Enzymes and Hormones Questions in English

(B) $Fermentation$ is a biochemical process in which complex organic compounds are broken down into simpler substances by the action of enzymes. This process releases energy in the form of heat,making it an $Exothermic$ reaction. Therefore,the correct option is $(B)$.

(C) Enzymes are biological catalysts that function by lowering the activation energy of a reaction,not by increasing it. Therefore,the statement that they always increase activation energy is false. Options $A$,$B$,and $D$ are true characteristics of enzymes.

(C) Enzymes that possess two distinct sites are known as allosteric enzymes.
These two sites are the $active \ site$ and the $allosteric \ site$.
The $active \ site$ is where the substrate binds to undergo the catalytic reaction.
The $allosteric \ site$ is a specific region on the enzyme where an effector or modulator molecule can bind.
This binding is reversible and regulates the enzyme's activity by inducing a conformational change.

(D) Enzymes are biological catalysts.
Catalysts function by providing an alternative pathway with lower activation energy for a reaction.
The lower the activation energy,the faster the rate of the reaction.
Therefore,enzymes speed up reactions by lowering the activation energy,not by increasing it.
Thus,the statement that they always increase activation energy is incorrect.

(D) An enzyme does not raise the activation energy; instead,it decreases the activation energy to increase the rate of the reaction and acts as a biological catalyst.

(B) The enzyme $Maltase$ specifically catalyses the hydrolysis of $Maltose$ into two molecules of $Glucose$. The reaction is represented as: $Maltose + H_2O \xrightarrow{Maltase} 2Glucose$. Therefore,the correct option is $B$.

(D) The efficiency of an enzyme in catalyzing a reaction is primarily due to its ability to provide an alternative pathway for the reaction with a lower activation energy $(E_a)$.
By lowering the activation energy,a larger fraction of reactant molecules can cross the energy barrier at a given temperature,thereby increasing the rate of the reaction.

(B) Enzymes are biological catalysts that are primarily composed of globular proteins.
These protein molecules possess a specific tertiary structure that gives them a rounded,ball-like shape,which is essential for their catalytic activity.

(D) biological catalyst is a substance that increases the rate of a chemical reaction within a living organism.
These catalysts are known as enzymes.
Enzymes are primarily proteinaceous in nature and possess an active site where the substrate binds to facilitate the reaction.

(A) . Ptyalin (also known as salivary amylase) is an enzyme present in saliva that initiates the digestion of starch into maltose.

(C) Enzymes are highly specific both in the reactions that they catalyze and in their choice of reactants,which are called substrates.
An enzyme usually catalyzes a single chemical reaction or a set of closely related reactions.
Therefore,the statement that enzymes can catalyze any reaction is incorrect.

(C) Enzymes are biological catalysts produced by living organisms that speed up biochemical reactions.

(B) The enzyme activity is maximum at an optimum temperature,which is approximately $310 \ K$ $(37 \ ^\circ C)$ for most human enzymes. Therefore,the correct option is $(B)$.

(B) Fermentation is a biochemical process in which complex organic compounds are broken down into simpler substances by the action of enzymes.
This process is accompanied by the release of heat,making it an $Exothermic$ reaction.

(D) The fermentation of starch into alcohol is a biochemical process catalyzed by enzymes such as diastase,maltase,and zymase.
$Starch \xrightarrow{\text{Enzymes}} \text{Alcohol}$

(C) The correct option is $C$.
Zymase is an enzyme complex that catalyzes the fermentation of sugar into ethanol and carbon dioxide.
The reaction is:
$C_6H_{12}O_6 (\text{Glucose or Fructose}) \xrightarrow{\text{Zymase}} 2C_2H_5OH (\text{Ethyl alcohol}) + 2CO_2$

(A) The commercial production of ethyl alcohol from starch involves three main enzymatic steps:
$1$. Starch is converted to maltose by the enzyme $Diastase$ (found in germinated barley):
$2(C_6H_{10}O_5)_n + nH_2O \xrightarrow{Diastase} nC_{12}H_{22}O_{11}$
$2$. Maltose is converted to glucose by the enzyme $Maltase$ (found in yeast):
$C_{12}H_{22}O_{11} + H_2O \xrightarrow{Maltase} 2C_6H_{12}O_6$
$3$. Glucose is converted to ethyl alcohol by the enzyme $Zymase$ (found in yeast):
$C_6H_{12}O_6 \xrightarrow{Zymase} 2C_2H_5OH + 2CO_2$
Therefore,the correct sequence of enzymes is $Diastase$,$Maltase$,and $Zymase$.

