CHAPTER 2 Cellular Chemistry 11. The principal solvent in the body is/are(a) lipids(oils),(b) water, (c)blood, (d) lymph fluid 12. Which of the following is a false sta (a) Acids increase hydrogen ion concentration in solution (b) Acids act as proton donors (c) Acids yield a higher hydroxide concentration than a hydrogen ion concentration 13. Anabolic reactions are(a)decomposition reactions, (b) synthesis reactions, (c) not part of the bodys metabolism,(d) those that break down molecules for use as energy sources 14. Deoxyribonucleotides are named according to(a) the base, (b)the sugar, (c)the phosphate group. (d) their position in the macromolecule. 15. Molecular weight is equal to(a) the sum of all the isotopic weights, (b) the sum of all the atomic weights (c) the sum of the atomic numbers, (d) none of the preceding 16. Phospholipids involve a phosphate group and (a) four or more fatty acids, (b) three fatty acids, (c)two fatty acids, (d)one fatty acid. 17. Of the following nitrogenous bases, which is found exclusively in RNA?(a)thymine, (b) guanine, (c)adenine, (d)ur Which represents the correct sequence in ascending order of size?(a)atom, amino acid, polypeptide, protein; (b)amino acid, atom, polypeptide, protein;(c)atom, amino acid, protein, polypeptide; (d)amino acid, atom, protein, polypeptide 19. lons have(a)only positive charges, (b)only negative charges, (c)either positive or negative charges, (d)no charges. 20. Atoms of the same atomic number but of different mass numbers(different numbers of nuclear particles) re referred to as(a)ions, (b)isotopes, (c)cations, (d) tight atoms 21. Which of the following is not an organic compound?(a) starch, (b)ribose, (c)carbon dioxide,(d) lipase 22. Which of the following is a disaccharide? (a) glucose, (b)ribose, (c) fructose,(d)lactose 23. The eight amino acids that cannot be formed in the body from other amino acids are referred to as(a) essential enzymes, (b) neutral amino acids, (c)normal amino acids, (d)essential amino acids. 24. Dehydration synthesis(a) requires water, (b)results in the splitting of molecules, (c)is the means for forming disaccharides, (d) occurs when glycogen stores are used by tissue cell 25. Nucleotides lack(a)a phosphate group, (b) an amino group, (c)a nitrogenous base, (d)a five-carbon sugar Tru eor]False l. Protons and electrons each have many times the mass of neutrons 2. Of the 118 presently known chemical elements, 75% are found in the bod 3. Sodium has atomic number 11 and mass number 23. Sodium. therefore. has 12 neutrons 4. Positively charged ions are called cations 5. Unsaturated fatty acids contain only single covalent bonds between carbon atoms. 6. Amino acids are linked by peptide bonds to form polypeptides 7. The specific nature of a protein is determined mainly by its amino acid sequence and the properties of the respective amino acid R-groups 8. Substances that increase the hydrogen ion concentration are called bases 9. Covalent bonds are far more important in living organisms than ionic bonds
11. The principal solvent in the body is/are (a) lipids (oils), (b) water, (c) blood, (d) lymph fluid. 12. Which of the following is a false statement? (a) Acids increase hydrogen ion concentration in solution. (b) Acids act as proton donors. (c) Acids yield a higher hydroxide concentration than a hydrogen ion concentration. (d) Acids have a low pH. 13. Anabolic reactions are (a) decomposition reactions, (b) synthesis reactions, (c) not part of the body’s metabolism, (d) those that break down molecules for use as energy sources. 14. Deoxyribonucleotides are named according to (a) the base, (b) the sugar, (c) the phosphate group, (d) their position in the macromolecule. 15. Molecular weight is equal to (a) the sum of all the isotopic weights, (b) the sum of all the atomic weights, (c) the sum of the atomic numbers, (d) none of the preceding. 