Q: What are the different ways in which glucose is oxidised to provide energy in various organism ?

\$\bullet\$ The breakdown of glucose involved into main processes: \$\bullet\$ \$\textbf{Glycolysis:}\$ It is the process in which 6 molecules of carbon break to form two molecules of pyruvate containing 3 carbon in each.\$\bullet\$ Further, the pyruvate molecule breaks down to form energy in different ways in various organisms:\$\bullet\$ \$\textbf{Aerobic respiration:}\$ It is the process in which pyruvate molecules break down to form water and carbon dioxide by releasing energy. \$\bullet\$ \$\textbf{Anaerobic respiration:}\$ It is the process in which pyruvate molecule breakdowns in the absence of oxygen which give rise to carbon dioxide, water and ethanol.

Q: What happens when \$D-glucose\$ is treated with the following reagents?(i) \$HI\$ (ii) Bromine water (iii) \$HNO_{3}\$.

\$(i)\$ When glucose is heated in the presence of \$HI\$, it reduces to \$n-hexane\$\$(ii)\$ On treatment with bromine water, glucose gets converted to gluconic acid\$(iii)\$ Glucose gets oxidized to saccharic acid on treatment with \$HNO_3\$All the reactions have been shown in the figure

Q: What are essential and non-essential amino acids? Give two examples of each type.

\$\text {Essential Amino Acids}:\$ Amino acids which can't be created in our body but can only be received from proper food or diet are called \$\text {Essential Amino Acids}\$. Examples- Histidine, Isoleucine, Lysine.\$\text {Non- essential amino acids}:\$ Amino acids which can be created in our body itself are \$\text {Non- essential amino acids}\$. Examples-alanine, arginine, asparagine, aspartic acid. Examples- Histidine, Isoleucine, Lysine.

Q: Which one of the following statements is correct, with reference to enzymes?

A) Correct option is (C)B) Explanation for correct option (C)Holoenzyme is the active form of the enzyme. It is made of 2 components called the apoenzyme and coenzyme. A cofactor can also be called a coenzyme if it is an organic molecule. The apoprotein itself is inactive. On binding with the cofactor, it gets activated resulting in the formation of a holoenzyme that is functional.

Q: \$\alpha\$-D-glucose and \$\beta\$-D-glucose are examples of:

\$\alpha\$-D-glucose and \$\beta\$-D-glucose is example of anomers An Anomer of a saccharide only differs in its structure at the anomeric carbon. Anomeric carbon being the functional group of the carbohydrate, which is usually the carboxyl group attached to it.Epimeres, differ at only one chiral center, not the anomeric carbon.Option C is correct.

Question 1

What are the different ways in which glucose is oxidised to provide energy in various organism ?

Accepted Answer

$\bullet$  The breakdown of glucose involved into main processes: $\bullet$  $\textbf{Glycolysis:}$ It is the process in which 6 molecules of carbon break to form two molecules of pyruvate containing 3 carbon in each.$\bullet$  Further, the pyruvate molecule breaks down to form energy in different ways in various organisms:$\bullet$  $\textbf{Aerobic respiration:}$ It is the process in which pyruvate molecules break down to form water and carbon dioxide by releasing energy. $\bullet$ $\textbf{Anaerobic respiration:}$ It is the process in which pyruvate molecule breakdowns in the absence of oxygen which give rise to carbon dioxide, water and ethanol.

Question 2

What happens when $D-glucose$ is treated with the following reagents?(i) $HI$ (ii) Bromine water (iii) $HNO_{3}$.

Accepted Answer

$(i)$ When glucose is heated in the presence of $HI$, it reduces to $n-hexane$$(ii)$ On treatment with bromine water, glucose gets converted to gluconic acid$(iii)$ Glucose gets oxidized to saccharic acid on treatment with $HNO_3$All the reactions have been shown in the figure

Question 3

What are the main characteristics of an enzyme?

Accepted Answer

Characteristics of an Enzyme :1. Speed up chemical reactions. 2. They are required in minute amounts. 3. They are highly specific in their action. 4. They are affected by temperature. 5. They are affected by pH. 6. Some catalyze reversible reactions. 7. Some require coenzymes. 8. They are inhibited by inhibitors.

Question 4

What are essential and non-essential amino acids? Give two examples of each type.

