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Correct Option is (C) I^A I^A or I^A I^O

(C) Sickle cell anaemia

Pleiotropy: Influencing more than one trait by a single gene.

Haemophilia: A metabolic disorder characterized by free bleeding from slight wound due to lack of formation of clotting substances. It is sex-linked recessive gene.

Sickle cell anaemia: It is a hereditary disease caused by a recessive mutant gene that controls haemoglobin structure, usually lethal in homozygotes.

Thalassemia: It is a group of hereditary haemolytic anemias.

Colour blindness: It is a sex-linked disease.

Multiple Allelism:

i. More than two alternative forms (alleles) of gene in a population occupying the same locus on a chromosome or its homologue are known as multiple alleles.

ii. ABO blood group system in humans is an example of multiple allelism, because gene I exists in three allelic forms IA, IB and IO.

iii. Here, allele I^A codes for type A blood, allele I^B codes for type B blood and allele I^O codes for type O blood.

iv. Allele I^O is recessive to the alleles I^A and I^B .

v. Thus, with these three alleles, we can have 6 different genotypes and 4 different phenotypes for blood groups.

vi.

Pleiotropy:

i. When a single gene controls two (or more) different traits, it is called pleiotropic gene and this phenomenon is called pleiotropy or pleiotropism. The ratio is 2:1 instead of 3:1.

ii. According to Mendel’s principle of unit character, one gene (factor) controls one character (trait), but sometimes single gene produces two related or unrelated phenotypic expressions.

iii. For example, the disease, sickle cell anaemia is caused by a gene Hb^s . Normal or healthy gene is Hb^A and is dominant.

iv. The carriers (heterozygotes – Hb^A/Hb^S ) show signs of mild anaemia as their RBCs become sickleshaped (half-moon shaped) in oxygen deficiency. They are said to have sickle-cell trait and are normal in normal conditions.

v. The homozygotes with recessive gene Hb^s however, die of fatal anaemia.

vi. Thus, the gene for sickle-cell anaemia is lethal in homozygous condition and produces sickle cell trait in heterozygous carrier.

vii. Two different expressions are produced by a single gene.

 Correct Option is (D) Incomplete or Co-dominance

Role of proteases is to degrade the proteins present inside a cell (from which DNA is being isolated). If the proteins are not removed from DNA preparation then they could interfere with any downstream treatment of DNA (such action of restriction endonuclease, DNA ligase etc).

A) Both a & b are true

(C) Polygenes

The additive or cumulative effect is shown by Polygenes.

(A) a pair of genes governing a specific character such as tallness or dwarfness

The alleles are a pair of genes governing a specific character such as tallness or dwarfness.

(C) polygenic inheritance

When single character is controlled by two or more genes is called polygenic inheritance.

(C) 3 pairs of genes

Skin colour in humans is controlled by three pairs of genes: Aa, Bb, Cc

 Correct Option is (B) Hb^S

Analyzing an individual's genetic material to determine predisposition to a particular health condition or to confirm a diagnosis of genetic disease.

 Correct Option is (B) 1:4:6:4:1

 Correct Option is (B) co-dominance

1. Glycerol is used as a sweetening agent in confectionery and beverages.

2. It is used in the manufacture of cosmetics and transparent soaps.

3. It is used in making printing inks and stamp pad ink and lubricant for watches and clocks.

4. It is used in the manufacture of explosive like dynamite and cordite by mixing it with china clay.

(a) Both A and R are correct and R is the correct explanation of A.

1. Vinyl alcohol

CH₂ = CHOH

IUPAC name: Ethenol

2. Sorbitol

HO – CH₂ – (CHOH)₄ – CH₂OH

IUPAC name : Hexan – 1, 2, 3, 4, 5, 6 – hexol

(c) E₁ mechanism

(a) Both A and R are correct and R is the correct explanation of A.

(c) Propan – 2 – ol

(a) Pyridine

(d) But – 2 – en – 1 – ol

(b)  CH₂ = CHOH

(a) Both A and R are correct and R is the correct explanation of A.

(b) Ethylene glycol

The mechanism of the reaction of ethanol with PCl₃ is SN² 

(a) Both A and R are correct and R is the correct explanation of A.

(d) Conc. H₂SO₄

(c) Unimolecular elimination reaction

In each of first five cases, there is only one monomer which gives corresponding homopolymer. In the sixth case hexamethylene diamine reacts with adipic acid to form the salt hexamethylene diammonium adipate which undergoes condensation to form Nylon 6, 6. Hence nylon 6, 6 is homopolymer. The polymer Buna-S is formed by polymerization of the monomers butadiene and styrene in presence of each other. The repeating units corresponding to the monomers butadiene and styrene are randomly arranged in the polymer. Hence Buna-S is copolymer.

(a) Both A and R are correct and R is the correct explanation of A.

(c) SN² reaction

(b) E₂ mechanism

(d) both (a) and (b)

(i) Addition polymerization 

(ii) Condensation polymerization

(b) Ethoxy ethane

(b) S_N2 reaction

(c)  Anisole

The mechanism involved in Williamson’s synthesis is S_N2

The organic liquid A is C₂HOH

(a) (CH₃)₂ CCH₂ 

Based un biodegradability, polymers are classified as biodegradable polymer and nonbiodegradable polymers.

(1) Biodegradable polymers: Polymers that are affected by microbes or disintegrate by themselves afler a certain period of time due to environmental degradation are called biodegradable polymers.

Examples: PHBV i.e., Polyhydroxy butyrate-CO-β-hydroxy valerate Dextron. Nylon-2-nylon-6.

(2) Non biodegradable polymers: Synthetic polymers do not disintegrate by themselves after a certain period or not affected by microbes, are called nonbiodegradhle polymers.

Examples: Bakelite, Nylon, Terylene.

(d) auto oxidation

(b) CH₃ – CH₂OH

(b) Both A and R are wrong

Step growth polymers : Nylon-6,6, terylene 

Chain growth polymers : Polythene, PVC.

(d) inter molecular hydrogen bonding in alcohols

Correct answer is

(c) Polystyrene

1. Branched chain polymer : The polymer consists of long and straight chain with smaller side chains give rise to branched chain polymers, e.g. Polypropylene 

2. Addition polymer : The polymer formed by the repeated addition of a large number of monomers (like alkenes) without loss of any small molecules are called addition polymers, e.g. polythene -[-CH₂ – CH₂ -]_n. It is a chain growth polymerization.

3. Condensation polymer : The polymers formed by the repeated condensation reaction between polyfunctional monomers with the elimination of some molecules such as water, hydrochloric acid, methanol, ammonia are called condensation polymers, e.g. Nylon-6, 6. 

4. Elastomers : Polymers in which the intermolecular forces of attraction between the polymer chains are the weakest. When polymer is stretched, it has ability to stretch and when the strain is relieved it returns to its original position. Thus, polymer shows elasticity and is called elastomers, e.g. natural rubber, neoprene, vulcanized rubber.

5. Homopolymer : A polymer made from only one type of repeating unit of one monomer is called homopolymer e.g. Polythene, PVC, etc.

6. Biodegradable polymer : Polymers which are affected by microbes or disintegrate by themselves after a certain period of time due to environmental degradation are called biodegradable polymers. 

Example : PHSV i.e. Polyhydroxy butyrate - CO-β-hydroxy valerate Dextron.