16. Phospholipids involve a phosphate group and (a) four or more fatty acids, (b) three fatty acids, (c) two fatty acids, (d) one fatty acid. 17. Of the following nitrogenous bases, which is found exclusively in RNA? (a) thymine, (b) guanine, (c) adenine, (d) uracil 18. Which represents the correct sequence in ascending order of size? (a) atom, amino acid, polypeptide, protein; (b) amino acid, atom, polypeptide, protein; (c) atom, amino acid, protein, polypeptide; (d) amino acid, atom, protein, polypeptide 19. Ions have (a) only positive charges, (b) only negative charges, (c) either positive or negative charges, (d) no charges. 20. Atoms of the same atomic number but of different mass numbers (different numbers of nuclear particles) are referred to as (a) ions, (b) isotopes, (c) cations, (d) tight atoms. 21. Which of the following is not an organic compound? (a) starch, (b) ribose, (c) carbon dioxide, (d) lipase 22. Which of the following is a disaccharide? (a) glucose, (b) ribose, (c) fructose, (d) lactose 23. The eight amino acids that cannot be formed in the body from other amino acids are referred to as (a) essential enzymes, (b) neutral amino acids, (c) normal amino acids, (d) essential amino acids. 24. Dehydration synthesis (a) requires water, (b) results in the splitting of molecules, (c) is the means for forming disaccharides, (d) occurs when glycogen stores are used by tissue cells. 25. Nucleotides lack (a) a phosphate group, (b) an amino group, (c) a nitrogenous base, (d) a five-carbon sugar. True or False _____ 1. Protons and electrons each have many times the mass of neutrons. _____ 2. Of the 118 presently known chemical elements, 75% are found in the body. _____ 3. Sodium has atomic number 11 and mass number 23. Sodium, therefore, has 12 neutrons. _____ 4. Positively charged ions are called cations. _____ 5. Unsaturated fatty acids contain only single covalent bonds between carbon atoms. _____ 6. Amino acids are linked by peptide bonds to form polypeptides. _____ 7. The specific nature of a protein is determined mainly by its amino acid sequence and the properties of the respective amino acid R-groups. _____ 8. Substances that increase the hydrogen ion concentration are called bases. _____ 9. Covalent bonds are far more important in living organisms than ionic bonds. 30 CHAPTER 2 Cellular Chemistry
CHAPTER 2 Cellular Chemistry 10. Hydrogen, carbon, nitrogen, and oxygen account for about half of the body weight. 11. Nucleic acid molecules are small and unspecialized molecules 12. Purine bases have a single ring of carbon and nitrogen atoms Completion 1.A is a combination of two or more atoms joined by chemical bonds 2 form when atoms give up or gain electrons and become either positively or negatively charged. bond is the strongest of the chemical bonds. 4. Composed of thousands of glucose molecules, the"food storage"polysaccharide in humans is called are four-carbon sugars. 6. Three molecule form the basic lipid molecule fats contain no double bonds between carbon molecules but 8. The base unique to RNA, substitutes for the base thymine 9. The nitrogenous bases are built onto the purine ring are the building blocks of proteins. Matching Match the chemical component with its description. 1. Carbohydrates (a) proton accepto 2. Protons and neutrons (b) adenine and guanine 3. Electrons (C)C(H,O) 4. Covalent bond 5. Nucleic acid 7. Proteins (g) subshells 8. Hydrogen bonds (h) dna and rna 9. Peptide bonds 10. Purine base O cytosine and thymine 12. Cation () secondary structure of proteins (m) water insoluble 14. Acid (n) shared electrons 15. Base (o)H2O—CH- COOH
_____ 10. Hydrogen, carbon, nitrogen, and oxygen account for about half of the body weight. _____ 11. Nucleic acid molecules are small and unspecialized molecules. _____ 12. Purine bases have a single ring of carbon and nitrogen atoms. Completion 1. A _________________________________is a combination of two or more atoms joined by chemical bonds. 2. ___________________________________ form when atoms give up or gain electrons and become either positively or negatively charged. 3. A(n) ___________________________________ bond is the strongest of the chemical bonds. 