Accepted Answer

$\text {Essential Amino Acids}:$  Amino acids which can't be created in our body but can only be received from proper food or diet are called $\text {Essential Amino Acids}$. Examples- Histidine, Isoleucine, Lysine.$\text {Non- essential amino acids}:$ Amino acids which can be created in our body itself are $\text {Non- essential amino acids}$. Examples-alanine, arginine, asparagine, aspartic acid. Examples- Histidine, Isoleucine, Lysine.

Question 5

Which one of the following statements is correct, with reference to enzymes?

Accepted Answer

A)&#9;Correct option is (C)B)&#9;Explanation for correct option (C)Holoenzyme is the active form of the enzyme. It is made of 2 components called the apoenzyme and coenzyme. A cofactor can also be called a coenzyme if it is an organic molecule. The apoprotein itself is inactive. On binding with the cofactor, it gets activated resulting in the formation of a holoenzyme that is functional.

Question 6

$\alpha$-D-glucose and $\beta$-D-glucose are examples of:

Accepted Answer

$\alpha$-D-glucose and  $\beta$-D-glucose is example of anomers  An Anomer of a saccharide only differs in its structure at the anomeric carbon. Anomeric carbon being the functional group of the carbohydrate, which is usually the carboxyl group attached to it.Epimeres, differ at only one chiral center, not the anomeric carbon.Option C is correct.

Question 7

Which of the following amino acid is neutral ?

Accepted Answer

Neutral Amino acids: Glycine, Alanine, leucine, Isoleucine, valine, phenylalanine, Proline, methionine, serine, threonine, tyrosine, cysteine, glutamine, asparagine, tryptophan.Acidic amino acids: Aspartic acid, glutamic acidBasic amino acids: Lysine, histidine, ArginineTherefore, option B is correct

Question 8

Which of the following is not true for enzymes?

Accepted Answer

A. Enzymes alters the speed of a chemical reaction. When reactions proceed from one direction to another, enzymes have to overcome an energy barrier to activate the inactive molecule. The amount of energy required to raise the energy of molecule at which chemical reaction can occur is called activation energy. Enzymes lower the activation energy of a reaction. Hence statement A is correct.B. Enzymes are water soluble colloidal macromolecules which are wholly or partially proteinaceous in nature. The protein part of enzyme is called apoenzyme while the non protein part is called prosthetic group which may be coenzyme or cofactor. Hence statement B is correct.C. Each enzyme has a substrate binding site called the active site. Binding of the substrate to this site produces a highly reactive short lived complex called enzyme substrate complex which breaks up into chemical products and unchanged enzyme along with the intermediate formation of enzyme-product complex. So, enzyme is not used up in the reactions. Hence statement C is incorrect.D. Enzymes function best at an optimum temperature 20-40&#176;C . The enzyme activity decreases with slight decrease or increase from the optimum temperature range. At very high temperature, enzyme activity decreases because denaturation of proteins occurs and enzyme becomes inactive. Hence statement D is correct.E. An enzyme has a distinct cavity or cleft in which substrate is bound. This cavity is known as active site which can hold a substrate molecule by its specific size, shape etc. Hence statement E is correct.So, the correct answer is 'Enzymes are used up in reactions'.

Question 9

What are enzymes? Name any one enzyme of our digestive system and write its function.

Accepted Answer

Enzymes are a group of catalysts functioning in biological system. They are usually proteinaceous substances produced by a living cell that catalyse biochemical reactions without themselves being changed in the process. Salivary amylase is an enzyme of our digestive system which converts starch into maltose, isomaltose and small dextrins called alpha dextrins.

Question 10

Which of the following statement is true for enzymes?

Accepted Answer

Enzymes are biological catalysts which speed up biochemical reactions. According to the most widely accepted theory, enzymes bind to the substrate molecule and form a transition state. During the progress of a reaction the substrates are separated from products by an energy barrier which the substrates need to cross. This energy barrier is called as the activation energy. The activation energy barrier in case of transition state is far less as compared to the activation energy barrier in absence of enzymes. Hence, the rate of reaction is more in case of enzyme catalyzed reactions due to the formation of transition state and lower activation energy requirement. This change is brought about by an apparent increase in energy level of substrate molecules.