Chapter 10 Flashcards
What are monosaccharides?
- The simplest form of carbohydrates
- Composed of a single aldehyde or ketose group that has two or more hydroxyl groups
The smallest monosaccharides (composed of three carbons) are…
- Dihydroxyacetone
- D-glyceraldehyde
- L-Glyceraldehyde
Ketose
- Is a monosaccaride
- Dihydroxyacetone is an example of a ketose because it contains a keto group (C=O)
- The ketone group as its most oxidized atom
Aldose
- Is a monosaccaride
- Glyceraldehyde is an example of an aldose because it contains an aldehyde group (C=O and H)
- C-1 atom contains aldehyde group
Dihydroxyacetone and Glyceraldehyde are referred to as _______ because they have three carbon atoms
Trioses
Ethryose is referred to as _____ because it has four carbon atoms
Tetrose
Ribose, ribulose, deoxyribose, xylose, xyulose are examples of ______ because they have five carbon atoms
Pentose
Glucose, mannose, galactose, fructose are examples of ______ because they have six carbon atoms
Hexose
Sedoheptulose is referred to as a _______ because it has seven carbon atoms
Heptose
If a monosaccharide has eight carbon atoms, it is referred to as ________
Octose
Neuraminic acid is an example of a ________ because it has nine carbon atoms
Nonose
Common monosaccharides will generally be in _______ form and _______ configuration
D-form; D-configuration
D-configuration is when those whose asymmetrical carbon atoms has a hydroxyl group projecting to the _______, whereas L-configurations are those whose whose asymmetrical carbon atoms has a hydroxyl group projecting to the _______
right; left
Common 5-carbon sugars are include:
- D-ribose (aldose)
- D-oxyribose (aldose)
Both above are sugar moieties in nucleic acids DNA and RNA
Common 6-carbon sugars are include:
- D-glucose (aldose)
- D-mannose (aldose)
- D-galactose (aldose)
- D-fructose (ketose)
Constitutional atoms
have identical molecular formulas, but differ in the order of the attachment of the atoms
What are stereoisomers?
Where atoms are connected in the same order but differ in spatial arrangement
What are enantiomers?
- A Stereoisomer
- Pair of molecules, each with one or more chiral centers, where atoms are mirrors of each other
What are chiral centers?
A carbon that has 4 unique atoms or groups attached to it
What are diastereoisomers?
- A Stereoisomer
- Pair of molecules, each w/ more than one asymmetric centre
- Atoms have opposite configurations; NOT mirrors of each other
What are epimers?
- A Diastereoisomers
- Pair of molecules (with more than one asymmetric centre) differing at a SINGLE asymmetric centre
What are anomers?
- A Diastereoisomers
- Differ at the new asymmetric anomeric carbon that’s formed due to the formation of a hemiacetal or hemiketal
A hemiacetal is formed when an ________ reacts with an alcohol
aldehyde
A hemiketal is formed when an ________ reacts with an alcohol
ketone
A pyranose is formed when the ______ in open chain form reacts with the _______, which forms an intramolecular hemiacetal
C1 aldehyde; C-5 hydroxyl,
A furnose is formed when the ________ in open-chain form reacts with the _______, which forms a five-membered cyclic hemiketal
C-2 keto group; C-5 hydroxyl group
This can also form if the C-2 keto group reacts with the C-6 hydroxyl group to form six-membered cyclic hemiketal
True or False: Reducing sugars don’t react with solutions of cupric ions while non-reducing sugars do
False: Reducing sugars react with solutions of cupric ions while non-reducing sugars do not
As a reducing sugar, glucose can react with _______ to form _______, also known as hemoglobin A1C. In this case, the hemoglobin is ______ functional
hemoglobin; glycosylated hemoglobin; fully
Determining and quantifying the amount of A1C hemoglobin in blood allows for what?
It allows for long-term monitoring and control of blood glucose levels, which is an important consideration for diabetics who have an increased rate of glycosylation due to increased blood glucose concentrations
Pyranose form predominates when ______ is free in solutions, which can result in a very sweet taste of the solution
fructose
Furanose form predominates in many ________ derivatives
fructose
______ and ______ form are classes of conformation for pyranose and furanose
chair; boat
In chair form, the substituents on the ring carbon atoms have two orientations. Name and describe both these orientations
Axial: these bonds are nearly perpendicular to the plane of the ring, hinder each other if they emerge on the same side of the ring
Equatorial: these bonds are nearly parallel to plane, are less crowded
A glycosidic bond covalent bond formed between an _______ or ______ of a monosaccharide and an ______, _______, or ______ atom of another molecule. The resulting product of this is a ________
aldehyde; ketone; oxygen, nitrogen, sulfur atom; glycoside
What is an O-glycosidic bond?
