Biology · Chemistry

Biomolecules and Enzymes

1,501 Questions

This topic focuses on biomolecules, specifically proteins, enzymes, and amino acids. It includes questions on enzyme structures, protein folding, and catalysis. These concepts are crucial for medical and biology competitive exams.

Enzyme catalysisProtein structuresAmino acid synthesisPolypeptide chainsBiomolecule properties

Biomolecules and Enzymes Questions

Multiple choice evs food trends types of ecological pyramids the muscular system and digestive system in human beings introduction to human digestive system

How many of the enzymes given below in block belong to brush border enzymes?
Multase, Nucleosidase, Enterokinase, Amylopsin, Steapsin, Nucleases, Erepsin, Carboxypeptidase, Lactase, Aminopeptidase

  1. Six

  2. Seven

  3. Five

  4. Four
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation

The brush borders of the intestinal lining are the site of terminal carbohydrate digestions. The microvilli that constitute the brush border have enzymes for this final part of digestion anchored into their apical plasma membrane as integral membrane proteins. Maltase, lactase, erepsin, nucleosidase are the brush border enzymes.

So, the correct option is 'four'.

Multiple choice zoology endocrine system and chemical co-ordination classification of hormones endocrine system and hormone hormones and metabolism

Identify the incorrect pair.

  1. Fatty acid- Insulin

  2. Glucose- Chitin

  3. Thymine- Nucleotide

  4. Amino acid- Hemoglobin

  5. Nitrogen- Uric acid
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

Chitin is a polymer of N-acetyl glucosamine which in turn is a derivative of glucose. 

Thymine one of the purine (nitrogenous base) that makes deoxyribonucleotide units of DNA. 
Hemoglobin has four protein subunits, two alpha-globin and two beta-globin. Uric acid is a heterocyclic compound of CHON. 
Insulin is a protein hormone secreted by the pancreas.
So, the correct answer is option A.

Multiple choice zoology endocrine system and chemical co-ordination classification of hormones endocrine system and hormone hormones and metabolism

When all the peptide bonds of a protein have been broken down, the result would be

  1. Polypeptides

  2. Oligopeptides

  3. Peptides

  4. Amino acids
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation

Proteins are polymers of amino acids linked by peptide bonds. Complete hydrolysis (breaking all peptide bonds) results in the constituent amino acids.

Multiple choice zoology endocrine system and chemical co-ordination classification of hormones endocrine system and hormone hormones and metabolism

Biogenic amines are synthesized from

  1. Tryptophan

  2. Tyrosine

  3. Glutamic acid

  4. Phenylalanine
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation
Amines are the compounds that contain an amine group. They are formed as a result of deamination, a process in which amino group is removed from the amino acid. Some hormones like epinephrine and norepinephrine are amines. They are derived from amino acid tyrosine. 
So, the correct answer is 'Tyrosine'.
Multiple choice zoology endocrine system and chemical co-ordination classification of hormones endocrine system and hormone hormones and metabolism

Which among the following amino-acids is not essentially required for health?

  1. Cystenine

  2. Leucine

  3. Phenylalanine

  4. Tyrosin
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

Cysteine is a nonessential amino acid (protein building block), meaning that cysteine can be made in the human body. Cysteine is one of the few amino acids that contains sulfur . Cysteine is a component of the antioxidant glutathione . The body also uses cysteine to produce taurine , another amino acid. So, the correct option is "A" (Cystenine).

Multiple choice

At what isoelectric point do caseins precipitate?

  1. pH 8.1

  2. pH 4.6

  3. pH 5.2

  4. pH 7.5
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

The isoelectric point is the pH at which a protein has no net charge and becomes least soluble. For casein, this occurs at a pH of 4.6, which is why milk curdles when it becomes acidic.

Multiple choice zoology applications of biotechnology biotechnological regulations pcr asexual modes of reproduction

Maize hybrids have been developed for higher amount of

  1. Lysine

  2. Leucine

  3. Methionine

  4. Cysteine
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation
  • Maize hybrids with higher lysine content were developed to improve the protein in corn.
  • This hybrid maize provides substantially higher levels of two essential amino acids - Lysine and tryptophan.
  • So the correct answer is 'Lysine'
Multiple choice chemistry surface chemistry enzyme catalysis catalysis proteins and enzymes

Identify the correct statement regarding enzymes.

  1. Enzymes are specific biological catalysts that possess well defined active sites.

  2. Enzymes are normally heterogeneous catalysts that are very specific in their action.

  3. Enzymes are specific biological catalysts that cannot be poisoned.

  4. Enzymes are specific biological catalysts that can normally function at very high temperature (T=1000K).
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

  • Enzyme catalysis is unique in its efficiency and a high degree of specificity.

There are various characteristics are exhibited by enzyme catalysts-
  • Most highly efficient: One molecule of an enzyme may transform one million molecules of the reactant per minute.

  • Highly specific nature: Each enzyme is specific for a given reaction, i.e., one catalyst cannot catalyse more than one reaction. 

  • Highly active under optimum temperature: The rate of an enzyme reaction becomes maximum at a definite temperature, called the optimum temperature.

  • Highly active under optimum pH: The rate of an enzyme-catalysed reaction is maximum at a particular pH called optimum pH, which is between pH values 5-7.

