Starch and Glycogen Biochemistry Quiz

Podcast

Play an AI-generated podcast conversation about this lesson

Questions and Answers

What is the primary structural difference between amylose and amylopectin?

Amylose consists solely of a(1-6) linkages.

Amylose is a linear polysaccharide linked by a(1-4) linkages while amylopectin is branched. (correct)

Amylose is branched while amylopectin is linear.

Amylose has a higher glucose unit count than amylopectin.

Which enzyme specifically hydrolyzes a(1-6) linkages found in amylopectin?

Pullulanase (correct)

Isoamylase (correct)

Alpha-amylase

Beta-amylase

During starch hydrolysis, what type of product is primarily produced by alpha-amylase?

D-glucose

Limit dextrins (correct)

Maltotriose

Maltose

Which of the following accurately describes the frequency of branch points in glycogen compared to amylopectin?

Glycogen has branches every 8 to 12 residues, more frequently than amylopectin. Signup and view all the answers

What is a characteristic of beta-amylase in starch hydrolysis?

It detaches maltose from the terminal glucose units. Signup and view all the answers

Which of the following accurately describes the role of glycogen in animal cells?

It acts as the main storage polysaccharide in animal cells. Signup and view all the answers

Which of the following properties relates to glucan enzymes in the context of starch hydrolysis?

They can hydrolyze a(1-4) and a(1-6) linkages from the non-reducing end. Signup and view all the answers

What type of linkages do dextrins primarily consist of after amylase action on starch?

Both a(1-4) and a(1-6) linkages Signup and view all the answers

Which derivative of monosaccharide features an amino group replacing a hydroxyl group at the 2nd carbon?

B-D-2-glucosamine Signup and view all the answers

What type of sugar acid is produced by the oxidation of the carbonyl carbon?

Aldonic acid Signup and view all the answers

Which sugar alcohol is produced from the reduction of mannose?

Mannitol Signup and view all the answers

Which statement accurately describes amino sugars?

Their synthetic pathway is especially active in connective tissues. Signup and view all the answers

What is the primary function of protein kinases in the context of sugar phosphates?

They catalyze phosphorylation reactions. Signup and view all the answers

Which of the following is a sugar acid produced by oxidizing both the carbonyl carbon and the last hydroxyl carbon?

Glucaric acid Signup and view all the answers

What is a characteristic feature of sugar phosphates?

They are monosaccharides with an added phosphate group. Signup and view all the answers

Which derivative of monosaccharide is formed by the reduction of glucose?

Glucitol Signup and view all the answers

Which amino sugar is specifically referred to as N-acetyl-glucosamine?

GluNac Signup and view all the answers

What property differentiates reducing disaccharides from non-reducing disaccharides?

Presence of a free aldehyde or keto group Signup and view all the answers

Which glycosidic bond linkage is formed between the glucose units in maltose?

α(1→4) Signup and view all the answers

Which enzyme is responsible for hydrolyzing sucrose into its constituent monosaccharides?

Invertase Signup and view all the answers

Sialic acid is derived from which type of compound?

Amino sugar Signup and view all the answers

What type of glycosidic linkage is not found in sucrose?

β(1→4) Signup and view all the answers

Which of the following disaccharides does not have a free reducing group?

Sucrose Signup and view all the answers

Which of the following tenets defines glycosidic bond nomenclature?

Linkage includes the anomeric configuration Signup and view all the answers

What structural feature differentiates cellulose from starch and glycogen?

Cellulose contains B-(1-4) glycosidic linkages. Signup and view all the answers

Which of the following correctly describes the enzymatic limitations of humans regarding cellulose?

Humans lack the enzyme cellulase to digest cellulose. Signup and view all the answers

How does dietary fiber, such as cellulose, affect the absorption of nutrients in humans?

It decreases the absorption of glucose and cholesterol. Signup and view all the answers

What is the primary structural difference between chitin and cellulose?

Chitin is composed of N-acetyl glucosamine units. Signup and view all the answers

What is the primary function of dextrans in dental health?

They are responsible for forming dental plaque. Signup and view all the answers

What does inulin primarily serve as in various plant species?

A reserve carbohydrate. Signup and view all the answers

Which bond type connects fructose molecules in inulin?

B-(2→1) glycosidic bond. Signup and view all the answers

For what physiological measurement is inulin primarily used?

Determining the rate of glomerular filtration. Signup and view all the answers

What type of glycosidic linkage connects the two monosaccharides in lactose?

B-(1-4) glycosidic linkage Signup and view all the answers

Which enzyme hydrolyzes glycogen and starch to glucose in the intestinal tract?

Isomaltase Signup and view all the answers

What distinguishes heteropolysaccharides from homopolysaccharides?

Heteropolysaccharides contain multiple types of monosaccharides. Signup and view all the answers

What is the primary function of cellulose in plants?

Cell wall structure Signup and view all the answers

What is the correct ratio of amylose to amylopectin in starch granules?

1:4 Signup and view all the answers

Which of the following statements about homopolysaccharides is correct?

They include polysaccharides like starch and cellulose. Signup and view all the answers

What type of polysaccharides do not typically contain more than two different types of monosaccharide units?

Heteropolysaccharides Signup and view all the answers

Which of the following polysaccharides is primarily associated with energy storage in animals?

Glycogen Signup and view all the answers

Which statement accurately describes glycosaminoglycans (GAGs)?

GAGs consist of repeating disaccharide units, typically an acidic sugar and an amino sugar. Signup and view all the answers

What is the primary function of salivary amylase during the digestion of carbohydrates in the mouth?

