p.28
Disaccharides and Their Hydrolysis
What is the role of membrane-bound hydrolases in the intestinal brush border?
They hydrolyze disaccharides.
What type of polymer is glycogen?
A branched homopolysaccharide of glucose.
p.65
Glycoconjugates: Proteoglycans, Glycoproteins, and Glycolipids
What are glycoproteins?
Proteins linked to oligosaccharides.
p.11
Stereochemistry of Carbohydrates
What are D-ketoses?
Ketoses that have the hydroxyl group on the penultimate carbon positioned on the right in a Fischer projection.
p.31
Galactose Metabolism and Lactose Intolerance
What is the process of converting Galactose to Glucose 1-Phosphate called?
Conversion through UDP-galactose.
What are the branch points in glycogen formed by?
α 1 → 6 linkers every 8-12 residues.
p.74
Lectins and Their Biological Functions
What is the role of the Le b oligosaccharide in ulcer formation?
It serves as a receptor for Helicobacter pylori on the gastric epithelium.
p.44
Extracellular Matrix and Cell Surface Polysaccharides
How does the peptidoglycan layer of Gram-positive bacteria interact with Gram stain?
It reacts with the Gram stain.
p.75
Glycoconjugates: Proteoglycans, Glycoproteins, and Glycolipids
What role do oligosaccharides play at the cell surface?
They are involved in recognition and adhesion.
What type of starch is highly branched?
Amylopectin is the highly branched form of starch.
p.11
Stereochemistry of Carbohydrates
What is an epimer?
A type of stereoisomer that differs at only one specific carbon atom.
p.76
Lectins and Their Biological Functions
What is the primary function of C-reactive protein (CRP)?
To limit tissue damage, acute inflammation, and autoimmune reactions.
p.28
Disaccharides and Their Hydrolysis
What happens to monosaccharides after they are produced from disaccharide hydrolysis?
They pass through intestinal cells to the bloodstream.
p.28
Disaccharides and Their Hydrolysis
Where do monosaccharides go after entering the bloodstream?
They are transported to the liver or other tissues.
p.60
Glycoconjugates: Proteoglycans, Glycoproteins, and Glycolipids
What is central to the function of glycoconjugates?
Molecular complementarity.
p.17
Glycoconjugates: Proteoglycans, Glycoproteins, and Glycolipids
What is the significance of oxidized sugar in bacterial cell walls?
It contributes to the structural integrity of the cell wall.
p.46
Extracellular Matrix and Cell Surface Polysaccharides
What is the structure of the cell wall in Gram-negative bacteria?
It consists of two bilayers with peptidoglycan in between.
p.11
Stereochemistry of Carbohydrates
In the context of D-ketoses, how do epimers differ?
They differ in configuration at one specific carbon atom while having the same molecular formula.
p.47
Glycoconjugates: Proteoglycans, Glycoproteins, and Glycolipids
Where is lipopolysaccharide (LPS) found?
Coating the outer membrane of Gram-negative bacteria.
How are polysaccharides different from DNA, RNA, and proteins?
Polysaccharides are not synthesized on templates that direct their sequence.
What is the consequence of the mechanisms of assembly for polysaccharides?
There is no template for polysaccharide synthesis.
p.25
Disaccharides and Their Hydrolysis
What is a typical example of a disaccharide?
Sucrose (cane sugar), made of D-glucose and D-fructose.
p.19
Monosaccharides and Disaccharides
What is a common use of sugar alcohols?
They are commonly used as low-calorie sweeteners in food products.
What type of polymer is cellulose?
A linear homo-polysaccharide of glucose.
p.24
Carbohydrates as Informational Molecules
What does Hb A1c measure in the context of diabetes?
It measures the average blood glucose levels over the past 2 to 3 months.
p.61
Glycoconjugates: Proteoglycans, Glycoproteins, and Glycolipids
What are syndecans?
Syndecans are a type of membrane heparan sulfate proteoglycans with a single transmembrane domain and an extracellular domain bearing 3–5 chains of heparan sulfate and chondroitin sulfate.
p.71
Lectins and Their Biological Functions
How do lectins contribute to signaling?
They mediate signaling and adhesion.
p.47
Glycoconjugates: Proteoglycans, Glycoproteins, and Glycolipids
What is lipopolysaccharide (LPS) composed of?
A lipid group anchored in the outer membrane joined to a polysaccharide with long chains and various repeating structures.
p.20
Carbohydrates as Informational Molecules
Name three examples of sugar alcohols.
Sorbitol, mannitol, and xylitol.
p.18
Monosaccharides and Disaccharides
What are deoxy sugars?
Monosaccharides with one or more hydroxyl groups replaced by hydrogens.
p.12
Monosaccharides and Disaccharides
What is the general formula for monosaccharides?
