Podcast
Questions and Answers
What determines the D or L configuration of a monosaccharide?
What determines the D or L configuration of a monosaccharide?
The –OH group of the highest chiral carbon
What is a triose?
What is a triose?
Which of the following are types of monosaccharides based on the number of carbon atoms?
Which of the following are types of monosaccharides based on the number of carbon atoms?
An aldose contains a ketone functional group.
An aldose contains a ketone functional group.
Signup and view all the answers
What is the difference between D-glucose and D-galactose?
What is the difference between D-glucose and D-galactose?
Signup and view all the answers
What are cyclic monosaccharides formed from?
What are cyclic monosaccharides formed from?
Signup and view all the answers
Which cyclic sugar form has a six-atom ring?
Which cyclic sugar form has a six-atom ring?
Signup and view all the answers
What is an anomeric carbon atom?
What is an anomeric carbon atom?
Signup and view all the answers
Haworth projection formulas accurately represent the stereochemistry of sugars.
Haworth projection formulas accurately represent the stereochemistry of sugars.
Signup and view all the answers
What is the biochemical importance of D-Ribose?
What is the biochemical importance of D-Ribose?
Signup and view all the answers
Are all carbohydrates sweet?
Are all carbohydrates sweet?
Signup and view all the answers
Give at least one medical use for carbohydrates.
Give at least one medical use for carbohydrates.
Signup and view all the answers
What are carbohydrates primarily classified on?
What are carbohydrates primarily classified on?
Signup and view all the answers
The human diet should ideally be about two-thirds carbohydrate by mass.
The human diet should ideally be about two-thirds carbohydrate by mass.
Signup and view all the answers
What process do green plants use to produce carbohydrates?
What process do green plants use to produce carbohydrates?
Signup and view all the answers
What is a chiral center?
What is a chiral center?
Signup and view all the answers
What does the term 'enantiomers' refer to?
What does the term 'enantiomers' refer to?
Signup and view all the answers
Achiral molecules possess handedness.
Achiral molecules possess handedness.
Signup and view all the answers
Which phrase correctly describes an optically active compound?
Which phrase correctly describes an optically active compound?
Signup and view all the answers
What is the role of insulin in the body?
What is the role of insulin in the body?
Signup and view all the answers
What happens when blood sugar levels drop too low?
What happens when blood sugar levels drop too low?
Signup and view all the answers
What can result from high glucose levels in cells?
What can result from high glucose levels in cells?
Signup and view all the answers
Why should carbohydrates be eaten before exercise?
Why should carbohydrates be eaten before exercise?
Signup and view all the answers
What happens to performance when all carbohydrates are used?
What happens to performance when all carbohydrates are used?
Signup and view all the answers
Eating carbohydrates is unnecessary for high endurance sports.
Eating carbohydrates is unnecessary for high endurance sports.
Signup and view all the answers
What are the two structural polysaccharides mentioned?
What are the two structural polysaccharides mentioned?
Signup and view all the answers
What is the structural component of plant cell walls?
What is the structural component of plant cell walls?
Signup and view all the answers
Chitin is the most abundant naturally occurring polysaccharide.
Chitin is the most abundant naturally occurring polysaccharide.
Signup and view all the answers
What are glycosaminoglycans (GAGs) also known as?
What are glycosaminoglycans (GAGs) also known as?
Signup and view all the answers
What is the role of proteoglycans?
What is the role of proteoglycans?
Signup and view all the answers
Which of the following is associated with the inflammatory response after tissue injury?
Which of the following is associated with the inflammatory response after tissue injury?
Signup and view all the answers
The 2nd most abundant naturally occurring polysaccharide, next to __________.
The 2nd most abundant naturally occurring polysaccharide, next to __________.
Signup and view all the answers
Hyaluronic acid is a small polysaccharide with 15–90 disaccharide residues.
Hyaluronic acid is a small polysaccharide with 15–90 disaccharide residues.
Signup and view all the answers
What is the medical condition characterized by an inability to metabolize galactose?
What is the medical condition characterized by an inability to metabolize galactose?
Signup and view all the answers
Match the following GAGs with their descriptions:
Match the following GAGs with their descriptions:
Signup and view all the answers
Which type of diabetes is generally diagnosed in children and teenagers?
Which type of diabetes is generally diagnosed in children and teenagers?
Signup and view all the answers
Match the following terms related to stereoisomerism and carbohydrates:
Match the following terms related to stereoisomerism and carbohydrates:
Signup and view all the answers
Diastereomers are _____ of each other.
Diastereomers are _____ of each other.
Signup and view all the answers
What is the structure being illustrated? (1) a-D-altrose, (2) b-D-altose, (3) a-L-altrose, (4) b-L-altrose.
What is the structure being illustrated? (1) a-D-altrose, (2) b-D-altose, (3) a-L-altrose, (4) b-L-altrose.
Signup and view all the answers
Which of the following monosaccharide structural relationships is CORRECT?
Which of the following monosaccharide structural relationships is CORRECT?
Signup and view all the answers
What form must all carbohydrates be in for cells to use them as an energy source?
