Rucete ✏ Campbell Biology In a Nutshell
Unit 1 THE CHEMISTRY OF LIFE — Concept 5.2 Carbohydrates Serve as Fuel and Building Material — Practice Questions
(Multiple Choice — Click to Reveal Answer)
1. What elements are found in all carbohydrates?
- Carbon, nitrogen, oxygen
- Carbon, hydrogen, oxygen
- Hydrogen, oxygen, sulfur
- Carbon, phosphorus, hydrogen
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2. Carbon, hydrogen, oxygen
2. What is the general formula for many monosaccharides?
- CH₂
- CH₄
- CH₂O
- C₂H₄O₂
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3. CH₂O
3. Which of the following is a monosaccharide?
- Sucrose
- Starch
- Glucose
- Cellulose
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3. Glucose
4. What type of sugar is formed when two monosaccharides are joined?
- Polysaccharide
- Disaccharide
- Pentose
- Trioses
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2. Disaccharide
5. What is the covalent bond called that links monosaccharides?
- Peptide bond
- Phosphodiester bond
- Hydrogen bond
- Glycosidic linkage
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4. Glycosidic linkage
6. What process forms a disaccharide from two monosaccharides?
- Hydrolysis
- Dehydration reaction
- Denaturation
- Neutralization
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2. Dehydration reaction
7. Which of the following is a disaccharide?
- Glucose
- Fructose
- Lactose
- Glycogen
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3. Lactose
8. What type of sugar is composed of many monosaccharides?
- Disaccharide
- Polysaccharide
- Monosaccharide
- Isomer
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2. Polysaccharide
9. What is the storage form of glucose in animals?
- Starch
- Cellulose
- Glycogen
- Chitin
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3. Glycogen
10. What is the storage polysaccharide in plants?
- Glycogen
- Chitin
- Starch
- Sucrose
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3. Starch
11. What is the structural polysaccharide found in plant cell walls?
- Starch
- Glycogen
- Cellulose
- Lactose
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3. Cellulose
12. Which of the following is not digestible by most animals?
- Glucose
- Starch
- Cellulose
- Sucrose
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3. Cellulose
13. What type of polysaccharide is chitin?
- Storage in plants
- Storage in animals
- Structural in animals and fungi
- Sugar used in photosynthesis
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3. Structural in animals and fungi
14. Which monosaccharide is common to both maltose and sucrose?
- Fructose
- Galactose
- Glucose
- Ribose
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3. Glucose
15. What is the main function of carbohydrates in cells?
- Genetic storage
- Hormone signaling
- Fuel and structural support
- Protein synthesis
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3. Fuel and structural support
16. Which is a structural isomer of glucose?
- Glycogen
- Fructose
- Sucrose
- Starch
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2. Fructose
17. What is the primary difference between starch and cellulose?
- Starch is a protein; cellulose is a sugar
- Starch is found in animals; cellulose in plants
- Starch has alpha linkages; cellulose has beta linkages
- Starch is a disaccharide; cellulose is a monosaccharide
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3. Starch has alpha linkages; cellulose has beta linkages
18. What is the term for two sugar monomers joined together?
- Monosaccharide
- Polysaccharide
- Disaccharide
- Oligosaccharide
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3. Disaccharide
19. Which of these carbohydrates is typically used for short-term energy storage?
- Cellulose
- Glycogen
- Chitin
- DNA
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2. Glycogen
20. What reaction breaks down polysaccharides into monosaccharides?
- Hydrolysis
- Dehydration
- Condensation
- Phosphorylation
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1. Hydrolysis
21. What enzyme is required to hydrolyze starch into glucose?
- Lactase
- Amylase
- Pepsin
- Lipase
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2. Amylase
22. Which carbohydrate is found in the exoskeleton of insects?
- Glycogen
- Cellulose
- Chitin
- Sucrose
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3. Chitin
23. Which of the following is NOT a polymer?
- Starch
- Glucose
- Cellulose
- Glycogen
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2. Glucose
24. What is a distinguishing feature of cellulose that makes it strong?
- Glycosidic linkages in random order
- Alpha glucose monomers
- Unbranched chains with hydrogen bonding between them
- Presence of nitrogen groups
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3. Unbranched chains with hydrogen bonding between them