CnH2nOn, where n is typically 3 or more.
p.9
Stereochemistry of Carbohydrates
What is the significance of epimers in carbohydrate chemistry?
Epimers can have different biological activities and properties despite having similar structures.
What allows ruminants and termites to use cellulose?
They live symbiotically with microorganisms that produce cellulase.
How are glucose monomers linked in cellulose?
By (β1 → 4) glycosidic bonds.
p.30
Galactose Metabolism and Lactose Intolerance
What is the treatment for galactosemia?
Carefully controlling dietary galactose.
p.24
Carbohydrates as Informational Molecules
What is the significance of a high Hb A1c level?
It indicates poor blood glucose control and an increased risk of diabetes complications.
p.61
Glycoconjugates: Proteoglycans, Glycoproteins, and Glycolipids
What type of chains do syndecans bear?
Syndecans bear 3–5 chains of heparan sulfate and chondroitin sulfate.
p.73
Lectins and Their Biological Functions
What triggers the movement of lymphocytes to the site of injury?
The interaction between lectins and their ligands in response to signals from the injury site.
p.26
Disaccharides and Their Hydrolysis
What is the role of enzymes in the formation of maltose?
Enzymes like maltase catalyze the hydrolysis of starch into maltose.
p.74
Lectins and Their Biological Functions
How does Helicobacter pylori interact with the gastric surface?
Through a bacterial surface lectin and the Le b oligosaccharide.
p.44
Extracellular Matrix and Cell Surface Polysaccharides
What does the Gram-positive cell wall consist of?
A single bilayer membrane with a peptidoglycan coat.
What is the primary structural form of starch?
Starch can be linear or highly branched.
p.65
Glycoconjugates: Proteoglycans, Glycoproteins, and Glycolipids
How are O-linked glycans attached to proteins?
Via threonine or serine hydroxyls.
p.5
Stereochemistry of Carbohydrates
What is an aldose?
A carbohydrate with aldehyde functionality.
p.25
Disaccharides and Their Hydrolysis
What are the most abundant carbohydrates?
Disaccharides, which consist of two monosaccharide units.
p.29
Galactose Metabolism and Lactose Intolerance
What is the function of lactase?
Converts lactose to glucose and galactose.
p.63
Extracellular Matrix and Cell Surface Polysaccharides
What is fibronectin?
A protein with separate domains to bind fibrin, heparan sulfate, and collagen, containing the RGD sequence.
What are oligosaccharides?
Short chains of monosaccharide units (more than 2 to 20) joined by glycosidic bonds.
p.19
Monosaccharides and Disaccharides
Can you name a few examples of sugar alcohols?
Examples include sorbitol, mannitol, and xylitol.
p.10
Stereochemistry of Carbohydrates
What is an epimer?
A type of diastereomer that differs in configuration at only one stereocenter.
p.2
Glycoconjugates: Proteoglycans, Glycoproteins, and Glycolipids
What are the three types of glycoconjugates?
Proteoglycans, Glycoproteins, and Glycolipids.
p.51
Glycoconjugates: Proteoglycans, Glycoproteins, and Glycolipids
What connects glycosaminoglycans to the core protein in proteoglycans?
A tetrasaccharide linker that connects to a Ser residue of the protein.
p.4
Glycoconjugates: Proteoglycans, Glycoproteins, and Glycolipids
How can carbohydrates interact with other biomolecules?
They can be covalently linked with proteins and lipids.
p.3
Carbohydrates as Informational Molecules
What is one function of carbohydrates in biochemistry?
Generating and storing biological energy.
p.27
Disaccharides and Their Hydrolysis
What are the two ends of a disaccharide called?
The reducing end and the nonreducing end.
p.69
Glycoconjugates: Proteoglycans, Glycoproteins, and Glycolipids
What directs the protein to glycan-binding proteins during folding?
Stepwise cleavage of Glc residues from N-linked glycans.
p.22
Monosaccharides and Disaccharides
Which ions can reducing sugars reduce?
Oxidizing agents such as peroxide, ferricyanide, and some metals like Cu²⁺ and Ag⁺.
p.3
Carbohydrates as Informational Molecules
How do carbohydrates control protein trafficking?
They assist in directing proteins to their proper locations.
p.75
Glycoconjugates: Proteoglycans, Glycoproteins, and Glycolipids
Why are oligosaccharides important for cell adhesion?
They provide specific binding sites for other cells and molecules.
p.6
Stereochemistry of Carbohydrates
How can chiral compounds be represented?
Using perspective formulas.
Why is glycogen important in muscle tissue?
It is more immediately available for energy release.
p.16
Monosaccharides and Disaccharides
What are sugar alcohols formed by?
Mild reduction of sugars.
p.59
Glycoconjugates: Proteoglycans, Glycoproteins, and Glycolipids
What type of glycosaminoglycans are affected in certain human diseases?
