Carbohydrate Biology Quiz

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Questions and Answers

What are the four major groups of carbohydrates based on their structure?

The four major groups of carbohydrates are monosaccharides, disaccharides, oligosaccharides, and polysaccharides.

Explain the difference between a monosaccharide and a disaccharide in terms of hydrolysis.

Monosaccharides are simple sugars that cannot be further hydrolyzed into simpler forms, while disaccharides contain two sugar units that can be broken down into monosaccharides through hydrolysis.

Provide two examples of how carbohydrates are used in the human body.

Carbohydrates serve as the chief source of energy for the body, and they are also constituents of compound lipids and conjugated proteins.

Explain the role of carbohydrate derivatives in medicine.

Certain carbohydrate derivatives act as drugs, such as cardiac glycosides and antibiotics. Signup and view all the answers

Describe the relationship between carbohydrate metabolism and diabetes mellitus.

Derangement of glucose metabolism, a key carbohydrate, is a hallmark of diabetes mellitus. Signup and view all the answers

What is the general formula for monosaccharides?

The general formula for monosaccharides is $C_nH_{2n}O_n$, where 'n' represents the number of carbon atoms. Signup and view all the answers

How does the general formula of carbohydrates relate to their name?

The general formula of carbohydrates often reflects a 1:1 ratio of carbon atoms to water molecules, thus the term "carbohydrate", meaning "carbon hydrate". Signup and view all the answers

Give an example of a disease caused by a deficiency in carbohydrate metabolism.

One example is galactosemia, a genetic disorder where individuals lack the enzymes needed to properly metabolize galactose, a sugar found in milk. Signup and view all the answers

What are the primary functions of glucose in erythrocytes and brain cells?

Erythrocytes and brain cells utilize glucose solely for energy production. Signup and view all the answers

Explain the role of fructose in the male reproductive system.

Seminal fluid is rich in fructose, which is utilized by sperm for energy. Fructose is produced in the seminiferous tubular epithelial cells from glucose. Signup and view all the answers

Describe the significance of galactose in the production of milk.

Galactose is synthesized in the mammary glands and combines with glucose to form lactose, the primary sugar in milk. Signup and view all the answers

What is the primary difference between α-sugars and β-sugars in terms of their structural orientation?

The position of the remaining —OH group determines whether a sugar is α or β. If the —OH is on the right side, it's α. If it's on the left side, it's β. Signup and view all the answers

What is the name of a ketotetrose, and what is one of its primary functions?

Erythrulose is a ketotetrose. It is an intermediate in glucose oxidation through the hexosemonophosphate shunt. Signup and view all the answers

Explain the concept of optical activity in relation to monosaccharides.

Optical activity refers to the ability of a substance with asymmetric carbon atoms to rotate plane polarized light either to the right or left. Signup and view all the answers

What are the two main categories of monosaccharides based on their carbonyl group?

Aldoses and ketoses. Signup and view all the answers

Describe the chemical reaction responsible for the formation of cyclic monosaccharides.

The formation of cyclic monosaccharides is due to a reaction between the carbonyl group of an aldehyde (in aldoses) or a ketone (in ketoses) and an alcoholic hydroxyl group within the same molecule. Signup and view all the answers

What is the common name for glucose?

Grape sugar or dextrose. Signup and view all the answers

What are the two possible ring forms that can be formed in cyclic monosaccharides?

Depending on the number of carbon atoms involved in the ring formation, two possible ring structures are formed: furanose (4 carbon ring) and pyranose (5 carbon ring). Signup and view all the answers

What are the four main aldopentoses, and how are they similar?

Ribose, arabinose, lyxose, and xylose. All are five-carbon sugars with an aldehyde group. Signup and view all the answers

Explain how the presence of asymmetric carbon atoms contributes to the diversity of monosaccharides.

Asymmetric carbon atoms lead to the formation of stereoisomers, which are molecules with the same chemical formula but different spatial arrangements of atoms. This diversity in structure contributes to the vast array of monosaccharides found in nature. Signup and view all the answers

What are the two main ketopentoses, and what is one key function of one of them?

