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Chapter 3 Summary

Key Takeaways

  • Biological Macromolecules and Their Importance: Living organisms require four major classes of biological macromolecules—carbohydrates, lipids, proteins, and nucleic acids—essential for structure, energy storage, genetic information, and cellular functions. These macromolecules are built from smaller subunits called monomers linked by covalent bonds.
  • Carbon’s Role in Molecular Diversity: Life is carbon-based due to carbon’s ability to form four covalent bonds, allowing for complex structures such as chains, rings, and branches. This versatility enables the diversity of biological molecules found in living organisms.
  • Formation and Breakdown of Macromolecules: Macromolecules are formed through dehydration synthesis, where monomers bond and release water. They are broken down via hydrolysis, which adds water to split polymers into monomers. Enzymes catalyze both processes, facilitating digestion and cellular metabolism.
  • Structure and Function of Carbohydrates, Lipids, and Proteins:
    • Carbohydrates provide energy (e.g., glucose, starch, glycogen) and structural support (e.g., cellulose, chitin).
    • Lipids (fats, phospholipids, steroids) store energy, form cell membranes, and act as hormones.
    • Proteins are polymers of amino acids with diverse functions, including enzymatic activity, transport, structural support, and immune defence.
  • Nucleic Acids as Genetic Blueprints: DNA and RNA are nucleic acids composed of nucleotides. DNA stores genetic information in a double-helix structure with base pairs (A-T, G-C), while RNA, typically single-stranded, plays a key role in protein synthesis, using uracil (U) instead of thymine (T).

OpenAI. (2025). ChatGPT. [Large language model]. https://chat.openai.com/chat
Prompt: Summarize the following content into five key takeaways.

 

Exercises

Text Description
1. Which of the following choices is an example of a monosaccharide?
  1. All options
  2. Galactose
  3. Glucose
  4. Fructose
2. What type of molecules are cellulose and starch examples of?
  1. Lipids
  2. Monosaccharides
  3. Disaccharides
  4. Polysaccharides
3. What parts are phospholipids important components of?
  1. The double bond in hydrocarbon chains
  2. The waxy covering on leaves
  3. The plasma membrane of cells
  4. The ring structure of steroids
4. What are the monomers that make up proteins called?
  1. Nucleotides
  2. Amino acids
  3. Chaperones
  4. Disaccharides

5. Functions that lipids serve in plants and/or animals include _____ and _____, and phospholipids and steroids are important components of _____.

6. Drag the words into the correct boxes
A change in _____ sequence can lead to the substitution of a different _____ for the normal one in a _____ chain that causes a change in _____ structure and function. For example, in sickle cell anemia, the _____ chain has a single _____ substitution. Because of this change, the _____ red blood cells assume a _____, which can result in serious health problems.
Possible answers:
  • amino acid
  • gene
  • disc-shaped
  • protein
  • amino acid
  • crescent shape
  • hemoglobin β
  • polypeptide
7. Amino acids are connected together in a chain by what type of bond?
  1. Ionic
  2. Van der Waals
  3. Hydrogen
  4. Covalent
8. The complex 3-D structure of this molecule is made up of a primary, secondary, tertiary, and sometimes quaternary level.
  1. Carbohydrate
  2. Lipid
  3. Nucleic acid
  4. Protein
9. There is a coating on the feathers of waterfowl such as ducks that keeps them from getting wet. What molecule would this water-repelling coating be made of?
  1. Lipid
  2. Nucleic acid
  3. Protein
  4. Carbohydrate
10. You are studying a newly discovered species and want to analyze its genetic information. What type of molecule would you analyze?
  1. Lipid
  2. Protein
  3. Carbohydrate
  4. Nucleic Acid
11. A molecule ending in “-ose” (such as glucose, dextrose, lactose) is most likely to be what type of macromolecule?
  1. Protein
  2. Carbohydrate
  3. Nucleic acid
  4. Lipid
12. Select all of the types of macromolecules that are commonly used as sources of energy.
  1. Carbohydrates
  2. Nucleic acids
  3. Lipids
  4. Proteins
13. You are analyzing a macromolecule and determine that it is made up of amino acids. What type of molecule is it?
  1. Nucleic Acid
  2. Protein
  3. Lipid
  4. Carbohydrate

14. Drag the macromolecules into the correct category. Categories: Proteins, Carbohydrates, Nucleic Acids, & Lipids.

  • Enzymes, structures, transport
  • Glucose
  • Amino Acids
  • Nucleotides
  • Sugar, phosphate, and nitrogenous base
  • Quick source of energy
  • Long-term energy storage
  • Store genetic information
  • Grains, fruits, and vegetables
  • Monosaccharides
  • Steroid hormones
  • DNA and RNA
  • Very complex 3-D structure
  • (C1H2O1)n
  • Fatty acids
  • Hydrophobic

