40 Questions
What is the basis of naming monosaccharides?
Functional groups and number of carbon atoms
What is the term for a carbon atom that has four different groups bonded to it?
Chiral carbon
What is the energy yield from one gram of digested carbohydrate?
4 kcal
What is the simplest carbohydrate that exhibits chirality?
Glyceraldehyde
What is the recommended daily caloric intake from carbohydrates according to the USDA?
45-65%
What is the purpose of a Fischer projection in representing monosaccharides?
To represent bonds around a chiral carbon
What is the basic formula for a monosaccharide?
(CH2O)n
What is the term for nonsuperimposable mirror images of a molecule?
Enantiomers
What is the molecular formula of glucose?
C6H12O6
What is the bonding type between two monosaccharides in a disaccharide?
Glycosidic bond
What is the cyclic form of glucose represented as?
Haworth projection
What is the term for a single sugar molecule?
Monosaccharide
What is the difference between the α and β isomers of glucose?
Location of the -OH on the acetal carbon
What is the backbone of a monosaccharide composed of?
Carbon, hydrogen, and oxygen
What is the importance of glucose in the human body?
It is a primary source of energy
What is the term for a chain of linked monosaccharide units?
Polysaccharide
What is the role of insulin and glucagon in regulating glucose levels?
They regulate glucose concentration in the blood
What is the main energy source for the body?
Glucose
What are the three components of a monosaccharide?
Carbon, hydrogen, and oxygen
What is the number of carbon atoms in the backbone of a monosaccharide?
3-7
What is another name for fructose?
Levulose
What is the primary sugar found in mammalian milk?
Galactose
What is the difference between ribose and β-D-2deoxyribose?
The presence of an –OH group on C-2
What is the function of Benedict's reagent?
To detect the presence of aldoses
What is the type of bond formed between two monosaccharides in a disaccharide?
Glycosidic bond
What is the difference between maltose and lactose?
The type of monosaccharides linked
What is the name of the genetic disease that results from the inability to convert galactose to a phosphorylated glucose molecule?
Galactosemia
What is the type of polysaccharide that is composed of multiple types of monosaccharides?
Heteropolysaccharide
What is the name of the polysaccharide that is a storage polymer of α-linked glucose found in plants?
Starch
What is the characteristic of the glycosidic bond formed in sucrose?
It is a 1,2 glycosidic bond
What is the primary function of starch in plants?
To store energy
Which of the following is a characteristic of cellulose?
It is a linear homopolymer
What is the main difference between glycogen and amylopectin?
Glycogen is a more branched polymer
Where is glycogen typically stored in animals?
In the liver and muscle cells
What is the repeating disaccharide of cellulose?
β-cellobiose
Why are animals unable to digest cellulose?
Because they lack the necessary enzymes
What is the configuration of the glycosidic bonds in cellulose?
β-1,4
Which of the following organisms is able to digest cellulose?
Bacteria in the gut of ruminants
What is the difference between amylose and amylopectin?
Amylopectin is a branched polymer, while amylose is linear
What is the function of glycogen in animals?
To store energy
Study Notes
Carbohydrates
- Carbohydrates are synthesized by photosynthesis in plants and are a major energy source.
- A gram of digested carbohydrate gives about 4 kcal of energy.
Monosaccharides
- Monosaccharides are single sugar molecules, also called simple sugars.
- Examples: glucose, fructose, galactose
- Composition: carbon, hydrogen, oxygen (basic formula: (CH2O)n, where n is an integer from 3 to 7)
- Characteristics:
- Have a backbone of 3 to 7 carbon atoms
- Classified as aldoses (aldehyde group) or ketoses (ketone group)
- Can be hexoses (6 carbon atoms), pentoses (5 carbon atoms), or tetrose (4 carbon atoms)
Fructose
- Also known as fruit sugar or levulose
- Found in honey, corn syrup, and fruits
- The sweetest sugar
Galactose
- Found in mammalian milk
- Principal sugar found in mammalian milk
- Very similar to glucose, differing only in the orientation of one hydroxyl group
Ribose and Deoxyribose
- Five-carbon sugars
- Components of many biologically important molecules
- Ribose: aldopentose, component of RNA
- Deoxyribose: differs from ribose in the absence of the –OH group on C-2
Benedict's Reagent
- An alkaline Cu2+ solution that oxidizes the aldehyde groups of aldoses
- Fades from blue to yellow as reaction occurs, forming a red-orange precipitate of Cu2O
- Used to test for glucose in urine
Reducing Sugars
- All monosaccharides and disaccharides except sucrose
- Can isomerize to aldoses via enediol reaction
Disaccharides
- Formed by linking two monosaccharides together
- Examples: sucrose (table sugar), lactose (milk sugar), maltose (malt sugar)
- Sucrose: formed by linking α-D-glucose with β-D-fructose
- Lactose: formed by joining β-D-galactose to D-glucose
- Maltose: formed by linking two D-glucose molecules
Polysaccharides
- Chains of linked monosaccharide units
- Examples: starch, glycogen, cellulose
- Starch: storage polymer of α-linked glucose found in plants
- Glycogen: storage polymer of α-linked glucose found in animals
- Cellulose: structural polymer of β-linked glucose found in plant cell walls
Glycoproteins
- Proteins with carbohydrate molecules (glycans) attached
- Involved in cell-cell interactions, immune response, and cell signaling
Chirality
- A carbon atom with four different groups bonded to it is a chiral carbon
- Any molecule containing a chiral carbon can exist as a pair of enantiomers
- Example: glyceraldehyde (the simplest carbohydrate) has a chiral carbon and thus, has two enantiomers
Test your knowledge on the classification and naming of monosaccharides, including hexoses, pentoses, and their functional groups. Learn how to identify and distinguish between different types of monosaccharides based on their carbon atoms and functional groups.
Make Your Own Quizzes and Flashcards
Convert your notes into interactive study material.
Get started for free
