1.1.2 Molecules Quiz

1. Explain why water is described as a dipolar molecule.

2. Give examples of hydrogen bond formation contributing to the structure of molecules.

3. Explain why sodium chloride dissolves in water.

4. Explain why some organic molecules, such as simple sugars and alcohols, form aqueous solutions but others, such as lipids, do not.

5. Why is water an important transport medium in animals? Write down as many examples of where water is important in transport as you can.

6. Suggest where in the human body, apart from the blood and the protoplasm of cells, you might find significant quantities of water. For each of your suggestions, suggest the function of the water.

7. The formula for stearic acid is C17H35COOH. It is often written out as CH3(CH2)16COOH . The formula for oleic acid (another fatty acid) is C17H33COOH. Suggest which of these two fatty acids is found in animal tissues and which in plants, giving reasons in support of your answer. Which one is likely to be liquid at room temperature.

8. Explain how phospholipids are involved in the structure of cell membranes.

9. Explain by means of a diagram how a glycosidic bond is formed when two monosaccharides, such as glucose, undergo a condensation reaction to form a disaccharide.

10. Glycogen are important storage molecules. Explain how they are suited to this function.

11. Describe how the structure of an α-helix is maintained. How does the structure of a β-pleated sheet differ?

12. Construct a table of differences between fibrous and globular proteins, giving an example of each.

13. Make a table to show the substances which need to be taken up by living animal cells. For each substance give a reason for uptake.

14. List the ways in which materials can be transported across membranes. For each method, state whether it is