Podcast
Questions and Answers
Amino sugars are primarily composed of N-acetyl glucosamine and N-acetyl galactosamine.
Amino sugars are primarily composed of N-acetyl glucosamine and N-acetyl galactosamine.
True
Glycosaminoglycans (GAGs) are synthesized exclusively in the cytoplasm.
Glycosaminoglycans (GAGs) are synthesized exclusively in the cytoplasm.
False
Chondroitin sulfate has a relatively long chain structure compared to other GAGs.
Chondroitin sulfate has a relatively long chain structure compared to other GAGs.
False
Heparin is known for its anticoagulant properties and is utilized in medical settings to prevent clotting.
Heparin is known for its anticoagulant properties and is utilized in medical settings to prevent clotting.
Signup and view all the answers
Glycoconjugates link carbohydrates to proteins and lipids, with proteoglycans and glycoproteins being the primary types.
Glycoconjugates link carbohydrates to proteins and lipids, with proteoglycans and glycoproteins being the primary types.
Signup and view all the answers
Monosaccharides can be classified as either aldoses or ketoses.
Monosaccharides can be classified as either aldoses or ketoses.
Signup and view all the answers
All carbohydrates possess the empirical formula Cx(H2O)y.
All carbohydrates possess the empirical formula Cx(H2O)y.
Signup and view all the answers
Glycogen is a type of monosaccharide found in the human body.
Glycogen is a type of monosaccharide found in the human body.
Signup and view all the answers
Reducing sugars can easily oxidize due to the presence of a free anomeric carbon.
Reducing sugars can easily oxidize due to the presence of a free anomeric carbon.
Signup and view all the answers
Complex carbohydrates include glycoproteins and proteoglycans.
Complex carbohydrates include glycoproteins and proteoglycans.
Signup and view all the answers
Benedict’s test is a method used to identify non-reducing sugars.
Benedict’s test is a method used to identify non-reducing sugars.
Signup and view all the answers
Anomeric carbon is a term used to describe a carbon that can form a glycosidic bond.
Anomeric carbon is a term used to describe a carbon that can form a glycosidic bond.
Signup and view all the answers
Gluconic acid is derived from the oxidation of D-glucose.
Gluconic acid is derived from the oxidation of D-glucose.
Signup and view all the answers
Carbohydrates are primarily sourced from animal products.
Carbohydrates are primarily sourced from animal products.
Signup and view all the answers
The term 'mucous membranes' relates to the structural components of carbohydrates.
The term 'mucous membranes' relates to the structural components of carbohydrates.
Signup and view all the answers
Glycogen is stored in the heart and spleen.
Glycogen is stored in the heart and spleen.
Signup and view all the answers
Starch is a structural polysaccharide predominantly found in plants.
Starch is a structural polysaccharide predominantly found in plants.
Signup and view all the answers
Glycoproteins contain covalently attached oligosaccharides to proteins.
Glycoproteins contain covalently attached oligosaccharides to proteins.
Signup and view all the answers
Amylopectin has a more branched structure than glycogen.
Amylopectin has a more branched structure than glycogen.
Signup and view all the answers
Iodine can produce a blue color when it interacts with amylose.
Iodine can produce a blue color when it interacts with amylose.
Signup and view all the answers
O-glycosidic bonds are formed through the amino acid aspartic acid.
O-glycosidic bonds are formed through the amino acid aspartic acid.
Signup and view all the answers
N-glycosidic bonds involve the side chain NH2 of tyrosine.
N-glycosidic bonds involve the side chain NH2 of tyrosine.
Signup and view all the answers
Cellulose is the most abundant polysaccharide on Earth.
Cellulose is the most abundant polysaccharide on Earth.
Signup and view all the answers
Glycosaminoglycans consist of linear polymers of repeating monosaccharides.
Glycosaminoglycans consist of linear polymers of repeating monosaccharides.
Signup and view all the answers
Transferrin is classified as a structural glycoprotein.
Transferrin is classified as a structural glycoprotein.
Signup and view all the answers
Sorbitol accumulation in the lens can lead to cataract formation due to osmotic stress.
Sorbitol accumulation in the lens can lead to cataract formation due to osmotic stress.
