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