Hydrolyzing α-(1-4) glycosidic bonds in polysaccharides. Signup and view all the answers

Why does carbohydrate digestion temporarily halt in the stomach?

The high acidity of the stomach inactivates salivary α-amylase. Signup and view all the answers

What activates salivary amylase for carbohydrate digestion in the mouth?

Presence of Cl ions. Signup and view all the answers

Which enzymes are responsible for the final hydrolysis of di- and oligosaccharides into monosaccharides in the small intestine?

α-glucosidases synthesized by intestinal mucosal cells. Signup and view all the answers

What is the primary product of the action of pancreatic amylase on dextrins?

A mixture of maltose, isomaltose, and limit dextrin. Signup and view all the answers

Which amino sugar is most commonly found in glycosaminoglycans?

D-glucosamine. Signup and view all the answers

Which of the following statements correctly identifies a property of GAGs?

GAGs contain carboxyl and sulfate groups, making them strongly negatively charged. Signup and view all the answers

Study Notes

Carbohydrate Chemistry

Carbohydrates are a class of organic compounds, including monosaccharides, disaccharides, and polysaccharides.
Monosaccharides are the simplest carbohydrates, consisting of a single sugar unit.
Disaccharides are formed by the condensation of two monosaccharides.
Polysaccharides are long chains of monosaccharides.

Derivatives of Monosaccharides

Sugar phosphates are formed by the addition of a phosphate group.
Sugar alcohols are formed by the reduction of the carbonyl group in a sugar.
Sugar acids are formed by the oxidation of a carbonyl or hydroxyl group.
Deoxy sugars have a hydroxyl group replaced by a hydrogen atom.
Amino sugars have a hydroxyl group replaced by an amino group.

Sugar Acids

Oxidation at carbon 1 yields aldonic acids (e.g., gluconic acid)
Oxidation at carbon 6 yields uronic acids (e.g., glucuronic acid)
Oxidation at both carbon 1 and 6 yields aldaric acids (e.g., glucaric acid).

Sugar Alcohols

Monosaccharides can be reduced to sugar alcohols at the carbonyl carbon.
Glucose is reduced to glucitol (sorbitol).
Galactose is reduced to galactitol (dulcitol).
Fructose is reduced to mannitol.

Deoxy Sugars

A hydroxyl group in a sugar may be replaced by a hydrogen atom to create a deoxy sugar.
Deoxyribose is present in ATP and DNA.
L-Fucose is found in glycoproteins.

Amino Sugars

Hydroxyl group attached to carbon 2 is replaced by an amino or acetyl-amino group.
Amino sugars are components of glycoproteins, glycosaminoglycans, and some antibiotics.
Glucosamine, galactosamine, and mannosamine are major amino sugars. Sialic acid is a nine-carbon compound derived from the hexosamines.

Glycosidic Bonds

Glycosidic bonds are formed between the anomeric carbon of one sugar and a hydroxyl group of another sugar.
Glycosidic bonds are named by the numbers of connected carbons (e.g., α(1→4)).
α-linkages and β-linkages are possible depending on the configuration of the anomeric carbon.

Disaccharides

Disaccharides are composed of two monosaccharides linked by a glycosidic bond.
They can be classified as reducing or non-reducing disaccharides depending on the availability of a free reducing group.
Common disaccharides include maltose, lactose, and sucrose.

Polysaccharides

Homopolysaccharides contain only one type of monosaccharide unit.
Cellulose, glycogen and starches are known examples.
Heteropolysaccharides contain two or more types of monosaccharide units
Glycosaminoglycans (GAGs) are important examples of heteropolysaccharides. They have acidic sugars (e.g. glucuronic and iduronic acids) and amino sugars (e.g. glucosamine and galactosamine) alternating in the chain.
They play structural roles in connective tissues

Starch

A polysaccharide composed of amylose and amylopectin.
Amylose is a linear polymer of glucose units linked by α(1–4) glycosidic bonds.
Amylopectin is a branched polymer of glucose units linked primarily by α(1–4) glycosidic bonds, but has branch points with α(1–6) bonds.

Glycogen

A branched polymer of glucose, used as an energy storage compound in animals.
Resembles amylopectin but with a more branched structure (branching points occur more frequently).

Cellulose

An unbranched polymer of glucose units linked by β(1–4) glycosidic bonds.
Cellulose cannot be digested by most humans. Its structure makes it an important component of plant walls..

Chitin

A linear homopolysaccharide consisting of N-acetyl glucosamine units with β(1–4) linkages.
Used by many arthropods as a structural component of their exoskeletons.

Dextrans and Dextrins

Dextrans are microbial polysaccharides made of glucose units.
Dextrins result from partial hydrolysis of starch.

Inulin

A fructose-based polysaccharide stored in some plants
Used in biomedical and physiological investigations.

Digestion and Absorption of Carbohydrates

Carbohydrate digestion begins in the mouth with salivary amylase.
Pancreatic amylase continues starch digestion in the small intestine.
Further digestive enzymes like the a- and β- glucosidases work in the small intestine to create monosaccharides.
Monosaccharides are absorbed in the small intestine via transporter proteins like SGLTs and GLUTs.

Studying That Suits You

Use AI to generate personalized quizzes and flashcards to suit your learning preferences.

Description

Test your knowledge on the structural differences between amylose and amylopectin, their hydrolysis processes, and the role of enzymes involved in starch breakdown. This quiz covers key concepts related to carbohydrates in biochemistry.