Amino Acids Seminar

Question 1

What do the amino acids have in common?

Answer 1

These all contain a carboxylic acid group (α-COOH) and a basic amino group (α-NH2).

Question 2

Isoelectric point:

Answer 2

The isoelectronic point or isoionic point is the pH at which the amino acid does not migrate in an electric field. This means it is the pH at which the amino acid is neutral, i.e. the zwitterion form is dominant.

Question 3

The amide linkage/bond = ?

Answer 3

The amide linkages are called peptide bonds or peptide linkages.

Question 4

Amino acid residue:

Answer 4

Each amino acid in the peptide is called an amino acid residue.

Question 5

Tuftsin:

Answer 5

Tuftsin is a tetrapeptide (Thr–Lys–Pro–Arg)

Question 6

Nucleotides consist of:

Answer 6

• Pentose sugar.
• Nitrogen-containing base.
• Phosphate.

Question 7

Pyrimidines

Answer 7

C, T, and U.

Question 8

Purines A and G.

Answer 8

A and G.

Question 9

How does the nucleotide form?

Answer 9

A nucleotide forms when the −OH on C5’ of a sugar bonds to phosphoric acid

Question 10

How are nucleotides joined?

Answer 10

Nucleotides are joined by phosphodiester bonds.

Question 11

The primary structure of RNA:

Answer 11

• Is a single strand of nucleotides with bases A, C, G, and U.
• Is linked by PHOSPHODIESTER BONDS between ribose and phosphate.

Question 12

In DNA:

Answer 12

In DNA, nucleotides containing bases A, C, G, and T are linked by ESTER BONDS between deoxyribose sugars and phosphate groups.

Question 13

α-carbohydrates:

Answer 13

α-carbohydrates have a cis configuration between the OH group and the CH2OH group.
This means that the OH group and the CH2OH group are on opposite sides of the ring.

Question 14

β-carbohydrates:

Answer 14

β-carbohydrates have a trans configuration between the OH group and the CH2OH group

Question 15

A glycosidic bond:

Answer 15

A glycosidic bond is formed between the hemiacetal or hemiketal group of a saccharide (or a molecule derived from a saccharide) and the hydroxyl group of some compound such as an alcohol.
A substance containing a glycosidic bond is a glycoside.

Question 16

Reducing and non-reducing sugars:

Answer 16

• A reducing sugar is any sugar that either has an aldehyde group or is capable of forming one in solution through isomerism.
• The aldehyde functional group allows the sugar to act as a reducing agent, for example in the Tollens’ test or Benedict’s reagent

Question 17

Location of double bonds in fatty acids:

Answer 17

Omega number – refers to the position of the double bond nearest the methyl (CH3) end of the carbon chain:

 - Omega-3 fatty acid
 - Omega-6 fatty acid

Question 18

Phospholipids:

Answer 18

Phospholipids – similar to triglycerides in structure except only 2 fatty acids + choline Phospholipids in foods: Lecithin, egg yolks, soybeans, wheat germ, peanuts.