4. Composed of thousands of glucose molecules, the “food storage” polysaccharide in humans is called ___________________________________. 5. ___________________________________ are four-carbon sugars. 6. Three ___________________________________ bound to one ___________________________________ molecule form the basic lipid molecule. 7. ___________________________________ fats contain no double bonds between carbon molecules, but ___________________________________ fats do. 8. The base ___________________________________, unique to RNA, substitutes for the base thymine. 9. The nitrogenous bases ___________________________________ and ___________________________________ are built onto the purine ring. 10. ___________________________________ are the building blocks of proteins. Matching Match the chemical component with its description. _____ 1. Carbohydrates (a) proton acceptor _____ 2. Protons and neutrons (b) adenine and guanine _____ 3. Electrons (c) Cn(H2 O)n _____ 4. Covalent bonds (d) Cl _____ 5. Nucleic acid (e) nucleus _____ 6. Lipids (f) proton donor _____ 7. Proteins (g) subshells _____ 8. Hydrogen bonds (h) DNA and RNA _____ 9. Peptide bonds (i) K _____ 10. Purine base (j) cytosine and thymine _____ 11. Pyrimidine bases (k) primary structure of proteins _____ 12. Cation (l) secondary structure of proteins _____ 13. Anion (m) water insoluble _____ 14. Acid (n) shared electrons _____ 15. Base (o) H O—C | R 2 H — COOH CHAPTER 2 Cellular Chemistry 31
CHAPTER 2 Cellular Chemistry Answers and Explanations for Review Exercises Multiple choice 1.(a) Neutral refers to an absence of electrical charge or balance of opposite electrical charges. Because electrons carry a negative charge, the same number of protons are needed to balance the overall electrical 2.(b) The atomic number represents the number of protons in an atom. 3.(a)A compound is a molecule composed of two or more atoms(e. g, H,O, NaCl 4.(d) Covalent and peptide bonds result from atoms sharing electrons 5.(a) lonic bonds result from the transfer of electrons. 6.(d)The prefix hydro-refers to hydrogen, and the suffix -carbons refers to carbon 7.(c)A carbon chain with an acid carboxyl group at one end is a fatty acid. 8.(b)Three fatty acid molecules combine with one glycerol molecule to form one fat molecule(see fig 2.7) 9.(c)Proteins contain nitrogen, whereas carbohydrates contain only carbon, hydrogen, and oxygen. 10.(d)A nucleic acid is composed of a five-carbon sugar bonded to a phosphate group and either a purine or a pyrimidine base(see fig. 2.10) ll.(b) Water is the principal solvent in the body 12.(c) Acids yield a higher hydrogen ion concentration. Bases yield a higher hydroxide concentration 13.(b) Anabolic reactions include the synthesis of large energy-storing molecules, such as glycogen, fat, and 14.(a) The components of DNA nucleotides are identical except for the nitrogenous base, which determines the chemical nature of the entire molecule 15.(b) The molecular weight is calculated by adding the atomic weights of all the atoms in the molecule 16.(c)Phospholipids involve a phosphate group and two fatty acid molecules 17.(d)The nitrogenous base uracil is found exclusively in RNA. 18.(a) Atoms are the building blocks for amino acids. Several amino acids strung together form a polypeptide. Several polypeptides strung together form a protein. 19.(c) lons can be positively or negatively charged(e. g, Na, Cl, H, OH) 20.(b) Isotopes of an atom contain the same number of protons but a different number of neutrons 21.(c) Carbon dioxide( CO, )and carbon monoxide( CO)are the only notable exceptions to the rule that molecules containing carbon are organic molecules. These molecules form in natural processes that do not involve other organic molecules, as well as in organic systems 22.(d) Lactose is composed of two monosaccharides: glucose and galactose bound together 23.(d) The essential amino acids are those eight that cannot be formed within the body 4.(c)A disaccharide forms when two monosaccharides combine in a dehydration synthesis reaction (see fig. 2.6 25.(b)A nucleotide consists of a five-carbon sugar covalently bonded to a nitrogenous base and a phosphate group. True or False 1. False: protons and neutrons are many times more massive than electrons. 2. False; of the 118 known chemical elements, only about 22 (1990)are found in the body 4. True
