Lecture Notes on Carbohydrate Structures and Isomers

These flashcards cover key concepts related to carbohydrate structures, the formation of anomers, Fischer and Haworth projections, and factors that influence sugar configurations.

What happens when oxygen approaches the carbonyl carbon in a reaction involving aldehydes and ketones?

A reaction can take place, resulting in different anomers.

What is the statistical expectation for the formation of anomers in carbohydrate reactions?

About a fifty-fifty mixture of each anomer.

What distinguishes the two different anomers formed from a carbonyl carbon?

It depends on which side of the carbonyl group the oxygen attacks.

What is the role of hydrogen in the formation of glycosidic bonds during carbohydrate reactions?

A hydrogen is lost from the hydroxyl group, allowing a bond to form between the oxygen and carbon atom.

What happens to the carbonyl oxygen during the formation of a ring structure?

The carbonyl oxygen takes a hydrogen and becomes a hydroxyl group.

How are carbon atoms numbered in the Fischer projection?

Start at the very top carbon and number downwards.

In terms of ring structure, what is the relationship between aldohexoses and pyranoses?

Aldohexoses form a six-membered ring structure known as pyranose.

How are ketohexoses different from aldohexoses in terms of carbon numbering?

In ketohexoses, the carbonyl carbon is carbon number two.

What is the significance of number one carbon in the Fischer projection for aldohexoses?

Carbon number one is the carbonyl carbon.

What defines the anomeric carbon in carbohydrate structures?

It is the carbon that becomes chiral when a ring forms.

How many atoms are typically in a pyranose ring structure?

Six atoms consisting of five carbons and one oxygen.

How does the formation of a furanose structure differ from a pyranose structure?

Furanose is a five-membered ring structure, while pyranose is six-membered.

What determines whether a sugar is a D-sugar or L-sugar in Fischer projection?

The orientation of the hydroxyl group on the terminal carbon.

In Haworth projection, how do you identify D-sugars?

If the terminal hydroxyl group points up in the Fischer projection, it is a D-sugar.

What is the terminal substituent for D-sugars?

The hydroxyl group on the bottom carbon of the Fischer projection.

In the debate of D versus L sugars, what does 'D' refer to?

The configuration of the hydroxyl group on the last carbon.

What does it mean for sugars to be 'anomers'?

They are diastereomers that differ at the anomeric carbon.

When looking at ring structures, how do you determine the anomeric configuration?

By the position of the hydroxyl group relative to the ring substituent.

What do we call the sugars where hydroxyl groups point opposite the ring substituent?

Alpha anomers.

What distinguishes beta anomers from alpha anomers?

Beta anomers have the hydroxyl group pointing in the same direction as the ring substituent.

What structural change occurs in carbohydrates during hydrolysis?

Macromolecules are split into smaller units by adding water.

What macronutrient is associated with triglycerides?

Fats.

What is the functional group connecting fatty acids to glycerin in triglycerides?

Ester functional group.

What is the result of hydrolyzing esters?

They are split into carboxylic acids and alcohols.

What is amination in the context of proteins?

It refers to how amino acids are bonded together.

How can we differentiate between glucose and galactose in the Haworth projection?

The placement of hydroxyl groups on certain carbons.

What convention helps determine if a sugar is a D-sugar in the ring format?

The position of the last hydroxyl relative to the ring.

What is the significance of the anomeric carbon when forming disaccharides?

It is where two monosaccharides are linked to form disaccharides.

How does one denote the specific type of monosaccharide?

By using the names of the sugars along with D or L designations.

What do you need to identify structure in the Fischer projection?

Correct numbering of carbon atoms.

How can the placement of the OH groups in the Fischer projection affect the structure?

They determine the arrangement of atoms in the Haworth projection.

What defines the term 'ring substituent' in monosaccharide structures?

The last substituent on the bottom of the Fischer projection.

How important is the Haworth projection in identifying sugars?

It provides a visual format to recognize structures easily.

What is the general expectation in exams regarding sugar structure identification?

Students must identify the correct ring structure from a Fischer projection.

What should you remember when converting Fischer projections to Haworth projections?

The orientation of hydroxyl groups and overall carbon ring numbering.

What do alpha anomers indicate when observed against D-sugars?

The hydroxy group is positioned opposite the terminal substituent.

How can one identify which sugars possess specific configurations?

By examining the orientation of hydroxyl groups on chiral carbons.

Why is it essential to understand monosaccharide structure for biological functions?

The structure determines function and interaction in biochemical pathways.

What role does water play in the process of hydrolysis?

Water facilitates the breaking down of macromolecules.

What is required to identify a particular monosaccharide accurately?

Knowledge of both D/L designation and alpha/beta configuration.

In biological systems, how do saccharides join to form larger structures?

They link together through glycosidic bonds.