Summary

• What elements do organic compounds always contain?

  Carbon (C), hydrogen (H), and oxygen (O)
• What are the important organic compounds in living organisms?

  Carbohydrates, proteins, lipids, nucleic acids, and enzymes
• What are inorganic compounds?


  Compounds that can contain any combination of elements but rarely contain hydrogen and carbon together
• What is the most important inorganic compound in living organisms?

  Water
• What is the main role of carbohydrates in living organisms?

  To provide energy
• What are monosaccharides? Give an example.

  The simplest carbohydrates, for example, glucose
• What are disaccharides and give an example?

  Formed when two monosaccharides combine, for example, sucrose
• What are polysaccharides and give examples?

  Formed by a large number of monosaccharides, for example, starch and cellulose
• What are lipids made up of?


  Three fatty acids and a glycerol molecule
• What is the role of lipids in living organisms?

  To supply energy and form structural components such as cell membranes
• What are proteins made up of?

  Large chains of amino acids
• What are the functions of proteins in living organisms?

  Important in cell structure and functions, such as transport of substances and regulation of body processes
• What are enzymes?


  Specialized proteins that speed up chemical reactions
• How are enzymes affected by environmental conditions?

  They are sensitive to temperature and pH
• What does the lock-and-key model explain?

  How enzymes work
• Where is DNA found in cells?

  In the nucleus
• Where does RNA occur in cells?

  In the nucleolus, cytoplasm, and on the ribosomes
• What role do nucleic acids play in cells?

  They control a cell's structure and functions
• What are vitamins?


  Organic compounds required by animals in very small quantities
• What can shortages of vitamins lead to?

  Deficiency diseases, for example, rickets caused by a lack of vitamin D
• What percentage of a cell's mass is made up of water?

  60-70%
• What is the role of water in living organisms?

  Required for many metabolic processes
• What are minerals?


  Inorganic compounds required by living things for normal growth, development, and functioning
• What are micro-elements?


  Elements needed in relatively small quantities by plants and animals
• How do animals obtain minerals?

  From the food they eat
• How do plants absorb minerals?

  Through their roots from the soil
• What is the effect of overusing artificial inorganic fertilizers?

  It breaks down the soil structure and can lead to eutrophication of water bodies