Chemistry M.C.Q (1 Marks)

3. Inclusion complex

Explanation:
Inclusion complex is a host-guest addition compound.
The space available within the crystal lattice of the host molecule, i.e., amylose is in the form of tunnels and the size of the tunnels is such that it can easily accommodate guest molecules, i.e., iodine molecules to form an addition compound called the inclusion complex.
The blue colour, however, disappears on heating and reappears on cooling.

1. I and II

Explanation:
Cyclic structures of monosaccharides which differ in structure at carbon-1 are known as anomers. Here, I and II are anomer because they differ from each other at carbon-1 only.

4. Uracil

Explanation:
Uracil is present in RNA but not in DNA.

3. Vitamin B

Explanation:
For some biochemical reactions a substance other than enzymes and substrate is required. These substances are called coenzymes (organic compounds) or cofactors (inorganic ions like zinc and copper etc.). The coenzymes usually serve as an acceptor or donor of an atom or a group.
Many coenzymes are derived from vitamins. B group of vitamins forma variety of coenzymes example Nicotinamide adenine dinucleotide (NAD) which is derived from vitamin niacin, Flavin adenine dinucleotide (FAD) which is derived from vitamin riboflavin, Coenzyme A which is derived from pantothenate, pyridoxal phosphate which is derived from pyridoxin, Thiamine pyrophosphate which is derived from thiamine etc.

3. Vitamins

Explanation:
Enzymes are simple if they are made up of only proteins example pepsin, amylase etc.
While conjugate enzymes have an additional non protein organic coenzyme or inorganic cofactor.
Loosely attached organic cofactors are called as coenzymes example NAD, FAD TPP etc.
Coenzymes are generally derived from vitamins like Thiamine (TPP), Riboflavin (FMN, FAD), Niacin (NAD), Pantothenate (CoA).

2. Source of energy

Explanation:
Carbohydrates are more suitable for the production of energy in the body then proteins and fats. 
Carbohydrate are also stored in the body cells as glycogen and are used for the production of energy whenever required.

1. Co-factors of enzymes.

Explanation:
Micronutrients or microelements are those elements which are required in quantity of less than 10 millimole/kg of dry matter.
Most of the micronutrients have a catalytic role. They are components of cofactors of enzymes, e.g., zinc (required for activity of alcohol dehydrogenase), copper (required for activity of cytochrome oxidase), nickel (required for activity of urease), etc. 

1. Nucleotides and nucleic acids.

Explanation:
Amino acids and proteins are similar to the nucleotides and nucleic acids.
Just as proteins are made up of numbers of amino acids, similarly nucleic acids, which include DNA (deoxyribonucleic acid) and RNA (ribonucleic acid), are made from monomers known as nucleotides.

3. Ethylene

Explanation:
All of the given options are phytohormones (plant hormones).  
Plant hormones control all the growth and development activities like cell division, enlargement, flowering, seed formation, dormancy and abscission.
The major function of the given hormones are as follows:  

1. Auxin- Cell elongation of stems and roots 
2. Cytokinin- Promotes lateral and adventitious shoot growth by inducing cell division. 
3. Ethylene- Hastens the ripening of fruits
4. Gibberellin-  Breaks seed dormancy promotes flowering. Hence, ethylene gas is used for the artificial ripening of fruits. 

4. All of the above

Explanation:
A distinct domain in an enzyme molecule may be a catalytic site, allosteric site that binds to the cofactor to form holoenzyme.

4. Hormones

Explanation:
Hormones are the chemical messengers that are produced by the endocrine system (composed of glands) but are transported to different parts of the body through the bloodstream.
Hormones play an important role in the control and coordination of the body.
For example, the growth of an individual is regulated by growth hormones secreted by the pituitary gland.

1. 35 - 40 degrees

Explanation:
Enzymes are biological catalysts which accelerate chemical reactions in organisms.
Optimum temperature is the temperature at which enzyme activity is maximum.
In humans, this temperature is 37.5°C that is same as the normal body temperature.
A rise in temperature above 40°C results in denaturation of the proteins of enzyme.

3. Temporary and unstable.

Explanation:
During an enzymatic reaction, a substrate goes through a transition state before it becomes a product.
It is proposed that the transition state is bound more strongly than either the substrate or the product, however, the transition state is inherently unstable and are transient.

2. Vitamins

Explanation:
Vitamins are essential components of our diet and are not produced by our body.

2. Organic

Explanation:
A coenzyme or metal ion that is very tightly or even covalently bound to the enzyme protein is called a prosthetic group.
These may be organic or inorganic in nature. For example includes flavin nucleotides and heme.
This accentuates the enzymatic activity.

2. Millon's reagent

Explanation:
The most common reagent for qualitative and quantitative analysis of amino acids is Millon's reagent. 
Million's reagent is a solution that is usually made by dissolving mercury in concentrated nitric acid and diluting with water and that when heated with phenolic compounds gives a red coloration, for proteins (especially tyrosine amino acids).

4. All the above

Explanation:
The source of retinol (vitamin A) are liver kidney and fish oil. Retinol is that form of vitamin A which is obtained from animal sources. 
Vitamin A comes from two sources. One group comes from animal sources and is called retinoids, which includes retinol.
The other group comes from plants and is called carotenoids, which includes beta-carotene. The body converts beta-carotene to vitamin A.