Signup and view all the answers
B-d-glucose is linked by b(1®4) linkages in cellulose.
B-d-glucose is linked by b(1®4) linkages in cellulose.
Signup and view all the answers
2’-deoxy ribose is the sugar found in RNA.
2’-deoxy ribose is the sugar found in RNA.
Signup and view all the answers
Immunoglobulins are examples of immunologic glycoproteins.
Immunoglobulins are examples of immunologic glycoproteins.
Signup and view all the answers
The formation of glycosidic bonds requires the loss of water.
The formation of glycosidic bonds requires the loss of water.
Signup and view all the answers
The O antigen is associated with α-1,3-N-acetylgalactosaminytransferase.
The O antigen is associated with α-1,3-N-acetylgalactosaminytransferase.
Signup and view all the answers
Hydrolysis of glycogen releases glucose at the reducing end.
Hydrolysis of glycogen releases glucose at the reducing end.
Signup and view all the answers
Blood group antigens are found solely on proteins within the erythrocyte membrane.
Blood group antigens are found solely on proteins within the erythrocyte membrane.
Signup and view all the answers
Ruminants are capable of digesting cellulose.
Ruminants are capable of digesting cellulose.
Signup and view all the answers
Maltose consists of glucose and galactose.
Maltose consists of glucose and galactose.
Signup and view all the answers
Glycosyltransferases are enzymes that assemble monosaccharide residues for blood group substances.
Glycosyltransferases are enzymes that assemble monosaccharide residues for blood group substances.
Signup and view all the answers
Proteoglycans are primarily made up of carbohydrate chains attached to a core protein.
Proteoglycans are primarily made up of carbohydrate chains attached to a core protein.
Signup and view all the answers
Lactose is a disaccharide that consists of glucose and fructose.
Lactose is a disaccharide that consists of glucose and fructose.
Signup and view all the answers
Chitin is a type of homopolysaccharide found in fungi.
Chitin is a type of homopolysaccharide found in fungi.
Signup and view all the answers
Gangliosides are simpler than glycosphingolipids due to their lack of complex oligosaccharides.
Gangliosides are simpler than glycosphingolipids due to their lack of complex oligosaccharides.
Signup and view all the answers
The terminal monosaccharide at the non-reducing end determines the blood group of an individual.
The terminal monosaccharide at the non-reducing end determines the blood group of an individual.
Signup and view all the answers
Insulin is required for glucose uptake in lens cells.
Insulin is required for glucose uptake in lens cells.
Signup and view all the answers
Glycation of proteins mainly involves the enzymatic reaction of sugars with amino groups.
Glycation of proteins mainly involves the enzymatic reaction of sugars with amino groups.
Signup and view all the answers
Glycogen is hydrolyzed by glycogen phosphorylase from the non-reducing end.
Glycogen is hydrolyzed by glycogen phosphorylase from the non-reducing end.
Signup and view all the answers
In diabetes, HbA1c is used as a marker for short-term glycemic control.
In diabetes, HbA1c is used as a marker for short-term glycemic control.
Signup and view all the answers
The main sources of starch include rice, corn, and potatoes.
The main sources of starch include rice, corn, and potatoes.
Signup and view all the answers
O-glycosidic bonds form between an -OH group of one monosaccharide and an -NH group of another compound.
O-glycosidic bonds form between an -OH group of one monosaccharide and an -NH group of another compound.
Signup and view all the answers
Glycogen and starch are both structural polysaccharides.
Glycogen and starch are both structural polysaccharides.
Signup and view all the answers
The hyperosmotic effect caused by sorbitol results in fluid infusion to counteract the osmotic gradient.
The hyperosmotic effect caused by sorbitol results in fluid infusion to counteract the osmotic gradient.
Signup and view all the answers
Polysaccharides are generally sweet and soluble in water.
Polysaccharides are generally sweet and soluble in water.
Signup and view all the answers
Hexokinase saturation leads to the activation of the aldose reductase pathway.
Hexokinase saturation leads to the activation of the aldose reductase pathway.
Signup and view all the answers
Glucose forms sorbitol through enzymatic reduction.
Glucose forms sorbitol through enzymatic reduction.