Sulfated glycosaminoglycans.
p.48
Glycoconjugates: Proteoglycans, Glycoproteins, and Glycolipids
What is the role of polysaccharide structures on cell surfaces?
They regulate cell-cell recognition and interaction.
p.17
Glycoconjugates: Proteoglycans, Glycoproteins, and Glycolipids
How do hexose derivatives impact bacterial structure?
They play a crucial role in forming the cell wall and its properties.
p.48
Glycoconjugates: Proteoglycans, Glycoproteins, and Glycolipids
What determines the uniqueness of the information in cell surface polysaccharides?
The enzymes that synthesize these polysaccharides.
p.29
Galactose Metabolism and Lactose Intolerance
What symptoms are associated with lactose intolerance?
Abdominal cramps and diarrhea.
p.61
Glycoconjugates: Proteoglycans, Glycoproteins, and Glycolipids
How are glypicans attached to the membrane?
Glypicans are attached to the membrane by a GPI anchor, which is a glycosylated derivative of the membrane lipid phosphatidylinositol.
What are the principal storage polysaccharides in plants?
Amylose and amylopectin, which together constitute starch.
p.24
Carbohydrates as Informational Molecules
How is Hb A1c typically expressed?
As a percentage of total hemoglobin.
How does amylopectin differ from amylose?
Amylopectin is branched and has branch points with (α 1 → 6) linkers occurring every 24-30 residues.
p.52
Glycoconjugates: Proteoglycans, Glycoproteins, and Glycolipids
What are glycosaminoglycans?
Heteropolysaccharides in the extracellular matrix unique to vertebrate animals and bacteria.
p.4
Monosaccharides and Disaccharides
What is the basic nomenclature for carbohydrates?
Number of carbon atoms in the carbohydrate + -ose (e.g., three carbons = triose).
What do granules contain that is essential for polysaccharide metabolism?
Enzymes that synthesize and degrade these polymers.
p.53
Glycoconjugates: Proteoglycans, Glycoproteins, and Glycolipids
What contributes to the negative charge in glycosaminoglycans?
Uronic acids (C6 oxidation) and sulfate esters.
p.52
Glycoconjugates: Proteoglycans, Glycoproteins, and Glycolipids
What is the structure of glycosaminoglycans?
Linear polymers of repeating disaccharide units.
p.58
Glycoconjugates: Proteoglycans, Glycoproteins, and Glycolipids
Where do proteoglycan aggregates cover to reduce friction?
Joint surfaces, specifically articular cartilage.
p.57
Glycoconjugates: Proteoglycans, Glycoproteins, and Glycolipids
What role do proteoglycans play in joint cushioning?
They absorb large amounts of water in the cartilage matrix.
p.64
Glycoconjugates: Proteoglycans, Glycoproteins, and Glycolipids
Why are viral proteins heavily glycosylated?
To help evade the immune system.
p.75
Carbohydrates as Informational Molecules
What is the 'sugar code'?
A concept describing how oligosaccharides mediate cell interactions.
p.15
Stereochemistry of Carbohydrates
What type of ring structures do monosaccharides with five or more carbons predominantly form?
Five (furan) or six (pyran) member ring structures.
What type of starch is composed of linear chains?
Amylose is the linear form of starch.
p.49
Extracellular Matrix and Cell Surface Polysaccharides
What is the extracellular matrix (ECM)?
Material outside the cell that fills the extracellular space in multicellular animal tissues.
p.13
Reactivity and Cyclization of Monosaccharides
What type of carbon atoms are electrophilic in carbohydrates?
Aldehyde and ketone carbons.
p.71
Lectins and Their Biological Functions
What are lectins?
Proteins that bind carbohydrates with high specificity and moderate to high affinity.
p.12
Monosaccharides and Disaccharides
What is the primary function of monosaccharides in living organisms?
They serve as a primary energy source.
p.19
Monosaccharides and Disaccharides
What is a structural characteristic of sugar alcohols?
They contain hydroxyl (–OH) groups, which makes them similar to alcohols.
p.73
Lectins and Their Biological Functions
How do lectins assist lymphocytes in responding to infections?
By binding to specific ligands on the surface of cells, guiding lymphocytes to the affected area.
What role do cell surface polysaccharides play?
They are recognition molecules.
p.26
Disaccharides and Their Hydrolysis
How is maltose formed?
By the condensation of two glucose molecules through a glycosidic bond.
p.69
Glycoconjugates: Proteoglycans, Glycoproteins, and Glycolipids
How do N-linked oligosaccharides assist in protein folding?
They extrinsically enhance glycoprotein folding in the glycoproteostasis network.
What is a heteropolysaccharide?
