Biomolecules MCQ Quiz in मल्याळम - Objective Question with Answer for Biomolecules - സൗജന്യ PDF ഡൗൺലോഡ് ചെയ്യുക

The correct answer is It serves as a part of the enzyme's active site

Concept:

Cofactors are non-protein chemical compounds or metallic ions that are required for an enzyme's biological activity to occur. Cofactors can be broadly categorized into three main types:-

• Prosthetic Groups: Tightly bound, integral to the enzyme (Haem, FAD, Biotin).
• Coenzymes: Loosely bound, temporary carriers (NAD+, Coenzyme A, TPP).
• Metal Ions: Can be loosely or tightly bound, involved in structural and catalytic roles (Zinc, Magnesium, Iron).

Explanation:

• Prosthetic groups are organic compounds and are distinguished from other cofactors in that they are tightly bound to the apoenzyme.
• For example, in peroxidase and catalase, which catalyze the breakdown of hydrogen peroxide to water and oxygen, haem is the prosthetic group and it is a part of the active site of the enzyme.

The correct answer is Statement 1 is true, but Statement 2 is false.

Concept:

• Ligases: These are enzymes that catalyze the joining of two molecules by forming new chemical bonds, such as C-O, C-S, or C-N, often requiring energy in the form of ATP.
• Hydrolases: These are enzymes that catalyze the hydrolysis of various bonds, involving the addition of water (H₂O) to break the bond. These are the enzymes that catalyze the hydrolysis of ester, ether, peptide, glycosidic, C-C, C-halide or P-N bonds.
• Lyases: These are enzymes that catalyze the removal of groups from substrates by mechanisms other than hydrolysis, typically forming double bonds.

Explanation:

• Statement 1: Ligases catalyze the joining of two compounds by forming bonds such as C-O, C-S, or C-N, which is true.
• Statement 2: Hydrolases do not catalyze the removal of groups by mechanisms other than hydrolysis. Instead, they catalyze the hydrolysis of various bonds. The enzymes that remove groups leaving double bonds are lyases. Therefore, Statement 2 is false.

The correct answer is 35° - 40°C

Explanation:-

• Enzymes are biological catalysts that speed up chemical reactions within living organisms. They are highly sensitive to temperature changes, and their activity is influenced by temperature.
• Enzymes have an optimal temperature range within which they function most efficiently.
• Enzymes are most functional within a moderate temperature range around the normal physiological temperature of the organism. For many enzymes found in human cells and most mesophilic organisms, the optimal temperature range is approximately 35°C to 40°C.
• At temperatures below this range, enzyme activity decreases as the rate of chemical reactions slows down.
• Conversely, at temperatures above this range, enzyme activity also decreases due to denaturation, where the enzyme's structure is disrupted, rendering it non-functional.

Conclusion:- 35° - 40°C is the most suitable temperature range for enzymes to be most functional.

Key Points

• Deoxyribonucleic acid or DNA is a polynucleotide of deoxyribonucleotides.
• Thus nucleotides are the basic units of these molecules.
• A nucleotide has 3 components -

1. Pentose sugar - It is ribose in RNA and deoxyribose in DNA.
2. Nitrogenous base - It is a nitrogen-containing molecule with the properties of a base. It is of 2 types: 
   1. Purine - It includes Adenine (A) and Guanine (G).
   2. Pyrimidine - It includes Cytosine (C), Thymine (T) and Uracil (U).
3. Phosphate group

​Explanation:

• Thymine is present only in DNA and gets replaced by Uracil in RNA.
• Therefore, a DNA strand will contain A, T, G and C bases, while RNA will contain A, U, G and C.
• Nucleoside -
  • It is formed when a nitrogenous base is linked to the pentose sugar by N-glycosidic linkage.
  • The nucleosides are named as deoxyadenosine, deoxyguanosine, deoxycytidine or deoxythymidine, depending on the nitrogenous base.
• ​Nucleotide -
  • ​It is formed when a phosphate group is linked to the 5'-OH of a nucleoside.
  • The linkage present is phosphoester linkage.

Correct Answer: Option 3

Concept:

• Enzymes are biological catalyst that increases the rate of a chemical reaction. Enzymes lower the activation energy and thus increase the rate of the reaction.
• The substance on which an enzyme acts is called a substrate.
• Examples of enzymes: Lipase acts on lipid molecules, Maltase acts on maltose, Invertase acts on sucrose (breaks down sucrose into glucose and fructose), etc.

Explanation:

• Apoenzyme: It is the protein part of an active enzyme. It is in an inactive state. The binding of another group of non-protein compounds activates the apoenzyme.
• Cofactor: Some enzymes require the binding of a non-protein compound for its activation. These compounds are called cofactors. In the absence of a cofactor, the enzyme remains in the inactive state - apoenzyme.
  • Vitamins, zinc ions, iron ions, etc. are some examples of cofactors
  • There are two basic groups of cofactors - the prosthetic group and the coenzymes.
• Prosthetic group: The cofactors that bind firmly to the apoenzyme are called prosthetic groups. These groups do not get modified during an enzymatic reaction. Eg: Heme in hemoglobin is an example of a prosthetic group.
• Coenzyme: The cofactor that is loosely bound to an apoenzyme are called coenzymes. These groups get modified during an enzymatic reaction.                             Eg: ATP is an important coenzyme in the human body.
• Holoenzyme: Holoenzyme is an active enzyme that is formed of an apoenzyme and a cofactor (coenzyme).