Signup and view all the answers
Deoxy sugars are monosaccharides that have additional hydroxyl groups compared to regular sugars.
Deoxy sugars are monosaccharides that have additional hydroxyl groups compared to regular sugars.
Signup and view all the answers
Cataracts are primarily caused by the accumulation of polyols in the lens.
Cataracts are primarily caused by the accumulation of polyols in the lens.
Signup and view all the answers
Sucrose consists of two monosaccharides joined by a β-1,2 glycosidic bond.
Sucrose consists of two monosaccharides joined by a β-1,2 glycosidic bond.
Signup and view all the answers
Study Notes
Carbohydrates of Physiologic Significance
- Carbohydrates are the most abundant compounds in nature, with cellulose being a notable example (100 billion tons annually).
- Saccharides (sugars) are polyhydroxy aldehydes or polyhydroxy ketones.
- They are synthesized in plants and animals.
- A carbohydrate's definition is a polyhydroxylated compound containing at least 3 carbon atoms.
- The molecular formula is generally Cx(H2O)y, but not all carbohydrates adhere to this formula (e.g., deoxy sugars, amino sugars).
Learning Objectives (ILOs)
- Students will be able to identify major monosaccharides, disaccharides, and polysaccharides in humans.
- They will understand the properties of monosaccharides, including nomenclature (number of carbons, functional groups), isomerism (structural, epimers, optical, D/L), anomeric carbons, and reducing/non-reducing sugars.
- The students will be able to describe the structures and functions of disaccharides (e.g., maltose, lactose, sucrose), storage polysaccharides (glycogen, starch), and complex carbohydrates (GAGs, glycoproteins, proteoglycans).
Functions of Carbohydrates
- Carbohydrates serve as energy sources.
- They are components of DNA, RNA, and intermediates in the biosynthesis of fatty acids & proteins.
- They also participate in biological transport, cell recognition, growth factors, and immune system modulation.
- Carbohydrates act as lubricants for mucous membranes and are structural components (e.g., cellulose).
Classification of Carbohydrates
- Carbohydrates are categorized into monosaccharides, oligosaccharides (disaccharides), and polysaccharides with further subdivisions.
- Monosaccharides are the simplest form (e.g., aldoses, ketoses).
- Oligosaccharides consist of a few monosaccharides linked together (e.g., disaccharides).
- Polysaccharides are polymers of monosaccharides (e.g., homopolysaccharides, heteropolysaccharides).
- Derived carbohydrates are formed by oxidation/reduction/amino/deoxy sugar derivations of the main classes.
Oxidation of Monosaccharides
- Free anomeric carbons can be oxidized.
- Benedict's test identifies reducing sugars, wherein the free anomeric carbon reacts changing a blue solution of copper ions to a brick red precipitate.
- Oxidation by glucose oxidase is a highly specific test for glucose, yielding gluconic acid and hydrogen peroxide.
Clinical Applications of Glucose Testing (glucometers and dipsticks)
- Glucose oxidase is utilized in glucometers to determine levels.
- The enzyme reacts with glucose, producing hydrogen peroxide, which leads to a color change (indicating glucose level).
- Similar reactions occur in urine dipsticks to measure glucose.
- These methods provide diagnostic tools.
Reducing and Non-Reducing Sugars
- Reducing sugars have free anomeric carbons which can be oxidized.
- Benedict's tests use the oxidation of copper ions, which change color to show the reducing sugars.
- Non-reducing sugars lack free anomeric carbons.
Reduction of Carbohydrates
- Carbohydrates can be reduced catalytically (using hydrogen and a catalyst) or enzymatically.
- The product is a polyol (sugar alcohol).
- For instance, glucose can be reduced to sorbitol.
- Glucose reduction/increase (especially in diabetes) can lead to cataract formation.
Special Monosaccharides: Deoxy Sugars
- Deoxy sugars are monosaccharides that lack one or more hydroxyl groups.
- 2-deoxyribose is an example, a component of DNA.
Glycosidic Bonds
- Glycosidic bonds link monosaccharides.
- These bonds form between an anomeric carbon of one monosaccharide and a hydroxyl or amine group of another compound by dehydration.
- Bonds can be O-glycosidic or N-glycosidic, depending on linking groups involved.
