Carbohydrates: Classification (aldoses and ketoses)
Definition and classification of carbohydrates based on their functional groups (aldoses, ketoses) and number of sugar units (mono-, oligo-, poly-saccharides).
What is Carbohydrates: Classification (aldoses and ketoses)?
Organic compounds composed of carbon, hydrogen, and oxygen, typically with the empirical formula Cn(H2O)m, that serve as a primary source of energy and structural components in living organisms. They are polyhydroxy aldehydes or polyhydroxy ketones.
Key points
- Define carbohydrates.
- Differentiate between aldoses and ketoses based on their functional groups.
- Identify examples of aldoses and ketoses.
- Understand the basic structural difference that defines aldoses and ketoses.
Common exam trap
Confusing the terms aldose and ketose.
Definitions
- Term
Carbohydrate
- Meaning
Organic compounds composed of carbon, hydrogen, and oxygen, typically with the empirical formula Cn(H2O)m, that serve as a primary source of energy and structural components in living organisms. They are polyhydroxy aldehydes or polyhydroxy ketones.
- Term
Aldose
- Meaning
A monosaccharide containing an aldehyde functional group (-CHO) as its most oxidized carbon.
- Term
Ketose
- Meaning
A monosaccharide containing a ketone functional group (C=O) as its most oxidized carbon.
Learning objectives
Define carbohydrates.
Differentiate between aldoses and ketoses based on their functional groups.
Identify examples of aldoses and ketoses.
Understand the basic structural difference that defines aldoses and ketoses.
Prerequisites
Basic organic chemistry concepts (functional groups like aldehydes and ketones).
Understanding of carbon chain structures.
Common mistakes
Confusing the terms aldose and ketose.
Forgetting that the functional group in ketoses is internal, not terminal.
Assuming all carbohydrates fit the Cn(H2O)m formula.
Not distinguishing between classification by functional group and classification by number of units.
Keywords
Carbohydrate
Saccharide
Aldose
Ketose
Polyhydroxy aldehyde
Polyhydroxy ketone
Glucose
Fructose
Functional group
Practice preview
Which of the following is an aldose?…
easy
Monosaccharides are classified based on their functional groups. An aldose with six carbon atoms is called a(n):…
easy
Consider the following monosaccharides: 1. Glyceraldehyde 2. Dihydroxyacetone 3. Ribose 4. Fructose. Which of these are classified as aldoses?…
medium