Chapter 5: An Introduction to Carbohydrates Flashcards
Carbohydrates are made up of which of the following monomeric subunits?
A) amino acids
B) free fatty acids
C) sugars
D) carbon atoms bonded to water
C) sugars
How do the hexoses glucose and galactose differ from each other?
A) They differ in the number of their carbon atoms.
B) They differ in the placement of their carbonyl group.
C) They differ in their chemical formula.
D) They differ in the spatial arrangement of their hydroxyl groups.
D) They differ in the spatial arrangement of their hydroxyl groups.
Which chemical formula could represent a carbohydrate?
A) C3H6O3
B) C3H3O3
C) C6H12O3
D) C5H10O10
A) C3H6O3
A carbohydrate with the molecular formula C3H6O3 would most accurately be classified as what type of sugar?
A) hexose
B) pentose
C) triose
D) aldose
C) triose
The predominant form of glucose dissolved in an aqueous solution is _____.
A) as a disaccharide
B) the linear form
C) as a ketose
D) the ring configuration
D) the ring configuration
Which one of the following statements about sugars is correct?
A) Amino acids undergo condensation reactions to form polysaccharides.
B) Monosaccharides undergo hydrolysis to form polysaccharides.
C) Monosaccharides undergo condensation reactions to form polysaccharides.
D) Monosaccharides form polysaccharides through phosphodiester linkages.
C) Monosaccharides undergo condensation reactions to form polysaccharides.
Both starch and cellulose are glucose polymers. Why can animals easily degrade starch but not cellulose?
A) Cellulose is much more rigid than starches because of the extensive hydrogen bonding between adjacent glucose polymers in cellulose. Animals are unable to destroy these hydrogen bonds.
B) Animals have enzymes to degrade α-1,4-glycosidic bonds but not α-1,6-glycosidic bonds.
C) The glucose of cellulose has amino functional groups that participate in the formation of glycosidic bonds. Animals do not have the enzymes necessary to degrade these bonds.
D) Animals have the enzymes to degrade α-1,4-glycosidic bonds but not β-1,4-glycosidic bonds.
D) Animals have the enzymes to degrade α-1,4-glycosidic bonds but not β-1,4-glycosidic bonds.
The extensive hydrogen bonding found among parallel glucose polymers of cellulose enables it to function in plants as a(n) _____.
A) storage polysaccharide
B) structural polysaccharide
C) energy source
D) transport molecule
B) structural polysaccharide
What is the difference between peptidoglycans, found in the cell walls of prokaryotes, and chitin, found in the exoskeletons of insects?
A) Peptidoglycan is a glucose polymer, whereas chitin is made up of glucosamines.
B) Chitin has a β-1,4 linkage between its glucosamines, whereas peptidoglycan has an α-1,4 linkage between its constituent glucosamines.
C) Parallel strands of glucosamines in chitin are cross-linked by hydrogen bonds, whereas parallel strands of peptidoglycan are linked by tetrapeptides.
D) Chitin is a protein polymer, whereas the peptidoglycan of bacteria is a carbohydrate polymer linked by amino acids.
C) Parallel strands of glucosamines in chitin are cross-linked by hydrogen bonds, whereas parallel strands of peptidoglycan are linked by tetrapeptides.
What is the major difference between amylose and amylopectin?
A) Amylopectin is readily digested by most animal enzymes, whereas amylose is not.
B) Amylose is composed of glucose, whereas amylopectin is a ribose polymer.
C) Amylose is the storage polysaccharide found in plants. Amylopectin is a storage polysaccharide of animals.
D) Amylose is a straight-chain polymer of glucose, whereas amylopectin is highly branched.
D) Amylose is a straight-chain polymer of glucose, whereas amylopectin is highly branched.
Which one of the following polysaccharides contains a modified monosaccharide?
A) glycogen
B) cellulose
C) starch
D) chitin
D) chitin
Simple sugars can differ from one another in which of the following ways?
A) Carbons in a monosaccharide are attached in a covalent bond known as a glycosidic linkage.
B) Some have a carbonyl group; others do not.
C) They can differ in the location of their carbonyl group.
D) Some pairs of monosaccharides are twins, sharing identical structures.
C) They can differ in the location of their carbonyl group.
What is an important function of glycoproteins in animal cells?
A) Glycoproteins catalyze metabolic reactions.
B) Glycoproteins serve as shuttles bringing molecules into a cell.
C) Glycoproteins contribute to the hydrophobicity of the cell membrane.
D) Glycoproteins are important in cell–cell recognition.
D) Glycoproteins are important in cell–cell recognition.
When cells need energy, reactions break down _____ in the cell and capture the released energy by synthesizing _____.
A) carbon dioxide; glucose
B) glucose; ATP
C) phosphate; carbohydrates
D) carbon dioxide; oxygen
B) glucose; ATP
Which of the following statements accurately compares the different polysaccharides?
A) Chitin, cellulose, and peptidoglycan consist of long, parallel strands linked to one another.
B) Cellulose and peptidoglycan are effective structural molecules, whereas chitin is primarily important for energy storage.
C) Chitin is found only in fungi, cellulose in plants, and peptidoglycan in bacteria.
D) Peptidoglycan is less complex and more abundant than either chitin or cellulose.
A) Chitin, cellulose, and peptidoglycan consist of long, parallel strands linked to one another.