15. Match macromolecule structure vs function.

Categories: Carbohydrate Structure, Carbohydrate Function, Protein Structure, Protein Function, Lipid Structure, Lipid Function, Nucleic Acid Structure, Nucleic Acid Function

Options:

  • Fatty acid chains contain between 4 and 24 carbons connected in a chain.
  • (C1H2O1)n molecules contain carbon-carbon and carbon-hydrogen bonds
  • The order of the 20 different amino acids determines the shape.
  • Polysaccharides form long fibrous chains.
  • Waxes are hydrophobic.
  • Specific order of nucleotides is important
  • Carbon-carbon and carbon-hydrogen bonds contain high amounts of energy.
  • Order of nucleotides provides instructions to the cell.
  • Long fibrous chains can build structures such as cell walls.
  • Hydrophobic molecules repel water.
  • Molecules can have many different functions depending on their shape.
  • Carbon-carbon and carbon-hydrogen bonds contain high amounts of energy.
Answers:
1.  a. all options
2. d. polysaccharides
3. c. the plasma membrane of cells
4. b. amino acids
5. Functions that lipids serve in plants and/or animals include energy storage/insulation and insulation/energy storage, and phospholipids and steroids are important components of cell membranes/cell membrane/membranes/membrane.
6. A change in gene sequence can lead to the substitution of a different amino acid for the normal one in a polypeptide chain that causes a change in protein structure and function. For example, in sickle cell anemia, the hemoglobin β chain has a single amino acid substitution. Because of this change, the disc-shaped red blood cells assume a crescent shape, which can result in serious health problems.
7. d. Covalent
8. d. Protein
9.  a. Lipid
10. d. Nucleic Acid
11. b. Carbohydrate
12. a. Carbohydrates; c. Lipids
13. b. Protein
14. Carbohydrates: Quick source of energy; Glucose; (C1H2O1)n; Grains, fruits, and vegetables; Monosaccharides

Proteins: Amino Acids; Very complex 3-D structure; Enzymes, structures, transport

Nucleic Acids: Store genetic information; DNA and RNA; Nucleotides; Sugar, phosphate, and nitrogenous base

Lipids: Fatty acids; Hydrophobic; Steroid hormones; Long-term energy storage

15. Carbohydrate Structure:

  • (C1H2O1)n molecules contain carbon-carbon and carbon-hydrogen bonds
  • Polysaccharides form long fibrous chains.

Carbohydrate Function:

  • Carbon-carbon and carbon-hydrogen bonds contain high amounts of energy.
  • Long fibrous chains can build structures such as cell walls.

Protein Structure:

  • The order of the 20 different amino acids determines the shape.

Protein Function:

  • Molecules can have many different functions depending on their shape.

Lipid Structure:

  • Fatty acid chains contain between 4 and 24 carbons connected in a chain.
  • Waxes are hydrophobic.

Lipid Function:

  • Hydrophobic molecules repel water.
  • Carbon-carbon and carbon-hydrogen bonds contain high amounts of energy.

Nucleic Acid Structure:

  • Specific order of nucleotides is important

Nucleic Acid Function:

  • Order of nucleotides provides instructions to the cell.