A polysaccharide made of multiple monomer units.
p.26
Disaccharides and Their Hydrolysis
What is the importance of maltose in nutrition?
It serves as an energy source through its breakdown into glucose.
p.4
Stereochemistry of Carbohydrates
What functional groups do carbohydrates commonly have?
They initially have a carbonyl group, which can be an aldehyde (aldose) or a ketone (ketose).
p.58
Glycoconjugates: Proteoglycans, Glycoproteins, and Glycolipids
What is a key characteristic of the material formed by proteoglycan aggregates?
Very low friction material.
p.3
Carbohydrates as Informational Molecules
How do carbohydrates assist in cell adhesion?
They facilitate the sticking of cells to one another.
p.64
Glycoconjugates: Proteoglycans, Glycoproteins, and Glycolipids
What role do carbohydrates play in glycoproteins?
They play a role in protein-protein recognition.
p.75
Glycoconjugates: Proteoglycans, Glycoproteins, and Glycolipids
How do oligosaccharides contribute to cell interactions?
By facilitating recognition and adhesion between cells.
p.15
Reactivity and Cyclization of Monosaccharides
What process leads to the formation of ring structures in monosaccharides?
Internal hemiacetal formation.
What is the molecular weight of glycogen?
It reaches several millions.
What is the structural characteristic of Gram-negative cell walls regarding peptidoglycan?
They involve a direct linkage between tetrapeptide segments.
p.20
Carbohydrates as Informational Molecules
What are sugar alcohols?
Sweeteners used in many sugarless gums and candies.
p.9
Stereochemistry of Carbohydrates
What are epimers?
Epimers are diastereomers that differ at only one stereogenic center.
p.9
Stereochemistry of Carbohydrates
Can you give an example of epimers?
D-glucose and D-mannose are examples of epimers.
p.60
Glycoconjugates: Proteoglycans, Glycoproteins, and Glycolipids
What is a glycoconjugate?
A biologically active molecule consisting of an informational carbohydrate joined to a protein or lipid.
p.5
Stereochemistry of Carbohydrates
What is a ketose?
A carbohydrate with ketone functionality.
Which form of starch contributes to its solubility in water?
Amylopectin, due to its branched structure.
What directs the program for polysaccharide synthesis?
The enzymes that catalyze the polymerization of monomer units.
p.48
Glycoconjugates: Proteoglycans, Glycoproteins, and Glycolipids
What types of polysaccharides are found on animal cell surfaces?
Glycoproteins and proteoglycans.
p.5
Stereochemistry of Carbohydrates
Can carbohydrates be constitutional isomers?
Yes, they can be constitutional isomers.
p.60
Lectins and Their Biological Functions
What results from the recognition of oligosaccharides by sugar-binding proteins?
A perfect fit between lectin and ligand.
p.49
Extracellular Matrix and Cell Surface Polysaccharides
What functions does the ECM serve in tissues?
Provides strength, elasticity, and acts as a physical barrier.
p.71
Lectins and Their Biological Functions
What does lectin multivalency refer to?
A single lectin molecule having multiple carbohydrate binding domains, which increases effective affinity.
p.63
Extracellular Matrix and Cell Surface Polysaccharides
What is the significance of the RGD sequence in fibronectin?
It allows binding to integrins.
p.29
Galactose Metabolism and Lactose Intolerance
What is lactase intolerance?
Inability to digest lactose due to the disappearance of lactase in adulthood.
p.16
Monosaccharides and Disaccharides
What are sugar esters, such as phosphate esters like ATP, important for?
They are important for cellular energy transfer.
Do polysaccharides have defined lengths or molecular weights?
No, they generally do not have defined lengths or molecular weights.
p.65
Glycoconjugates: Proteoglycans, Glycoproteins, and Glycolipids
How are N-linked glycans attached to proteins?
Via asparagine amino groups.
p.20
Carbohydrates as Informational Molecules
What products commonly contain sugar alcohols?
Sugarless gums and candies.
p.19
Monosaccharides and Disaccharides
What are sugar alcohols?
Sugar alcohols are a type of carbohydrate that are used as sweeteners and have a chemical structure similar to both sugars and alcohols.
p.8
Stereochemistry of Carbohydrates
What are epimers?
Stereoisomers that differ at only one chiral center.
p.68
Glycoconjugates: Proteoglycans, Glycoproteins, and Glycolipids
What is one function of N-linked oligosaccharides related to proteins?
They can alter the chemical and physical properties of proteins.
p.63
Extracellular Matrix and Cell Surface Polysaccharides
What role do integrins play in cell interactions?
They mediate signaling between the cell interior and ECM molecules.
p.24
Carbohydrates as Informational Molecules
Why is Hb A1c important in diabetes management?
