluconeogenesis
Enzymes that function primarily in the reductive direction utilize the ___&_____
cofactor pair as co-factors as opposed to oxidative enzymes that utilize the ___&_____ as
cofactor pair
NADP+
/NADPH
NAD+
/NADH
cells of the ___, ____,___,___,___have high levels of the PPP enzymes
liver, adipose tissue, adrenal cortex, testis and lactating
mammary gland
In fact 30% of the oxidation of
glucose in the liver occurs via the PPP
erythrocytes utilize the reactions of the
PPP to generate large amounts of NADPH used in the reduction of glutathione
The
conversion of ribonucleotides to deoxyribonucleotides (through the action of ribonucleotide
reductase) requires NADPH as the electron source; therefore, any rapidly proliferating cell
needs large quantities of NADPH.
The pentose phosphate pathway occurs in the ____ in two phases:;namely
Cytoplasm
oxidative and nonoxidative. Phases
Oxidative phase steps
Glucose-6-phosphate is converted to 6-phospho gluconolactone in the first step.
Require
(GPD), NADP+ as a cofactor.
And ___ molecule of NADPH is produced @ this stage
1
The formation of _____e is the rate-limiting step in the pathway
6-phospho gluconolactone
The formation of 6-phospho gluconolactone is the rate-limiting step in the pathway, and the regulation of the pathway is affected by the activity of glucose-6-phosphate dehydrogenase.
In the second step, 6-phospho gluconolactone is hydrolyzed by gluconolactone hydrolase to form 6-phosphogluconic acid.
In the third step, 6-phosphogluconic acid is dehydrogenated to form ribulose-5-phosphate.
involves oxidation and decarboxylation
Require
6-phosphogluconate dehydrogenase
3-keto-6-phosphogluconate is a transient compound formed during this step, which spontaneously undergoes decarboxylation to yield ribulose-5-phosphate.
The carbon dioxide (CO2) released during decarboxylation is derived from the carboxyl group (COOH) of gluconic acid.
& NADPH is generated in this step.
In oxidative phase
2 molecule of NADPH
& co2 is released
Non oxidative phase
The non-oxidative phase involves ___&___ reactions of various sugar molecules.
isomerization and condensation
Three important intermediates in this phase are
Ribose-5-phosphate, fructose-6-phosphate, and glyceraldehyde-3-phosphate.
In step 4, ribulose-5-phosphate is isomerized to either ribose-5-phosphate or epimerized to xylulose-5-phosphate.
Step 5 involves the first __ reaction,
transketolase
where transketolase enzyme transfers a two-carbon unit (with a keto group) from xylulose-5-phosphate to ribose-5-phosphate. This forms sedoheptulose-7-phosphate and glyceraldehyde-3-phosphate.
Transketolase is a thiamine pyrophosphate (TPP) dependent enzyme. Its activity is decreased in thiamine deficiency
Step 6 is the transaldolase reaction, where a three-carbon unit is transferred from sedoheptulose-7-phosphate to glyceraldehyde-3-phosphate, resulting in the formation of fructose-6-phosphate.
involves the second transketolase reaction, where a two-carbon unit is transferred from xylulose-5-phosphate to erythrose-4-phosphate. This forms fructose-6-phosphate and glyceraldehyde-3-phosphate
Step 8 focuses on the regeneration of glucose-6-phosphate
Two molecules of glyceraldehyde-3-phosphate from step 7 are condensed to form one fructose-6-phosphate. Then, fructose-6-phosphate is converted back to glucose-6-phosphate.
The regeneration of glucose-6-phosphate involves the reversal of step___&____
4 of glycolysis and step 2 of glycolysis.
The level of NADP+ plays a crucial role in regulating the pathway
The first reaction catalyzed by glucose-6-phosphate dehydrogenase (G6PD) is the rate-limiting step of the pathway.
____regulates the oxidative pathway
G6PD activity is inhibited by its product, NADPH. Therefore, the level of NADPH regulates the oxidative phase of the pathway.
The oxidative phase is controlled by the availability and level of NADP+.
The non-oxidative phase of the pathway is regulated by the requirement for
pentoses
(sugar molecules with five carbon atoms
Insulin, induces the expression of G6PD. Therefore, insulin can increase the overall activity of the pathway.
When there is a higher demand for NADPH, the pathway proceeds to completion meaning
one molecule of glucose is completely oxidized to carbon dioxide (CO2)
The complete oxidation of glucose to CO2 generates more NADPH to meet the increased demand
& it produces Ribosome 5 P
Result of PPP
when it is not solely used for ribose-5-phosphate (R5P) production,
oxidation of glucose-6-phosphate (G6P), a 6-carbon sugar, into a 5-carbon sugar.
G6P is converted into ribulose-5-phosphate (5C) through a series of reactions in the oxidative phase of the PPP.
non-oxidative phase of the PPP, 3 molesof ribulose-5-phosphate) can be converted back into 2 moles of glucose-6-phosphate) and 1 mole of (glyceraldehyde-3-phosphate)
enables the production of more NADPH.
glyceraldehyde-3-phosphate, can take two different paths for utilization which are
It can be shunted to glycolysis, where it can be further oxidized to pyruvate
can be utilized by gluconeogenic enzymes to generate such as fructose-6-phosphate or glucose-6-phosphate
Significance of HMP shunt
NADPH produced in the oxidative phase is a powerful antioxidant
Consequently, the oxidative phase of the pentose phosphate pathway is
also quite active in cells that are at high risk for oxidative damage, such as red blood cells.
_____ plays a role in reducing oxidized proteins and acts as an antioxidant.
Glutathione
The PPP is involved in the production of NADPH, which is required for the reduction of oxidized glutathione (G-S-S-G) to reduced glutathione (2 G-SH).
Glutathione reductase, which catalyzes the reduction of oxidized glutathione, requires NADPH as a cofactor.
Reduced glutathione (G-SH) helps remove hydrogen peroxide (H2O2) from cells through the action of glutathione peroxidase, converting it into water and an alcohol.
Disruption in the level of NADPH can have a significant impact on a cell’s ability to handle oxidative stress.
In red blood cells the PPP is the primary pathway for NADPH production, which is crucial for the reduction of oxidized glutathione to maintain cellular health.
Defects in NADPH production can lead to
haemolytic anaemia in erythrocytes.
In lens metabolism, a portion of glucose is metabolized through the PPP to generate NADPH, which is necessary for converting oxidized glutathione to reduced glutathione.
During phagocytosis, the reactions of the PPP are significantly increased in leukocytes. NADPH generated in this pathway is utilized by NADPH oxidase to produce superoxide anions (O2–) that aid in destroying phagocytosed materials.
A clinical application of the PPP relates to
haemolytic anaemia caused by glucose-6-phosphate dehydrogenase (G-6-PD) deficiency. Individuals with this deficiency have impaired NADPH generation, and exposure to oxidant drugs can result in red blood cell hemolysis.
