Carbohydrates Questions in English

(D) . In Jerusalem artichoke ($Helianthus$ $tuberosus$),the reserve food material is stored in the form of $Inulin$.
$Inulin$ is a polysaccharide consisting of a chain of fructose units.
It is commonly found in the roots and tubers of plants belonging to the family $Asteraceae$ (e.g.,Jerusalem artichoke,Dahlia).
It often appears as fan-shaped crystals within the cells.

(C) Glycogen is the primary storage form of glucose in animals.
It is primarily stored in the liver and skeletal muscles.
The liver stores glycogen to maintain blood glucose levels,while muscles store glycogen to provide energy for muscle contraction.

(C) $ATP$ $(Adenosine \text{ } Triphosphate)$ is known as the energy currency of the cell.
It stores chemical energy in its high-energy phosphate bonds, which is released to perform various cellular activities.
Therefore, the correct option is $C$.

(C) Glycogen is a polysaccharide that serves as a form of energy storage in animals and fungi. In animal cells,it is primarily stored in the liver and muscle cells. Within these cells,glycogen is found as granules located in the $Cytoplasm$.

(A) Starch and cellulose are polysaccharides,which are complex carbohydrates.
These compounds are polymers composed of many repeating units of simple sugars,specifically glucose (a monosaccharide).
Therefore,simple sugars are the building blocks of these complex carbohydrates.

(A) Fructose is a naturally occurring monosaccharide found in many fruits and is known as fruit sugar.
It is the sweetest among all naturally occurring sugars.
Its relative sweetness index is approximately $170$,whereas the sweetness index of glucose is $70$ and sucrose is $100$.

(C) Plants are characterized by the presence of a cell wall made of cellulose and the storage of carbohydrates in the form of starch.
$1$. Cellulose is a structural polysaccharide that provides rigidity to the plant cell wall.
$2$. Starch is the primary storage polysaccharide in plants,synthesized from glucose produced during photosynthesis.
Therefore,cellulose and starch are the characteristic components of plants.

(B) The correct answer is $B$.
Disaccharides are carbohydrates composed of two units of monosaccharides,such as sucrose,maltose,and lactose.
Maltose is formed by the condensation of two glucose units.

(C) Inulin is a polymer of fructose,known as a fructan.
It is classified as a polysaccharide.
It is commonly found in the roots and tubers of plants like the dahlia ($Dahlia$ $pinnata$).

(B) Monosaccharides are the simplest form of carbohydrates that cannot be further hydrolyzed into smaller sugar units. They are classified based on the number of carbon atoms they contain. Pentoses (containing $5$ carbon atoms,e.g.,ribose) and hexoses (containing $6$ carbon atoms,e.g.,glucose and fructose) are the most common examples of monosaccharides.

(B) When corn is immersed in boiling water,the heat causes the hydrolysis of complex carbohydrates (like starch or disaccharides) present in the corn into simpler sugars like monosaccharides.
Monosaccharides are inherently sweeter than complex carbohydrates.
Therefore,upon cooling,the solution tastes sweet due to the presence of these monosaccharides.

(B) Cellulose is a linear,fibrous polysaccharide found in the cell walls of plants.
It is composed of a long chain of $D$-glucose units linked together by $\beta(1 \rightarrow 4)$ glycosidic bonds.
Since it consists of many glucose monomers,it is classified as a polysaccharide of glucose.

(C) Carbohydrates are classified based on the number of sugar units they contain.
Monosaccharides are the simplest form of carbohydrates,consisting of a single sugar unit that cannot be further hydrolyzed into smaller carbohydrate molecules.
Examples include glucose,fructose,and galactose.
Starch is a polysaccharide,and canesugar (sucrose) is a disaccharide.

(A) Sucrose is a disaccharide,which is a common form of sugar found in sugarcane and sugar beets.
It is formed by the condensation of one molecule of $D$-glucose and one molecule of $D$-fructose.
These two monosaccharides are linked together by a glycosidic bond between the anomeric carbon of glucose and the anomeric carbon of fructose.