Ribulose and xylulose. Ribulose is important in the Calvin cycle of photosynthesis. Signup and view all the answers

What are the three main aldohexoses, and what makes them significant?

Glucose, mannose, and galactose. They are important energy sources for humans and other organisms, particularly glucose. Signup and view all the answers

What is the difference in structure between aldotrioses and ketotrioses?

Aldotrioses have an aldehyde group (–CHO), while ketotrioses have a ketone group (–CO). Signup and view all the answers

What are the key differences in composition between trioses, tetroses, pentoses, and hexoses?

They differ in the number of carbon atoms: trioses have 3, tetroses have 4, pentoses have 5, and hexoses have 6. Signup and view all the answers

Explain the concept of optical isomerism in carbohydrates and provide an example of a simple carbohydrate that exhibits this property.

Optical isomerism in carbohydrates refers to the ability of a carbohydrate molecule to exist in two forms that are mirror images of each other. These forms are called enantiomers. A simple example of a carbohydrate exhibiting optical isomerism is glyceraldehyde, which has one asymmetric carbon atom and therefore exists in two optically active forms. Signup and view all the answers

Describe the difference between aldose and ketose sugars and provide an example of each.

Aldose sugars contain an aldehyde group (-CHO), while ketose sugars contain a ketone group (C=O). Glucose is an example of an aldose sugar, while fructose is an example of a ketose sugar. Signup and view all the answers

What are epimers? Provide two examples of epimers, specifying which carbon atom differs between them.

Epimers are isomers of carbohydrates that differ in the configuration of only one asymmetric carbon atom. For example, glucose and mannose are epimers at carbon 2, while glucose and galactose are epimers at carbon 4. Signup and view all the answers

Explain the process of anomer formation in carbohydrates and provide two examples of anomers.

Anomer formation is the process of creating isomers of carbohydrates that differ in the configuration of the hydroxyl group attached to the anomeric carbon atom. This occurs in ring structures, where the anomeric carbon is derived from the carbonyl group (C1 in aldoses, C2 in ketoses). Examples of anomers include α and β glucose, and α and β fructose. Signup and view all the answers

What are deoxy sugars? Briefly describe their formation and give one example of a deoxy sugar found in a biological molecule, mentioning the molecule.

Deoxy sugars are carbohydrates where a hydroxyl group has been replaced by a hydrogen atom, resulting in the loss of one oxygen atom. They are formed through specific enzymatic reactions. Deoxyribose is a common deoxy sugar found in DNA. Signup and view all the answers

Explain how the direction of rotation of plane polarized light is used to classify carbohydrates as dextrorotatory or levorotatory. Provide examples of each type.

Carbohydrates are classified as dextrorotatory (d or +) if they rotate plane-polarized light to the right, and levorotatory (l or -) if they rotate it to the left. Glucose is an example of a dextrorotatory carbohydrate, while fructose is an example of a levorotatory carbohydrate. Signup and view all the answers

Describe the relationship between the number of asymmetric carbon atoms in a carbohydrate molecule and the number of possible optical isomers.

The number of possible optical isomers for a carbohydrate molecule is determined by the number of asymmetric carbon atoms. Each asymmetric carbon atom can have two possible configurations, so the total number of possible isomers is 2^n, where n is the number of asymmetric carbon atoms. For instance, glucose has 4 asymmetric carbon atoms, thus it can theoretically exist in 2^4 = 16 isomeric forms. Signup and view all the answers

Briefly explain the role of asymmetric carbon atoms in determining the optical activity of carbohydrates. Provide a specific example.

Asymmetric carbon atoms are carbon atoms that are bonded to four different groups. This arrangement leads to non-superimposable mirror-image forms (enantiomers), which exhibit different optical activities. For example, glyceraldehyde, with one asymmetric carbon, has two enantiomers, one dextrorotatory and the other levorotatory. Signup and view all the answers

Name two amino sugars that are essential components of glycosaminoglycans, and specify the glycosaminoglycan each is found in.