  • Enzymes are normally homogeneous catalysts.

Hence, options A is the correct answers

          Multiple choice chemistry surface chemistry enzyme catalysis catalysis proteins and enzymes

          Some drugs do not bind the enzyme's active site, instead, bind to a different site of an enzyme. This site is called:

          1. allosteric site

          2. substrate site

          3. ionic site

          4. competitive site
          Reveal answer Fill a bubble to check yourself
          A Correct answer
          Explanation

          A substance produced by a living organism which acts as a catalyst to bring about a specific biochemical reaction.

          In their catalytic activity, enzymes perform two major functions:

          (i) The first function of an enzyme is to hold the substrate for a chemical
          reaction. Active sites of enzymes hold the substrate molecule in a
          suitable position, so that it can be attacked by the reagent effectively.
          (ii) The second function of an enzyme is to provide functional groups
          that will attack the substrate and carry out chemical reaction.
           Drugs inhibit any of the above mentioned activities of enzymes.
          Drugs inhibit the attachment of substrate on active site of enzymes
          in two different ways;
          (i) Drugs compete with the natural substrate for their attachment
          on the active sites of enzymes. Such drugs are called competitive
          inhibitors.
          (ii) Some drugs do not bind to the enzyme’s active site. These bind to a different site of enzyme which is called allosteric site. This binding of inhibitor at allosteric site changes the shape of the active site in such a way that substrate cannot
          recognise it.

          Multiple choice chemistry surface chemistry enzyme catalysis catalysis proteins and enzymes

          Which of the following is true?

          1. Enzymes are non - proteinaceous nitrogen containing compounds.

          2. Amylase convert starch into amylose.

          3. Biocatalysts, catalyse the reaction occurring in living beings.

          4. Enzymes are not found in plants.
          Reveal answer Fill a bubble to check yourself
          C Correct answer
          Explanation

          Enzymes are biological catalysts that speed up biochemical reactions occurring in living organisms. Most enzymes are proteinaceous in nature (though some are RNA ribozymes), and they are widely found in both plants and animals. Option C accurately describes their fundamental role as biocatalysts.

          Multiple choice chemistry surface chemistry enzyme catalysis catalysis proteins and enzymes

          Which statement about enzymes is not correct?

          1. Enzymes are in colloidal state.

          2. Enzymes are catalysts.

          3. Enzymes can catalyse any reaction.

          4. Urease is an enzymes.
          Reveal answer Fill a bubble to check yourself
          C Correct answer
          Explanation

          Enzymes are proteins and are giant molecules making them colloidal particles. They are shape selective and catalyzes a specific reaction in which they are suitable.  But they cannot catalyze any reaction.

          Urease is an enzyme and catalyzes the hydrolysis of urea to ammonia and carbon dioxide.

          Multiple choice chemistry surface chemistry enzyme catalysis catalysis proteins and enzymes

          Identify the correct statement regarding enzymes.

          1. Enzymes are specific biological catalyst that possess well defined active state.

          2. Enzymes are normally heterogeneous catalyst that are very specific in their action.

          3. Enzymes are specific biological that cannot be poisoned.
          4. Enzymes are specific biological catalyst that can normally function at very high temperature $ ( T \simeq 1000 K).$
          Reveal answer Fill a bubble to check yourself
          A Correct answer
          Explanation
          Enzyme Catalysis - These are catalysts in the living system. Enzymes are substances which by their their presence, alter the rate of anybiological event. These are mainly proteins, and enzyme action is structure specific.
          Enzyme catalysis is the increase in the rate of a chemical reaction by the active site of a protein. The protein catalyst (enzyme) may be part of a multi-subunit complex, and/or may transiently or permanently associate with a Cofactor (e.g. adenosine triphosphate). 
          Catalysis of biochemical reactions in the cell is vital due to the very low reaction rates of the uncatalysed reactions. A key driver of protein evolution is the optimization of such catalytic activities via protein dynamics.
          They decrease activation energy by providing alternate pathway (enzyme reacts with the substrate to form an intermediate ES complex, which would be impossible in the absence of the enzyme) for the process.
          Multiple choice chemistry surface chemistry enzyme catalysis catalysis proteins and enzymes

          Enzymes are ____ specific in action.

          1. highly

          2. not

          3. may be

          4. may not
          Reveal answer Fill a bubble to check yourself
          A Correct answer
          Explanation

          Enzymes are highly specific in action.
          Almost every biochemical reaction is controlled by its own specific enzymes.
          Thus, the enzyme urease catalyzes the hydrolysis of urea. No other enzyme catalyzes this reaction.

          Multiple choice chemistry surface chemistry enzyme catalysis catalysis proteins and enzymes

          Active sites are essential for enzyme action.

          1. True

          2. False
          Reveal answer Fill a bubble to check yourself
          A Correct answer
          Explanation
          The active site is the region of an enzyme where substrate molecules bind and undergo a chemical reaction. The active site consists of residues that form temporary bonds with the substrate (binding site) and residues that catalyse a reaction of that substrate (catalytic site).
          Thus, the active site of the enzyme is responsible for its catalytic action. Thus it is essential for enzyme action.