Biomolecules

The structure of protein that remains intact after the coagulation of egg white on boiling is the Primary structure.

The correct answer is Option B.

The primary structure of a protein is the sequence of amino acids that are linked by peptide bonds.

This sequence dictates the protein's higher levels of structure including secondary, tertiary, and quaternary structures.

Regardless of the change in the protein's conformation due to denaturation (such as what happens during boiling of egg white), the sequence of amino acids remains the same since the peptide bonds do not get broken under such conditions.

When egg white is boiled, the proteins denature, which means the structure of the protein becomes altered due to the breakdown of non-covalent interactions that hold the protein's higher-order structures together.

This includes: Secondary structure: This involves hydrogen bonding within the peptide backbone, producing structures such as alpha-helices and beta-sheets.

Tertiary structure: This involves the overall three-dimensional folding of the protein, driven by interactions such as hydrogen bonds, ionic bonds, hydrophobic interactions, and disulfide bridges.

Quaternary structure: This involves the arrangement and interactions of multiple protein subunits in a multi-subunit complex.

During coagulation caused by heat, the weak hydrogen and ionic bonds of secondary and tertiary structures are broken and the proteins can aggregate or form gel-like structures, changing the consistency of the egg white.

However, the covalent peptide bonds of the primary structure stay intact throughout this process.

Proteins are natural polymers composed of $\alpha$-amino acids which are connected by peptide linkages.

Hence proteins upon acidic hydrolysis produce $\alpha$-amino acids.

Let's analyze each statement to identify the incorrect one about glucose.

Option A: Glucose remains in multiple isomeric forms in its aqueous solution.

This statement is correct.

Glucose exists in equilibrium with various isomeric forms in solution, including its linear form and two cyclic forms (alpha and beta anomers) that result from the formation of a hemiacetal bond within the molecule itself.

The interconversion between these forms is known as mutarotation.

Option B: Glucose is soluble in water because of having an aldehyde functional group.

This statement is incorrect though it might seem partially true at first glance.

While the aldehyde group can participate in hydrogen bonding, the primary reason glucose is highly soluble in water is due to its multiple hydroxyl (-OH) groups that can form hydrogen bonds with water molecules.

The ability to form numerous hydrogen bonds makes glucose highly water-soluble, not just the presence of an aldehyde group.

Option C: Glucose is an aldohexose.

This statement is correct.

Glucose is classified as an aldohexose because it contains an aldehyde group (-CHO) on its first carbon and has a total of six carbon atoms, making it a hexose sugar.

Option D: Glucose is one of the monomer units in sucrose.

This statement is correct.

Sucrose is a disaccharide composed of two monomers: glucose and fructose.

Thus, glucose is indeed one of the monomer units in sucrose.

In summary, the incorrect statement about glucose is Option B: Glucose is soluble in water because of having an aldehyde functional group.

The primary reason for its solubility in water is the hydroxyl groups' ability to form extensive hydrogen bonding, not solely the presence of an aldehyde functional group.

Hydroxyapatite :

Fluoroapatite :

The ninhydrin test is a chemical test which is used to detect the presence of amino acids or proteins.

When amino acids or proteins react with ninhydrin, a deep blue or purple color is produced, which is indicative of a positive test.

This reaction primarily occurs due to the reaction of ninhydrin with the free amino groups (-NH2) present in amino acids or proteins.

Let's examine each option: Option A: Polyvinyl chloride - Polyvinyl chloride, commonly known as PVC, is a synthetic polymer.

It does not contain amino acids or free amino groups.

Therefore, it does not give a positive test with ninhydrin.

Option B: Cellulose - Cellulose is a carbohydrate polymer consisting of glucose units.

It is the main constituent of the cell wall in plants.

Like PVC, cellulose does not contain amino acids or free amino groups, so it also does not give a positive test with ninhydrin.

Option C: Egg albumin - Egg albumin is a protein found in egg whites.

Proteins are made up of amino acids linked by peptide bonds, and free amino groups are present in the structure of proteins.

Therefore, egg albumin reacts with ninhydrin and gives a positive test by producing a deep blue or purple color.

Option D: Starch - Starch is a polysaccharide composed of glucose units and is a carbohydrate like cellulose.

It does not possess amino acids or free amino groups.

Consequently, starch does not give a positive test with ninhydrin.

Based on the explanation, the correct answer is Option C: Egg albumin, as it is the only option among the ones listed that contains proteins, which have free amino groups capable of reacting with ninhydrin to give a positive test.

The correct answer is Option A: (B) and (D).

