Test: Biomolecules - 1 - NEET MCQ

Oils have lower melting point (e.g., gingely oil) and hence remain as oil in winters.

The given molecule is adenylic acid. It is a nucleotide found in RNA. It is an ester of phosphoric acid with the nucleoside adenosine. It consists of a phosphate group, a pentose sugar ribose, and the nucleobase adenine.

Double helix model of DNA was proposed by James Watson and Francis Crick in 1953 based on X-ray diffraction data produced by Maurice Wilkins and Rosalind Franklin.

Proteins human haemoglobin consists of 4 subunits. Two of these are identical toeach other. Hence, two subunits of αα type and two subunits of ββ type together constitute the human haemoglobin (Hb).

The number of substrate molecules changed per minute by a molecule of enzyme is called turn over number. Higher the turn over number more effective is the enzyme.

The diagram shown is a uracil which is a pyramidine belonging to nitrogen bases.

Fat consists of molecules of fatty acids and molecules of glycerin. Each molecule of fat contain three molecules of fatty acids and one molecule of glycerine3. 

The paired bases are stacked on the inside of the double helix with one base pair is every 3.4 angstrom. Now the distance between 23 base pair are (3.4) ×23 =78.2 angstrom.

According to Chargaff's base pair rule, DNA from any cell of an organism should have a 1:1 ratio of pyrimidine and purine bases, that is, the total amount of purines = total amount of pyrimidines.  In this, the amount of guanine is equal to the amount of cytosine and the amount of adenine is equal to the amount of thymine. The ratio of A: T = 1 and the ratio of G: C = 1. According to Chargaff's rule, G + C / A + T ratio varies with the species but is constant for a species. 

• There are 20 naturally occurring amino acids.
• All the amino acids except glycine are chiral. Amino acids are classified as acidic, basic or neutral based on the relative number of amino and carboxylic groups.
• Amino acids are classified as essential amino acids and non-essential based on whether they are synthesized in the body or not.

• Proteins are polymers of amino acids undergo dehydration to form a peptide linkage.
• Dipeptides are formed by a single peptide bond and a tripeptide through two peptide bonds and so on.

In most fungi the structural polysaccharide of cell wall is chitin. In plant cells cell wall is made up of cellulose.

Both DNA and RNA consists of polymers of nucleotides. RNA is single stranded but DNA is double stranded. DNA polynucleotide contains thymine but RNA polynucleotide contains uracil.

Protein molecules get denatured due to high temperature, very high or low pH and high energy radiation but there is no effect due to high pressure.

Based on number of amino and carboxyl groups, there are acidic (e.g., glutamic acid), basic (lysine) and neutral (valine) amino acids. Similarly, there are aromatic amino acids (tyrosine, phenylalanine, tryptophan).

Uracil nitrogenous base is produces nucleoside only with ribose sugar. This nucleoside is present only inside the RNA and absent in DNA.

Each turn of DNA spirals contains 10 base pairs. So, in five turns of DNA total number of Base pair is 5×10=50 base pairs.

Enzymes have a particular optimum range of working temperature, below which their activity decreases.

• Primary structure of protein is formed by peptide linkages between two amino acids.
• Secondary structure, i.e. α-Helix and β-Sheath, of protein is formed by hydrogen bonds.
• Tertiary structure of protein is formed by sulphide linkages between different amino acids Quaternary structure is formed when multiple chains of polypeptides held together by hydrogen bonds.

Plant cell walls are made of cellulose. Paper made from plant pulp is cellulose.

• Enzymes are proteins or non-proteins that act as bio-catalysts.
• Holoenzymes comprise of a prosthetic group and an apoenzyme.
• Prosthetic group can be either co-factors or co-enzymes.
• Cutting a potato is a physical change and doesn’t lead to the breakage of bonds in the enzymes present in it.

One full turn of the helical strand would involve ten steps or ten base pairs. The pitch would be 34Å.

Amino acids are organic compounds containing an amino group and an acidic group as substituents on the same carbon, i.e. the α-carbon. Hence, they are called α-amino acids.