BCHM 4115: Lectures 13-17

On your own paper, draw the Hayworth projection for α-D-Fructofuranose

Answer explanation

1. 1. Is this an aldose or a ketose?

2. 2. Is this a D or L sugar?

Answer explanation

1. 1. An aldose, as indicated by the "CHO" group, which represents an aldehyde functional group. This means it will cyclize into a hemiacetal.

2. 2. This is a D-sugar, specifically D-glucose. This is determined by the OH group on the highest-numbered stereocenter (C-5) pointing to the RIGHT.

Which one depicts a ceramide?

• 
• 
• 
• 

Answer explanation

A ceramide consists of a sphingosine backbone connected to a fatty acid via an amide linkage. There are NO sugar moieties on a ceramide.

What makes cartilage so flexible?

Answer explanation

Cartilage is flexible due to proteoglycan–hyaluronate aggregates that are highly hydrated. Proteoglycans bind to long filaments of hyaluronic acid with the assistance of a link protein. When cartilage is compressed, water is squeezed out and is then reabsorbed when the stress is diminished, allowing for reversible hydration that cushions joints and supports flexibility.

_ are a superfamily of plasma

immunity proteins that contain L-type lectin folds

and require Ca2+ ions for ligand binding.

(a)  

Answer explanation

Carbohydrates on proteins can be O-linked via these three residues:

Answer explanation

-Serine (S)

-threonine (T)

-Hyroxylysine (Hyl)

Draw the product of this reaction (on your own paper), and identify the resulting structure.

Answer explanation

OH + aldehyde = hemiacetal

OH + ketone = hemiketal

The hemiacetals/hemiketals are the structures that cyclize.

• 1. Name the bond that links these two monosaccharides.

• 2. Is this an α or β linkage?

• 3. Is this disaccharide a reducing sugar? Explain why or why not.

Answer explanation

1. 1. A glycosidic bond

3. 2. A β-linkage, as indicated by the *

5. 3. This disaccharide IS a reducing sugar, as indicated by the "HOH," which shows the presence of a free hydroxyl (–OH) group on the anomeric carbon. This free –OH allows the sugar to participate in the redox reactions characteristic of reducing sugars.

Why are trans fats generally considered to be worse for you than saturated fats?

Answer explanation

Although trans fats raise "bad" cholesterol (LDL) to a slightly lesser extent than saturated fats, they also lower the "good" cholesterol (HDL), which makes them more harmful overall. In contrast, saturated fats raise both LDL and HDL cholesterol levels.

In summary:

• Trans fats: ↓ HDL + ↑ LDL

• Saturated fats: ↑ HDL + ↑ LDL (to a slightly greater extent)

A 15 carbon terpene has 1._ isoprene units and is known as 2._.

• 1. 1. 5

  2. 2. sesquiterpene

• 1. 1. 5

  2. 2. sesterterpene

• 1. 1. 3

  2. 2. sesquiterpene

• 1. 1. 3

  2. 2. sesterterpene

Answer explanation