(D) The bacterium $Leuconostoc \ mesenteroides$ possesses the enzyme dextransucrase.
This enzyme catalyzes the synthesis of a complex branched polysaccharide known as dextran from sucrose.
Dextran is a glucose polymer that serves as a storage polysaccharide in certain bacteria and is also used commercially in medical applications,such as blood plasma volume expanders.

(A) Starch is a polysaccharide,which is a polymer of glucose units. During the formation of the starch chain,water molecules are removed during the condensation process between glucose monomers. The general chemical formula for starch is represented as $(C_6H_{10}O_5)_n$,where $n$ represents the number of glucose units in the polymer chain.

(A) Fructose is a ketohexose sugar that is significantly sweeter than glucose. By storing fructose in ripening fruits,plants attract animals and birds,which aids in seed dispersal. From an evolutionary and ecological perspective,the sweetness of fructose serves as a biological signal to ensure the fruit is consumed when ripe,thereby facilitating the reproductive success of the plant.

(C) Carbohydrates are primarily produced through the process of photosynthesis.
Photosynthesis is performed by organisms that contain chlorophyll or other photosynthetic pigments,such as green plants,algae,and certain bacteria (e.g.,cyanobacteria).
Fungi and viruses are heterotrophic or parasitic and cannot synthesize their own carbohydrates via photosynthesis.
Therefore,the correct group of organisms that produce carbohydrates is some bacteria (photosynthetic bacteria),algae,and green plant cells.

(D) Cellulose is a polysaccharide composed of a long chain of $\beta-D-glucose$ units linked by $\beta(1 \rightarrow 4)$ glycosidic bonds.
Since it is made up of only one type of monomer (glucose),it is classified as a homoglycan.
Because glucose is a hexose sugar (a sugar with $6$ carbon atoms),cellulose is specifically termed a homoglycan hexosan.

(D) Maltose is a disaccharide formed by the condensation of two molecules of $\alpha-D$-glucose.
These two glucose units are linked together by an $\alpha-1,4$-glycosidic bond.
Therefore,the correct composition of maltose is two glucose units.

(A) Callose is a polysaccharide,specifically a $\beta-1,3$-glucan,which is a type of complex sugar.
It is synthesized in the plant cell wall and is known to stain blue with aniline blue dye.
Upon complete hydrolysis,callose breaks down into glucose units.

(B) Ribulose is a $5$-carbon sugar that contains a ketone group at the $C-2$ position.
Therefore,it is classified as a ketose sugar.
Ribulose phosphate is the phosphorylated form of this ketose sugar,which plays a crucial role in the Calvin cycle as a precursor to Ribulose-$1,5$-bisphosphate $(RuBP)$.

(D) Pentose sugars are monosaccharides that contain $5$ carbon atoms.
$Xylulose$,$Ribose$,and $Ribulose$ are all examples of pentose sugars.
Therefore,all the options listed contain $5$ carbon atoms.

(D) Sedoheptulose is a ketose sugar that contains $7$ carbon atoms in its molecular structure.
It is an important intermediate in the pentose phosphate pathway and the Calvin cycle (photosynthesis).
The prefix 'sedo-' refers to its origin,and '-hept-' indicates the presence of $7$ carbon atoms.

(A) $Glucose$ is a simple sugar $(monosaccharide)$ that is directly utilized by cells during cellular respiration to produce $ATP$.
Because it does not require complex digestion or conversion processes like fats or proteins, it serves as the primary and instantaneous source of energy for the body.
Fats and proteins are typically used as energy sources only when $glucose$ levels are depleted or under specific metabolic conditions.

