Chapter 5: Carbohydrates
Carbohydrate molecular formula
(CH2O)n carbonyl group hydroxyl group carbon- hydrogen bonds (C-H)
Polymers that contain sugars... (a) may store hereditary information. (b) may store energy. (c) may protect cells. Both (b) and (c). (a), (b), and (c).
(a), (b), and (c).
How do monosaccharides structurally vary?
1. Location of the carbonyl group 2. Number of carbon atoms present 3. Spatial arrangement of their atoms 4. Linear and alternative ring form
Cellulose, chitin, and peptidoglycan function as structural molecules and withstand pulling and pushing forces well. Which structural feature is most directly responsible? See Section 5.3 A. Structural polysaccharides exist as sets of long, parallel strands that are linked to one another. B. Structural polysaccharides are built with β1, 4glycosidic linkages that are very strong. C. Structural polysaccharides exist as highly branched helices. D. Structural polysaccharides are built with β-1,4-glycosidic linkages, which are very resistant to hydrolysis.
A. Structural polysaccharides exist as sets of long, parallel strands that are linked to one another.
Cellulose is _____. A. a major structural component of plant cell walls B. a polymer composed of fructose monomers C. a storage polysaccharide for energy in plant cells D. used by plants to make glycogen E. a monomer of starch.
A. a major structural component of plant cell walls
Molecules that are amphipathic must contain _____. A. both hydrophilic and hydrophobic regions B. both carbohydrates and lipids C. glycerol D. carbon rings
A. both hydrophilic and hydrophobic regions
Which of these is a polysaccharide? A. cellulose B. galactose C. glucose D. lactose E. sucrose
A. cellulose
Glycogen
Animals store sugar stored in liver and muscle cells can be broken into glucose monomers for energy highly branched alpha-glucose polymer, nearly identical to starch - branches occur in about 1 out of 10 monomers
Select the statement that is incorrect. A. Complex sugars are carbohydrates. B. All carbohydrates have the general formula Cn(H2O)n. C. Simple sugars are carbohydrates. D. Simple sugars contain only carbon, oxygen, and hydrogen atoms.
B. All carbohydrates have the general formula Cn(H2O)n.
The bond that joins two monosaccharides into a disaccharide is a(n) _____. A. hydrogen bond B. glycosidic bond C. van der Waals bond D. ionic bond
B. glycosidic bond
galactose + galactose —> _____ by _____. A. sucrose + water ... dehydration synthesis B. lactose + water ... dehydration synthesis C. cellulose + water ... hydrolysis D. maltose + water ... dehydration synthesis E. starch + water ... dehydration synthesis
B. lactose + water ... dehydration synthesis
A simple sugar is composed of equal parts carbon and water, which gave rise to the general name of any sugar as a ____.
Carbohydrate
Carbohydrates hydroxyl groups structure.
Carbohydrates are aldehydes or ketones with multiple hydroxyl groups.
Which statement most accurately describes how the carbohydrates you ate during breakfast today are functioning in your body right now? See Section 5.3 A. They are storing chemical energy, indicating cell identity, and serving as the primary structural components of plasma membranes. B. They are storing and replicating hereditary information. C. They are catalyzing a variety of chemical reactions. D. They are storing chemical energy, indicating cell identity, and serving as raw material for synthesizing other molecules.
D. They are storing chemical energy, indicating cell identity, and serving as raw material for synthesizing other molecules.
glucose + glucose —> _____ by _____. A. sucrose + water ... dehydration synthesis B. lactose + water ... hydrolysis C. cellulose + water ... hydrolysis D. maltose + water ... dehydration synthesis E. starch + water ... dehydration synthesis
D. maltose + water ... dehydration synthesis
Which of these is a source of lactose? A. sugar cane B. starch C. sugar beets D. milk E. potatoes
D. milk
Lactose, the sugar in milk, is a ____, because it can be split into two monosaccharides.
Disaccaride
Glycogen A. the form in which plants store sugars B. a polysaccharide found in plant cell walls C. a transport protein that carries oxygen D. a source of saturated fat E. a polysaccharide found in animals
E. a polysaccharide found in animals
A____ cannot be hydrolyzed any further.
Monosaccharide
Starch
Plant store sugar Composed of alpha- glucose monomers Forms helix - amylose: unbranched starch; only alpha-1,4-glycosidic linkages - amylopectin: branched starch; some alpha-1,6-glycosidic linkages - branches occur about once in every 30 monomers
A carbohydrate that yields many monosaccharides when hydrolyzed is a ____.
Polysaccharide
chitin
a structural polymer found in cell walls of fungi and exoskeletons of insects and crustaceans monomers is N-acetylglucamine (NAG) Structure is similar to cellulose - beta-1, 4- glycosidic linkages with every other monomer flipped - linear strands with hydrogen bonds between them
amylopectin
branched starch; some alpha-1,6-glycosidic linkages - branches occur about once in every 30 monomers
_____ is the most abundant organic compound on Earth.
cellulose
What do carbohydrates do in cell identity?
display information on the outer surface of cells. - glycoproteins - glycolipids
glycolipids
key molecules in cell-cell recognition and signaling carbohydrates attached to lipids
glycoproteins
key molecules in cell-cell recognition and signaling carbohydrates attached to proteins
What do carbohydrates do?
precursors to larger molecules provide fibrous structure indicated cell identity Store chem energy
Cellulose
structural polymer forms a protective layer around plant cells called the cell wall made of beta- glucose monomers joined by beta-1,4-glycosidic linkages every other glucose of flipped - linear molecule
Peptidoglycan
structural polymer found in bacterial cell walls - long backbones of alternating monosaccharides - joined by beta- 1,4- glycosidic linkages - short amino acids chains form peptide bonds between adjacent strands
amylose
unbranched starch; only alpha-1,4-glycosidic linkages
