carbohydrates Flashcards
carbohydrates are
biological macromolecule containing C=O and OH group.
major type of carbohydrates
sugar (saccharides)
functions of carbohydrates
significant fraction of the dietary calories
storage form of energy
cell membrane components
structural component of organisms
glyceraldehyde is a
a) aldose , triose sugar
b)ketose , triose sugar
c) aldose ,pentose sugar
d)ketose ,hexose sugar
aldose, triose sugar
dihydroxyacetone is a
a) aldose , triose sugar
b)ketose , triose sugar
c) aldose ,pentose sugar
d)ketose ,hexose sugar
ketose, triose sugar
sugar building block of DNA
D-Ribose sugar
most common and important aldohexose sugar
glucose (building unit of starch, cellulose, and sucrose)
most common naturally occurring ketose sugar found in plants , bonded to glucose to form sucrose
D-Fructose
measurement of Hba1c levels can determine
glycemic control
compounds that have the same chemical formula but have different structure are called
isomers
examples of isomers
fructose, glucose, mannose, galactose isomers having chemical formula C6H12O6
epimers are
carbohydrate isomers that differ in configuration around only one specific carbon atom
example of epimer
glucose and galactose {C4 epimer}
glucose and mannose {c-2 epimer}
why glucose and mannose are isomers but not epimer
differ in position of -oh grp in c-4 and c-2
special type of isomerism in the pair of structures that are mirror images of each other
enantiomers
the two members of the pair are designated as
D- nd L- sugar
vast majority of the sugar in humans are
D- sugar
difference between D- and L- isomers
-OH group on the asymmetric carbon that is farthest atom from the carbonyl carbon is on the
D- isomer: right
L-isomer: left
name the enzyme that can interconvert D- and L- isomers
Racemases
(enzymes are specific in binding either the D or L form)
less than 1% of each of the monosaccharides 5 or more carbon exist in which form in solution
open chain or acyclic
99% of monosaccharide found in solution are
ring or cyclic form
creation of anomeric carbon generate a new pair of isomer
α and β configurations (α-D-glucopyranose and β-D-glucopyranose)
alpha and beta are referred as
diastereomers (not mirror images)
enzymes can distinguish between these two structures and use one or the other preferentially
glycogen and cellulose are synthesized from
glycogen: α-D-glucopyranose
cellulose: β-D-glucopyranose.
the cyclic alpha and beta anomers of a sugar in a solution spontaneously form a equilibrium mixture the process is called
mutarotation
if hydroxyl group on the anomeric carbon of a cyclized sugar is not linked to another compound by glycosidic bond
sugar act as a reducing agent (reducing sugar)
sugar that react with chromogenic agents causing reagent to be reduced and colored
reducing sugar (aldehyde group of acyclic sugar become oxidized
reducing sugar groups
all monosaccharides but not all disaccharides
test that can detect a reducing sugar in urine
colorimetric test
positive colorimetric test indicates
underlying pathology (sugars are normally present in urine)
monosaccharides can joint to form
disaccharides, oligosaccharides, polysaccharides
lactose is made of
galactose + glucose
sucrose is made of
glucose + fructose
maltose is made up of
glucose + glucose
important polysaccharides which are polymer of glucose
branched - glycogen : animal source
-starch : plant source
unbranched - cellulose : plant source
the bond that link sugar are called
glycosidic bond
glycosidic bond is formed by enzyme known as
glycosytransferases
glycosytransferases will use which as substrate
nucleotide sugar such as uridine diphosphate glucose
glycosidic bonds between sugars are named according to the
numbers of the connected carbons
#with regards to the position of the anomeric hydroxyl group of the sugar involved in the bond
name of bond with respect to the configuration are
β configuration - β-bond
α configuration - α-bond
bond formation in lactose
b/w carbon 1 of β-galactose and carbon 4 of glucose
linkage is a β(1→4) glycosidic bond.
