class1 Flashcards
What are glucides?
Molecules that are organic, found in all living beings, serving as structural elements or energy reserves.
Examples include cellulose in plants and glycogen in animals.
What characterizes the structure of glucides?
Chains of carbon with hydroxyl (OH), aldehyde (CHO), ketone (C=O), carboxylic acid (COOH), and amine (NH2) groups.
These functional groups define their reactivity and classification.
How are glucides classified?
Into oses and osides.
Oligosides and polysides are subcategories of osides.
What is the general formula for oses?
C_nH_{2n}O_n where n varies from 3 to 6.
This is why they were historically called hydrates of carbon.
What is the difference between aldoses and ketoses?
Aldoses contain an aldehyde group (CHO), while ketoses contain a ketone group (C=O).
This distinction affects their reactivity and classification.
Define stereoisomerism in the context of glucides.
The presence of chiral carbons, which possess four different substituents.
This leads to different spatial arrangements of the molecules.
What is the formula to calculate the number of isomers based on the number of chiral carbons?
x = 2^n, where n is the number of chiral carbons.
This illustrates how the number of possible isomers increases exponentially with more chiral centers.
What are enantiomers?
Compounds that are mirror images of each other.
They have similar physical properties but can have different biological activities.
What are epimers?
Compounds that differ only by the configuration of one asymmetric center.
This subtle difference can lead to significant variations in properties and functions.
Fill in the blank: The representation of carbohydrate structures in a linear form is often done using _______.
the Fischer projection.
This method helps in visualizing the configuration of the molecules.
What are the two forms of glyceraldehyde?
D-glyceraldehyde and L-glyceraldehyde.
They are enantiomers of each other.
What do you call compounds with the same general formula but different spatial arrangements?
Isomers.
This includes both enantiomers and epimers.
What are the components of the classification of oses?
- Number of carbons (n)
- Nature of the functional group
This classification helps in identifying and categorizing various sugars.
What is the significance of chiral carbons in carbohydrates?
They lead to stereoisomerism, affecting the properties and biological functions of the sugars.
This is crucial for the understanding of metabolic pathways and enzyme interactions.
True or False: All oses have at least one chiral carbon.
False.
Some oses, like dihydroxyacetone, do not have any chiral carbons.