It helps in diagnosing diabetes and monitoring long-term glucose control.
p.10
Stereochemistry of Carbohydrates
How do D-aldoses relate to epimers?
D-aldoses can have different epimers based on variations in stereochemistry at specific carbon atoms.
p.73
Lectins and Their Biological Functions
What is a key function of lectins in the immune response?
They help in the adhesion of lymphocytes to endothelial cells during inflammation.
p.41
Glycoconjugates: Proteoglycans, Glycoproteins, and Glycolipids
What are bacterial cell walls composed of?
1 or 2 bilayers and a peptidoglycan shell.
p.50
Glycoconjugates: Proteoglycans, Glycoproteins, and Glycolipids
What are proteoglycans?
Macromolecules consisting of 1+ sulfated glycosaminoglycan chains joined covalently to a membrane or secreted protein.
p.23
Glycoconjugates: Proteoglycans, Glycoproteins, and Glycolipids
What role does hydrogen peroxide play in colorimetric glucose analysis?
It oxidizes organic molecules into highly colored compounds.
p.51
Glycoconjugates: Proteoglycans, Glycoproteins, and Glycolipids
What are glycosphingolipids?
A class of glycolipids with a specific backbone structure, rich in neurons, playing a role in signal transduction.
p.27
Disaccharides and Their Hydrolysis
Why is sucrose classified as a nonreducing sugar?
Because both anomeric carbons are involved in the glycosidic bond.
p.69
Glycoconjugates: Proteoglycans, Glycoproteins, and Glycolipids
What role do glycan-binding proteins play in protein folding?
They promote and assess folding, exporting folded proteins and degrading misfolded ones.
p.52
Glycoconjugates: Proteoglycans, Glycoproteins, and Glycolipids
What makes glycosaminoglycans acidic?
The presence of sulfate or carboxylate groups.
p.21
Glycoconjugates: Proteoglycans, Glycoproteins, and Glycolipids
What are sugar esters?
Phosphate esters of glucose, fructose, and other monosaccharides.
p.12
Monosaccharides and Disaccharides
What are monosaccharides?
The simplest form of carbohydrates, consisting of single sugar molecules.
p.72
Lectins and Their Biological Functions
What role do selectins play in the inflammatory response?
They mediate cell-cell recognition and adhesion.
p.46
Extracellular Matrix and Cell Surface Polysaccharides
What is a characteristic feature of Gram-negative cells?
They are described as 'hairy'.
Which organisms can secrete cellulase to utilize cellulose?
Fungi, bacteria, and protozoa.
p.18
Monosaccharides and Disaccharides
What is rhamnose a component of?
Ouabain, a toxic cardiac glycoside.
What can ruminants and termites absorb into their bloodstreams?
Freed glucose from cellulose metabolism.
What are natural carbohydrates usually found as?
Polymers, including storage and structure molecules.
p.16
Monosaccharides and Disaccharides
What are acetals, ketals, and glycosides the basis for?
Oligo- and polysaccharides.
p.27
Disaccharides and Their Hydrolysis
What is a characteristic of the glycosidic linkage in disaccharides?
It involves the anomeric carbon on one sugar, while the other is usually free.
p.62
Glycoconjugates: Proteoglycans, Glycoproteins, and Glycolipids
Which protein interaction is characterized by the attraction between nonpolar regions?
Hydrophobic interactions.
p.3
Carbohydrates as Informational Molecules
How do carbohydrates contribute to molecular recognition?
They play a role in the immune system.
p.22
Monosaccharides and Disaccharides
What are reducing sugars?
Sugars capable of reducing cupric ion, characterized by free anomeric carbons.
p.53
Extracellular Matrix and Cell Surface Polysaccharides
What are two functions of glycosaminoglycans in connective tissue?
Formation of extracellular matrix and lubrication of joints.
p.54
Glycoconjugates: Proteoglycans, Glycoproteins, and Glycolipids
What is dermatan sulfate a component of?
The extracellular matrix of skin.
p.76
Lectins and Their Biological Functions
How does CRP act on damaged membranes?
By binding to phosphocholine moieties.
p.76
Lectins and Their Biological Functions
What is CRP a diagnostic marker for?
Inflammation and an indicator of heart disease risk.
Why can't most animals use cellulose as a fuel source?
They lack the enzyme to hydrolyze (β 1 → 4) linkages.
What is the primary function of tetrapeptides in peptidoglycan?
To link adjacent backbone chains.
p.2
Monosaccharides and Disaccharides
What are the two main types of simple carbohydrates?
Monosaccharides and Disaccharides.
p.8
Stereochemistry of Carbohydrates
How do diastereomers differ from each other?
Diastereomers have different physical properties such as water solubility and melting temperature.
What is the structural characteristic of cellulose?
It is tough and water insoluble.
p.10
Stereochemistry of Carbohydrates
Why is understanding epimers important in carbohydrate chemistry?
