Podcast
Questions and Answers
What type of carbohydrate contains only a single polyhydroxy aldehyde or polyhydroxy ketone unit?
What type of carbohydrate contains only a single polyhydroxy aldehyde or polyhydroxy ketone unit?
An achiral molecule has mirror images that are superimposable.
An achiral molecule has mirror images that are superimposable.
True
What distinguishes enantiomers from diastereomers in stereoisomerism?
What distinguishes enantiomers from diastereomers in stereoisomerism?
Enantiomers are mirror images of each other that are nonsuperimposable, while diastereomers are not mirror images and differ in configuration at one or more stereocenters.
A carbohydrate made up of three to ten monosaccharide units is called an ______.
A carbohydrate made up of three to ten monosaccharide units is called an ______.
Signup and view all the answers
Match the following terms with their definitions:
Match the following terms with their definitions:
Signup and view all the answers
What is the primary role of biochemistry?
What is the primary role of biochemistry?
Signup and view all the answers
All carbohydrates yield polyhydroxy aldehydes upon hydrolysis.
All carbohydrates yield polyhydroxy aldehydes upon hydrolysis.
Signup and view all the answers
A molecule with four different groups bonded to a central atom is referred to as having a ______ center.
A molecule with four different groups bonded to a central atom is referred to as having a ______ center.
Signup and view all the answers
Which of the following describes enantiomers?
Which of the following describes enantiomers?
Signup and view all the answers
All optical active compounds rotate the plane of polarized light in the same direction.
All optical active compounds rotate the plane of polarized light in the same direction.
Signup and view all the answers
What is the primary difference between aldoses and ketoses?
What is the primary difference between aldoses and ketoses?
Signup and view all the answers
D-Fructose is also known as ______ and fruit sugar.
D-Fructose is also known as ______ and fruit sugar.
Signup and view all the answers
Which of the following is the most abundant monosaccharide in nature?
Which of the following is the most abundant monosaccharide in nature?
Signup and view all the answers
Match the following monosaccharides with their characteristics:
Match the following monosaccharides with their characteristics:
Signup and view all the answers
D-Galactose is frequently encountered as a free monosaccharide.
D-Galactose is frequently encountered as a free monosaccharide.
Signup and view all the answers
The prefix ______ means 'minus an oxygen' in the context of the structure of 2-deoxyribose.
The prefix ______ means 'minus an oxygen' in the context of the structure of 2-deoxyribose.
Signup and view all the answers
What defines the D or L form of a monosaccharide?
What defines the D or L form of a monosaccharide?
Signup and view all the answers
Anomers are cyclic monosaccharides that differ only in the position of substituents on the anomeric carbon.
Anomers are cyclic monosaccharides that differ only in the position of substituents on the anomeric carbon.
Signup and view all the answers
Name one example of a five-atom ring cyclic monosaccharide.
Name one example of a five-atom ring cyclic monosaccharide.
Signup and view all the answers
A reducing sugar is a carbohydrate that gives a positive test with _______ and _______ solutions.
A reducing sugar is a carbohydrate that gives a positive test with _______ and _______ solutions.
Signup and view all the answers
Match the following terms with their definitions:
Match the following terms with their definitions:
Signup and view all the answers
Which of the following is true about aldehydes in monosaccharides?
Which of the following is true about aldehydes in monosaccharides?
Signup and view all the answers
Glycoside formation is one of the important reactions of monosaccharides.
Glycoside formation is one of the important reactions of monosaccharides.
Signup and view all the answers
What is produced from the oxidation of monosaccharides?
What is produced from the oxidation of monosaccharides?
Signup and view all the answers
Study Notes
Biochemistry
- Biochemistry is the study of chemical substances and their interactions within living organisms.
- It explores how cells produce essential molecules and maintain life through chemical reactions, with new discoveries made regularly.
Carbohydrates
- Carbohydrates are polyhydroxy aldehydes, ketones, or compounds that yield polyhydroxy aldehydes or ketones upon hydrolysis.
- Examples: Glucose (polyhydroxy aldehyde), Fructose (polyhydroxy ketone)
Types of Carbohydrates
- Monosaccharides contain a single polyhydroxy aldehyde or ketone unit.
- Disaccharides consist of two monosaccharide units linked together.
- Oligosaccharides comprise three to ten monosaccharide units covalently bonded.
- Polysaccharides are polymeric carbohydrates with many monosaccharide units linked together.
Mirror Images
- Superimposable mirror images are reflections where all points coincide when the images are overlapped.
