W10 L1 - Mono and Disaccharides

Flashcards about sugars, monosaccharides, disaccharides, etc.

Apart from DNA and proteins, what is the third class of really important biomolecules?

Carbohydrates.

Why are carbohydrates the most abundant biomolecules on the planet?

Present in so many plants and, well, all plants and all animals, there's huge amounts of cellulose produced per year.

What two roles, in general, do sugars, monosaccharides, and carbohydrates have?

Structural and signaling roles.

Towards the end of this lecture series, what are we going to be talking about?

The multiplicity of carbohydrates and how they can form exceptionally in-depth codes.

What are monosaccharides?

They are single units such as glucose and fructose.

What are oligosaccharides?

Consist of two to ten monosaccharides joined together and include sucrose and maltose.

What are glycosidic bonds?

A covalent bond that links a sugar’s anomeric carbon to another sugar or molecule, forming disaccharides or polysaccharides

What are polysaccharides?

Contain potentially thousands of units of monosaccharides and can be linear or branched.

What are three simple properties of monosaccharides?

Colorless, crystalline, and soluble.

What does a monosaccharide look like?

An unbranched carbon chain linked by single bonds, one double bond to an oxygen, and other carbons bonded to hydroxyls.

What determines the two basic categories of monosaccharides?

Position of the carbonyl group.

What is an aldose?

The carbonyl is at the very top where it's got a proton coming off one end, a hydrogen coming off one end, and then it's got a carbon coming off the other end.

What is a ketose?

Has two carbon partners and so that the carbonyl group is further down the chain.

What are the types of monosaccharides based on the number of carbon atoms present?

Trioses, tetroses, pentoses, and hexoses.

Give examples of trioses.

Glyceraldehyde and hydroxy acetone.

Why are trioses very important?

Involved in the very basic energy forming processes in every single one of your cells.

Why are pentoses exceptionally important?

Present in nuclear material, both DNA and RNA, such as ribose sugar.

Give examples of hexoses.

Glucose and fructose.

What is the difference between deoxyribose and ribose?

They only differ because the oxygen is missing in the deoxyribose, hence the name deoxyribose.

What happens when carbons are bound to four different things, making them chiral?

They are mirror images of each other that cannot superimpose.

What are the two different forms of glyceraldehyde?

L glyceraldehyde where the hydroxyl is on the left, or the D glyceraldehyde where you have the hydroxyl on the right.

When looking at glucose especially with more than one chiral carbon, what is considered the reference carbon?

The reference carbon is a carbon furthest away from the carbonyl atom.

When you look at the reference carbon, how do you know if it is a D glucose?

When the hydroxyl is on the right.

What are L and D forms also known as?

Enantiomers.

How do you store information in monosaccharides?

It's a way you can store information is by the order of these hydroxyls.

What are epimers?

Just a shift around a single carbon.

When are two different sugars considered epimers?

When you get a shift of the hydroxyl from left to right in a single carbon.

What form of monosaccharides are we all more familiar with, linear or cyclic?

That is the predominant form of most of the five and six carbon monosaccharides.

How do monosaccharides transition from linear to cyclic?

Carbonyl attacking hydroxyl group where the one attacks the five in the case of glucose and you see a bond being formed at the position between one and five.

In the case of a five membered ring like ribose, where is the oxygen bridge?

Between one and carbon four.

What does an anima mean?

Whether the hydroxyls below the ring or above the ring.

What is the alpha anima?

The CH2OH is above the ring or on opposite sides of the ring.

What is the beta anima?

The CH2OH and the OH on the same side of the ring.

What is a pyranose?

Six member ring.

What are furanoses?

Five member rings.

With the Haworth projection, what bond do you need to remember?

Remember, five is going to bond all the way back here to one.

D enantiomers have what above the ring?

C6 above the ring.

In alpha enemas, what is opposite C6?

The hydroxyl opposite C6.

What happens during mutarotation?

Bond can break and it can become linear and then reform either in the alpha or beta form.

What is a reducing sugar?

A process where sugars can reduce things.

What was the whole process of looking for reducing sugars the basis for?

Blood sugar measurement.

What are disaccharides?

Two monosaccharides joined to one another.

What is a hemiacetal bond?

Formed when monosaccharides go through ring formation.

What is an acetal bond?

When the hemiacetal bond then can be attacked by the alcohol from another glucose or another monosaccharide.

What happens when the glycosidic bond is formed?

The formation of a glycosidic bond locks the anomeric carbon in either the α or β configuration, preventing the sugar from undergoing mutarotation (interconversion between α and β forms).

What is maltose's short name?

Maltose has a short short name of Gluc, alpha 1 4 Gluc.

Why can't sucrose mutarotate and be reducing?

Because both hemiacetals are locked.

What is the difference between Acetal and Glycosidic bonds?

The acetyl is a general chemical bond that results from the reaction of hydroxyl groups, linking the sugars together.

A glycosidic bond is a type of acetal bond formed between two sugar monosaccharides.

What is the anomeric carbon in a sugar molecule?

It is the carbon that was part of the carbonyl group (aldehyde or ketone) before the sugar formed a ring.

How do you identify the anomeric carbon in a cyclic sugar?

Look for the carbon attached to two oxygens: one in the ring and one as a hydroxyl group (–OH) or glycosidic bond.

In aldoses like glucose, which carbon is the anomeric carbon?

Carbon 1 (C1) — it was the aldehyde carbon in the open-chain form.

In ketoses like fructose, which carbon is the anomeric carbon?

Carbon 2 (C2) — it was the ketone carbon in the open-chain form.

Why is the anomeric carbon important?

It is the site where glycosidic bonds form and is involved in mutarotation if unbonded.