Biomolecules

Statement-I: Lysine, arginine are essential and basic amino acids.

• Essentiality: Lysine is an essential amino acid, meaning the human body cannot synthesize it and it must be obtained from the diet. Arginine is often considered a conditionally essential amino acid (essential during growth, pregnancy, or illness) but is frequently grouped with essential amino acids in general contexts.

• Basicity: Basic amino acids have an extra amino group or other basic group in their side chain, which is protonated and positively charged at physiological pH.

  • Lysine has a primary amino group (-NH2) at the end of its side chain.

  • Arginine has a guanidinium group in its side chain.

  Both are indeed basic amino acids.

  Therefore, Statement-I is correct.

Statement-II: Leucine, phenylalanine are non essential and neutral amino acids.

• Essentiality:

  • Leucine is one of the nine essential amino acids.

  • Phenylalanine is also an essential amino acid.

  Thus, the claim that they are "non-essential" is incorrect.

• Neutrality:

  • Leucine has an aliphatic, nonpolar side chain, making it a neutral amino acid.

  • Phenylalanine has an aromatic, nonpolar side chain, making it a neutral amino acid.

  Thus, the claim that they are "neutral amino acids" is correct.

Since the first part of the statement (non-essential) is incorrect, Statement-II as a whole is not correct.

Conclusion:

Statement-I is correct.

Statement-II is not correct.

This corresponds to Option C.

The final answer is $\boxed{C}$

The correct structure of $\beta$-D-(-)-fructofuranose is

The reaction requires a free aldehyde group which is not readily available in cyclic structure.

Enzymetic reaction given in option (b) is incorrect for conversion of starch to maltose. The correct form is,

$ \text { Starch } \xrightarrow{\text { Amylase }} \text { Maltose } $

Essential amino acid : Leucine and Histidine

Non essential amino acid : Tyrosine and cysteine.

Essential are those which human body does not produce and vice-versa.

A nucleoside of RNA is composed of a nitrogenous base (like uracil adenine, cytosine or guanine) attached to a ribose sugar molecules.

The correct structure is

1. Amylose:

   • Amylose is a linear polymer made up of D-glucose units.

   • The glucose units are linked together by α-1,4-glycosidic bonds.

2. Amylopectin:

   • Amylopectin is a branched polymer of D-glucose units.

   • The linear chains are formed by α-1,4-glycosidic bonds.

   • Branching occurs due to α-1,6-glycosidic bonds at intervals.

3. Cellulose:

   • Cellulose is a linear polymer of D-glucose units.

   • The glucose units are linked by β-1,4-glycosidic bonds. This type of linkage gives cellulose its rigid, structural properties.

Now, let's match List-I (Glycosidic linkage) with List-II (Polysaccharide):

• (A) α-1,4: This linkage is characteristic of the linear chains in both amylose and amylopectin. Since amylose only has α-1,4 linkages for its main structure, it's the most direct match here. So, A - (I) Amylose.

• (B) β-1,4: This linkage is unique to (III) Cellulose among the given options. So, B - (III) Cellulose.

• (C) α-1,4, α-1,6: The presence of both α-1,4 and α-1,6 linkages indicates a branched polysaccharide with alpha linkages, which is characteristic of (II) Amylopectin. So, C - (II) Amylopectin.

Therefore, the correct matching is:

• A - I

• B - III

• C - II

The aminoacids, which can be synthesised in the body are called non-essential amino acid. While those amino acids which cannot be synthesised in the body must be obtained through diet. Thus, among the given amino acids.

Essential amino acid is $X=$ Lysine, Arginine, Non-essential amino acid is $Y=$ Alanine, Serine, Tyrosine

Statement–I:

Cane sugar is a disaccharide of α-D-glucose and β-D-fructose.

• Cane sugar is sucrose.

• The structure of sucrose consists of α-D-glucose and β-D-fructose units joined by an α,β‑1→2 glycosidic linkage.

✅ Statement-I is correct.

Statement–II:

Milk sugar is a disaccharide of α-D-glucose and β-D-galactose.

• Milk sugar is lactose.

• Lactose is composed of β-D-galactose and β-D-glucose, linked by a β‑1→4 glycosidic bond.