- Nonsuperimposable mirror images are reflections where not all points coincide when the images are overlapped.
Chirality
- Chiral center: An atom or element within a molecule with four different groups attached in a tetrahedral arrangement.
- Chiral molecule: A molecule whose mirror images are nonsuperimposable.
- Achiral molecule: A molecule whose mirror images are superimposable.
Stereoisomerism: Enantiomers and Diastereomers
- Stereochemistry is the study of the relative spatial arrangement of atoms in molecules and their manipulation.
- Stereoisomers are isomers with the same molecular and structural formulas but differ in the orientation of atoms in space.
- Enantiomers are stereoisomers whose molecules are nonsuperimposable mirror images of each other.
- Diastereomers are stereoisomer whose molecules are not mirror images of each other.
Solutions
- Fischer projection formula: A two-dimensional representation of the spatial arrangement of groups around chiral centers.
- Haworth projection formula: A two-dimensional representation of the three-dimensional structure of a cyclic monosaccharide.
Special Terminology for Cyclic Monosaccharide Structures
- Anomeric carbon atom: The hemiacetal carbon atom present in a cyclic monosaccharide structure.
- Anomers: Cyclic monosaccharides that differ only in the positions of substituents on the anomeric carbon.
Cyclic Forms of Other Monosaccharides
- Pyranose: A cyclic monosaccharide containing a six-atom ring.
- Furanose: A cyclic monosaccharide containing a five-atom ring.
Reactions of Monosaccharides
- Oxidation: This chemical process involves the loss of electrons from a substance, which can lead to the formation of various types of acids. Specifically, oxidizing agents can transform sugars into aldonic acid, which contains a carboxylic acid group; aldaric acid, which has carboxylic acid groups at both ends; or alduronic acid, which contains a carboxylic acid group at one end and an alcohol at the other.
- Reduction: The carbonyl group is reduced to a hydroxyl group using hydrogen as the reducing agent.
- Glycoside formation: A reaction between the anomeric carbon atom of a monosaccharide and an alcohol.
- Phosphate ester formation: A reaction between a monosaccharide and phosphoric acid.
- Amino sugar formation: A reaction between a monosaccharide and an amine.
Reducing Sugar
- Carbohydrates that give a positive test with Tollens and Benedict's solutions.
- Monosaccharides, aldoses, and ketoses are reducing sugars.
Constitutional Isomers
- Share the same molecular formulas but have different connectivities.
Designating Handedness Using Fischer Projection Formulas
- The D or L form of a monosaccharide is determined by the position of the terminal CH2OH group on the highest-numbered ring carbon atom.
- The α or β configuration is determined by the position of the –OH group on carbon 1 relative to the CH2OH group.
Dextrorotatory and Levorotatory Compounds
- Optically active compound: A compound that rotates the plane of polarized light.
- Dextrorotatory compound: A chiral compound that rotates the plane of polarized light in a clockwise direction.
- Levorotatory compound: A chiral compound that rotates the plane of polarized light in a counterclockwise direction.
Classification of Monosaccharides
- Aldose: A monosaccharide containing an aldehyde functional group.
- Ketose: A monosaccharide containing a ketone functional group.
Biochemically Important Monosaccharides
-
D-Glyceraldehyde and Dihydroxyacetone
- D-Glyceraldehyde is the simplest aldose and a crucial intermediate in carbohydrate metabolism. It possesses one chiral carbon, leading to two enantiomers: D-glyceraldehyde, which is the naturally occurring form, and L-glyceraldehyde.
- Dihydroxyacetone, on the other hand, is the simplest ketose sugar. It has no chiral centers and exists mainly in its D-form, which plays an important role as a substrate in various biochemical pathways, including glycolysis.
: Simplest monosaccharides, important intermediates in glycolysis.
-
D-Glucose: Most abundant in nature, also known as dextrose and blood sugar.
-
D-Galactose: Found in milk, also called brain sugar.
-
D-Fructose: Important ketohexose, also known as levulose and fruit sugar.
-
D-Ribose: Aldopentose, component of RNA.
-
2-Deoxyribose: Aldopentose, component of DNA.
Cyclic Forms of Monosaccharides
- Cyclic structures are the predominant form of monosaccharides in aqueous solutions.
Studying That Suits You
Use AI to generate personalized quizzes and flashcards to suit your learning preferences.
Related Documents
Description
This quiz explores the fascinating world of biochemistry, focusing on carbohydrates and their classifications. Discover the different types of carbohydrates, including monosaccharides, disaccharides, oligosaccharides, and polysaccharides, and their chemical significance in living organisms.