Bond formed between the anomeric carbon atom of glucose and a hydroxyl group of another molecule
What is a N-glycosidic bond?
Bond formed between the anomeric carbon atom of glucose and an amine
Oligosaccharides contain two or more _______ linked by ________
monosaccharides; o-glycosidic bonds
Homoglycan is a _______ type of saccharide
single
Heteroglycan is a _______ of saccharides
mixture
Describe a homopolymer
- A polymer made up of many repeating copies of a single repeating unit
- All monosaccharide units in a polysaccharide are the same
Cellulose is a major polysaccharide of ________ found in plants, which serves more ______ roles than _______ roles, for example, acts as a important component to the cell wall
glucose; structural; nutritional
Disaccharide are carbohydrate consisting of __________ joined by an __________
two sugars; O-glycosidic bond
True or False: Glycotransferases are a number of specific enzymes that catalyze the formation of glycosidic bonds
True
Oligosaccharides are synthesized through the action of ___________
glycotransferases
Monosaccharide substrate for glycotransferases is activated by the attachment to _________, which are activated __________
uridine diphosphate (UDP); sugar nucleotides
Sucrose is…
a) a common table sugar
b) obtained from sugar cane and sugar beets
c) both
c) both
In sucrose, the anomeric carbon atom of ________ and
________ are joined; configuration of this glycosidic linkage is ______ for glucose and ______ for fructose
glucose unit; fructose unit; alpha; beta
What is invertase?
When sucrose is cleaved into its component monosaccharides by enzyme sucrose
What is lactose?
a) A disaccharide of milk
b) consists of galactose joined by a B-1,4 glycosidic linkage
c) both
c) both
Lactose is hydrolyzed to these monosaccharides by _____ in humans and ______ in bacteria
lactase; B-galactosidase
Maltose is…
a) three glucose units joined by an a-1,6 glycosidic bond
b) three glucose units joined by an a-1,4 glycosidic bond
c) two glucose units joined by an a-1,4 glycosidic bond
c) two glucose units joined by an a-1,4 glycosidic bond
Maltose comes from the hydrolysis of large _________, such as starch or glycogen), and is in turn, hydrolyzed to glucose by ______ (a-glucosidase)
polymeric oligosaccharides; maltase
Name the three classes of glycoproteins
- Glycoproteins
- Proteoglycans
- Mucins
Glycoproteins are….
Protein that have specific carbohydrate moiety attached
(Form when a carbohydrate group can be covalently attached to a protein)
Proteoglycans are ______ containing one or more covalently linked __________ chain
proteins; glycosaminoglycan
The protein component of proteoglycans are conjugated a particular polysaccharide known as ________
glycosaminoglycan
What are glycosaminoglycans?
A heteropolysaccharide made up of repeating polysaccharide units containing the amino sugar glucosamine or galactosamine)
True or False: Mucins consist mainly of a carbohydrate where the protein component is extensively glycosylated to serine or threonine residues by N-acetylgalactosamine
True
True or False: Mucins do not serve important roles in digestion
False: Mucins serve as lubricants and do have important roles in digestion
Cartilage is composed of __________ and ________
a) proteoglycan aggrecan and collagen
b) collagen and mucin
c) glycosaminoglycans and collagen
a) proteoglycan aggrecan and collagen
Glycosaminoglycan component of aggrecan cushions join by _______ water on impact, then _______ water
releasing; rebinding
True or False: Chitin is the least abundant carbohydrates in the world
False: Chitin (glycosaminoglycan found in exoskeleton of insects) is one of the most abundant carbohydrates in the world
Human ABO groups reflect ______ of glycotransferases
specificity
True or False: All blood groups share the oligosaccharide foundation called O (or sometimes H) antigen
True
In blood type A, _________ is added to the O by a specific glycosyltransferase
N-acetylgalactosamine
In blood type B, ______ is added by another transferase
galactose
True or False: In blood type O, there are active glycosyltransferases
False: In blood type O, there are no active glycosyltransferases
What are lectins?
Lectins are specific carbohydrate binding proteins
Lectins are a particular class of ____________
Glycan-binding proteins
Lectins on one cell recognize and bind to _______ on another cell with multiple __________. Such binding facilitates ___________
carbohydrates; weak interactions; cell-cell interaction
In response to injury or infection, ________ will travel through the vasculature and will be recruited to sites of injury or infection by adhering to ____________ and traversing through the lining
lymphocytes; endothelial cells
Sectins are a class of
a) proteins
b) lectins
c) lipids
b) lectins
True to False: Some selectins bind immune cells to sites of injury
True
True or False: Some selectins allow attachment of an embryo to the mother’s uterus
True