(D) The enzyme $Diastase$ is responsible for the hydrolysis of $Starch$ into $Maltose$.
The reaction is represented as:
$Starch \xrightarrow{Diastase} Maltose$.

(B) Invertase is an enzyme that catalyzes the hydrolysis of sucrose into fructose and glucose.
The chemical reaction is: $C_{12}H_{22}O_{11} + H_2O \xrightarrow{\text{Invertase}} C_6H_{12}O_6 (\text{glucose}) + C_6H_{12}O_6 (\text{fructose})$.

(D) Diastase enzyme converts starch into maltose.

(B) is the correct answer.
$Pepsin$,$ptyalin$,and $lipase$ are enzymes,whereas $cellulose$ is a carbohydrate (polysaccharide) and not an enzyme.

(A) Enzymes are biological catalysts that are almost exclusively globular proteins. They speed up biochemical reactions by lowering the activation energy.

(C) Enzymes are biological complex nitrogenous substances produced in living cells (typically proteins) that significantly speed up the rate of virtually all of the chemical reactions that take place within cells.
They are vital for life and serve a wide range of important functions in the body,such as aiding in digestion and metabolism.

(C) $i$. False: Enzymes contain various nucleophilic groups (e.g.,$-OH$,$-SH$,$-NH_2$) in their active sites that participate in catalysis.
$ii$. True: Enzymes exhibit high stereospecificity and substrate specificity.
$iii$. True: Enzymes function by providing an alternative pathway with a lower activation energy $(E_a)$.
$iv$. True: Pepsin is a digestive enzyme that breaks down proteins into peptides.
Therefore,statements $ii$,$iii$,and $iv$ are correct.

(D) The primary function of enzymes in living systems is to catalyse biochemical reactions.
Enzymes are highly substrate-specific and accelerate reactions by providing an alternate pathway with lower activation energy.

(D) Enzymes are biological catalysts that speed up biochemical reactions.
They are primarily proteinaceous in nature,meaning they consist of amino acids.
They exhibit optimum activity at specific temperatures,which for human enzymes is typically around the body temperature of $37.5^{\circ} C$.
Therefore,all the given statements are correct.

(B) Enzymes are highly efficient catalysts for biochemical reactions.
They speed up the reaction by providing an alternative pathway with lower activation energy.

(D) Lipase is an enzyme that catalyzes the hydrolysis of fats (lipids) into fatty acids and glycerol,not proteins.
$Lipid \xrightarrow{\text{Lipase}} \text{Fatty acid} + \text{Glycerol}$
Chymotrypsin,Pepsin,and Trypsin are all proteases involved in protein digestion.

(C) The metabolic process that produces chemical changes in organic substrates through the action of enzymes is known as $Fermentation$.
In biochemistry,it is narrowly defined as the extraction of energy from carbohydrates in the absence of oxygen.

(B) Biological catalysts are known as enzymes.
All enzymes are proteins,which are polymers composed of amino acids.
Therefore,a biological catalyst is essentially an amino acid chain (protein).

(D) Enzymes are biological catalysts produced by living organisms that accelerate biochemical reactions.
Most enzymes are globular proteins that possess a unique $3D$ structure,which is essential for their catalytic activity.
Specifically,the tertiary structure of proteins forms the functional enzyme.
Therefore,enzymes are proteins with a specific structure.
Example: $Maltase$ catalyzes the hydrolysis of maltose into glucose.

(B) The enzyme $Zymase$ converts glucose into alcohol.
It is found in yeast.
$\mathop {{C_6}{H_{12}}{O_6}}\limits_{{\text{glucose}}}$ $\xrightarrow{{{\text{zymase}}}} \mathop {2{C_2}{H_5}OH + 2C{O_2}}\limits_{{\text{ethyl alcohol}}}$

(D) . Enzymes are shape-selective,specific biological catalysts that possess well-defined active sites and function optimally at physiological temperatures.

(C) The reaction shows the hydrolysis of a triglyceride (fat) into glycerol and three fatty acid molecules.
Lipases are a group of enzymes that specifically catalyze the hydrolysis of fats (triglycerides) into their component fatty acids and glycerol.
Therefore,the enzyme used in the above reaction is Lipase.

