Cell Compounds ( /44)

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1 Biology The LINK: First Assignment (Part 2) Name: Cell Compounds ( /44) Worksheet: /31 Quiz: /13 For Office Use Only: PLO A3 Indicators 1 2 PLO B2 Indicators 1 2 PLO B3 Indicators 1 2 PLOs Met Use the information found in the Part 2 Readings to answer the following questions. Please put your answers into your own words, as directly copied answers will receive a zero grade. Lesson 1: Water 1. Sketch a ball and stick diagram of a water molecule. Label the atoms and indicate the partial charges that exist in a water molecule. [You may provide a copy/pasted diagram provided you cite the source... e.g. the URL if from the webpage from which the diagram was obtained]. (2 marks) 2. What type of bond is found between the hydrogen and oxygen atoms in the water molecule? (1 mark) 3. What is the name given to the attractive forces that exist between water molecules that are close to each other and causes them to stick together? (1 mark) 4. a) Draw a diagram with five water molecules to illustrate hydrogen bonding between water molecules (start with one molecule in the middle). (2 marks) b) How many water molecules can hydrogen bond with a single water molecule? (1 mark) Page 1 of 6

2 5. List two everyday observations that provide evidence of water molecules sticking together because of hydrogen bonding. (2 marks) Lesson 1.2: The Many Roles of Water 6. Describe and give an example for the role of water in each circumstance (6 marks): a) Water as a solvent: b) Water as a temperature regulator: c) Water as a lubricant: Lesson 1.3: Acids, Bases and Buffers 7. Define the following terms (3 marks): a) Acid: b) Base: c) ph scale: Page 2 of 6

3 8. Label the following ph values as acidic, basic or neutral (5 marks). a) ph 0: b) ph 7: c) ph 13: d) ph 6: e) ph 9: 9. Hydrochloric acid (HCl), a strong acid, is added to a beaker of pure water (3 marks). a) What is the ph of pure water in the beaker before the acid is added? b) How does the hydrogen ion (H + ) concentration change after the acid is added? c) What happens to the ph in the beaker as the acid is added? 10. If the ph of a solution changes from a value of 6 to a value of 4 how much has the hydrogen ion (H + ) concentration changed? (1 mark) 11. If the ph of a solution changes from a value of 9 to a value of 12 how much has the hydroxide ion (OH - ) concentration changed? (1 mark) 12. What is a buffer? (1 mark) 13. Why is ph balance important in biological systems? What prevents rapid or large changes to the ph in the blood of humans? (2 marks) Page 3 of 6

4 Biology 12 Cell Compounds Quiz Name: This quiz is open book (you may use your notes or other reference materials to answer the questions). (13 marks) Multiple Choice: Please circle the letter of the best answer (or type an X beside). 1) Which of the following is necessary for hydrogen bonding: a) Peptide bonds. b) Hydrogen ions. c) Polar molecules. d) Equal sharing of electrons. 2) For a water molecule, the charge associated with oxygen is, while the charges associated with the hydrogen atoms are. a) Negative, positive. b) Partially negative, partially positive. c) Positive, negative. d) Partially positive, partially negative. 3) The type of bond between two water molecules is: a) an ionic bond. b) a peptide bond. c) a covalent bond. d) a hydrogen bond. 4) The phenomenon of surface tension is a result of between water molecules. a) Cohesion. b) Adhesion. c) Capillary action. d) Imbibition. 5) Water molecules are: a) Charged and polar. b) Uncharged and polar. c) Charged and non-polar. d) Uncharged and non-polar. Page 4 of 6

5 6) Water is an excellent solvent because the water molecule is: a) Ionic. b) Polar. c) Acidic. d) Saturated. 7) A role of water in cells of the human body is to: a) Emulsify fats. b) Act as a solvent. c) Act as an enzyme. d) Denature proteins. 8) A solution with a high concentration of hydrogen ions (H+) is: a) Basic. b) Acidic. c) Neutral. d) Isotonic. 9) A solution with a ph of 2 is: a) a strong base. b) a strong acid. c) neutral. d) a weak base. 10) Acids are defined as compounds that dissociate in water to release: a) chloride ions (Cl - ). b) calcium ions (Ca 2+ ). c) hydrogen ions (H + ). d) Hydroxide ions (OH - ). 11) The purpose of a buffer system is to cause: a) a basic ph to become acidic. b) a constant ph to be maintained. c) a basic ph to become neutral. d) an acidic ph to become neutral. Page 5 of 6

6 12) Although hydrogen ions are regularly released in the circulatory system, the ph of the blood remains relatively constant. This indicates the presence of a: a) base. b) buffer. c) nucleic acid. d) polysaccharide. 13) Many of the body s systems function as a neutral ph. The number that represents this ph is: a) 3. b) 5. c) 7. d) 9. ================================== Congratulations! You have completed the First Assignment for Biology 12 at The Link! Please attach Parts 1 and 2 of your first assignment to your registration forms and submit them according to the instructions given in the registration web page. After your forms have been accepted, you may meet your teacher if you wish (although this is not mandatory). Your teacher will you with instructions on how to get started on the remainder of the course. Thank you, and we will see you soon! === End of Document === Page 6 of 6

Cell Compounds, Bonds, Reactions - 1

Biology 12 Name: KEY Cell Compounds, Bonds, Reactions - 1 Order of Subtopics Covered: 1. Chemical Bonds a. Ionic b. Covalent 2. Water a. Hydrogen Bonds b. Importance 3. Acids & Bases a. ph b. Buffers 4.