Let’s analyze each statement: (A) Enzymes are biocatalysts. - This statement is correct.

Enzymes are indeed biocatalysts, meaning they are natural catalytic substances produced by living organisms to speed up chemical reactions in cells without being consumed in the process.

They are crucial for a myriad of biological processes.

(B) Enzymes are non-specific and can catalyse different kinds of reactions. - This statement is incorrect.

Enzymes are highly specific in nature; they typically catalyze only one kind of reaction or a very limited range of reactions.

This specificity is a result of the unique 3D structure of the enzyme molecule, particularly the active site where substrate molecules bind.

(C) Most enzymes are globular proteins. - This statement is correct.

The vast majority of enzymes are indeed globular proteins.

This means they are folded into a compact shape which is crucial for their function.

Their globular structure allows for the creation of specific active sites where the chemical reactions take place.

(D) Enzyme - oxidase catalyses the hydrolysis of maltose into glucose. - This statement is incorrect.

The enzyme that catalyses the hydrolysis of maltose into glucose is maltase, not oxidase.

Oxidases are a class of enzymes that catalyze the transfer of electrons to oxygen, and are involved in oxidation reactions, not in the hydrolysis of sugars.

Therefore, the incorrect statements regarding enzymes are (B) Enzymes are non-specific and can catalyse different kinds of reactions, and (D) Enzyme - oxidase catalyses the hydrolysis of maltose into glucose, making Option A the correct choice.

The nine essential amino acids that must be obtained from the diet are: Histidine Isoleucine Leucine Lysine Methionine Phenylalanine Threonine Tryptophan Valine From the provided list: Valine (A) is essential.

Proline (B) is non-essential.

Lysine (C) is essential.

Threonine (D) is essential.

Tyrosine (E) is non-essential (it is considered conditionally essential, but under normal conditions it is non-essential).

Thus, the essential amino acids among those listed are Valine, Lysine, and Threonine.

So the correct answer is:

A) Amylose - Polysaccharide of glucose units with glycosidic linkage $\alpha-1,4$.

The source is plant.

So, the linkage is $\alpha-c_1-C_4$.

Glucose units in amylose are linked by alpha bonds between the $1^{\text{st }}$ and $4^{\text{th }}$ carbon atoms.

Amylose match with $\alpha-c_1-c_4$, plant (A) with (IV) B) Cellulose - The glycosidic linkage in cellulose is $\beta-1,4$.

Glucose monomers are joined by linkage between the $c_1$ of the one glucose ling and the $C_4$ of the next ring.

Source is plant Cellulose match with $\beta-C_1-C_4$, plant.

(B) with (I) c) Glycogen - Glycogen is a polymer of glucose that is stored in animals as an energy reserve.

It is used as carbohydrate storage in animals.

It is a polymer of $\alpha$-glucose with $\alpha-1,4$-glycosidic and $\alpha-1,6$-glycosidic links. $\alpha-1,4$-linkage forms during linear polymer. $\alpha-1,6$ - linkage forms during the formation of branching.

Glycogen match with $\alpha-C_1-C_4$, animal (C) with (II) D) Amylopectin - It is the polymer of glucose units linked by $\alpha-1,4$ and $\alpha-1,6$ glycosidic bonds. $x-1,4$ - glucose units linked in a linear way.

$\alpha-1,6$ - These bonds branch out from the linear chains of glucose units.

They are stored in large complexes called starch granules in plants.

Amylopectin match with $\alpha-c_1, c_4, \alpha-c_1-c_6$, plant (D) with (III).

Answer: $(A)-($ IV $),(B)-(I),(C)-($ II $),(D)-($ III $)$.

Option (3).

Correct Answer: Ascorbic Acid Ascorbic acid is commonly known as Vitamin C.

It is a water-soluble vitamin essential for various bodily functions, including:

It helps protect cells from damage caused by free radicals.

It is crucial for the formation of collagen, a protein necessary for skin, cartilage, tendons, ligaments, and blood vessels.

It supports the immune system by enhancing the body's natural defenses.

It improves the absorption of non-heme iron from plant-based foods.

Among the given options, only ascorbic acid qualifies as a vitamin.

(A) Sucrose $\rightarrow \alpha_1-\beta_2$ Glycosidic linkage (B) Maltose $\rightarrow \alpha$ 1-4 Glycosidic linkage (C) Lactose $\rightarrow \beta$ 1-4 Glycosidic linkage (D) Amylopectin $\rightarrow \alpha$ 1-4 and $\alpha$ 1-6 Glycosidic linkage