(A) Adenosine diphosphate $(ADP)$ consists of an adenosine molecule (adenine + ribose) attached to two phosphate groups.
In the structure of $ADP$,there is only one high-energy phosphoanhydride bond between the two phosphate groups.
When $ADP$ undergoes hydrolysis,it releases energy: $ADP + Pi \rightarrow ATP$ (in synthesis) or $ADP \xrightarrow{\text{hydrolysis}} AMP + Pi + 7.3 \text{ kcal}$.
Therefore,$ADP$ contains one high-energy bond.

(B) $ATP$ (Adenosine Triphosphate) is known as the energy currency of the cell. It is the primary molecule used for immediate energy transfer in biological processes. While fats and carbohydrates store more energy per gram,$ATP$ is the most readily available and direct source of chemical energy for cellular work.

(D) Starch is a polymer of glucose,and all the options provided (wheat starch,rice starch,and potato starch) are chemically composed of the same monomeric units,which are glucose molecules.
Since the chemical composition of starch is identical regardless of its source,the energy released upon the complete oxidation of $1 \text{ gram}$ of starch is the same for all these sources.
Therefore,the energy produced per gram is equal for wheat starch,rice starch,and potato starch.

(C) Glycogen is a complex carbohydrate known as a polysaccharide. It serves as the primary storage form of glucose in animals. It is synthesized from glucose molecules through a process called glycogenesis and is primarily stored in the liver and skeletal muscle cells to maintain blood glucose levels and provide energy during metabolic demand.

(A) $Chitin$ is a nitrogenous polysaccharide composed of $N$-acetylglucosamine units. It is a structural polysaccharide that occurs in the exoskeleton of arthropods and the cell walls of fungi.

(C) disaccharide is a carbohydrate formed when two monosaccharides are joined by a glycosidic linkage.
$Maltose$ is a disaccharide composed of two molecules of glucose $(C_6H_{12}O_6 + C_6H_{12}O_6 \rightarrow C_{12}H_{22}O_{11} + H_2O)$.
Galactose and Fructose are monosaccharides.
Dextrin is a polysaccharide (a short-chain polymer of glucose).

(A) . Glucose is considered the primary cellular fuel for the body.
It is the simplest form of carbohydrate that cells use to produce $ATP$ (Adenosine Triphosphate) through the process of cellular respiration.
While other substances like fats and proteins can also provide energy,glucose is the most readily available and preferred source for immediate energy requirements in most cells.

(C) Starch and cellulose are both polysaccharides,which are complex carbohydrates.
They are polymers composed of many repeating units of simple sugars,specifically $D-glucose$ molecules linked together by glycosidic bonds.
Therefore,the correct answer is simple sugars.

(C) $Glycogen$ is a polysaccharide that serves as the primary form of energy storage in animals. When the body has excess glucose,it is converted into $Glycogen$ and stored primarily in the liver and skeletal muscles to be used as a reserve fuel when needed.

(B) The correct answer is $B$.
Carbohydrates are the primary source of energy for most animals.
They are organic compounds composed of carbon,hydrogen,and oxygen.
Rich sources of carbohydrates include cereals (like rice,wheat,and maize),fruits,milk,and potatoes.
Rice is a staple food that provides a high concentration of starch,which is a complex carbohydrate.

(B) The correct answer is $B$.
Carbohydrates are classified based on the number of sugar units:
$1$. Monosaccharides: These are simple sugars that cannot be hydrolyzed further (e.g.,glucose,fructose,galactose).
$2$. Disaccharides: These consist of two monosaccharide units linked together (e.g.,sucrose,maltose,lactose).
$3$. Polysaccharides: These are complex carbohydrates consisting of long chains of monosaccharide units (e.g.,starch,glycogen,cellulose,dextrins).
Therefore,starch,glycogen,and cellulose are all polysaccharides.

(C) Lactose $({C_{12}}{H_{22}}{O_{11}})$ is known as milk sugar.
It is a disaccharide formed by the glycosidic linkage between one molecule of glucose and one molecule of galactose.

(B) Carbohydrates are the primary and most efficient source of energy for the body compared to proteins and fats.
They are broken down into glucose,which is oxidized during cellular respiration to produce $ATP$.
Excess carbohydrates are stored in the body cells as glycogen and are mobilized for energy production whenever required.