25. What type of reaction would build a polysaccharide?
- Hydrolysis
- Dehydration
- Oxidation
- Reduction
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2. Dehydration
26. Why can’t humans digest cellulose efficiently?
- It contains nitrogen
- It lacks glycosidic linkages
- Humans lack enzymes to break beta linkages
- It is hydrophobic
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3. Humans lack enzymes to break beta linkages
27. Which feature of cellulose enables it to form rigid structures?
- Presence of sulfhydryl groups
- Alpha-glucose orientation
- Hydrogen bonds between parallel chains
- Random folding of chains
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3. Hydrogen bonds between parallel chains
28. Why is starch digestible but cellulose is not (for most animals)?
- Starch is smaller
- Starch has beta linkages
- Starch has alpha linkages, which our enzymes recognize
- Cellulose dissolves too quickly
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3. Starch has alpha linkages, which our enzymes recognize
29. Which two monosaccharides make up maltose?
- Glucose + Glucose
- Glucose + Fructose
- Glucose + Galactose
- Fructose + Fructose
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1. Glucose + Glucose
30. What makes glycogen more suitable for animal energy storage compared to starch?
- It’s smaller and nonpolar
- It’s more branched and compact
- It’s made of cellulose
- It contains nitrogen
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2. It’s more branched and compact
31. What distinguishes structural polysaccharides from storage polysaccharides?
- Presence of carbon atoms
- Glycosidic linkage type and function
- Degree of solubility
- Location in the nucleus
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2. Glycosidic linkage type and function
32. How does chitin differ from cellulose?
- Chitin has amino groups attached
- Cellulose has double bonds
- Chitin is found only in plants
- Chitin contains sulfur
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1. Chitin has amino groups attached
33. What type of organism produces enzymes capable of digesting cellulose?
- Humans
- Bacteria and some protists
- Insects
- Viruses
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2. Bacteria and some protists
34. What allows herbivores like cows to digest cellulose?
- They have acidic stomachs
- They chew food longer
- They host symbiotic microbes in their digestive systems
- They convert cellulose into starch first
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3. They host symbiotic microbes in their digestive systems
35. Which carbohydrate has beta 1–4 linkages and forms linear, unbranched chains?
- Starch
- Glycogen
- Cellulose
- Fructose
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3. Cellulose
36. What is the molecular formula of glucose, and what ratio does it reflect?
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Glucose has the formula C₆H₁₂O₆, reflecting a 1:2:1 ratio of carbon, hydrogen, and oxygen.
37. Explain how a glycosidic linkage is formed between two monosaccharides.
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It forms via a dehydration reaction, where a hydroxyl group (—OH) and a hydrogen (—H) are removed to create a covalent bond between the sugars.
38. Compare the structure of starch and cellulose in terms of their monomer orientation and glycosidic linkages.
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Starch has alpha-glucose monomers joined by α(1→4) linkages, forming helical chains; cellulose has beta-glucose with β(1→4) linkages forming straight, rigid chains.
39. Why can most animals not digest cellulose?
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They lack the enzymes needed to break β(1→4) glycosidic linkages found in cellulose.
40. Describe how herbivores such as cows are able to digest cellulose.
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They rely on symbiotic microbes in their digestive systems that produce cellulase enzymes to break down cellulose.
41. What is the structural role of cellulose in plant cells?
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Cellulose is the primary component of plant cell walls, providing rigidity and support through hydrogen bonding between chains.
42. Explain the functional significance of chitin in fungi and arthropods.
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Chitin forms the cell walls of fungi and exoskeletons of arthropods, offering strength and protection due to its tough, nitrogen-containing structure.
43. What makes glycogen more readily mobilized for energy use than starch?
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Its highly branched structure allows enzymes easier and faster access to glucose monomers.
44. How is a disaccharide different from a polysaccharide?
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A disaccharide consists of two monosaccharides linked together, while a polysaccharide is composed of many monosaccharide units.
45. What is the significance of isomerism in monosaccharides like glucose and fructose?
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They have the same chemical formula but different structures, leading to different functional properties and biological roles.
46. What determines whether a polysaccharide is used for storage or structure?
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The type of glycosidic linkage (alpha or beta) and the branching pattern determine its biological function.
47. Name one disaccharide and the two monomers that form it.
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Sucrose, made of glucose and fructose.
48. Why do starch and cellulose, both made of glucose, have such different properties?
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They differ in the orientation of glucose monomers and the type of glycosidic bonds (alpha in starch, beta in cellulose), affecting structure and digestibility.
49. How do humans use carbohydrates for quick energy?
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Monosaccharides like glucose are rapidly absorbed and used in cellular respiration to generate ATP.
50. What role do glycosidic linkages play in carbohydrate function?
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They determine the structure of the carbohydrate and influence whether it's used for energy storage or structural support.