BIOCHEM QUIZ 5

What is the purpose for todays lab?

To determine the weight percentage of reducing sugars in a diluted fruit juice sample which contains fructose.

• As well, we will test a sucrose solution to see if it is a reducing sugar.

Two common types of monosaccharides

1. glucose

2. galactose

3. fructose

4. ribose

What organ uses glucose for fuel?

the brain

what molecule for plants and animals acts as a store for glucose?

animals → glycogen

plants → starch

Calculation question

final and initial

convert microlitres into mL

microlitres x 10^-3 = mL

then

final/initial = dilution factor

Whats the glucose cell in plant wall and which bond connects it?

Cellulose and B-1,4 glycosidic links

Function of polysaccharides

primarily function as energy storage and structural support.

Is lactose a reducing sugar?

Yes, because it has an anomeric carbon available for bonding.

Reducing sugar

A reducing sugar is a sugar that has a free aldehyde or ketone group capable of acting as a reducing agent, allowing it to donate electrons in redox reactions (e.g., glucose, maltose, lactose).

What is Maillard reaction?

Reaction of a reducing sugar and amino acid to give browned colour of food.

Most important monosaccharides

1. pentose

2. hexose

General structural formula for carb

(CH2O)n

Aldehydes vs Ketones

Aldehydes have carbonyl at the end, ketones have carbonyl in the middle