Chapter 2 Introductory Chemistry

Transcription

1 Name Date Physiology & Anatomy Chapter 2 Introductory Chemistry Think About It: Name the three sub-atomic particles, and describe their charge properties: If an atom has 8 protons and 9 electrons, what is its net charge? If an atom has 11 protons and 10 electrons, what is its net charge? How is the mass number of an atom different from its atomic number? Figure 2.1 Question What is the atomic number of carbon? Figure 2.2 Question Which four of these elements are most abundant in living organisms? Name each of the above atoms. Chapter 2 Introductory Chemistry 1

2 Figure 2.3 Question Which of the molecules shown here is a compound? Think About It: Circle the following formulas which represent compounds. O 2 H 2 O CO 2 NaCl When sodium chloride (NaCl) is dissolved in water, it breaks into sodium ions (Na + ) and chloride ions (Cl - ). Which is the cation? Which is the anion? Figure 2.4 Will the element potassium (K) be more likely to form an anion or a cation? Explain. (Hint: Look back to Figure 2.2 for the atomic structure of K.) Figure 2.5 Studying the two images at the right, indicate what is the main difference between a covalent bond and ionic bond? Chapter 2 Introductory Chemistry 2

3 Think About It: Describe the means by which hydrogen bonds form. What is the difference between potential and kinetic energy? Fat stored in the body s cells is a form of what kind of energy? Describe the four different types of chemical reactions in the text: Checkpoint 1. Compare the meanings of atomic number, mass number, ion, and molecule. Chapter 2 Introductory Chemistry 3

4 2. What is the significance of the valence (outer) electron shell of an atom? 3. Distinguish among ionic, covalent, and hydrogen bonds. 4. Explain the difference between anabolism and catabolism. Which involves synthesis reactions? Think About It: List and describe the four properties of water that explain why it is such a vital compound for living organisms: Chapter 2 Introductory Chemistry 4

5 What is an acid? What is a base? What is a salt? Figure 2.6 The compound CaCO 3 (calcium carbonate) dissociates into a calcium ion (Ca 2+ ) and a carbonate ion (CO 3 2- ). Is it an acid, a base, or a salt? Explain. What about H 2 SO 4, which dissociates into two H + and one SO 4 2-? Explain. If you were suffering from an acid stomach from too many soft tacos, which of the above substances would you choose to neutralize the acid? Figure 2.7 Which ph is more acidic, 6.82 or 6.91? Which ph is closer to neutral, 8.41 or 5.59? Think About It: Carbohydrates are divided into three groups, based on their size. What are those three groups? Provide an example of each Chapter 2 Introductory Chemistry 5

6 Figure 2.8 Questions How many carbons are there in fructose? In sucrose? Contrast the mechanistic processes of hydrolysis and dehydration syntheses. Figure 2.9 Questions Which body cells store glycogen? What monomers make up glycogen molecules? Think About It: How are lipids different from carbohydrates? How are they similar? What is the function of lipids in the body? Chapter 2 Introductory Chemistry 6

7 Why are lipids an ideal storage form of chemical energy? If you decide to cut fats out of your diet in an effort to control your weight, and instead eat lots and lots of yummy carbohydrates and proteins, will you lose fat? What does the body do with excess energy intake in the form of carbohydrates and proteins? Martian scenario You and your Martian exercise buddy are comparing your progress in your attempts at better fitness. The conversation takes a quick turn in the wrong direction when you both compare your weights (bad idea). You both figure out you weigh exactly the same (and you are both the same height). Since your friend is a Martian however, she explains that she stores excess energy in the form of carbohydrates, not as lipids. You then show her your brand-new scuba-diving outfit, and she squeals with glee at its coolness. She tries to put it on how does it fit? Explain. Figure 2.10 Questions How many double bonds are there in a monounsaturated fatty acid? Describe the chemical characteristics of saturated, monounsaturated, and polyunsaturated fats. How do these chemical characteristics affect their physical characteristics? Chapter 2 Introductory Chemistry 7

8 Figure 2.11 Question Looking at the two figures below, describe how a phospholipid differs from a triglyceride, both functionally and structurally. Figure 2.12 Question Which dietary lipids are thought to contribute to atherosclerosis? Compare the figure above of the steroids cholesterol and estradiol with the structures of phospholipids and triglycerides. How are the steroids different both structurally and functionally from phospholipids and triglycerides? Chapter 2 Introductory Chemistry 8

9 Figure 2.13 Question How many peptide bonds would there be in a tripeptide? What three atoms are common to carbohydrates, fats and proteins? What is the name of the process whereby a polypeptide chain is broken down to amino acids? Describe the process whereby amino acids are joined together to form a polypeptide chain. Figure 2.14 Question What part of an enzyme combines with its substrate? Figure 2.15 Question Which nitrogenous base is not present in RNA? Which nitrogenous base is not present in DNA? Figure 2.16 Question What are some cellular activities that depend on energy supplied by ATP? Chapter 2 Introductory Chemistry 9

10 Checkpoint 5. How do inorganic compounds differ from organic compounds? 6. What function does water perform in the body? 7. Distinguish among saturated, monounsaturated, and polyunsaturated fats. 8. What are the important properties of enzymes? 9. How do DNA and RNA differ, both structurally and functionally? Chapter 2 Introductory Chemistry 10