Glucosamine is found in heparin and hyaluronic acid. Galactosamine is found in chondroitin sulfate. Signup and view all the answers

What specific type of linkage connects the carbohydrate residue to the noncarbohydrate residue in a glycoside?

Acetal linkage of carbon-I. Signup and view all the answers

Explain the relationship between neuraminic acid and sialic acids.

Sialic acids are acylated derivatives of neuraminic acid, meaning they are modified forms of neuraminic acid with an acyl group attached. Signup and view all the answers

Describe the structure of muramic acid, highlighting its key components.

Muramic acid is composed of N-acetylglucosamine (GlcNAc) linked to a lactic acid residue. Signup and view all the answers

What is the significance of amino sugars in the context of antibiotic activity, providing an example?

Amino sugars are believed to contribute to the antibiotic activity of certain drugs, such as erythromycin, which contains dimethyl amino sugar. The specific mechanism of action of amino sugars in antibiotics is complex and varies depending on the drug. Signup and view all the answers

What is meant by ‘invert sugar’ and how is it formed?

Invert sugar is a mixture containing equal amounts of glucose and fructose, formed by the hydrolysis of sucrose using the enzyme sucrase (invertase). Signup and view all the answers

Explain the clinical application of sucrose in relation to edema.

Sucrose is used in the treatment of edemas such as cerebral edema due to its ability to alter the osmotic condition of the blood. This causes water to move from the tissues into the blood, reducing the edema. Signup and view all the answers

What is the reason why sucrose cannot be utilized when administered parenterally?

Sucrose cannot be utilized when administered parenterally because the body lacks the enzyme sucrase in the bloodstream to break it down into glucose and fructose. Signup and view all the answers

What is the primary function of glycogen in animals, and where is it primarily stored?

Glycogen serves as a storage form of energy in animals and is primarily stored in the liver and muscles. Signup and view all the answers

Explain the key difference between amylose and amylopectin in terms of their molecular structures.

Amylose is a linear chain of glucose units, while amylopectin is a highly branched polymer of glucose. Signup and view all the answers

What is postmortem glycogenolysis, and why does it eventually cease?

Postmortem glycogenolysis is the breakdown of glycogen after death, but it ceases when the pH drops to 5.5 due to the accumulation of lactic acid from glucose metabolism. Signup and view all the answers

Describe the process of glycogenolysis. What is its role in maintaining blood glucose levels?

Glycogenolysis is the breakdown of glycogen into glucose, which is released into the bloodstream to maintain blood glucose levels, particularly during periods of fasting or intense physical activity. Signup and view all the answers

What are dextrins, and how are they produced?

Dextrins are shorter chain carbohydrates produced by the partial hydrolysis of starch by acids or enzymes. Signup and view all the answers

Explain the relationship between the deficiency of a specific enzyme and the occurrence of diarrhea.

A deficiency in the enzyme responsible for hydrolyzing disaccharides, such as sucrose, can prevent their proper digestion in the gut, leading to undigested sugars in the intestines, which draws water into the lumen, causing diarrhea. Signup and view all the answers

Explain the role of amylase in the digestion of starch.

Amylase is an enzyme that breaks down starch into smaller units called dextrins, which are then further hydrolyzed into glucose. Signup and view all the answers

What is the relationship between starch and its dietary sources? Provide three examples of foods rich in starch.

Starch is a storage form of carbohydrate found in many plants. Common dietary sources of starch include potatoes, rice, and bread. Signup and view all the answers

Flashcards

Definition of Carbohydrates

Carbohydrates are aldehyde or ketone derivatives of polyhydric alcohols, or yield these on hydrolysis.

Biomedical Importance of Carbohydrates

They serve as energy sources, constituents of lipids and proteins, and certain derivatives are used as drugs.

Role in Disease

Metabolic dysfunctions like galactosemia and diabetes relate to carbohydrate metabolism.

Types of Carbohydrates

Carbohydrates are classified into monosaccharides, disaccharides, oligosaccharides, and polysaccharides.