• The glucose part in lactose is β-D-glucose, not α-D-glucose.

❌ Statement-II is not correct.

✅ Final Answer:

Option C:

Statement-I is correct, but Statement-II is not correct.

• Convulsions occur when there is an issue with the normal functioning of the nervous system.

• Vitamin that prevents convulsions: Pyridoxine (Vitamin B₆) is required for the synthesis of neurotransmitters such as GABA.

  Deficiency of Vitamin B₆ → decreased GABA formation → neuronal hyperexcitability → convulsions.

Now let’s check the source:

• Vitamin B₆ (Pyridoxine) is found in cereals, pulses, nuts, and non-vegetarian foods.

✅ Correct answer:

X = Pyridoxine (Vitamin B₆)

Y = Cereals

Answer: Option D — Pyridoxine, cereals

Statement I is correct, but statement II is not correct. The correct form is, $\alpha$-Helix and $\beta$-pleated sheet structure of protein represent secondary structure of it.

Statement I:

“Lactose is composed of α‑D‑glucose and β‑D‑glucose.”

🧠 Recall:

Lactose (milk sugar) is a disaccharide consisting of β‑D‑galactose and β‑D‑glucose, linked by a β(1→4) glycosidic bond:

$ \text{β‑D‑Galactose}-(1→4)-\text{β‑D‑Glucose}. $

Therefore, it is not composed of two glucose molecules — one of the units is galactose.

✅ Hence, Statement I is incorrect.

Statement II:

“Lactose is a reducing sugar.”

🧠 Explanation:

In lactose, the glucose unit still has a free anomeric carbon (the hemiacetal group), so it can undergo mutarotation and reduce Benedict’s or Fehling’s solution.

Thus, lactose is a reducing sugar.

✅ Statement II is correct.

✅ Final Answer:

Option D: Statement I is not correct, but Statement II is correct.

A. Glucocorticoids →

They are secreted from the adrenal cortex (e.g., cortisol) and function mainly in carbohydrate metabolism (they increase blood glucose level).

✅ A → IV (Control the carbohydrate metabolism)

B. Mineralocorticoids →

Also from the adrenal cortex (e.g., aldosterone); they regulate water and salt balance through the kidneys.

✅ B → III (Control the level of excretion of water and salt by the kidneys)

C. Progesterone →

Secreted by the corpus luteum; prepares the uterus for implantation of the fertilized egg.

✅ C → II (Prepares uterus for implantation of fertilised egg)

D. Estradiol →

An estrogen that plays a key role in the control of the menstrual cycle.

✅ D → I (In the control of menstrual cycle)

✅ Final Matching:

A–IV, B–III, C–II, D–I

Correct Option: C

Cane sugar and amylose contain $\alpha$-D glucose unit. Milk sugar and cellulose contains $\beta$-D glucose unit.

Adenine and cytosine contains purine and pyrimidine base of DNA.

$ \text { The given structure of uracil. } $

(I) Hydrolysis of sucrose

Sucrose $(a q)+\mathrm{H}_2 \mathrm{O} \xrightarrow{x}$Glucose + fructose

Enzyme $x=$ Invertase

(II) Fermentation of glucose

Glucose $\xrightarrow{(y)}$ Ethanol $+\mathrm{CO}_2$

Enzyme $y=$ Zymase

The incorrect statements regarding amylose is, given in option (c). The correct form is,

Amylose is a linear not a highly branched polymer of $\alpha$-D-(+)-glucose unit.

The improper functioning of adrenal cortex $(X)$ results in Addison's disease.

Estradiol $(Y)$ hormone is responsible for the developments, of secondary female character.

Riboflavin ( $\mathrm{B}_2$ ) deficiency leads to cheilosis (cracks at mouth corners), glossitis, and digestive issues. Vitamin A is related to vision; C for scurvy; Niacin for pellagra.