11 10. Why is ATP important? Critical Thinking Applications 1. While having a tea party, your three-year-old cousin Sabrina added milk, lemon juice, and lots of sugar to her tea. The tea now has strange white lumps floating in it. What caused the milk to curdle? Explain. 2. Joy is very proud of her healthy diet. I drink only pure spring water and eat organic foods. I have a chemical-free body. Annoyed, Sonia replied, Ever hear of H 2 O? Explain the error in Joy s reasoning. 3. Albert, Jr., was trying out the new Super Genius Home Chemistry Kit that he got for his birthday. He decided to test the ph of his secret formula: lemon juice and diet cola. The ph was 2.5. Next, he added tomato juice and with his disgusting mixture, the ph tested at 3.5. Smirking, he exclaimed, Wow! That s twice as strong! Does Albert Jr. possess the keen intellect of a Super Genius? Explain. 4. During chemistry lab, Maria places sucrose (table sugar) in a glass beaker, adds water and stirs. As the table sugar crystals disappear, she loudly proclaims that she has chemically broken down the sucrose into fructose and glucose. Is Maria s chemical analysis correct? Chapter 2 Introductory Chemistry 11

12 SELF QUIZ 1. A substance that dissociates in water to form H + is called a. an acid b. a salt c. a buffer d. a base e. a nucleic acid 2. Ionic bonds are characterized by a. sharing electrons between atoms b. their ability to form strong, stable bonds c. atoms giving away and taking electrons d. the type of bonding formed in most organic compounds e. an attraction between water molecules 3. If an atom has two electrons in its second electron shell and its first electron shell is filled, it will tend to a. lose two electrons from its second electron shell b. lose the electrons from its first electron shell c. lose all of the electrons from the first and second electron shells d. gain six electrons in its second electron shell e. share two electrons in its second electron shell 4. Matter that cannot be broken down into simpler substances by chemical reactions is known as a. a molecule b. an antioxidant c. a compound d. a buffer e. a chemical element 5. Chlorine (CI) has an atomix number of 17. An atom of chlorine may become a chloride ion (CI - ) by a. losing one electron b. losing on neutron c. gaining one proton d. gaining one electron e. gaining two electrons 6. Which of the following is NOT true? a. A substance that separates in water to form some cation other than H + and some anion other than OH - is known as salt. b. A solution that has a ph of 9.4 is acidic. c. A solution with a ph of 5 is 100 times more acidic than distilled water, which has a ph of 7. d. Buffers help to make the body s ph more stable e. Amino acids are linked by peptide bonds. 7. Which of the following organic compounds are not paired with their correct subunits (building blocks)? a. glycogen, glucose b. proteins, monosaccharides c. DNA, nucleotides d. lipids, glycerol, and fatty acids e. ATP, ADP, and P 8. The type of reaction by which a disaccharide is formed from two monosaccharides is known as a a. decomposition reaction b. hydrolysis reaction c. dehydration synthesis reaction d. reversible reaction e. dissociation reaction Chapter 2 Introductory Chemistry 12

13 9. Which of the following contains the genetic code in human cells? a. DNA b. enzymes c. RNA d. glucose e. ATP 10. What is the principal energy-transferring molecule in the body? a. ADP b. RNA c. DNA d. ATP e. NAD 11. Which of the following statements about water is NOT true? a. It is involved in many chemical reactions in the body. b. it is an important solvent In the human body. c. It helps lubricate a variety of structures in the body. d. Tt can absorb a large amount of heat without changing its temperature. e. It requires very little heat to change from a liquid to a gas. 12. The difference in H + concentration between solutions with a ph of 3 and a ph of 5 is that the solution with the ph of 3 has H+. a. 2 times more b. 5 times more c. 10 times more d. 100 times more e. 200 times more 13. Which of the following is NOT a true statement about enzyme activity? a. Enzymes form a temporary complex with their substrates. b. Enzymes are not permanently altered by the chemical reactions they catalyze. c. All proteins are enzymes. d. Enzymes are considered to be organic catalysts. e. Enzymes are subject to cellular control. 14. For each item in the following list, place an R if it applies to RNA or a D if it refers to DNA; use R and D if it applies to both RNA and DNA. a. composed of nucleotides b. forms a double helix c. contains thymine d. contains the sugar ribose 15. An organic compound that consists of C, H, and O, and that can be broken down into glycerol and fatty acids is a a. triglyceride b. nucleic acid c. monosaccharide d. carbohydrate e. protein 16. Why is it important to consume foods that contain antioxidants? a. They provide a source of energy for the body. b. They help inactivate damaging free radicals. c. They make up the body s genes. d. They act as buffers to help maintain the body s ph. e. They are important solvents in the body. 17. If an enzyme is exposed to an extremely high temperature, it will a. divide b. release energy c. become an electrolyte d. form hydrogen bonds e. denature 18. In what form are lipids stored in adipose (fat) tissue of the body? a. triglycerides b. glycogen c. cholesterol d. polypeptides e. disaccharides Chapter 2 Introductory Chemistry 13

14 19. Approximately 96% of your body s mass is composed of which of the following elements? Place an X beside each correct answer. calcium iron nitrogen phosphorus sodium chlorine carbon oxygen sulfur hydrogen potassium magnesium 20. Match the following: a. inorganic compound A. glycogen b. monosaccharide B. enzyme c. polysaccharide C. glucose d. component of triglycerides D. water e. lipase E. glycerol Chapter 2 Introductory Chemistry 14