chapter 1 - biological molecules

• The structure of proteins is determined by the primary, secondary, tertiary, and quaternary structures.
• What are the four types of biological molecules essential for living organisms?

  Carbohydrates, lipids, proteins, and nucleic acids
• What elements are found in carbohydrates?

  Carbon (C), hydrogen (H), and oxygen (O)
• What elements are found in lipids?

  Carbon (C), hydrogen (H), and oxygen (O)
• What elements are found in proteins?

  Carbon (C), hydrogen (H), oxygen (O), nitrogen (N) and sometimes sulphur(S)
• What elements are found in nucleic acids?

  Carbon (C), hydrogen (H), oxygen (O), nitrogen (N), and phosphorus (P)
• How are carbohydrates used by cells?

  As respiratory substrates and structural components in plasma membranes and cell walls
• What roles do proteins play in living organisms?

  They form cell structures, act as enzymes, and serve as chemical messengers and blood components
• What is a condensation reaction?

  A reaction that joins molecules together with the formation of a chemical bond and the elimination of a water molecule
• What is a hydrolysis reaction?

  A reaction that breaks a chemical bond between two molecules using a water molecule
• Compare condensation and hydrolysis reactions.

  • Condensation Reaction:
  • Joins molecules
  • Forms a chemical bond
  • Eliminates a water molecule

  
  

  • Hydrolysis Reaction:
  • Breaks chemical bonds
  • Uses a water molecule
• What elements do all carbohydrates, including glucose, contain?

  Oxygen, carbon, and hydrogen
• What are monosaccharides?

  Simple sugars that are monomers from which larger carbohydrates are made
• Give two examples of monosaccharides.

  Glucose and fructose
• What is a key feature of monosaccharides?

  They are soluble in water
• Why can glucose be transported around organisms?

  Because it contains many hydroxyl (OH) groups that form hydrogen bonds with water
• What happens when the bonds in glucose are broken?

  Energy is released
• What is the general formula for monosaccharides?

  (CH2O)n
• How are monosaccharides classified?

  • Based on the number of carbons:
  • Pentose sugars (5 carbons)
  • Hexose sugars (6 carbons)
• What is formed when two monosaccharides undergo a condensation reaction?

  A glycosidic bond
• What occurs during the condensation reaction between two monosaccharides?

  A hydroxyl group on one monosaccharide reacts with a hydroxyl group on another, releasing water
• What disaccharide is formed from glucose and fructose?

  Sucrose
• What disaccharide is formed from glucose and galactose?

  Lactose
• What are polysaccharides?

  Polymers usually containing tens, hundreds, or thousands of monosaccharides
• What type of reaction do polysaccharides undergo when hydrolyzed?

  Hydrolysis
• What are the properties of polysaccharides?

  • Compact(coiled) - lot of energy can be stored
  • Insoluble in water - do not impact the water potential of the cell
  • Large - prevents diffusion out of cells
  • Easily hydrolyzed - to α-glucose for energy
• What is cellulose made of?

  Thousands of beta glucose molecules
• What is the role of cellulose in plants?

  It provides rigidity to plant cell walls
• How are cellulose molecules arranged to provide strength?

  there are hydrogen bonds which are formed between adjacent cross links. The cellulose molecules are arranged in parallel to form microfibrils and macrofibrils
• What are the two types of groups that can be found in lipids?

  Hydrophilic and hydrophobic groups
• What are the characteristics of phospholipids

  
  

  • Composed of 2 phospholipid layers
  • One layer is hydrophilic, the other is hydrophobic
  • Formed due to the repulsion of water by fatty acids
• What is the role of phospholipids in cellular structures?

  They create a barrier that separates the inside of the cell from the outside environment
• What is the structure of a phospholipid?

  A phospholipid consists of a glycerol and 2 fatty acids
• How do phospholipids arrange themselves in water?

  Hydrophilic heads face water while hydrophobic tails face away
• What are the main functions of proteins?

  • Enzymatic activity
  • Transport (e.g., hemoglobin)
  • Structural support
• What are the building blocks of proteins?

  Amino acids
• What is the process by which amino acids form proteins?

  Condensation reactions
• How many standard amino acids are there?

  20
• What types of bonds contribute to the tertiary structure of a protein?

  ionic, disulfide, and hydrogen bonds
• What is the primary structure of proteins?

  The sequence of amino acids joined by a peptide bond