What form must all carbohydrates be in for cells to use them as an energy source?
Signup and view all the answers
Polysaccharides are saccharide units that contain 3 to 10 units.
Polysaccharides are saccharide units that contain 3 to 10 units.
Signup and view all the answers
What is the primary source of energy for cells?
What is the primary source of energy for cells?
Signup and view all the answers
The process that forms glycosides from cyclic monosaccharides involves a reaction with _____ in acid solution.
The process that forms glycosides from cyclic monosaccharides involves a reaction with _____ in acid solution.
Signup and view all the answers
D-Fructose is the sweetest tasting sugar.
D-Fructose is the sweetest tasting sugar.
Signup and view all the answers
What metabolic condition leads to the presence of D-Glucose in urine?
What metabolic condition leads to the presence of D-Glucose in urine?
Signup and view all the answers
Match the following disaccharides with their common names:
Match the following disaccharides with their common names:
Signup and view all the answers
What is the structure of the glycosidic linkage in Maltose?
What is the structure of the glycosidic linkage in Maltose?
Signup and view all the answers
Which of the following is a common reaction of monosaccharides?
Which of the following is a common reaction of monosaccharides?
Signup and view all the answers
What are the three common natural amino sugars?
What are the three common natural amino sugars?
Signup and view all the answers
Which type of polysaccharide serves as an energy storage polysaccharide in animals?
Which type of polysaccharide serves as an energy storage polysaccharide in animals?
Signup and view all the answers
Polysaccharides are typically sweet and soluble in water.
Polysaccharides are typically sweet and soluble in water.
Signup and view all the answers
Study Notes
Carbohydrates Overview
- Carbohydrates are the most abundant bioorganic molecules on Earth.
- They constitute about 75% of dry plant materials, produced through photosynthesis (reactants: carbon dioxide, water; energy source: sunlight).
- Major carbohydrate sources for humans and animals come from dietary plant materials, ideally two-thirds of the average diet by mass.
Classification of Carbohydrates
- Carbohydrates are classified based on molecular size into:
- Monosaccharides: Single sugar units (e.g., glucose and fructose).
- Disaccharides: Two sugar units linked (e.g., sucrose).
- Oligosaccharides: Short chains of sugar units.
- Polysaccharides: Long chains of sugar units (e.g., starch, cellulose).
Molecular Structure and Chirality
- Carbohydrates can be polyhydroxy aldehydes or polyhydroxy ketones.
- Chirality refers to "handedness" in molecules; chiral molecules have non-superimposable mirror images.
- The presence of a chiral center (a carbon atom bonded to four different groups) determines chirality.
- Chiral molecules exhibit different biological responses; the body may respond differently to left-handed versus right-handed forms.
Importance of Chiral Molecules
- Right-handed and left-handed forms can elicit different responses in biological systems.
- Example: Human body reacts 20 times more effectively to the right-handed form of epinephrine compared to its left-handed counterpart.
Stereoisomerism
- Stereoisomers share the same molecular formula but differ spatially:
- Enantiomers: Non-superimposable mirror images (e.g., right and left-handed forms).
- Diastereomers: Stereoisomers that are not mirror images (e.g., cis-trans isomers).
Designating Handedness Using Fischer Projections
- Enantiomers can rotate polarized light (dextrorotatory = clockwise, levorotatory = counterclockwise).
- D,L system helps determine configuration based on the highest-numbered chiral center's hydroxyl group:
- If -OH is right, it is a D-isomer.
- If -OH is left, it is an L-isomer.
- Fischer projections visually represent spatial arrangement around chiral centers.
Summary
- Understanding carbohydrates involves reviewing molecular structures, classifications, and the importance of chirality in their biological functions.
- Applications of carbohydrates extend to their roles in energy storage, structural roles in plants, and their implications in health, notably in carbohydrate-related diseases.### Structures and Classification of Monosaccharides
- Monosaccharides typically contain 3 to 7 carbon atoms.
- Three-carbon monosaccharides are called trioses (e.g., glyceraldehyde).
- Four-carbon monosaccharides are tetroses (e.g., erythrose).
- Five-carbon monosaccharides are pentoses (e.g., ribose, arabinose).
- Six-carbon monosaccharides are hexoses (e.g., glucose, fructose).
- Aldoses contain an aldehyde functional group; ketoses contain a ketone functional group.
- Classification can be based on both the number of carbon atoms and functional groups (e.g., aldohexose, ketopentose).
- "Sugar" refers to both monosaccharides and certain disaccharides, often associated with sweetness.
Optical Isomers and Chiral Centers
- The number of possible optical isomers is determined by the number of chiral centers in the monosaccharide.
- Each chiral carbon can result in varying configurations, affecting the sugar's stereoisomers.
- Aldohexose (6C) can produce 16 optical isomers; aldohexose has 4 chiral centers.
- Ketoses have fewer optical isomers due to fewer chiral centers.
Epimers
- Epimers are forms of carbohydrates that differ at only one chiral center (e.g., D-glucose and D-galactose differ at carbon 4).
- Unlike enantiomers, epimers are not mirror images of each other.
