Enzymes and Hormones Questions in English

(C) The hydrolysis of maltose into glucose is catalyzed by the enzyme $Maltase$. The reaction is as follows:
$C_{12}H_{22}O_{11} (maltose) + H_2O \xrightarrow{Maltase} 2C_6H_{12}O_6 (glucose)$.

(C) Enzymes are biological catalysts that are highly specific in nature. They do not catalyze any reaction; rather,each enzyme is specific to a particular substrate or reaction. Therefore,the statement that 'Enzymes are catalyzed in any reaction' is incorrect.

(C) Enzymes are biological catalysts that speed up biochemical reactions in living organisms by lowering the activation energy. Therefore,they catalyze biochemical reactions.

(C) Enzymes are biological catalysts that speed up biochemical reactions in living organisms.
Chemically,almost all enzymes are $Globular \ proteins$ that have a specific three-dimensional structure required for their catalytic activity.

(D) Enzymes are highly active at their optimum temperature. Therefore,the statement that they are least active at optimum temperature is incorrect.

(A) Enzymes are biological catalysts that are almost exclusively composed of proteins. They speed up biochemical reactions in living organisms by lowering the activation energy.

(B) Insulin is a hormone secreted by the pancreas. It promotes the conversion of glucose into glycogen in the liver,a process known as glycogenesis,which helps in lowering blood glucose levels.

(D) Enzymes are highly specific biological catalysts that lower the activation energy of biochemical reactions,making them proceed efficiently at physiological temperatures.

(B) Oxytocin is a peptide hormone consisting of $9$ amino acids. It is produced in the hypothalamus and stored in the posterior pituitary gland. It plays a crucial role in childbirth and lactation.

(B) Hormones are not produced continuously; they are synthesized by the body according to its requirements.

(B) Insulin is a peptide hormone produced by the beta cells of the pancreatic islets. It plays a crucial role in regulating the metabolism of carbohydrates,fats,and proteins by promoting the absorption of glucose from the blood into liver,fat,and skeletal muscle cells. Therefore,it is classified as a hormone.

(A) The conversion of glucose into ethanol is a fermentation process catalyzed by the enzyme $Zymase$.
The chemical reaction is:
$C_6H_{12}O_6 \xrightarrow{Zymase} 2C_2H_5OH + 2CO_2$
Therefore,the correct option is $A$.

(D) Louis Pasteur was the first to conduct a scientific study of fermentation.

(D) Organic catalysts,also known as enzymes,are proteinous in nature and are derived from living cells,whereas inorganic catalysts are typically metals or metal oxides.

(D) Most enzymes are proteinous in nature.
They are highly specific in their action.
They get denatured by high temperatures or $UV$ rays.
At the optimum temperature,enzyme activity is at its maximum,not minimum.

(C) Adrenaline is known as the emergency hormone.
It is released during stress conditions.
It stimulates glycogenolysis in the liver,which leads to the release of glucose into the bloodstream to provide energy for the 'fight or flight' response.

(C) Thyroxine is $3, 5, 3', 5'$-tetraiodothyronine. It is secreted by the follicular cells of the thyroid gland. The structure is shown below:
$HO-C_6H_2I_2-O-C_6H_2I_2-CH(NH_2)COOH$
Thyroxine stimulates the consumption of oxygen and thus,the metabolism of all cells or tissues in the body.

(C) Amine hormones are derived from amino acids. $Thyroxine$ is an amine hormone,which is an iodinated derivative of the amino acid tyrosine.
It is secreted by the thyroid gland.
Its primary function is to regulate the metabolism of carbohydrates,proteins,and lipids in the body.

(D) In the process of digestion,the proteins present in food material are hydrolysed to amino acids.
In this process,two enzymes,$pepsin$ and $trypsin$,are involved as follows:
$Proteins$ $\xrightarrow{Pepsin \ (A)} Polypeptides$ $\xrightarrow{trypsin \ (B)} Amino \ acids$

(B) Glucagon is a peptide hormone because it consists of a chain of $29$ amino acids linked by peptide bonds.
Adrenaline is an amino acid derivative.
Testosterone is a steroid hormone.
Thyroxine is an iodinated amino acid derivative.

(B) The conversion of glucose into ethyl alcohol is catalyzed by the enzyme $Zymase$,not $Diastase$.
$Diastase$ is used for the conversion of starch into maltose.
Therefore,the match in option $B$ is $INCORRECT$.

