Chirality and Carbohydrates Lecture

These flashcards cover key concepts from the lecture on chirality and carbohydrates, including definitions, classifications, and the significance of molecular structures.

What is a chiral object?

An object that cannot be superimposed on its mirror image, such as human hands.

What does chirality in a molecule require?

A chiral molecule must have a chiral carbon, which is bonded to four different atoms or groups.

What are enantiomers?

Pairs of molecules that are non-superimposable mirror images of each other.

How can you determine if a carbon is chiral?

A carbon is chiral if it is attached to four different atoms or groups.

What is the difference between structural isomers and stereoisomers?

Structural isomers have the same molecular formula but different connectivity, while stereoisomers have the same connectivity but differ in the spatial arrangement of atoms.

What is the name of a molecule that has two identically attached atoms?

An achiral molecule.

What defines a compound as an aldehyde?

An aldehyde contains a carbonyl group (C=O) at the end of a carbon chain with at least one hydrogen attached to the same carbon.

What is the general formula for a monosaccharide?

The general formula is Cn(H2O)n, where n is typically a whole number greater than or equal to 3.

What is a Fischer projection?

A two-dimensional representation of a molecule where the most oxidized group is at the top and horizontal lines represent bonds that project out of the plane.

What are the cyclic forms of carbohydrates formed through?

The reaction between a carbonyl group and a hydroxyl group, forming a hemiacetal.

What do you call the carbon in a cyclic sugar that is formed from the carbonyl group?

The anomeric carbon.

What distinguishes alpha and beta anomers in cyclic sugars?

Alpha anomers have the hydroxyl group on the anomeric carbon oriented down, while beta anomers have it oriented up.

What happened to the hydroxyl group during the cyclization of glucose?

It reacts with the carbonyl group to form a hemiacetal and create a new chiral center.

Cyclic monosaccharides can switch between which two forms?

Cyclic and open-chain forms.

What are the main types of carbohydrates mentioned in the lecture?

Monosaccharides, disaccharides, and polysaccharides.

What type of configuration does an L stereoisomer have?

The hydroxyl group is located on the left side of the chiral carbon.

How are D and L forms of sugars determined?

By the position of the hydroxyl group on the chiral carbon furthest from the carbonyl group.

What is the significance of chirality in drug design?

Chiral molecules can have different biological effects; one form may be therapeutic while the other could be harmful.

How does the hydroxyl group on carbon-4 impact the classification of sugars?

In D-galactose, the hydroxyl group on carbon-4 is also directed to the left, distinguishing it from D-glucose.

What is a common structural representation for carbohydrates?

Haworth structure, which represents cyclic forms of sugars.

What do we mean by simple and complex carbohydrates?

Simple carbohydrates include monosaccharides and disaccharides, while complex carbohydrates consist of polysaccharides.

What process breaks down disaccharides into monosaccharides?

Hydrolysis, using water in the presence of an acid or enzyme.