Proteins

Given below are two statements:

Statement I: A protein is imagined as a line, the left end represented by first amino acid (C-terminal) and the right end represented by last amino acid (N-terminal).

Statement II: Adult human haemoglobin, consists of 4 subunits (two subunits of $\alpha$ type and two subunits of $\beta$ type).

In the light of the above statements, choose the correct answer from the options given below:

Explain beta turn in proteins.

Explain briefly four levels of protein structure.

Which among the following is a non-polymeric biomolecule that can be found in acid insoluble fraction?

Assertion: Active site of an enzyme is a crevice or pocket into which the substrate fits.

Reason: In tertiary structure of protein chain when folds upon itself, the chain criss-crosses itself, and many crevices are formed.

The correct option among the following is:

Choose the correct statements from the following:

A) Protein threads exist throughout as rigid rods.

B) By dehydration, a glycosidic bond is formed.

C) Adult human haemoglobin has $4$ subunits.

D) Litmus paper does not turn into blue colour with iodine.

What is an amino acid?

For being functional, a protein has to acquire at least

Amino acids have both an amino group and a carboxyl group in their structure. Which amongst the following is an amino acid?

Biologist describes protein at _____ levels.

Protein act as a

Essential amino acids are those which are

How many amino acids are used to form protein?

Which of the following amino acids contain sulphur?

Methionine and cysteine contain an element which is

A protein $X$ with isoelectric point $6.5$ was isolated. It was prepared in three different buffers $P,Q$ and $R$ with $\mathrm{pH}4.0,6.5$ and $8.5$, respectively. With respect to the net charge on protein $X$, the correct option is

Proteins in biological systems are polypeptides that are exclusively made from $L$-amino acids. A peptide, $P$, with $L$-amino acids of a particular sequence always adopts a right-handed alpha helical structure. Under identical conditions, if all the amino acids of the peptide $P$ are changed to $D$-amino acids, then the expected conformation from the options given below would be _____.

Three given polypeptides $(\mathrm{P},\mathrm{Q}$ and $\mathrm{R})$, of same size and same $\mathrm{pI}(7.2)$, have a single aspartic acid in each of them. In polypeptide $\mathrm{P}$, the aspartic acid residue is on the surface. In polypeptide $\mathrm{Q}$, it is surrounded by negatively charged residues, whereas in polypeptide $\mathrm{R}$ it is deeply buried in a hydrophobic core. $\mathrm{pKa}$ of the side chain carboxylate of free (in solution) aspartic acid is $3.65$. The polypeptides are in a buffer of $\mathrm{pH}$ $7.4$. The change in $\mathrm{pKa}$ of the aspartic acid side chain carboxylate in the polypeptides $\mathrm{P}, \mathrm{Q}$ and $\mathrm{R}$ is likely to

A small viral peptide can insert its $6$ amino acids (represented as a barrel) into the lipid bilayer as depicted in the figure given below.

The table depicts the different properties of amino acids.

What are the types of amino acid?