Question

2. Describe the structure of a typical amino acid and explain how they chemically combine to make a protein

3. Describe the process of catabolic repression by glucose concentration, as seen in the lac operon control.

Answer 1

Amino acid is a micromolecule. It is a monomer for the formation of proteins. An amino acid is a very unique structure comprised of four different groups attached to a central carbon atom.

One of the groups is a carboxyl group and the other group is an amino group. Because of these two groups, the molecule is named as amino acid. The other group is a variable R group which provides specificity to every amino acid. This group is different in all the amino acids. The fourth group is a hydrogen atom. All of these are bonded to the central carbon atom. Because the central carbon atom is bonded to 4 different groups, the central carbon atom is known as the chiral carbon.

Except for glycine, all the amino acids are optically active. It is because of the attachment of four different groups to the central carbon atom. Glycine is not optically active because the are group is hydrogen only. So it has to hydrogen attached to the central carbon atom.

Amino acids polymerize with each other to form peptides. The peptide chain for upon itself to form three dimensional functional protein. The polymerization of amino acid is brought about by condensation reaction. The amino group of 1 amino acid and the carboxyl group of an other amino acid are involved in this process. They join together by the formation of peptide Bond which is the type of covalent bond along with the loss of one molecule of water. Every one molecule of peptide Bond formed in was the loss of one molecule of water.

Every protein if having two distinct terminal. The Terminal with amino group of amino acid is that n-terminal and the one with carboxyl group is the C terminal.

According to guidelines, only first question can be answer.

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