Question

Note: Respond To All Questions From Part A To C

A. Write Four Conceptual Multiple Choice Questions and Included Your Answer Key For Your Questions for "carbohydrates" B. Write Four Conceptual Multiple Choice Questions and Included Your Answer Key For Your Questions for "monosaccharaides C. Write Four Conceptual Multiple Choice Questions and Included Your Answer Key For Your Questions for "cellulose

Answer 1

A. Multiple choice questions for Carbohydrates:

1. Carbohydrates are defined as:

i. Polyhydroxyaldehydes or ketones or substances which produce them upon hydrolysis

ii. Biopolymers of alpha amino acids linked by peptide bonds

iii. Consists of fatty acids and glycerol

iv. Consists of sugar, phosphate groups

Answer: i. Polyhydroxyaldehydes or ketones or substances which produce them upon hydrolysis

Explanation: Carbohydrates are polyhydroxyaldehydes or ketones or substances which produce them upon hydrolysis

Biopolymers of alpha amino acids linked by peptide bonds are called as proteins

Fats consists of fatty acids and glycerol

Nucleic acids consists of sugar, phosphate groups
Hence the answer is i.

2. Carbohydrates give a positive result for the following test(s):

i. Molisch Test

ii. Fehling's Test

iii. Seliwinoff's Test

iv. All of the above

Answer: iv. All of the above

Molisch test is a general test for carbohydrates where the aqueous extract of the sugar sample, is treated with alpha naphthol in alcohol. Finally concentrated sulphuric acid is added from the sides of the test tube. Formation of violet color shows the presence of carbohydrates

Fehling's test is done to distinguish reducing and non reducing sugars. Fehling's A and B solution are added to the sample sugar solution and heated. Appearance of red color concludes that sugar is a reducing sugar

Seliwinoff's test is used to identify the hexose sugars which are consisting of ketone group for example. fructose. The sugar solution is treated with seliwinoff's reagent and heated. Red color represents the sample contains a ketose sugar. As all of the tests mentioned in the options were tests done for carbohydrates, the correct choice is all of the above

3. The amount of energy obtained from one gram of carbohydrate is

i. 4 calories

ii. 4 kilocalories

iii. 9 calories

iv. 9 kilocalories

Answer: i. 4 calories

Explanation: Carbohydrates and proteins yield 4 calories of energy per gram. While lipids yield 9 calories of energy.

Difference between calorie and kilocalorie. A calorie is defined as the energy required to increase the temperature of 1 gram of water by 1 degree celsius. As calorie is very little in value, kilocalorie is used to express the energy yields where 1 kilocalorie = 1000 calories

4. Examples of non-carbohydrate substance in the given options:

i. Glucose

ii. Sucrose

iii. Starch

iv. Enzyme

Answer: iv. Enzyme

Explanation: Glucose is a monosaccharide, whereas sucrose is a disaccharide consisting of glucose and fructose and Starch is a homopolysaccharide. All of which are classes of carbohydrates. On the other hand, enzymes are biocatalysts which increases the rate of reaction and specific to substrate and temperature.

B. Four conceptual multiple choice questions for monosaccharides:

1. The general formula of monosaccharides is

i. C_n (H₂ O)_n-2

ii. C_n (H₂ O)_n-1
iii. C_n (H₂ O)_n

iv. C_n H₂ O

Answer: iii. C_n (H₂ O)_n

Explanation: C_n (H₂ O)_n-2 is the general formula of trisaccarides and C_n (H₂ O)_n-1 is a general formula of disaccharides and C_n H₂ O is not the general formula for classes of carbohydrates. Hence the answer is iii

2. Reference monosaccharide to represent all the other structures of carbohydrates is:

i. Glucose

ii. Glyceraldehyde

iii. Dihydroxyacetone

iv. Erythrose

Answer: ii. Glyceraldehyde

Glyceraldehyde is a triose and contains aldehyde group with formula of C3H6O3 and used to represent the structure of other carbohydrates. Glucose is a hexose and comes later to glyceraldehyde in carbon skeleton. Dihydroxyacetone is a ketose sugar having same general formula with that glyceraldehyde. Erythrose is a tetrose with a formula of C4H8O4 and comes next to glyceraldehyde

3. High water solubility of the monosaccharides is attributed to one of the following:

i. Carbonyl group

ii. Carbon skeleton

iii. Polyhydroxy groups

iv. Both i and ii.

Answer: iii. Polyhydroxy groups

Polyhydroxy groups are responsible for water solubility and play a vital role in storage and transport of monosaccharides in living systems. Carbon skeleton and carbonyl group do not account for water solubility

4. The property of monosaccharides:

i. Non reducing sugars

ii. Complexating sugars

iii. Reducing sugars

iv. Basic sugars

Answer: iii. Reducing sugars

Monosaccharides are reducing sugars due to the presence of aldehyde group or ketone group which can convert to aldehyde by tautomerization. So remaining all other properties like basicity, complexation in the given options are false

C. Four conceptual multiple choice questions for Cellulose:

1. The class of cellulose is:

i. Monosaccharide

ii. Disaccharide

iii. Oligosaccharide

iv. Polysaccharide

Answer: d. Polysaccharide

Starch is a homopolysaccharide which will yield only onekind of monomers upon hydrolysis. The other options like monosaccharides include glucose, fructose; disaccharides include lactose, maltose, sucrose; Oligosaccharides include Stachyose, Rhamninose

2. Identification test for Starch is:

i. Iodine Test

ii. Ruthenium red test

iii. Saliwanoff's test

iv. Bial Orcinol's test

Answer: i. Iodine test

Iodine test gives blue color with starch, whereas winered color with glycogen, ruthenium red test is for identification of mucilage, Seliwinof's test is for identification of ketose sugars, fBial orcinol's test is for pentose sugars detection

3. Chemical structure of starch comprises of the following homopolysaccharides:

i. Amylose and Amylopectin

ii. Glucose and Galactose

iii. Glucose and fructose

iv. Two glucose units

Answer: i. Amylose and Amylopectin

Amylose and amylopectin are the two principal components for starch. Amylose consists of glucose with alpha 1-4 glycosidic bonds. whereas amylose is a branched molecule with glucose in alpha 1-4 linkage in linear chain and alpha 1-6 linkage in branching.

Glucose and galactose units are present in lactose, while glucose and fructose units are seen in sucrose and two glucose units are seen in maltose

4. The main storage form of glucose in plants is :

i. Glycogen

ii. Starch

iii. Glucose

iv. Adenosine Triphosphate (ATP)

Answer: ii. Starch

Starch is depot food source for plants, while glycogen is for animals, Glucose is ready form of energy and not storage form. ATP is the energy currency of the cell but not a energy source