Things to remember for chem

Question 1

Carbohydrate definition

Answer 1

Polymers of simple sugars. The functional group features of carbohydrates/sugars are polyhydroxyaldehydes or polyhydroxyketones or compounds formed by linking up polyhydroxyaldheydes or
polyhydroxyketones i.e., carbohydrates are polymers of simple sugars.

Question 2

Blood sugar

Answer 2

D-Glucose , aldohexose

Question 3

D or L

Answer 3

For any carbohydrate, the D or L designation is based on the configuration of the chiral carbon farthest from the carbonyl group. D-sugars have a hydroxyl group at the bottom most chiral carbon, on the right when the molecule is drawn in the Fischer Projection if the -OH is on the left, then it is an L-sugar

Question 4

epimers

Answer 4

diastereoisomers that differ at only
one stereogenic centre

Question 5

Simple classification of amino acids

Answer 5

Amino acids can be classified very simply into 3 groups - neutral, acidic, basic,
depending on the acidity or basicity of the side chain. Learn this classification. Neutral amino acids have no acidic nor basic functionality in the R side-chain.
Acidic amino acids have an additional carboxylic acid function in the R side-chain
Basic amino acids have a basic amino group in the R side-chain.

Question 6

Zwitter-ion

Answer 6

We represent amino acids as dipolar ions known as zwitterions.
(German zwitter = hybrid or double ion).
Zwitterions arise by internal proton transfer from the acidic carboxyl-group to the
basic amino-group i.e., an acid-base reaction occurs within the molecule.
This charged form is a zwitterion.
It is a a dipolar ion with no net
charge.

Question 7

The Isoelectric Point (pI)

Answer 7

the pH at which an amino acid has no net charge i.e., the amino acid exists as a zwitterion.