31 Years NEET Previous Year Questions: Biomolecules - 2 - NEET MCQ

rRNA occurs inside ribosomes. m RNA brings information from DNA to polypeptides. hnRNA are heterogenous nuclear RNA.

In competitive inhibition the inhibitor resembles the substrate in structure and hence compete for the active site of the enzyme.

Km (Michealis Menten constant). It is defined as that substrate concentration at which under optimum conditions the rate of an enzyme catalysed reaction reaches half the maximum rate. Km is inversely proportional to affinity of enzyme for its substrate.

Help in regulating metabolism.

The general structure of an amino acid is

where R is an alkyl or aryl group.
In Glycine R is also a hydrogen atom. Therefore glycine is the simplest amino acid.

Endonucleases hydrolyse internal phosphodiester bonds in a polynucleotide chain (i.e. DNA). While exonucleases hydrolyse terminal phosphodiester bonds in a polynucleotide chain (i.e., DNA).

J.D. Watson and F.H.C. Crick (1953) showed that DNA has a double helical structure with two polynucleotide chains structure with two polynucleotide chains connected by hydrogen bonds and running in opposite directions (antiparallel). The antiparallel strands of a DNA molecule means that the phosphate groups at the start of two DNA strands are in opposite position (pole).

Some bacteria (such as Rhodopseudomonas), algae and green plants cell produces carbohydrates.

Coenzyme is an organic substance that enhances the action of an enzyme by binding with the protein molecule. Holoenzyme is a biochemically active compound formed by the combination of an enzyme with a coenzyme. Apoenzyme is the protein of an enzyme to which the coenzyme attaches to form an active enzyme Isoenzyme is one of the several forms of an enzyme that catalyse the same reaction but differ from each other in such properties as substrate affinity and maximum rates of enzyme substrate reaction.

Cofactor is a non protein part of the enzyme. It can be metal ions or the organic chemical. The cofactors which are organic chemicals are known as coenzyme. These are loosely attached to the apoenzyme. The tightly bound coenzymes are prosthetic group.

So, the correct answer is option D

The plant ash reveals the presence of 40 elements but all are not essential for plant nutrition, only a few are essential for growth and development of plants. These are called as the essential elements. The essential elements may be grouped as major elements or macronutrients and trace elements or micronutrients, based on their requirement by plants. The macronutrient elements are required in large amounts and form the plant constituents. The major elements are otherwise also known as macronutrients. These include carbon, hydrogen, oxygen, nitrogen, phosphorus, potassium, calcium, magnesium and sulphur. Of these approximately ninety percent of plant body is made of carbon, hydrogen, oxygen, nitrogen, calcium and phosphorous.

Malonate is a powerful inhibitor of cellular respiration, because it binds to the active site of the succinate dehydrogenase in the citric acid cycle but does not react, thereby competes with succinate, since it does not have the -CH2-CH2- group as in succinate which is required for dehydrogenation. For the oxidative phosphorylation reaction, malonate is an inhibitor for complex II which again contain succinate dehydrogenase.

Massive ions like Na+ facilitate the absorption of substances like amino acid and glucose through Co transport. 

Lecithin is a fat like substance called a phospholipid, which is a part of plasma membrane.

There are certain enzymes which have slightly different molecular structure but have similar catalytic function such enzymes are known as isoenzymes. Holoenzymes is the active compound formed by combination of a coenzyme and an apoenzyme. Apoenzyme is the protein component of an enzyme, to which the coenzyme attaches to form an active enzyme. Coenzyme are organic non-protein molecules  that bind with the protein molecule (apoenzyme) to form the active enzyme (holoenzyme).

Glycogen is a polysaccharide, which is synthesized and stored in the liver. It is released into the blood by breakdown of simple glucose, and energy is released.

DNA and RNA are both polymers of nucleotides . DNA has deoxyribose sugar while RNA  has ribose sugar. DNA has thymine while RNA has uracil in place of thymine.

Collagen is the most abundant protein of animal world. Rubisco (ribulose biphosphte carboxylase - oxygenase) is not only the most abundant protein in plants but also the whole biosphere.

Proteins are building blocks of the body. The proteins are made up of amino acids. The amino acids are linked together by peptide bonds to form a protein. The amino acids consist of amine group made up of nitrogen and hydrogen and the carboxyl group at the end and a side chain of R group which is specific to a particular amino acid. This specific group brings a variability to the proteins. If R group is H it is glycine while if it is CH_2​ it is alanine. The sequence of amino acids determines the protein. 

So, the correct answer is option D.

Palmitic acid is one of the most common saturated fatty acids found in animals and plants. It has 16 carbons including the carboxyl carbon. Adenylic acid is a nucleotide consisting of adenine, ribose or deoxyribose, and a phosphate group. It is a constituent of DNA or RNA. It is also called adenosine monophosphate. Amino acids are organic acids (with carboxylic group COOH) having amino group (–NH₂) generally attached to Carbon or carbon next to carboxylic group. The carbon also bears a variable alkyl group (R) or hydrogen or hydrocarbon. In alanine is represented by methyl group.

A saturated or unsaturated fatty acid esterified to a glycerol molecule to which a phosphate group is also attached forms phosphoglycerides. Phosphoglycerides are major structural components of cell membranes. They are, therefore, also called membrane lipids. Lecithin is one example.

The essential chemical components of many enzymes are vitamins, e.g., coenzyme nicotinamide adenine  dinucleotide (NAD) and NADP contain vitamin niacin.

Transition state structure formed during an enzymatic reaction is transient and unstable.

Explanation:
Chitin is the most abundant amino polysaccharide polymer found in nature, and it is the building material that gives crustaceans, insects, and fungi their exoskeletons and cell walls their strength.

Chitin is a nitrogen-containing modified polysaccharide made up of units of N-acetyl-D-glucosamine (more precisely, 2-(acetylamino)-2-deoxy-D-glucose).
Final answer: Macromolecule chitin is a nitrogen-containing polysaccharide

Almost all enzymes are proteins. There are some nucleic acids that behave like enzymes. There are called ribozyme (also called RNA enzyme or catalytic RNA).

In the given figure a tetrapeptide is shown. Here, amino acids are indicated as (a), (b) (c) and (d). (a) indicates N-terminal amino acid and (d) indicates C-terminal residue. As it can be seen from the figure sulphur containing amino acid is b and carboxyl group (-COOH) containing amino acid is (d). Residue (d) indicates glutamic acid, an acidic residue due to presence of (-COOH) group.