Orgo 2 carbohydrates and Fischer projections notes

What are carbohydrates?

Carbohydrates are organic molecules made up of carbon, hydrogen, and oxygen. They are a primary energy source for living organisms.

True or False: Carbohydrates are only found in plants.

False. Carbohydrates are found in both plants and animals, serving various functions such as energy storage and structural components.

Fill in the blank: The general formula for monosaccharides is ___ .

CₙH₂ₙOₙ, where n is typically 3 or more.

Examples of monosaccharides?

- Glucose - Fructose - Galactose

What is a disaccharide?

A disaccharide is formed when two monosaccharides are joined by a glycosidic bond. Common examples include sucrose and lactose.

Compare starch and glycogen.

Both are polysaccharides. Starch is primarily found in plants, while glycogen is found in animals. Starch has a linear and branched structure, whereas glycogen is highly branched.

What are oligosaccharides?

Oligosaccharides consist of 2 to 10 monosaccharide units linked together. They play roles in cell recognition and signaling.

What is cellulose?

Cellulose is a polysaccharide made of glucose units, forming a rigid structure in plant cell walls. It is indigestible by humans.

True or False: Carbohydrates can be classified as simple and complex.

True. Simple carbohydrates consist of one or two sugar units, while complex carbohydrates consist of longer chains of sugar units.

Cause → Effect: Excess carbohydrate intake leads to ___ .

Increased fat storage due to excess glucose being converted to fat.

What are glycosidic bonds?

Glycosidic bonds are covalent bonds that link monosaccharides together in carbohydrates, formed through a dehydration reaction.

Fill in the blank: The primary function of carbohydrates is ___ .

To provide energy to cells.

Short example: How is sucrose formed?

Sucrose is formed by the condensation reaction between glucose and fructose, leading to a glycosidic bond.

What are sugar alcohols?

Sugar alcohols, like sorbitol and mannitol, are derived from sugars and have reduced caloric content, often used as sweeteners.

What is the role of carbohydrates in the body?

Carbohydrates provide energy, support cell structure, and are involved in metabolism and signaling pathways.

True or False: All carbohydrates are sweet.

False. Not all carbohydrates are sweet; polysaccharides like cellulose are not sweet.

What are Fischer projections?

Fischer projections are 2D representations of carbohydrates, showing the configuration of chiral centers. They help visualize the spatial arrangement of atoms.

True or False: Fischer projections are only used for sugars.

False. While commonly used for sugars, Fischer projections can represent any molecule with chiral centers.

Identify the horizontal bonds in Fischer projections.

Horizontal bonds project out of the plane, towards the viewer, while vertical bonds project behind the plane.

Fill in the blank: In a Fischer projection, the most oxidized carbon is at the _____.

top.

How do you convert from Fischer to Haworth structure?

To convert, rotate the Fischer projection 90 degrees and close the ring by connecting the carbonyl carbon to the appropriate hydroxyl group.

What do the vertical bonds represent?

Vertical bonds in Fischer projections represent groups that are oriented behind the plane of the page.

Comparison: Fischer projections vs. Haworth structures.

- Fischer: 2D, linear representation - Haworth: 3D, cyclic representation Both depict carbohydrate structure but in different forms.

True or False: All chiral centers in Fischer projections have the same priority.

False. The priority of groups around chiral centers varies, influencing the molecule's stereochemistry.

What is the significance of D and L notation?

D and L notation indicates the orientation of the highest-numbered chiral carbon. D (right) and L (left) help determine the carbohydrate's configuration.

Identify the role of the carbonyl group in Fischer projections.

The carbonyl group (C=O) determines whether the carbohydrate is an aldose (aldehyde) or a ketose (ketone).

Fill in the blank: The number of stereoisomers for a carbohydrate is calculated as _____.

2^n, where n is the number of chiral centers.

How to determine the D/L configuration?

Look at the highest-numbered chiral center; if the hydroxyl group (OH) is on the right, it is D; if on the left, it is L.

Fischer projection for D-glucose: The configuration at C4 is _____.

D-glucose has the hydroxyl group (OH) on the right at C4.

What happens when a Fischer projection is flipped?

Flipping a Fischer projection inverts the orientation of all substituents, changing the configuration of the molecule.

List two common carbohydrates represented in Fischer projections.

- Glucose - Fructose

Define what a chiral center is.

A chiral center is a carbon atom bonded to four different groups, leading to non-superimposable mirror images (enantiomers).