Answers and Explanations for Review Exercises Multiple Choice 1. (a) Neutral refers to an absence of electrical charge or balance of opposite electrical charges. Because electrons carry a negative charge, the same number of protons are needed to balance the overall electrical charge. 2. (b) The atomic number represents the number of protons in an atom. 3. (a) A compound is a molecule composed of two or more atoms (e.g., H2O, NaCl). 4. (d) Covalent and peptide bonds result from atoms sharing electrons. 5. (a) Ionic bonds result from the transfer of electrons. 6. (d) The prefix hydro- refers to hydrogen, and the suffix -carbons refers to carbon. 7. (c) A carbon chain with an acid carboxyl group at one end is a fatty acid. 8. (b) Three fatty acid molecules combine with one glycerol molecule to form one fat molecule (see fig. 2.7). 9. (c) Proteins contain nitrogen, whereas carbohydrates contain only carbon, hydrogen, and oxygen. 10. (d) A nucleic acid is composed of a five-carbon sugar bonded to a phosphate group and either a purine or a pyrimidine base (see fig. 2.10). 11. (b) Water is the principal solvent in the body. 12. (c) Acids yield a higher hydrogen ion concentration. Bases yield a higher hydroxide concentration. 13. (b) Anabolic reactions include the synthesis of large energy-storing molecules, such as glycogen, fat, and protein. 14. (a) The components of DNA nucleotides are identical except for the nitrogenous base, which determines the chemical nature of the entire molecule. 15. (b) The molecular weight is calculated by adding the atomic weights of all the atoms in the molecule. 16. (c) Phospholipids involve a phosphate group and two fatty acid molecules. 17. (d) The nitrogenous base uracil is found exclusively in RNA. 18. (a) Atoms are the building blocks for amino acids. Several amino acids strung together form a polypeptide. Several polypeptides strung together form a protein. 19. (c) Ions can be positively or negatively charged (e.g., Na, Cl, H, OH). 20. (b) Isotopes of an atom contain the same number of protons but a different number of neutrons. 21. (c) Carbon dioxide (CO2 ) and carbon monoxide (CO) are the only notable exceptions to the rule that molecules containing carbon are organic molecules. These molecules form in natural processes that do not involve other organic molecules, as well as in organic systems. 22. (d) Lactose is composed of two monosaccharides: glucose and galactose bound together. 23. (d) The essential amino acids are those eight that cannot be formed within the body. 24. (c) A disaccharide forms when two monosaccharides combine in a dehydration synthesis reaction (see fig. 2.6). 25. (b) A nucleotide consists of a five-carbon sugar covalently bonded to a nitrogenous base and a phosphate group. True or False 1. False; protons and neutrons are many times more massive than electrons. 2. False; of the 118 known chemical elements, only about 22 (1990) are found in the body. 3. True 4. True 32 CHAPTER 2 Cellular Chemistry
CHAPTER 2 Cellular Chemistry 5. False: ur ated fatty acids contain two covalent bonds between carbon ate 7. True 8. False; bases increase the hydroxide ion(OH )concentration, whereas acids increase the hydrogen ion 10. False: H, C, N, and O account for over 90% of human body weight 11. False: nucleic acids are large, highly specialized molecules 12. False: purine bases have a double ring of carbon and nitrogen atoms; pyrimidine bases have a singl carbon and nitrogen ring Completion 6. fatty acids, gly 2. Ionic bonds 7. Saturated unsaturated 9. adenine, guanine 10. Amino acids Matching l.(c) 6.(m) l1.( (e) 7.(o) 9.(k) 14.(0 15.(a)