(A) Maltase catalyzes the hydrolysis of the disaccharide maltose into the simple sugar glucose.
Maltase is secreted by the intestine,as some portion of starch is transformed into maltose by pancreatic or salivary enzymes called amylase during food digestion.

(A) Maltose is obtained by the partial hydrolysis of starch using the enzyme $Diastase$,which is present in malt.
The chemical reaction is:
$2(C_6H_{10}O_5)_n + nH_2O \xrightarrow{Diastase} nC_{12}H_{22}O_{11} \text{ (Maltose)}$

(A) . Allosteric effect: $A$ molecule binds to a site other than the active site of the enzyme,changing its shape. Thus,$A \to R$.
$B$. Competitive inhibitor: $A$ molecule competes with the substrate for the active site of the enzyme. Thus,$B \to P$.
$C$. Receptor: These are proteins crucial for chemical communication in the body. Thus,$C \to Q$.
$D$. Poison: These molecules often bind to the enzyme covalently,inhibiting its activity. Thus,$D \to S$.
Therefore,the correct match is $A \to R, B \to P, C \to Q, D \to S$.

(C) The function of enzymes in the living system is to catalyse biochemical reactions.
Enzymes are highly substrate-specific and catalyze reactions by providing an alternate pathway of lower activation energy.

(A) Insulin is a peptide hormone produced by the $\beta$-cells of the pancreatic islets. It plays a crucial role in regulating blood glucose levels by promoting the uptake of glucose into cells and stimulating glycogenesis,which is the conversion of glucose into glycogen for storage in the liver and muscles.

(C) Proteolytic enzymes are enzymes that break down proteins into smaller polypeptides or amino acids. $Pepsin$ is a well-known proteolytic enzyme found in the stomach that initiates the digestion of proteins. $Insulin$ is a hormone,$Diastase$ is an amylolytic enzyme (breaks down starch),and $Adenine$ is a nitrogenous base.

(C) Enzymes are biological catalysts that are highly specific in their action $(ii)$.
They function by providing an alternative pathway with lower activation energy for the reaction $(iii)$.
Pepsin is a well-known proteolytic enzyme that breaks down proteins into peptides $(iv)$.
Enzymes possess various functional groups,including nucleophilic groups (like $-OH, -SH, -NH_2$) in their active sites,which participate in the catalytic mechanism. Therefore,statement $(i)$ is incorrect.

(C) Many enzymes require a non-protein component for their activity,which is known as a cofactor. If this non-protein part is tightly bound to the apoenzyme (the protein part),it is specifically called a $Prosthetic \ group$.

(A) The enzyme $Pepsin$ is a digestive protease found in the stomach.
It catalyzes the hydrolysis of $Proteins$ into smaller peptides and $Amino \ acids$.

(A) Enzymes are biological catalysts that are primarily proteinaceous in nature.
They exhibit maximum activity at the physiological temperature of the body (approximately $37^{\circ}C$).
While some enzymes may contain non-protein components (cofactors),they are not classified as carbohydrates or nucleic acids.
Therefore,the statement that they show maximum activity at body temperature is the correct characteristic.

(B) Enzymes are biological catalysts that are primarily composed of proteins.
Proteins are polymers of amino acids linked by peptide bonds.
Therefore,enzymes are classified as polypeptides or proteins.

(A) The hormone $Adrenaline$ (also known as $Epinephrine$) is secreted by the adrenal medulla in response to stress,fear,or excitement. It prepares the body for a $fight-or-flight$ response by increasing heart rate,blood pressure,and blood glucose levels. Therefore,it is commonly referred to as the $fight-or-flight$ hormone.

(B) $Insulin$ is a peptide hormone produced by the beta cells of the pancreatic islets. It plays a crucial role in regulating blood glucose levels by facilitating the uptake of glucose into cells,thereby lowering blood sugar levels.

(C) The hormone $Thyroxine$,secreted by the thyroid gland,plays a crucial role in regulating the basal metabolic rate $(BMR)$ of the body. It controls the metabolism of carbohydrates,proteins,and fats,thereby maintaining energy balance and growth.

(D) The male sex hormone is $Testosterone$.
$Progesterone$ and $Estrone$ are female sex hormones.
$Epinephrine$ is a hormone secreted by the adrenal medulla involved in the fight-or-flight response.
Therefore,the correct option is $D$.