Epimers can have significantly different properties and biological functions.
p.23
Glycoconjugates: Proteoglycans, Glycoproteins, and Glycolipids
What does glucose oxidase convert glucose into?
Glucono-δ-lactone and hydrogen peroxide.
Why are glycogen and starch insoluble?
Due to their high molecular weight.
p.50
Glycoconjugates: Proteoglycans, Glycoproteins, and Glycolipids
Where are proteoglycans primarily found?
In all extracellular matrices.
p.70
Glycoconjugates: Proteoglycans, Glycoproteins, and Glycolipids
What is α-1-Antitrypsin deficiency associated with?
Dysfunction of glycoproteostasis.
p.3
Carbohydrates as Informational Molecules
What role do carbohydrates have in cellular protection?
They are components of bacterial and plant cell walls.
p.54
Glycoconjugates: Proteoglycans, Glycoproteins, and Glycolipids
What are hyaluronates and where are they found?
Hyaluronates are glycosaminoglycans consisting of up to 25,000 disaccharide units, found in the vitreous humor of the eye and synovial fluid.
p.21
Glycoconjugates: Proteoglycans, Glycoproteins, and Glycolipids
Why are sugar esters important?
They are important metabolic intermediates.
p.9
Stereochemistry of Carbohydrates
How do epimers differ from anomers?
Epimers differ at any one stereogenic center, while anomers differ at the anomeric carbon.
p.49
Extracellular Matrix and Cell Surface Polysaccharides
What are the main components of the ECM?
Proteoglycan aggregates, collagen fibers, and elastin.
p.72
Lectins and Their Biological Functions
What are selectins?
A family of plasma membrane lectins that mediate cell-cell recognition and adhesion.
p.8
Stereochemistry of Carbohydrates
Are epimers mirror images of each other?
No, epimers are NOT mirror images and therefore are NOT enantiomers.
p.10
Stereochemistry of Carbohydrates
What are D-aldoses?
A type of monosaccharide with an aldehyde group and a specific stereochemistry.
What defines polysaccharides?
Sugar polymers containing more than 20 monosaccharide units.
p.70
Glycoconjugates: Proteoglycans, Glycoproteins, and Glycolipids
What is glycoproteostasis?
The maintenance of proper folding and functioning of glycoproteins.
p.62
Glycoconjugates: Proteoglycans, Glycoproteins, and Glycolipids
What are the four types of protein interactions with NS domains of Heparan Sulfate?
The specific types include electrostatic interactions, hydrophobic interactions, hydrogen bonding, and van der Waals forces.
p.27
Disaccharides and Their Hydrolysis
What determines the distinguishing features of different disaccharides?
The order of the two monomer units, if they are different kinds.
What is cotton primarily composed of?
Nearly pure fibrous cellulose (usually 94% cellulose).
p.73
Lectins and Their Biological Functions
Why are lectin-ligand interactions important during an immune response?
They ensure that lymphocytes reach the correct location to combat infection or tissue damage.
p.69
Glycoconjugates: Proteoglycans, Glycoproteins, and Glycolipids
What happens to proteins with native conformation in the glycoproteostasis network?
They selectively transit from the ER to the Golgi.
p.50
Glycoconjugates: Proteoglycans, Glycoproteins, and Glycolipids
What are glycoproteins?
Proteins that have one or several oligosaccharides joined covalently.
What is the main role of starch in plants?
It is the main storage polysaccharide.
p.58
Glycoconjugates: Proteoglycans, Glycoproteins, and Glycolipids
How does aggrecan interact with collagen in cartilage?
Aggrecan interacts strongly with collagen in the extracellular matrix (ECM) of cartilage.
p.3
Carbohydrates as Informational Molecules
What structural role do carbohydrates play in biology?
They maintain biological structure, such as cellulose.
p.30
Galactose Metabolism and Lactose Intolerance
Why is galactose important in the diet?
It is an important component in the infant diet (milk).
p.67
Glycoconjugates: Proteoglycans, Glycoproteins, and Glycolipids
What is the characteristic of the O oligosaccharide in relation to antibodies?
It does not elicit antibodies in most humans.
p.12
Monosaccharides and Disaccharides
What is the difference between aldoses and ketoses?
Aldoses contain an aldehyde group, while ketoses contain a ketone group.
p.63
Extracellular Matrix and Cell Surface Polysaccharides
What molecules does fibronectin bind to?
Fibrin, heparan sulfate, and collagen.
What is the structure of amylose?
It is water-soluble and an unbranched polymer of (α 1 → 4) linked residues.
p.2
Working with Carbohydrates
What is a key focus in working with carbohydrates?