• Option 1: Holoenzyme = Coenzyme + Cofactor - INCORRECT
  • Holoenzyme is made up of a protein molecule (apoenzyme) and a non-protein moelcule (cofactor/coenzyme).
• Option 2: Apoenzyme = Holoenzyme + Coenzyme - INCORRECT
  • ​Apoenzyme is the inactive part of a holoenzyme (active state) which when bound with coenzyme gets activated.
• Option 3: Holoenzyme = Apoenzyme + Coenzyme - CORRECT
  • ​Holoenzymes are active enzymes that are formed by the binding of an apoenzyme with a coenzyme.
• Option 4: Coenzyme = Apoenzyme + Holoenzyme - INCORRECT
  • ​Coenzymes are non-protein molecule that when bound with an apoenzyme activates it forming a holoenzyme.

So the correct answer is option 3.

Correct answer: 1)

Concept:

• Hormones are chemical messengers that are secreted in small quantities.
• Endocrine glands secrete hormones.
• Endocrine glands are ductless glands, and they secrete hormones directly into the bloodstream.

Explanation:

Option 1:

• Epinephrine also known as adrenaline is an amino acid derivative hormone. It is produced by the adrenal glands.
• It is known as an emergency hormone that is released during fear, fight, or flight. So, it is known as the 3F hormone.

Option 2:

• Ecdysone is a steroid hormone produced by some insects and by some other arthropods.
• Insects shed their exoskeleton as they grow, this is known as ecdysis or molting.
• Ecdysis is regulated by the hormone ecdysone.
• This hormone is secreted by corpora allata.

Option 3:

• Estriol is also a steroid hormone that works as a weak estrogen.
• It is one of the major endogenous estrogens.
• This hormone is important for pregnancy and also helps in labor and delivery.

Option 4:

• Estradiol is also a steroid hormone. It is also the type of estrogen involved in regulating the menstrual cycle and maintaining the reproductive system of females.
• This hormone is present in the female body throughout her reproductive years.

So, the correct answer is option 1.

The correct answer is Iodine.

Note: As per the official answer key, the given answer is Potassium but in actual the correct answer would be Iodine because the thyroid gland requires iodine to produce the hormone thyroxine (T4)

Key Points

• The thyroid gland requires iodine to produce the hormone thyroxine (T4).
• Thyroxine plays a crucial role in regulating metabolism, growth, and development.
• Iodine deficiency can lead to thyroid-related issues such as goiter and hypothyroidism.
• Seafood, dairy products, and iodized salt are good sources of dietary iodine.
• The recommended daily intake of iodine varies by age, gender, and physiological status (e.g., pregnancy).

Additional Information

• Sodium
  • Essential for maintaining fluid balance and nerve function.
  • Commonly found in table salt and processed foods.
• Calcium
  • Vital for bone health and muscle function.
  • Found in dairy products, leafy greens, and fortified foods.
• Potassium
  • Important for heart function and muscle contraction.
  • Present in bananas, oranges, and potatoes.

The correct answer is A- iv, B-iii, C- ii, D-i

Explanation:

• A. Arachidonic acid -iv. Unsaturated fatty acid:-  Arachidonic acid is a long-chain polyunsaturated fatty acid with 20 carbons and 4 cis double bonds. It is a precursor in the biosynthesis of various eicosanoids, which are signaling molecules involved in inflammation and other physiological functions.
• B. Cellulose -iii. Negative iodine test): Cellulose is an unbranched polymer of glucose linked by β(1→4) glycosidic bonds. It does not form a colored complex with iodine, thus showing a negative iodine test. This property distinguishes it from starch and glycogen.Cellulose does not contain complex helices and hence cannot hold I₂.
• C. Palmitic acid -ii. Saturated fatty acid: Palmitic acid is a saturated fatty acid (C16:0), found in both animals and plants. 
• D. Starch- i. Positive iodine test): Starch is a polysaccharide formed by glucose units, primarily consisting of amylose and amylopectin. Amylose, due to its helical structure, reacts with iodine to produce a characteristic blue-black color, indicating a positive iodine test. 

The correct answer is Cysteine

Explanation:

Heterocyclic rings are rings that contain atoms of at least two different elements as members of their ring(s)

• Cytosine: Cytosine is one of the four main nitrogenous bases found in DNA and RNA. It has a heterocyclic ring structure.
• Cytidine: Cytidine is a nucleoside comprising the base cytosine attached to a ribose sugar, and thus contains a heterocyclic ring.
• Cysteine: Cysteine is an amino acid. It does not have a heterocyclic ring in its structure; its structure includes a linear chain with a thiol group.
• Uridine: Uridine is a nucleoside consisting of the base uracil attached to a ribose sugar, and thus contains a heterocyclic ring.

Therefore, the correct answer is Cysteine

The correct answer is A-II, B-IV, C-I, D-III

Explanation:

A. Lipase - II. Ester bond

• Lipase is an enzyme that catalyzes the breakdown of fats (lipids) into glycerol and fatty acids. This process involves the hydrolysis of ester bonds within the lipid molecules.

B. Nuclease - IV. Phosphodiester bond

• Nucleases are enzymes that cleave the phosphodiester bonds between nucleotides in nucleic acids (DNA and RNA). This results in the breakdown of the nucleic acid polymers into shorter fragments or individual nucleotides.

C. Protease - I. Peptide bond

• Proteases are enzymes that catalyze the hydrolysis of peptide bonds in proteins. This leads to the degradation of proteins into smaller peptides or amino acids.

D. Amylase - III. Glycosidic bond

• Amylase is an enzyme that catalyzes the hydrolysis of glycosidic bonds in starches (polysaccharides), breaking them down into simpler sugars like maltose or glucose.