- Glycosidic bonds create di-, oligo-, and polysaccharides.
Naming Glycosidic Bonds
- Glycosidic bonds are named based on the carbon atoms involved and the orientation of the anomeric carbon.
- Example: Maltose (α-1, 4) bond, indicates a bond between carbons 1 and 4.
Disaccharides
- Two monosaccharides linked by an O-glycosidic bond form disaccharides.
- Examples include glucose + glucose (maltose), glucose + fructose (sucrose), and galactose + glucose (lactose).
Disaccharides: Structure and Function
- Disaccharides have unique structures (determined by which carbons are linked).
- These structures determine their functions.
Lactose Intolerance
- Lactose intolerance is the inability to digest lactose (glucose and galactose linkages).
- The inability to digest the disaccharide lactose causes symptoms like gas, bloating, and abdominal pain.
- Lactose intolerance arises from decreased or absent Lactase activity.
Polysaccharides
- Polysaccharides are complex carbohydrates, long chains of monosaccharides linked together.
- They have characteristics like being white, amorphous (glassy), and non-reducing.
- Polysaccharides are categorized as homopolysaccharides (single monosaccharides) like glycogen, cellulose, and heteropolysaccharides.
Glycogen
- Glycogen is a branched storage polysaccharide.
- It is found in liver and muscle.
- It provides short term glucose storage, and its branches facilitate quick glucose mobilization.
Starch
- Starch, a storage polysaccharide in plants, consists of amylose and amylopectin.
- Amylose is a linear chain, while amylopectin is a branched chain.
- Iodine staining of starch yields diagnostic blue colors due to interactions with amylose.
Cellulose
- Cellulose, a structural polysaccharide in plants, is a linear polymer with β-1, 4 linkages of glucose that our bodies cannot digest
- It provides structural support.
Glycosaminoglycans (GAGs)
- GAGs are linear polymers of repeating disaccharides with amino sugars (acetylglucosamine or galactosamine) and uronic acids (glucuronic or iduronic).
- They are strongly negatively charged due to carboxyl groups.
- GAGs are synthesized in the ER and Golgi and degraded in lysosomes.
- They function in ground substance (to bind water producing gel-like matrix), lubrication, and cell signaling/adhesion.
Members of GAGs
- Notable GAGs include chondroitin sulfates, keratan sulfates, hyaluronic acid, heparin, and dermatan sulfate which have diverse roles within the body.
Proteoglycans
- Proteoglycans consist of a core protein attached to glycosaminoglycans.
- They are found on cell surfaces and in the extracellular matrix.
- Proteoglycans modulate cell growth, provide elasticity, and influence properties of connective tissues like cartilage and skin.
Glycoproteins
- Glycoproteins are proteins with covalently attached oligosaccharides.
- The attachment can be O-linked (serine/threonine) or N-linked (asparagine).
- Abundant in various proteins throughout the body: structural, transport, hormones, enzymes, immunoglobulins/antigens, and in blood groups.
Blood Group Antigens
- Blood group antigens are glycoproteins or glycolipids.
- They are on red blood cells.
- ABO blood group systems are based on sugar molecules present, determined genetically.
ABO blood group system
- ABO blood groups are determined by specific glycosyltransferases.
- These enzymes add sugar molecules to a precursor protein or lipid, leading to the formation of A, B, or O antigens.
Glycolipids
- Glycolipids are lipids with attached carbohydrate chains.
- Classified into glycosphingolipids (ceramide backbone) including glycocerebrosides and gangliosides.
- Glycolipids have diverse roles, for instance, in cell recognition and development.
Glycation of Proteins
- Glycation is a nonenzymatic process.
- Sugars (e.g., glucose) react with proteins, forming stable products.
- Glycation is a long-term glycemic indicator, and high levels indicate poor management of blood glucose levels (diabetes).
Studying That Suits You
Use AI to generate personalized quizzes and flashcards to suit your learning preferences.
Related Documents
Description
Test your knowledge on carbohydrates, including amino sugars, glycosaminoglycans, and their functions. This quiz covers important concepts such as reducing sugars, glycoproteins, and biochemical tests like Benedict’s test. Ideal for students studying biochemistry or molecular biology.