Understanding their structure, function, and interactions.
p.41
Glycoconjugates: Proteoglycans, Glycoproteins, and Glycolipids
What distinguishes Gram-negative bacterial cell walls?
Two bilayers with a thin peptidoglycan shell in between.
p.57
Glycoconjugates: Proteoglycans, Glycoproteins, and Glycolipids
How are glycosaminoglycans linked to the core protein?
From the anomeric carbon of xylose to serine hydroxyl.
p.64
Glycoconjugates: Proteoglycans, Glycoproteins, and Glycolipids
How is carbohydrate attached to a protein in glycoproteins?
Via its anomeric carbon to amino acids on the protein.
p.52
Glycoconjugates: Proteoglycans, Glycoproteins, and Glycolipids
What types of sugars are found in glycosaminoglycans?
N-acetylgalactosamine or N-acetylglucosamine or their derivatives.
p.57
Glycoconjugates: Proteoglycans, Glycoproteins, and Glycolipids
What happens to cartilage during joint movement?
Cartilage is compressed, expelling water.
p.72
Lectins and Their Biological Functions
How do selectins affect immune cells?
They help move immune cells through the capillary wall.
p.49
Extracellular Matrix and Cell Surface Polysaccharides
How does the ECM affect tumor cells?
It acts as a barrier for tumor cells seeking to invade new tissues.
p.68
Glycoconjugates: Proteoglycans, Glycoproteins, and Glycolipids
How do N-linked oligosaccharides affect protein stability?
They can stabilize protein conformations and/or protect against proteolysis.
p.67
Glycoconjugates: Proteoglycans, Glycoproteins, and Glycolipids
How are the A and B antigens formed?
By the addition of GalNAc or Gal, respectively, to the O oligosaccharide.
p.2
Carbohydrates as Informational Molecules
What is the significance of carbohydrates in biological systems?
They function as informational molecules, often referred to as the Sugar Code.
p.62
Glycoconjugates: Proteoglycans, Glycoproteins, and Glycolipids
What type of interaction involves charged groups in protein and NS domains?
Electrostatic interactions.
What is the typical composition of starch in terms of amylose and amylopectin?
Starch is typically 10-30% amylose and 70-90% amylopectin.
p.57
Glycoconjugates: Proteoglycans, Glycoproteins, and Glycolipids
What are proteoglycans linked to?
Different glycosaminoglycans linked to a core protein.
p.64
Glycoconjugates: Proteoglycans, Glycoproteins, and Glycolipids
What is a glycoprotein?
A protein with small oligosaccharides attached.
What characterizes a branched polysaccharide?
It has multiple types of glycosidic bonds.
p.53
Glycoconjugates: Proteoglycans, Glycoproteins, and Glycolipids
What structural feature do glycosaminoglycans have that minimizes charge repulsion?
They form an extended hydrated molecule.
p.57
Glycoconjugates: Proteoglycans, Glycoproteins, and Glycolipids
How do proteoglycans provide a reservoir of growth factors?
By binding growth factor proteins in the glycocalyx at the cell surface.
p.22
Monosaccharides and Disaccharides
Why is glucose considered a reducing sugar?
Because it has a free anomeric carbon that can reduce oxidizing agents.
p.54
Glycoconjugates: Proteoglycans, Glycoproteins, and Glycolipids
What role do glycosaminoglycans play in proteoglycans?
They are constituents of proteoglycans.
p.8
Stereochemistry of Carbohydrates
What type of stereoisomers are epimers classified as?
Epimers are classified as diastereomers.
p.71
Lectins and Their Biological Functions
What role do lectins play in protein targeting?
They are involved in intracellular targeting of newly synthesized proteins.
p.51
Glycoconjugates: Proteoglycans, Glycoproteins, and Glycolipids
What role do glycolipids play in the plasma membrane?
They are components with hydrophilic head groups that are oligosaccharides.
p.41
Glycoconjugates: Proteoglycans, Glycoproteins, and Glycolipids
How are tetrapeptides connected in Gram-positive bacteria?
By a pentaglycine bridge.
p.23
Glycoconjugates: Proteoglycans, Glycoproteins, and Glycolipids
What type of detection is used in portable glucose sensors?
Electrochemical detection.
p.57
Glycoconjugates: Proteoglycans, Glycoproteins, and Glycolipids
What is one function of proteoglycans regarding cell growth?
Modulation of cell growth processes by binding growth factor proteins.
p.22
Monosaccharides and Disaccharides
What is the significance of reducing sugars in diagnostic tests?
They are used as the basis for tests for blood sugar levels.
p.72
Lectins and Their Biological Functions
What other process do selectins mediate besides inflammation?
The rejection of transplanted organs.
p.68
Glycoconjugates: Proteoglycans, Glycoproteins, and Glycolipids
What happens when monosaccharide units are cleaved from N-linked glycoproteins in blood?