(A) The hormone $Insulin$ is secreted by the pancreas. It plays a crucial role in regulating blood glucose levels by promoting the uptake of glucose by cells and stimulating the conversion of excess glucose into glycogen in the liver and muscles,a process known as glycogenesis.

(A) The enzyme $Diastase$ is responsible for the hydrolysis of starch into maltose.
The reaction is: $2(C_6H_{10}O_5)_n + nH_2O \xrightarrow{Diastase} nC_{12}H_{22}O_{11}$ (Maltose).

(B) The activity of an enzyme is highly $pH$ dependent because enzymes are proteins,and their tertiary structure (which determines their active site) is maintained by ionic and hydrogen bonds that are sensitive to $pH$ changes.
When the $pH$ changes,these bonds break,leading to denaturation of the enzyme and loss of catalytic activity.
While it is true that $pH$ can affect the solubility of proteins (as they are least soluble at their isoelectric point),this is not the primary reason why enzyme activity is $pH$ dependent.
Therefore,both statements are correct,but the reason does not explain the assertion.

(N/A) Enzymes are complex,nitrogenous organic compounds produced by living plants and animals. They are essentially protein molecules of high molecular mass that form colloidal solutions in water. They are also known as 'biochemical catalysts'.
Mechanism of enzyme catalysis:
$1$. Binding: The surface of an enzyme contains cavities with characteristic shapes,which possess active groups such as $-NH_2$,$-COOH$,etc.
$2$. Complex Formation: Reactant molecules (substrates) with a complementary shape fit into these cavities,similar to how a key fits into a lock,forming an enzyme-substrate $(ES)$ complex.
$3$. Product Formation: The $ES$ complex then decomposes to yield the product and regenerate the enzyme.
This process is represented as:
$E + S \rightleftharpoons ES \rightarrow E + P$
(Where $E$ = Enzyme,$S$ = Substrate,$ES$ = Enzyme-Substrate complex,$P$ = Product)

(N/A) Enzymes are biocatalysts,which are primarily proteins that accelerate biological reactions. They are highly specific in nature and catalyze only a particular reaction for a specific substrate. Enzymes are typically named after the substrate or class of substrate they act upon,and sometimes after the reaction they catalyze.
For example,the enzyme that catalyzes the hydrolysis of maltose into glucose is named maltase.
$\underset{\text{Maltose}}{C_{12}H_{22}O_{11}} + H_2O$ $\xrightarrow{\text{Maltase}} \underset{\text{Glucose}}{2C_6H_{12}O_6}$
Similarly,enzymes that catalyze the oxidation of one substrate coupled with the reduction of another are called oxidoreductases.
The name of an enzyme typically ends with the suffix '$-ase$'.

(N/A) Enzymes are globular proteins that act as biocatalysts in living systems. Life is possible due to various chemical reactions in living organisms,such as the digestion of food,absorption of molecules,and energy production. These processes involve sequences of reactions occurring under mild conditions with the help of enzymes.
Enzymes are highly specific for a reaction and a substrate. They are generally named after the compound or class of compounds upon which they work. For example,the enzyme that catalyses the hydrolysis of maltose into glucose is named maltase:
$C_{12}H_{22}O_{11} \xrightarrow{\text{Maltase}} 2C_6H_{12}O_6$
Sometimes,enzymes are named after the reaction they catalyse. For example,enzymes that catalyse the oxidation of one substrate with the simultaneous reduction of another are called oxidoreductases. The name of an enzyme typically ends in $-ase$.
Mechanism: Enzymes are required in small quantities. Similar to chemical catalysts,enzymes reduce the magnitude of activation energy. For example,the activation energy for the acid hydrolysis of sucrose is $6.22 \ kJ \ mol^{-1}$,whereas it is only $2.15 \ kJ \ mol^{-1}$ when catalysed by the enzyme sucrase.

(N/A) For understanding the interaction between a drug and an enzyme,it is important to know how enzymes catalyse the 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. Substrates bind to the active site of the enzyme through a variety of interactions such as ionic bonding,hydrogen bonding,van der Waals interaction,or dipole-dipole interaction.
$(ii)$ The second function of an enzyme is to provide functional groups that will attack the substrate and carry out the chemical reaction.
Macromolecules of biological origin that perform various functions in the body are called enzymes; those which are crucial to the communication system in the body are called receptors.