(A) Messenger proteins,such as some types of hormones,transmit signals to coordinate biological processes between different cells,tissues,and organs.
Hormones are non-nutrient chemicals which act as intercellular messengers and are produced in trace amounts.

(D) Cortisone is not a sex hormone; it is a glucocorticoid that regulates the metabolism of fats,carbohydrates,and proteins.

(D) . Glucagon is secreted from alpha cells of islets of Langerhans of pancreas. It increases blood sugar level by stimulating glycogenolysis and gluconeogenesis.
$B$. Thyroxine is secreted from the thyroid gland. It stimulates the consumption of oxygen by metabolically active tissues and increases the oxidation of glucose in tissues.
$C$. Parathormone is secreted from the parathyroid gland. It increases calcium reabsorption from the bones and causes mobilization of calcium into the blood.
$D$. Calcitonin is secreted from the $C$-cells of the thyroid gland and acts on bones and kidneys to reduce blood calcium levels.
Therefore,blood calcium level is increased by parathormone. The correct answer is $D$.

(C) The first hormone to be isolated and chemically synthesized was adrenaline (epinephrine). It was identified and isolated by the Japanese chemist Jokichi Takemine in $1901$ and subsequently synthesized in the laboratory.

(B) Insulin is a hormone secreted by the pancreas that lowers blood glucose level by promoting the uptake of glucose by cells and the conversion of glucose to glycogen by the liver and skeletal muscle.

(B) Insulin is a proteinaceous hormone secreted by $\beta$-cells of the Islets of Langerhans in the pancreas of our body.

(B) $Oxytocin$ is a peptide hormone secreted by the posterior pituitary gland. It plays an important role in childbirth and milk ejection for feeding the baby.

(D) Lipase is the enzyme responsible for the hydrolysis of triglycerides (fats) into fatty acids and glycerol.
The reaction is represented as:
$Triglyceride + 3H_2O \xrightarrow{\text{Lipase}} \text{Glycerol} + 3 \text{Fatty acids}$
Therefore,the correct option is $D$.

(A) Pheromones are chemical substances secreted by an organism that trigger a social response in members of the same species.
These compounds are used to communicate information such as alarm,food trails,or sexual attraction to other members of the same species.
In contrast,hormones are internal chemical messengers,and allomones are chemicals that influence the behavior of a different species.

(C) Pheromones are chemical substances secreted outside the body of insects that trigger a social response in members of the same species.

(B) The digestive system of ruminants like cows and buffaloes contains microorganisms that produce the enzyme $Cellulase$.
This enzyme is capable of breaking down cellulose,which is the primary component of plant cell walls found in materials like paper and cloth.
Therefore,$Cellulase$ is the correct enzyme.

(D) The enzyme $Zymase$ is a complex of enzymes found in yeast.
It catalyzes the fermentation of glucose $(C_6H_{12}O_6)$ into ethanol $(C_2H_5OH)$ and carbon dioxide $(CO_2)$.
The chemical reaction is: $C_6H_{12}O_6 \xrightarrow{Zymase} 2C_2H_5OH + 2CO_2$.

(D) Enzymes are complex nitrogenous organic compounds produced by living plants and animals. They are actually protein molecules of high molecular mass and form colloidal solutions in water. They are very effective catalysts that catalyze numerous reactions,especially those connected with natural processes. Key characteristics include:
$1$. They are highly specific in nature.
$2$. They function optimally at specific temperatures (usually $298-310 \ K$) and $pH$.
$3$. They possess specific active sites (e.g.,$lock \ and \ key$ mechanism) where the substrate binds to undergo the reaction.
Therefore,option $D$ is the correct statement.

(D) Enzymes are biological catalysts that speed up chemical reactions by lowering the activation energy $(E_a)$ of the reaction.
Option $D$ states that enzymes increase the activation energy,which is incorrect.
Therefore,the incorrect statement is $D$.

(C) The enzyme $Urease$ specifically catalyzes the hydrolysis of $Urea$ $(NH_2CONH_2)$ into ammonia $(NH_3)$ and carbon dioxide $(CO_2)$. The reaction is represented as: $NH_2CONH_2 + H_2O \xrightarrow{Urease} 2NH_3 + CO_2$.