Cyclic Monosaccharides: Haworth Projection
- Monosaccharides can exist in cyclic forms, represented by Haworth projection formulas.
- Cyclic structures result from the reaction of carbonyl groups with hydroxyl groups.
- Pyranoses (six-atom rings) and furanoses (five-atom rings) are the two cyclic forms.
- The formation of cyclic monosaccharides usually leads to two stereoisomers known as anomers (alpha and beta forms).
- The anomeric carbon is the hemiacetal carbon; its configuration defines the type of anomer.
Biochemically Important Monosaccharides
- D-Ribose: Essential component of nucleic acids and ATP; involved in various metabolic pathways.
- D-Ribulose: An intermediate in the pentose phosphate pathway.
- D-Arabinose: Present in various plant gums; constituent of glycoproteins.
- D-Glucose: Known as the "sugar" of the body; normal concentration is 70-100 mg/dL; key energy source.
- D-Fructose: Found in fruit juices; used by the liver and considered the sweetest sugar.
- D-Galactose: Derived from lactose; crucial for brain function and appears in glycolipids.
- D-Mannose: Found in plant mannans; a constituent of glycoproteins used for prevention of certain diseases.### Urinary Tract Infections (UTIs)
- UTIs are common infections affecting the urinary system, often treated with antibiotics.
- Understanding carbohydrate metabolism can help manage genetic disorders like carbohydrate-deficient glycoprotein syndrome.
Reactions of Monosaccharides
- Five major reactions include oxidation to acidic sugars, reduction to sugar alcohols, glycoside formation, phosphate ester formation, and amino sugar formation.
Oxidation to Acidic Sugars
- Involves redox reactions of monosaccharides, transforming them into acidic forms:
- Aldonic Acid: Acid group at terminal carbon.
- Alduronic Acid: Acid group at the terminal carbon opposite the aldehyde.
- Aldaric Acid: Acid groups at both ends of the molecule.
Reduction to Sugar Alcohols
- Carbonyl group can be reduced to a hydroxyl group.
- The product is a sugar alcohol (e.g., D-glucose reduced to D-glucitol or D-sorbitol) used in cosmetics and as a sweetener.
Glycoside Formation
- Hemiacetal forms of monosaccharides react with alcohols to create acetals, termed glycosides.
- Glycosides can exist in alpha and beta forms, defined by the orientation of the -OH group.
Phosphate Ester Formation
- Hydroxyl groups of monosaccharides may react with oxyacids to form phosphates.
- Forming glucose 1-phosphate and glucose 6-phosphate is important for carbohydrate metabolism.
Amino Sugar Formation
- A hydroxyl group replaced by an amino group leads to amino sugar formation (common examples: glucosamine and galactosamine).
- Amino sugars are crucial in constructing polysaccharides like chitin and hyaluronic acid.
Disaccharides
- Formed from the glycosidic linkage between two monosaccharides functioning as a hemiacetal and an alcohol.
- Glycosidic linkages consist of carbon–oxygen–carbon bonds.
Features of Disaccharides
- Maltose: Comprised of two D-glucose units, linked by α(1-4) linkage.
- Cellobiose: Comprised of β(1-4) glucose and galactose units.
- Lactose: Composed of D-galactose and D-glucose with β(1-4) linkage.
- Sucrose: Comprising glucose and fructose via α,β(1-2) linkage.
Oligosaccharides
- Contain 3 to 10 monosaccharides linked via glycosidic bonds.
- Example trisaccharide: Raffinose (α-D-galactose, α-D-glucose, β-D-fructose).
- Example tetrasaccharide: Stachyose (two α-D-galactose, one α-D-glucose, one β-D-fructose).
Importance of Oligosaccharides
- Blood types (O, A, B, AB) are defined by specific oligosaccharides on red blood cells.
Polysaccharides
- Polymers of numerous monosaccharide units, often non-sweet and limited in solubility.
- Used as thickeners in cooking due to the hydrophilic nature of -OH groups.
Types of Polysaccharides
-
Storage Polysaccharides:
- Starch: Energy storage in plants, includes amylose (linear) and amylopectin (branched).
- Glycogen: More branched than amylopectin, serves as energy storage in animals.
-
Structural Polysaccharides:
- Cellulose: Main component of plant cell walls, indigestible by humans.
- Chitin: Structural element in exoskeletons of arthropods, similar structure to cellulose.
-
Acidic Polysaccharides:
- Composed of disaccharide repeating units with amino sugars and negative charges (e.g., hyaluronic acid and heparin).
Glycosaminoglycans (GAGs)
- Also known as mucopolysaccharides, consist of repeating disaccharide units.
- Often contain one amino sugar, playing essential roles in biological processes such as joint lubrication and cellular hydration.
Studying That Suits You
Use AI to generate personalized quizzes and flashcards to suit your learning preferences.
Related Documents
Description
Explore the crucial concepts surrounding monosaccharides, including their D or L configurations, types such as trioses, and the structural differences between D-glucose and D-galactose. This quiz will test your understanding of the formation and classification of these important carbohydrates.