Enzymes are complex nitrogenous organic compounds produced by living plants and animals. They are protein molecules of high molecular mass that form colloidal solutions in water.
They act as highly efficient catalysts for numerous reactions,especially those associated with natural biological processes. Because they catalyze reactions within living organisms,they are termed biochemical catalysts,and the phenomenon is known as biochemical catalysis.
Examples of enzyme-catalyzed reactions:
$(i)$ Inversion of cane sugar: The enzyme invertase converts cane sugar into glucose and fructose.
$C_{12}H_{22}O_{11(aq)} + H_2O_{(l)} \xrightarrow{\text{Invertase}} C_6H_{12}O_{6(aq)} + C_6H_{12}O_{6(aq)}$
$(ii)$ Conversion of glucose into ethyl alcohol: The enzyme zymase converts glucose into ethyl alcohol and carbon dioxide.
$C_6H_{12}O_{6(aq)} \xrightarrow{\text{Zymase}} 2C_2H_5OH_{(aq)} + 2CO_{2(g)}$
$(iii)$ Conversion of starch into maltose: The enzyme diastase converts starch into maltose.
$2(C_6H_{10}O_5)_{n(aq)} + nH_2O_{(l)} \xrightarrow{\text{Diastase}} nC_{12}H_{22}O_{11(aq)}$
$(iv)$ Decomposition of urea: The enzyme urease catalyzes the decomposition of urea into ammonia and carbon dioxide.
$NH_2CONH_{2(aq)} + H_2O_{(l)} \xrightarrow{\text{Urease}} 2NH_{3(g)} + CO_{2(g)}$

(N/A) There are a number of cavities present on the surface of colloidal particles of enzyme. These cavities are of characteristic shape and possess active groups such as $-NH_2$,$-COOH$,$-SH$,$-OH$,etc. These are actually the active centres on the surface of enzyme particles. The molecules of the reactant which have complementary shape,fit into these cavities like a key fits into a lock. On account of the presence of active groups,an activated complex is formed which then decomposes to yield the products.
Thus,the enzyme catalysed reactions may be considered to proceed in two steps.
Step-$1$: Binding of enzyme to substrate to form an activated complex.
$E + S \rightleftharpoons ES^{*}$
Step-$2$: Decomposition of the activated complex to form product.
$ES^{*} \rightarrow E + P$

(N/A) Yes,the vital functions of the body such as digestion are affected during fever.
Enzymes are biological catalysts that are most active at an optimum body temperature of approximately $37^{\circ}C$.
During fever,the body temperature rises above this optimum level.
This increase in temperature leads to the denaturation or reduced efficiency of enzymes,which disrupts the normal biochemical reactions,including the digestion process.

(N/A) The enzymes $Invertase$ and $Zymase$ are used to prepare ethanol from sucrose by fermentation.
Step $1$: Hydrolysis of sucrose into glucose and fructose by $Invertase$.
$C_{12}H_{22}O_{11} + H_{2}O$ $\xrightarrow{\text{Invertase}} C_{6}H_{12}O_{6} (\text{glucose}) + C_{6}H_{12}O_{6} (\text{fructose})$
Step $2$: Conversion of glucose/fructose into ethanol by $Zymase$.
$C_{6}H_{12}O_{6} \xrightarrow{\text{Zymase}} 2C_{2}H_{5}OH + 2CO_{2}$

(N/A) Hormones are molecules that act as intercellular messengers. They are secreted by endocrine glands in the body,poured directly into the bloodstream,and transported to the site of action.
Classification: Chemically,hormones are classified as steroid hormones,peptide hormones,and amine hormones.
$i$. Peptide hormones: Examples include insulin and endorphins. Insulin maintains blood sugar levels by responding to glucose spikes,while glucagon increases blood glucose levels. Together,they regulate glucose homeostasis.
$ii$. Amine hormones: Examples include epinephrine and norepinephrine,which mediate responses to external stimuli. Thyroxine,an iodinated derivative of the amino acid tyrosine,regulates metabolism. Low levels cause hypothyroidism (lethargy,obesity),while high levels cause hyperthyroidism. Iodine deficiency leads to goiter,which is managed by iodized salt.
$iii$. Steroid hormones: Produced by the adrenal cortex and gonads. Glucocorticoids control carbohydrate metabolism and stress responses. Mineralocorticoids regulate water and salt excretion by the kidneys. Dysfunction of the adrenal cortex can lead to Addison's disease. Gonadal hormones like testosterone (male) and estradiol/progesterone (female) are responsible for secondary sexual characteristics and reproductive functions.