Carbohydrate Biology Quiz

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

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.

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

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

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

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

<p>The general formula of carbohydrates often reflects a 1:1 ratio of carbon atoms to water molecules, thus the term &quot;carbohydrate&quot;, meaning &quot;carbon hydrate&quot;.</p> Signup and view all the answers

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

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

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

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

<p>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.</p> Signup and view all the answers

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

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

<p>Aldoses and ketoses.</p> Signup and view all the answers

<p>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.</p> Signup and view all the answers

<p>Grape sugar or dextrose.</p> Signup and view all the answers

<p>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).</p> Signup and view all the answers

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

<p>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.</p> Signup and view all the answers

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

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

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

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

<p>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.</p> Signup and view all the answers

<p>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.</p> Signup and view all the answers

<p>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.</p> Signup and view all the answers

<p>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.</p> Signup and view all the answers

<p>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.</p> Signup and view all the answers

<p>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.</p> Signup and view all the answers

<p>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.</p> Signup and view all the answers

<p>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.</p> Signup and view all the answers

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

<p>Acetal linkage of carbon-I.</p> Signup and view all the answers

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

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

<p>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.</p> Signup and view all the answers

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

<p>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.</p> Signup and view all the answers

<p>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.</p> Signup and view all the answers

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

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

<p>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.</p> Signup and view all the answers

<p>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.</p> Signup and view all the answers

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

<p>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.</p> Signup and view all the answers

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

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