(C) During starvation,the body first utilizes the readily available energy reserves. Glycogen stored in the liver and muscles is the primary source of glucose and is mobilized first to maintain blood glucose levels. Once glycogen stores are depleted,the body begins to break down fats,and finally,proteins are used as a last resort.

(C) Lactose is commonly known as milk sugar.
It is a disaccharide composed of one molecule of $D-galactose$ and one molecule of $D-glucose$ linked by a $\beta-1,4-glycosidic$ bond.
Apart from being the primary carbohydrate in milk,it is also found in the flowers of certain plants.

(B) reducing sugar is a carbohydrate that possesses a free aldehyde or ketone group, which allows it to act as a reducing agent.
All monosaccharides, such as glucose, fructose, and galactose, are reducing sugars because they contain a free anomeric carbon.
Sucrose is a non-reducing sugar because its glycosidic bond involves the anomeric carbons of both glucose and fructose, leaving no free aldehyde or ketone group.
Gluconic acid is an oxidation product of glucose and does not function as a reducing sugar in the same manner.
$\beta - \text{methyl galactoside}$ is a glycoside where the anomeric hydroxyl group is replaced by a methoxy group, making it non-reducing.
Therefore, Galactose $(C_6H_{12}O_6)$ is a monosaccharide and acts as a reducing sugar.

(C) The iodine test is a chemical test used to detect the presence of starch,which is a type of polysaccharide carbohydrate.
When iodine solution $(I_2KI)$ is added to a sample containing starch,it forms a complex that results in a characteristic blue-black color.
Therefore,the iodine test is specifically used for the detection of starch (carbohydrates).

(C) Maltose is a disaccharide composed of two glucose units linked by an $\alpha-1,4$-glycosidic bond. Upon hydrolysis,it breaks down into two molecules of glucose. In contrast,lactose yields glucose and galactose,while sucrose yields glucose and fructose.

(C) $Glycogen$ is a branched polymer of glucose. It is stored primarily in the muscles and liver of animals, and due to its structural similarity to starch, it is commonly referred to as 'animal starch'.

(D) Heparin is a naturally occurring anticoagulant produced by the body.
Chemically,it is classified as a mucopolysaccharide,specifically mucoitin-polysulphuric acid.
It is a complex polysaccharide composed of repeating units of glucosamine and glucuronic acid,which are esterified with sulphuric acid.

(D) $Hyaluronic \text{ acid}$ lubricates ligaments and tendons and is an important constituent of the synovial fluid of bone joints, the vitreous humor of the eyes, etc.

(A) The brain primarily relies on $Glucose$ as its main source of energy.
$Glucose$ is a simple sugar that easily crosses the blood-brain barrier to provide the necessary $ATP$ required for neuronal activity and maintaining membrane potentials.
While other substrates can be used under specific conditions,$Glucose$ remains the essential fuel for normal brain function.

(A) Honey is a natural product produced by honeybees from nectar.
It mainly consists of simple sugars,specifically fructose $(45\%)$ and glucose $(32-37\%)$.
Since both fructose and glucose are simple sugars,they are classified as monosaccharides.

(D) Rice is considered the richest source of carbohydrates among the given options. It contains approximately $75-80\%$ starch,which is a complex carbohydrate. While maize,wheat,and barley also contain significant amounts of carbohydrates,rice is widely recognized as the primary staple food providing the highest concentration of readily available carbohydrates for human consumption.

(A) Carbohydrates are primarily synthesized through the process of photosynthesis. Photosynthesis is performed by organisms that possess chlorophyll or similar pigments capable of capturing light energy. These include green plants,algae,and certain photosynthetic bacteria (such as cyanobacteria). Fungi and viruses lack the ability to perform photosynthesis and therefore do not produce carbohydrates in this manner. Thus,the correct group is some bacteria,algae,and green plant cells.