3. Temperature

Explanation:
Enzymes are proteinaceous in nature.
There are intra and intermolecular bonds that hold proteins in their secondary and tertiary structures. 
The increase in the temperature over an optimum range leads to the disruption of bonds.
This makes the enzymes sensitive to heat.

2. Being proteinaceous in nature.

Explanation:
Biochemically, enzymes are polymers of amino acids. They are not amino acids but are polymers of amino acids.
Most of the enzymes barring a few exceptions are proteins. Few non-proteinaceous enzymes are catalytic RNAs.

1. Sucrose

Explanation:
Silver mirror test with Tollen's reagent is given by the molecule which contains aldehyde group. But, sucrose has no aldehyde group and rest of the molecule have aldehyde group.
Hence, glucose, fructose and lactose, each gives silver mirror test except sucrose.

4. Starch.

Explanation:
Iodine is used in chemistry as an indicator for starch. When starch is mixed with iodine in solution, an intensely dark blue colour develops, representing a starch/iodine complex.
Starch is a substance common to most plant cells and so a weak iodine solution will stain starch present in the cells. Iodine is one component in the staining technique known as Gram staining, used in microbiology.

3. Glycylalanine (dipeptide)

Explanation:
If the amino group of glycine and carboxylic acid group of alanine undergo elimination of water molecule, the formed compound is glycylalanine (dipeptide).

4. To accelerate the rate of chemical reactions.

Explanation:
Enzymes are biocatalysts that causes a change in the rate of a chemical reaction i.e they may enhance (accelerate) or reduce the rate of a chemical reaction. 

3. 1 : 10,00,000

Explanation:
The enzyme attaches to the active site of the substrate. On attachment to the active site, the substrate is changed into the product. The active site has a residue that helps in the attachment of the substrate.
The substrate molecules form a temporary bond with the enzyme at the active site.
The ratio of enzyme to substrate molecules can be as high as 1 : 10,00,000. If the amount of substrate increases more than this, it will not get the vacant active site for attachment which terminates the reaction.

2. Ascorbic acid.

Explanation:
Aspartic acid is vitamin C. Aspartic acid is an amino acid. Adipic acid and saccharic acid are dicarboxylic acids.

4. All of the above

Explanation:
For some biochemical reactions, a substance other than enzymes and substrate is required.
These substances are called as coenzymes or cofactors.
The coenzymes usually serve as an acceptor or donor of an atom or a group, example - nicotinamide adenine dinucleotide (NAD) which is derived from vitamin niacin, flavin adenine dinucleotide (FAD) which is derived from vitamin riboflavin, Coenzyme A which is derived from pantothenate etc.

1. Nucleic acids

Explanation:
The prosthetic group present in nucleoproteins is nucleic acids. 
Nucleoproteins are proteins of cell nuclei and are main component of chromatin.
They are present in every living cell a well as in virus and baceteria.
Example- protamines, histones.

1. A nitrogenous base

Explanation:
The four nitrogenous bases present in DNA are adenine (A), guanine (G), cytosine (C) and thymine (T).

2. End products on the rate of enzymatic reaction.

Explanation:
Feedback mechanism is a regulatory mechanism for the enzyme action where the end product inhibits the action of the enzyme when its concentration exceeds the need of the cell.
This helps to maintain the homeostasis.

1. Primary structure of proteins.

Explanation:
The sequence of amino acids in a polypeptide chain in called primary structure of proteins.

3. It is present in roots and seeds of plants.

Explanation:
Starch is the polysaccharide which is present in roots and seeds of plants.
It is present in all photosynthesis plants. It is present is seeds in form of granules.

1. Van der Waals forces.
2. Disulphide linkage.

In fibrous proteins, main forces which stabilize structures of proteins are disulphide linkages and van der Waals.

3. Lipase

Explanation:
Bile salts act as activator of lipase as they emulsify fat globules into smaller droplet like structure called micelles thereby, increasing the surface area accessible to lipid hydrolyzing enzymes.
The bile acids also help to solubilize lipid breakdown products.

3. Phosphate - sugar base.

Explanation:
In nucleic acids, the sequence is phosphate-sugar base. Nucleic acids are polymeric macromolecules, or large biological molecules, essential for all known forms of life.
Nucleic acids, which include DNA (deoxyribonucleic acid) and RNA (ribonucleic acid), are made from monomers known as nucleotides.
Each nucleotide has three components: a 5-carbon sugar, a phosphate group and a nitrogenous base.
If the sugar is deoxyribose, the polymer is DNA. If the sugar is ribose, the polymer is RNA.

1. Monosaccharides

Explanation:
A polysaccharide is a polymer of monosaccharides.
For example cellulose (a polysaccharide) is a polymer of D-glucose (monosaccharide).

2. Agarobiose

Explanation:
Agarose is a polymer of agarobiose.
Agarose:- Agarose is a polysaccharide, generally extracted from certain red seaweed.
It is a linear polymer made up of the repeating unit of agarobiose, which is a disaccharide made up of D - galactose and 3, 6 - anhydro - L - galactopyranose.

4. Glycogen

Explanation:
Glycogen is stored in the liver of animals.