Biomolecules

The method of DNA replication in which two strands of DNA separate and synthesize new strands is called Semiconservative replication. During semiconservative replication, each new DNA molecule consists of one parental strand and one newly synthesized strand.

So, the correct option is (C): Semiconservative

Proteoglycans are molecules found in the extracellular matrix of connective tissues like cartilage. Chondroitin is a type of glycosaminoglycan (GAG) that is commonly found as part of proteoglycans in cartilage, contributing to its structural integrity.

So, the correct option is (A): Chondroitin

The factor responsible for inhibition of enzymatic processes during feedback is the end product. In feedback regulation, when the concentration of the end product of a biochemical pathway reaches a certain level, it can inhibit or slow down the enzymatic reactions earlier in the pathway. This helps maintain homeostasis and prevent the overproduction of a particular substance.

So, the correct option is (C): End product

Glycoprotein has a carbohydrate as a prosthetic group. Glycoproteins are proteins that have carbohydrates (oligosaccharides) attached to them. These carbohydrates can serve various functions, such as cell recognition, signaling, and stability.

So, the correct option is (A): Glycoprotein

Lysosome contains Hydrolytic enzymes. Lysosomes are membrane-bound organelles containing enzymes that break down various macromolecules and cellular waste materials through hydrolysis.

So, the correct option is (B): Hydrolytic enzymes

UAC is the codon that specifies the amino acid Tyrosine in protein synthesis. It is not a start or stop codon. Start codon is typically AUG (not provided in the options), and UUU is a codon for Phenylalanine, not a stop codon.

So, the correct option is (D): UAC–Tyrosine

Carbon, hydrogen, and oxygen make up the bulk of organic compounds in plants, such as carbohydrates, lipids, and proteins. These elements are essential for the structure and energy storage in plant cells. While other elements like nitrogen, phosphorus, potassium, calcium, magnesium, and sulfur are also important for plant growth, they are present in much smaller quantities compared to carbon, hydrogen, and oxygen.

So, the correct option is (D): Carbon, hydrogen and oxygen

Beri-Beri is caused by a deficiency of vitamin B₁ (thiamine), not vitamin B₆ (pyridoxine).

So, the correct option is (D): Vitamin B₆–Beri-beri

Many trace elements serve as essential co-factors for enzymes, which are biological catalysts that facilitate chemical reactions within cells. These trace elements are required in small quantities but play crucial roles in various biochemical processes, often by assisting enzymes in their catalytic functions.

So, the correct option is (A): co-factors of enzymes

Glycine is the simplest amino acid because it has a hydrogen atom as its side chain (R-group), making it the smallest and simplest in terms of chemical structure.

So, the correct answer is (C): Glycine

Endonucleases are enzymes that hydrolyze internal phosphodiester bonds in a polynucleotide chain, cleaving the DNA or RNA at specific locations within the molecule. Exonucleases, on the other hand, remove nucleotides from the ends of the molecule, not from internal positions. Lipases and proteases are not involved in nucleic acid hydrolysis; lipases are involved in lipid metabolism, and proteases are enzymes that cleave peptide bonds in proteins.

So, the correct option is (C): Endonuclease

The Km value, also known as the Michaelis-Menten constant, is a measure of the substrate concentration at which an enzyme reaches half of its maximum catalytic activity. Lower Km values indicate higher affinity of the enzyme for the substrate and, often, greater catalytic efficiency. Therefore, comparing the Km values of two enzymes can provide insights into their relative catalytic efficiencies.

So, the correct option is (A): the Km value

The correct statement regarding enzyme inhibition is Competitive inhibition is seen when the substrate and the inhibitor compete.
Explanation:
(A) This statement is not correct. Non-competitive inhibition cannot be overcome by adding more substrate because the inhibitor binds to a different site on the enzyme, not the active site where the substrate binds.
(B) This statement is not entirely accurate. In competitive inhibition, the inhibitor molecule competes with the substrate for binding to the active site of the enzyme, not to an "inhibitor protein."
(D) This statement is also not correct. Non-competitive inhibitors bind to the enzyme reversibly, meaning they can eventually dissociate from the enzyme, although they don't compete with the substrate for the active site.

So, the correct statement is (C): Competitive inhibition is seen when the substrate and the inhibitor compete.

