Which form of RNA has a structure resembling clover leaf ?
rRNA occurs inside ribosomes. m RNA brings information from DNA to polypeptides. hnRNA are heterogenous nuclear RNA.
Which of the following statements regarding enzyme inhibition is correct?
In competitive inhibition the inhibitor resembles the substrate in structure and hence compete for the active site of the enzyme.
The catalytic efficiency of two different enzymes can be compared by the
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.
Enzymes, vitamins and hormones can be classified into a single category of biological chemicals, because all of these
Help in regulating metabolism.
Which of the following is the simplest amino acid?
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.
Which one of the following hydrolyses internal phosphodiester bonds in a polynucleotide chain?
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).
Antiparallel strands of a DNA molecule means that
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).
Carbohydrates, the most abundant biomolecules on earth, are produced by :
Some bacteria (such as Rhodopseudomonas), algae and green plants cell produces carbohydrates.
An organic substance bound to an enzyme and essential for its activity is called
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.
About 98 percent of the mass of every living organism is composed of just six element including carbon, hydrogen, nitrogen, oxygen and
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.
A competitive inhibitor of succinic dehydrogenase is
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.
Carrier ions like Na+ facilitate the absorption of substances like:
Massive ions like Na+ facilitate the absorption of substances like amino acid and glucose through Co transport.
Which one of the following structural formulae of two organic compounds is correctly identified along with its related function ?
Lecithin is a fat like substance called a phospholipid, which is a part of plasma membrane.
Enzymes having slightly different molecular structure but performing identical activity are
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).
A polysaccharide, which is synthesized and stored in liver cells, is
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.
One of the similarities between DNA and RNA is that both
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.
Which one is the most abundant protein in the animal world
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.
The enormous diversity of protein molecules is due mainly to the diversity of
There are 20 amino acids known. All the amino acids follow the basic structure. It consists of a carbon atom in the middle surrounded by three chemical bases.
Two out of three bases are the amino (NH2 group) and the carboxylic group (COOH). The third group is a simple hydrogen atom present in all the amino acids.
The fourth group is called an R group that determines the nature of the amino acid. This R group can be as simple as a hydrogen atom and may also contain complex rings. On the basis of the R group, the amino acid can be polar or non-polar, acidic or basic or neutral.
Thus the enormous diversity of protein molecules is mostly due to the diversity in the R group.
So, the correct option is 'R groups on the amino acids'.
Which one of the following biomolecules is correctly characterized?
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 phosphoglycerate is always made up of :
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 coenzymes are :
The essential chemical components of many enzymes are vitamins, e.g., coenzyme nicotinamide adenine dinucleotide (NAD) and NADP contain vitamin niacin.
Transition state str ucture of the substrate formed during an enzymatic reaction is :
Transition state structure formed during an enzymatic reaction is transient and unstable.
Macro molecule chitin is :
Chitin or fungal cellulose that is nitrogen containing polysaccharide and heteropolymer of NAG.
Which of the following statements aboutenzymes is wrong?
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).
The figure shows a hypothetical tetrapeptide portion of a protein with parts labelled A-D. Which one of the following option is correct?
[NEET Kar. 2013]
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.