Flashcards

Text Description
  1. Biological macromolecules: Large, complex molecules essential to life
  2. Organic: Molecules containing carbon; fundamental to living organisms
  3. Carbon skeleton: chain or ring of carbon atoms that forms the backbone of an organic molecule
  4. Monomers: Building block of larger molecules; Monomers link together to form a polymer
  5. Polymer: A large molecule composed of repeating building blocks called monomers
  6. Dehydration synthesis: A chemical reaction where two molecules bond by removing a water molecule
  7. Hydrolysis: A chemical reaction where a molecule is split into two smaller molecules by the addition of a water molecule
  8. Carbohydrates: biological macromolecule that serves as a primary energy source for living organisms; sugars
  9. Monosaccharides: simplest form of carbohydrates, consisting of single sugar molecules; e.g. glucose, fructose, galactose
  10. Isomer: Molecules with the same chemical formula but different structural arrangements
  11. Disaccharides: Carbohydrates composed of two monosaccharides bonded together; e.g. sucrose, lactose
  12. Polysaccharides: Complex carbohydrates composed of long chains of monosaccharides linked together; e.g. starch, glycogen, cellulose, chitin
  13. Chitin: Structural polysaccharide forming the exoskeleton of insects and fungal cell walls
  14. Starch: Energy-storage polysaccharide in plants; composed of glucose units
  15. Glycogen: Energy-storage polysaccharide in animals; stored mainly in liver and muscle cells
  16. Cellulose: Structural polysaccharide provides rigidity to plant cell walls; it is not digestible by humans (“dietary fibre”)
  17. Lipids: Diverse group of hydrophobic compounds that are insoluble in water; e.g. fats, phospholipids, steroids
  18. Fats: A type of lipid that serves as a major energy source, provides insulation, and protects vital organs
  19. Triglyceride: composed of one glycerol molecule bonded to three fatty acid chains
  20. Saturated Fatty Acids: Fatty acids with no double bonds between carbon atoms; solid at room temperature (e.g. animal fats)
  21. Unsaturated Fatty Acids: Fatty acids containing one or more double bonds; liquid at room temperature (e.g. plant oils)
  22. Oil: Unsaturated fats; liquid at room temperature; usually of plant origin
  23. Phospholipid: Major component of cell membranes; contains a hydrophilic “head” and two hydrophobic “tails”
  24. Steroids: Lipids with a ring structure; important components of cell membranes (e.g. cholesterol) or are hormones (e.g. testosterone and estrogen)
  25. Proteins: Biological macromolecules composed of amino acids; most abundant organic molecules in living organisms; have a wide range of functions
  26. Amino Acids: Building blocks (monomers) of proteins, each containing an amino group, a carboxyl group, and a unique side chain
  27. Peptide Bond: A covalent bond formed between two amino acids during protein synthesis
  28. Polypeptides: Long chains of amino acids linked together by peptide bonds; Fold into specific shapes to form proteins
  29. Primary Protein Structure: Sequence of amino acids in a protein chain
  30. Secondary Protein Structure: Local folding of polypeptide chains into alpha-helices and beta-pleated sheets stabilized by hydrogen bonds
  31. Tertiary Protein Structure: The overall three-dimensional shape of a polypeptide is formed by interactions among amino acid side chains
  32. Quaternary Protein Structure: Structure formed by two or more polypeptide chains (subunits) assembling into a functional protein
  33. Denaturation: Loss of protein structure and function due to environmental conditions like heat, pH, or chemicals
  34. Nucleic Acids: Biological macromolecules essential for storing and transmitting genetic information; e.g. DNA and RNA; composed of long chains of nucleotides
  35. Nucleotides: building blocks of nucleic acids (DNA and RNA); Each nucleotide consists of a nitrogenous base, a sugar molecule and a phosphate group
  36. DNA: Deoxyribonucleic Acid; Genetic material in living organisms
  37. RNA: Ribonucleic Acid; Molecule involved in protein synthesis; single-stranded nucleic acid essential for translating DNA instructions into proteins
  38. 4 main biological macromolecules: Carbohydrates, Lipids, Proteins, Nucleic Acids
  39. Why is carbon a versatile atom? Contains four electrons in its outer shell so can form four covalent bonds with other atoms or molecules. Carbon atoms often link together to form a variety of carbon skeletons
  40. Groups of carbohydrates: monosaccharides, disaccharides, polysaccharides
  41. Monomer of carbohydrates: monosaccharide
  42. Functions of starch: Energy storage for plants
  43. Functions of glycogen: Energy storage for animals
  44. Functions of cellulose: Provides structural support in plant cell walls; helps maintain cell shape and rigidity
  45. Functions of chitin: Provides structural support in fungal cell walls; forms exoskeletons in arthropods
  46. Groups of lipids: Fats, phospholipids, steroids
  47. Common feature of all lipids: hydrophobic (“water-fearing”); insoluble in water because they are nonpolar molecules
  48. Functions of fats: long-term energy storage, insulation for body and protect vital organs
  49. Functions of phospholipids: form cell membranes
  50. Saturated fats are saturated with: hydrogen
  51. Monomer of proteins: amino acid
  52. Components of amino acids: Central carbon atom bonded to an amino group (NH2), a carboxyl group (COOH), a hydrogen atom, and a variable side group (R group)
  53. Types of proteins: Enzymes, transport, structural, hormones, defence, contractile, storage
  54. Levels of protein structure: Primary, secondary, tertiary, quaternary
  55. Monomer of nucleic acids: nucleotide
  56. Components of nucleotide: Nitrogenous base, a pentose (five-carbon) sugar, and a phosphate group
  57. Types of nucleic acids: DNA and RNA
  58. Structure of DNA: double-helix; sugar-phosphate backbone; sugar is deoxyribose; nitrogenous bases are adenine (A), guanine (G), cytosine (C), and thymine (T)
  59. Structure of RNA: single stranded; sugar-phosphate backbone; sugar is ribose; nitrogenous bases are adenine (A), guanine (G), cytosine (C), and uracil (U)

OpenAI. (2025). ChatGPT. [Large language model]. https://chat.openai.com/chat
Prompt: Can you give me brief summaries of these key terms

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