Given that, alanine is the C-terminal amino acid and N-terminal must be chiral. So, glycine is not used at the N-terminal because it is achiral. So, possible sequence of tetrapeptides are

Val-Gly-Ser-Ala

Val-Ser-Gly-Ala

Ser-Gly-Val-Ala

Ser-Val-Gly-Ala

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 : $\left[3\left(\mathrm{Ca}_3\left(\mathrm{PO}_4\right)_2\right) \cdot \mathrm{Ca}(\mathrm{OH})_2\right]$

Fluoroapatite : $\left[3\left(\mathrm{Ca}_3\left(\mathrm{PO}_4\right)_2\right) \cdot \mathrm{CaF}_2\right]$

The given structure is of glucose.

Glucose does not give Schiff test due to absence of aldehyde group in ring structure, glucose on reaction with $\mathrm{Br}_2 / \mathrm{H}_2 \mathrm{O}$ give gluconic acid which is mono carboxylic acid.

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.

Are bases of DNA molecule. As DNA contain four bases, which are adenine, guanine, cytosine and thymine.

The coagulation of an egg on heating is because of Option A: Denaturation of protein occurs. When an egg is heated, the proteins in the egg (primarily albumins) undergo denaturation. This process involves the structural alteration of the protein molecules without breaking the peptide bonds that hold the amino acid sequences together. Denaturation causes the proteins to unfold and then aggregate into a new, solid structure, which is what you observe as the egg white and yolk changing from liquid to solid. This change is principally caused by the disruption of non-covalent bonds in the protein, such as hydrogen bonds, ionic bonds, and hydrophobic interactions.

Option B is incorrect because the biological property of the protein does indeed change during the process. The protein in its denatured (coagulated) form does not function in the same way as it did in its native form.

Option C is also incorrect because the primary structure of the protein, defined by its amino acid sequence linked by peptide bonds, remains unaltered during denaturation. The process does not involve the breaking of these peptide linkages.

Lastly, Option D is incorrect because the secondary structure of the protein, which includes α-helices and β-pleated sheets formed by hydrogen bonding, typically undergoes significant alteration during denaturation, contributing to the observable change in the egg's texture.

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.

$\alpha$-Glucose and $\alpha$-Galactose differ in configuration of one asymmetric carbon. Thus they are epimers.

$\alpha$ and $\beta$-glucose differ at anomeric carbon. Thus they are anomers.

$\alpha$-Glucose and $\alpha$-Fructose have different functional groups. Thus they are functional isomers.

A (adenine) pairs with T (thymine)

T (thymine) pairs with A (adenine)

G (guanine) pairs with C (cytosine)

C (cytosine) pairs with G (guanine)

T (thymine) pairs with A (adenine)

T (thymine) pairs with A (adenine)

C (cytosine) pairs with G (guanine)

A (adenine) pairs with T (thymine)

1. A pairs with T

2. T pairs with A

3. G pairs with C

4. C pairs with G

5. T pairs with A

6. T pairs with A

7. C pairs with G

8. A pairs with T

Glucose $\xrightarrow[\Delta]{\mathrm{NaHCO}_3}$ no reaction

Glucose $\xrightarrow[\Delta]{\mathrm{HNO}_3}$ saccharic acid

Glucose $\xrightarrow[\Delta]{\mathrm{HI}}$ n-hexane

Glucose $\xrightarrow[\Delta]{\mathrm{Br}_2}$ Gluconic acid

Sucrose do not contain hemiacetal group.

Hence it does not give test with Fehling solution.

While all other give positive test with Fehling solution

A-II, B-III, C-I, D-IV

Fact based.

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

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

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.

Phosphodiester linkage

The reaction will takes place as follows

Statement $ I $ is incorrect but statement II is correct. The correct form of statement $ I $ is,

Lactose commonly known as milk sugar is made up of $ \beta $-D-galactose $ (A) $ and $ \beta $-D-glucose $ (B) $.

Vitamin $\mathrm{B}_6$ is also called as pyridoxine.

Vitamin $\mathrm{B}_{12}$ is also called as cyanocobalamin.

Vitamin $B_2$ is also called as Riboflavin.

Vitamin $B_1$ is also called as Thiamine.

Cellulose is a polysaccharide and it is made of $\beta$-D glucose units joined through 1, 4-glycosidic linkage.

Hormones act as intracellular messangers. Intracellular messanger also called as chemical messanger. It is because they are chemical agent that go around the body to tell particular cell to play a specific action.