Carbohydrates, including cellulose, starch, glycogen, glucose, fructose, and others, constitute the most prevalent biomolecules on Earth. These carbohydrates are generated through photosynthesis, a process that involves the reduction of atmospheric carbon dioxide using light energy. Photosynthesis is primarily carried out by green plants, including aquatic algae, which convert carbon dioxide into carbohydrates. While some bacteria can also perform photosynthesis, their process differs in that they rely on chemical energy instead of light energy and do not produce oxygen as a byproduct, in contrast to the photosynthesis occurring in green plants.

So, the correct option is (C): Some bacteria, algae and green plant cells

Enzymes facilitate chemical reactions in metabolism, vitamins are essential coenzymes and cofactors that assist enzymes, and hormones are chemical messengers that regulate various metabolic processes in the body.

So, the correct option is (D): help in regulating metabolism

Telomerase is an enzyme that is a Ribonucleoprotein.
Telomerase is composed of both protein and RNA components, making it a ribonucleoprotein complex. It plays a crucial role in maintaining the length and integrity of telomeres at the ends of eukaryotic chromosomes.

So, the correct option is (D): Ribonucleoprotein

In the pulp and paper industry, the process of delignification is essential to remove lignin from wood and obtain pure cellulose fibers, which can be used to make high-quality paper products. Removing lignin is a critical step because lignin is a non-cellulosic component that can interfere with paper quality and strength.

So, the correct option is (A): Preparation of pure cellulose by removing lignin

Coenzymes are organic molecules that bind to enzymes and are required for their proper functioning. They often participate in enzyme-catalyzed reactions by donating or accepting chemical groups during the reaction. Coenzymes are essential for the catalytic activity of many enzymes.

So, the correct option is (A): coenzyme

To determine the correct set of statements on lipids, we will evaluate each statement listed:

• Statement (a): Lecithin found in the plasma membrane is a glycolipid.
  Lecithin is actually a type of phospholipid, not a glycolipid. Therefore, this statement is incorrect.
• Statement (b): Saturated fatty acids possess one or more c = c bonds.
  Saturated fatty acids do not contain any c = c (carbon-to-carbon double) bonds; they only have single bonds between the carbons. Therefore, this statement is incorrect.
• Statement (c): Gingely oil has a lower melting point, hence remains as oil in winter.
  Gingely oil, also known as sesame oil, is high in unsaturated fats, which have lower melting points and remain liquid at lower temperatures compared to saturated fats. This statement is correct.
• Statement (d): Lipids are generally insoluble in water but soluble in some organic solvents.
  This is a characteristic property of lipids. They are hydrophobic and do not dissolve in water but are soluble in organic solvents like ethanol and chloroform. This statement is correct.
• Statement (e): When fatty acid is esterified with glycerol, monoglycerides are formed.
  When one molecule of fatty acid is esterified with glycerol, a monoglyceride is indeed formed. This statement is correct.

Based on the evaluation:

• Correct Statements: (c), (d), and (e)

The correct answer is:

To verify the two statements, let us analyze each one based on biological principles.

Statement I: It asserts that low temperature keeps an enzyme inactive while high temperature denatures enzyme proteins, thereby destroying their activity. Enzymes are proteins which can be affected by temperature changes. At low temperatures, enzyme activity is reduced because molecules move slower and have less kinetic energy, temporarily inactivating the enzyme. Conversely, at high temperatures, the heat causes the enzymes to denature, altering their structure and rendering them nonfunctional. Therefore, Statement I is true.

Statement II: It posits that when an inhibitor resembles the substrate's molecular structure and inhibits enzyme activity, it is known as a competitive inhibitor. Competitive inhibitors compete with the substrate for the active site of the enzyme because of their structural similarity. This type of inhibition can be overcome by increasing substrate concentration. Hence, Statement II is also true.

Conclusion: Based on the analysis, both statements are true.

Melonate inhibits the growth of pathogenic bacteria by inhibiting the activity of Succinic dehydrogenase.

Succinic dehydrogenase, also known as succinate dehydrogenase or succinate-coenzyme Q reductase, is an enzyme involved in the electron transport chain and the tricarboxylic acid (TCA) cycle in bacteria. It catalyzes the conversion of succinate to fumarate, playing a crucial role in energy production.

Melonate is a competitive inhibitor of succinic dehydrogenase. It structurally resembles succinate and competes with it for binding to the active site of the enzyme. By binding to and inhibiting succinic dehydrogenase, melonate disrupts the normal functioning of the TCA cycle and electron transport chain, leading to a decrease in ATP production and inhibiting the growth of pathogenic bacteria.

Therefore, the correct option is (D): Succinic dehydrogenase