5. False; unsaturated fatty acids contain two covalent bonds between carbon atoms. 6. True 7. True 8. False; bases increase the hydroxide ion (OH) concentration, whereas acids increase the hydrogen ion (H) concentration. 9. True 10. False; H, C, N, and O account for over 90% of human body weight. 11. False; nucleic acids are large, highly specialized molecules. 12. False; purine bases have a double ring of carbon and nitrogen atoms; pyrimidine bases have a single carbon and nitrogen ring. Completion 1. molecule 6. fatty acids, glycerol 2. Ionic bonds 7. Saturated, unsaturated 3. covalent 8. uracil 4. glycogen 9. adenine, guanine 5. Tetroses 10. Amino acids Matching 1. (c) 6. (m) 11. (j) 2. (e) 7. (o) 12. (i) 3. (g) 8. (l) 13. (d) 4. (n) 9. (k) 14. (f) 5. (h) 10. (b) 15. (a) CHAPTER 2 Cellular Chemistry 33
CHAPTER 3 Cell structure and function Objective a To understand the cellular organization of the human body Cells are the basic building blocks of all life and form the basis of our bodies. lthough these cells are derived from a relatively uniform population of precursor cells, they ultimately differentiate into an impres- sive range of specialized cells and tissues. Despite their specializations, all cells possess common structures and characteristics. A generalized cell(see fig. 3. 1)is encased within a cell(plasma) membrane and con- tains specialized structures known as organelles(lit. small organs), which are suspended within the fluid filled interior(cytoplasm). These organelles perform special functions for the cell. In addition, the DNA of the cell is housed within a membrane-bound nucleus. A protein-based cytoskeleton provides form to the cell. membrane Microtubules Vacuole Figure 3. 1 The structure of a cell 3.1 Distinguish among cytoplasm, cytosol, and cytoskeleton. The fluid space within a cell is referred to generally as the cytoplasm. This space is crowded with protein fibers, tubules, compartments, and organelles, all suspended in a gelatinous fluid (cytosol). The protein fibers and tubules contribute to a framework that gives shape to the cell and provides internal divisions This framework is the cytoskeleton The cytosol, also known as the intracellular fluid, is continuous with the extracellular fluid(the uid surrounding the cells)across the semipermeable membrane of the cells. Movement of fluid across this membrane is driven by concentrations of dissolved and soluble substances inside and outside the cell
CHAPTER 3 34 Cell Structure and Function Objective A To understand the cellular organization of the human body. Cells are the basic building blocks of all life and form the basis of our bodies. Although these cells are derived from a relatively uniform population of precursor cells, they ultimately differentiate into an impressive range of specialized cells and tissues. Despite their specializations, all cells possess common structures and characteristics. A generalized cell (see fig. 3.1) is encased within a cell (plasma) membrane and contains specialized structures known as organelles (lit. small organs), which are suspended within the fluidfilled interior (cytoplasm). These organelles perform special functions for the cell. In addition, the DNA of the cell is housed within a membrane-bound nucleus. A protein-based cytoskeleton provides form to the cell. Nucleus (chromatin) Nuclear membrane Nucleolus Endoplasmic reticulum Microtubules Vacuole Lysosome Golgi apparatus Mitochondrion Cell membrane Figure 3.1 The structure of a cell. 3.1 Distinguish among cytoplasm, cytosol, and cytoskeleton. The fluid space within a cell is referred to generally as the cytoplasm. This space is crowded with protein fibers, tubules, compartments, and organelles, all suspended in a gelatinous fluid (cytosol). The protein fibers and tubules contribute to a framework that gives shape to the cell and provides internal divisions. This framework is the cytoskeleton. The cytosol, also known as the intracellular fluid, is continuous with the extracellular fluid (the fluid surrounding the cells) across the semipermeable membrane of the cells. Movement of fluid across this membrane is driven by concentrations of dissolved and soluble substances inside and outside the cell