why lactose remain as a reducing sugar
anomeric end of the glucose residue is not involved in the glycosidic linkage
bond in maltose
α (1-4) glycosidic b/w c1 - c4 OHs of two glucoses
It is the of α anomer
a disaccharides product of cellulose breakdown
cellobiose
name of bond in cellobiose
β (1-4) glycosidic , β anomer
carbohydrate that attached by glycosidic bonds to noncarbohydrate structures like
a) purine and pyrimidine
b)aromatic ring
c)proteins
d)lipids
a) nucleic acid
b) steroids and bilirubin
c) glycoproteins, proteoglycans
d) glycolipids
carbohydrate that attached by glycosidic bonds to noncarbohydrate structures to form
glycosides
the structure and bond of the group on the noncarbohydrate molecule to which the sugar is attached is an -NH2 group is
N-glycoside
N-glycosidic linkage
if the group attached to sugar is an -OH called
O- glycoside
O-glycosidic linkage
all sugar-sugar glycoside bonds are
O-type linkage
how do living cell produce and utilize energy
most energy used through hydrolysis of ATP molecule into ADP molecule
the prosses which ADP continually convert to ATP molecule as called
cellular respiration
from where the cells will get energy for converting to ATP
breaks chemical bonds in glucose, releasing stored energy
name the pathways used to release the energy from glucose and other food component
- glycolysis
2.kreb cycle ( citric acid cycle) - electron transport chain
- alcoholic fermentation or lactic acid fermentation
amt of energy released from glycolysis
2 net ATP
Name the two pathways that lead after glycolysis in presence of oxygen
kreb’s cycle, ETC
In absence of oxygen glycolysis is followed by
alcoholic or lactic acid fermentation
glycolysis + krebs cycle +ETC combined make up
cellular respiration
equation for cellular respiration
6O2 + C6H12O6 ——- 6CO2 + 6H2O + energy (ATP)
oxidation of glucose to give pyruvate (aerobic) or lactate (anaerobic) is
glycolysis
site of glycolysis
cytoplasm of all tissue cells
in which type of tissues glycolysis have physiological importance
tissues of no mitochondria : mature RBC
which cell relays glycolysis exclusively for energy
RBC
which is the source of energy for skeletal muscle during high intensity exercise
glycolysis
how glycolysis help in adipose tissue and liver function
source of glycerol-p for triacylglycerol synthesis
source of acetyl-CoA for fatty acid synthesis
name the enzyme help on conversion of glucose to glucose 6 phosphate
hexokinase
ATP produced, utilized, net energy produced in anaerobic glycolysis
produced: 4
utilized: 2
net energy: 2
ATP produced utilized and net energy produced in aerobic respiration is
produced: 8-10
utilized: 2
net energy: 6-8
regeneration of NAD+ in aerobic and anaerobic glycolysis are
through respiratory chain in mitochondria
through lactate formation
oxygenation of tissue is done through the formation of
2,3 bis-phosphoglycerate (BPG) decreases the affinity of HB to o2
what are the products of anaerobic fermentation
lactic acid or ethyl alcohol and carbon dioxide
equation of alcoholic fermentation
pyruvic acid + NADH ethyl alcohol + CO2 + NAD+
alcoholic fermentation occurs in
yeast
name the catalyst in reaction of converting NADH to NAD+
alcohol dehydrogrnase
name the processes which shares in carbohydrate metabolism
pyruvate carboxylation, decarboxylation
lactic acid fermentation occurs in which type of organism
anaerobic organism lack a respiratory chain
what is needed for the glyceraldehyde-3-phosphate dehydrogenase reaction of glycolysis
NAD+
the complete pathway, including glycolysis and reoxidation of NADH is called
fermentation
what catalysis the reduction of the keto in pyruvate to a hydroxyl, yielding lactate
lactate dehydrogenase
where will oxidization of pyruvate occur
liver