It targets them for degradation in the liver.
p.67
Glycoconjugates: Proteoglycans, Glycoproteins, and Glycolipids
What does R represent in the context of glycoproteins?
Either a protein molecule or a lipid molecule.
p.70
Glycoconjugates: Proteoglycans, Glycoproteins, and Glycolipids
Name another disease linked to glycoproteostasis issues.
Congenital hypothyroidism.
What defines a linear polysaccharide?
It has one type of glycosidic bond.
p.52
Glycoconjugates: Proteoglycans, Glycoproteins, and Glycolipids
What are important examples of glycosaminoglycans?
Chondroitin sulfates, keratan sulfates, dermatan sulfates, and hyaluronic acid.
p.23
Glycoconjugates: Proteoglycans, Glycoproteins, and Glycolipids
What color change occurs with o-dianisidine in the presence of hydrogen peroxide?
It changes from faint orange (reduced) to bright orange (oxidized).
p.64
Glycoconjugates: Proteoglycans, Glycoproteins, and Glycolipids
Which amino acids commonly connect carbohydrates in glycoproteins?
Serine (Ser), Threonine (Thr), and Asparagine (Asn).
p.54
Glycoconjugates: Proteoglycans, Glycoproteins, and Glycolipids
Which glycosaminoglycans are found in tendons and cartilage?
Chondroitins and keratan sulfate.
p.73
Lectins and Their Biological Functions
What is the role of lectin-ligand interactions in lymphocyte movement?
They facilitate the migration of lymphocytes to the site of infection or injury.
p.29
Galactose Metabolism and Lactose Intolerance
What does the lactase persistence phenotype indicate?
Production of lactase into adulthood.
p.51
Glycoconjugates: Proteoglycans, Glycoproteins, and Glycolipids
What is a proteoglycan unit composed of?
A 'core protein' with covalently attached glycosaminoglycan(s).
p.41
Glycoconjugates: Proteoglycans, Glycoproteins, and Glycolipids
What characterizes Gram-positive bacterial cell walls?
One bilayer and a thick peptidoglycan outer shell.
p.53
Glycoconjugates: Proteoglycans, Glycoproteins, and Glycolipids
What are the two types of monomers that can be found in glycosaminoglycans?
N-acetyl-glucosamine or N-acetyl-galactosamine.
p.22
Monosaccharides and Disaccharides
What happens to reducing sugars during redox reactions?
They are converted into sugar acids.
p.3
Carbohydrates as Informational Molecules
What is the role of carbohydrates in biological lubricants?
They help reduce friction between surfaces.
p.54
Glycoconjugates: Proteoglycans, Glycoproteins, and Glycolipids
What properties do glycosaminoglycans provide to the extracellular matrix?
Viscosity, adhesiveness, and tensile strength.
p.26
Disaccharides and Their Hydrolysis
What is maltose?
A disaccharide formed from two glucose molecules.
p.70
Glycoconjugates: Proteoglycans, Glycoproteins, and Glycolipids
What can result from dysfunction of glycoproteostasis?
Retention of aggregated and misfolded proteins in the ER.
What is the molecular weight range of carbohydrates?
From as small as 90 g/mol (glyceraldehyde) to greater than 200,000,000 g/mol (amylopectin).
What is a homopolysaccharide?
A polysaccharide made of one monomer unit.
p.27
Disaccharides and Their Hydrolysis
Why is lactose considered a reducing sugar?
Because the glucose residue is at its reducing end.
p.69
Glycoconjugates: Proteoglycans, Glycoproteins, and Glycolipids
What occurs to misfolded proteins in the glycoproteostasis network?
They are retained in the ER and/or degraded.
How many reducing and nonreducing ends do glycogen and amylopectin have?
One reducing end and many nonreducing ends.
p.50
Glycoconjugates: Proteoglycans, Glycoproteins, and Glycolipids
What is the structure of oligosaccharide portions in glycoproteins?
They are heterogenous and rich in information.
p.58
Glycoconjugates: Proteoglycans, Glycoproteins, and Glycolipids
What role do proteoglycan aggregates play in joint surfaces?
They provide lubrication and load balancing.
p.50
Glycoconjugates: Proteoglycans, Glycoproteins, and Glycolipids
Where can glycoproteins be found?
On the outer face of the plasma membrane, in the ECM, in blood, and in organelles such as Golgi complexes, secretory granules, and lysosomes.
p.53
Extracellular Matrix and Cell Surface Polysaccharides
How do glycosaminoglycans contribute to the extracellular matrix?
They form a meshwork with fibrous proteins.
p.64
Glycoconjugates: Proteoglycans, Glycoproteins, and Glycolipids
Do bacteria glycosylate their proteins?
Only some bacteria glycosylate a few of their proteins.
