Basic Chemistry

Essentials of Anatomy and Physiology Basic Chemistry Short Answer Figure 2.1 1) The structure of the functional protein is __________. Answer: B 2) The structure of the nucleotide is __________. Answer: E 3) The structure of the polysaccharide is __________. Answer: C 4) The structure of the monosaccharide is __________. Answer: A 5) When a change in matter alters the basic nature of the substance, it is called a __________ change. Answer: chemical 6) Inactive or stored energy is called __________ energy. Answer: potential 7) Isotopes differ from each other only in the number of __________ they possess. Answer: neutrons 8) Decomposition of a protein produces __________. Answer: amino acids 9) The sum of the protons and neutrons in an atom is called the __________. Answer: atomic mass number 10) Compounds that contain carbon-hydrogen bonding are collectively termed __________ compounds. Answer: organic 11) Polar molecules, like water, result when electrons are shared __________. Answer: unequally 12) The outermost shell of an atom is called the __________ shell. Answer: valence 13) An acid is a molecule that releases (donates) __________. State the answer in two ways. Answer: protons; hydrogen ions 14) All __________ have an amine (N) group. Answer: amino acids 15) Glycogen and starch are examples of a specific category of carbohydrates called __________. Answer: polysaccharides 16) A solution with a pH of 11.7 is __________ times more acidic than a solution with a pH of 8.7. Answer: 1000 17) Cholesterol is an example of a __________, a specific category of lipids. Answer: steroids 18) Enzymes are examples of __________ proteins. State the answer in two ways. Answer: globular; functional 19) The building blocks of nucleic acids are called __________. Answer: nucleotides 20) The universal energy compound that provides visible energy to cells is __________. Answer: ATP (adenosine triphosphate) Multiple Choice 1) Inactive energy is referred to as: A) mechanical energy B) potential energy C) kinetic energy D) radiant energy E) electrical energy Answer: B 2) An atom with 11 protons, 12 neutrons, and 10 electrons is a(n): A) molecule B) anion C) cation D) isotope E) radioisotope Answer: C 3) The movement of ions across cell membranes is an example of: A) radiant energy B) chemical energy C) electrical energy D) mechanical energy E) potential energy Answer: C 4) Ninety-six percent of the human body is composed of the elements: A) carbon, calcium, sodium, and oxygen B) carbon, oxygen, iron, and potassium C) carbon, oxygen, hydrogen, and nitrogen D) calcium, magnesium, potassium, and iron E) sodium, potassium, hydrogen, and sulfur Answer: C 5) The most abundant element in the human body is: A) carbon B) oxygen C) hydrogen D) nitrogen E) calcium Answer: B 6) The simplest atom—containing one proton, one electron, and no neutrons—is: A) carbon B) hydrogen C) oxygen D) nitrogen E) sodium Answer: B 7) Atomic mass is equivalent to the number of __________ in an atom. A) protons B) neutrons C) electrons D) protons and electrons E) protons and neutrons Answer: E 8) Which of these elements composes bone: A) calcium B) sulfur C) chlorine D) iron E) iodine Answer: A 9) Which of the following is the role of magnesium: A) it is present in bone, and is an important cofactor for enzyme activity in a number of metabolic reactions B) it is needed to make functional thyroid hormones C) it is a component of the functional hemoglobin molecule that transports oxygen within red blood cells, as well as a component of some enzymes D) it is the major extracellular cation in its ionic form, and is important for water balance, conduction of nerve impulses, and muscle contraction E) it is a major extracellular anion in its ionic form Answer: A 10) An atom with an atomic number of 14 will have __________ electrons in its valence shell. A) 2 B) 4 C) 8 D) 10 E) 14 Answer: B 11) Which of the following statements is correct regarding the electrical charge of subatomic particles: A) protons are positively charged, electrons are neutral, and neutrons are negatively charged B) protons are positively charged, electrons are negatively charged, and neutrons are neutral C) protons are negatively charged, electrons are neutral, and neutrons are negatively charged D) protons are negatively charged, electrons are positively charged, and neutrons are neutral E) protons are neutral, electrons are negatively charged, and neutrons are positively charged Answer: B 12) An atom has 6 protons, 8 neutrons, and 6 electrons. Its atomic mass is: A) 2 B) 6 C) 8 D) 14 E) 20 Answer: D 13) The atomic number of an atom reveals the number of: A) electrons in the atomic nucleus B) protons in the atomic nucleus C) protons plus neutrons D) protons plus electrons E) neutrons plus electrons Answer: B 14) Isotopes have different numbers of __________; thus they also have different __________. A) protons; atomic numbers B) neutrons; atomic masses C) electrons; atomic numbers D) protons; atomis masses E) neutrons; atomic numbers Answer: B 15) An atom that has lost two electrons is called a(n): A) isotope B) anion C) radioisotope D) cation E) proton Answer: D 16) The subatomic particles that are responsible for the chemical behavior of atoms are the: A) protons B) neutrons C) electrons D) isotopes E) ions Answer: C Figure 2.2 17) What is the atomic number of the atom in Figure 2.2: A) 2 B) 3 C) 4 D) 6 E) 12 Answer: D 18) When a pair of electrons is shared equally between two atoms, the bond formed is called a(n): A) ionic bond B) hydrogen bond C) carbon bond D) polar covalent bond E) nonpolar covalent bond Answer: E 19) Which of these examples is a compound: A) H2 B) CH4 C) O2 D) N2 E) 2H Answer: B 20) In order to break a disaccharide down into simple sugar units: A) water molecules must be added to each bond B) water molecules must be removed from each bond C) carbon atoms must be added to each bond D) carbon atoms must be removed from each bond E) water molecules and carbon atoms must be removed from each bond Answer: A 21) The reaction A + B ? AB is an example of a(n): A) exchange reaction B) synthesis reaction C) decomposition reaction D) denaturation reaction E) dehydration reaction Answer: B 22) Water is useful in body processes because: A) it is a good solvent B) it acts as an enzyne C) it has a low heat capacity D) it is a product in hydrolysis reactions E) it is chemically inert Answer: A 23) The joining of amino acids to form a protein is an example of: A) a decomposition reaction B) an exchange reaction C) a synthesis reaction D) a denaturation reaction E) a hydrolysis reaction Answer: C 24) Which of the following solutions is the weakest acid: A) a solution with a pH of 2.4 B) a solution with a pH of 5.2 C) a solution with a pH of 6.4 D) a solution with a pH of 8.6 E) a solution with a pH of 10.1 Answer: C 25) A solution with a pH of 7: A) is acidic B) releases more hydrogen ions than hydroxyl ions into solution C) releases more hydroxyl ions than hydrogen ions into solution D) is basic E) is neutral Answer: E 26) Which of the following is an example of an inorganic molecule: A) a fatty acid B) an amino acid C) cholesterol D) sodium chloride E) RNA Answer: D 27) Vitamin D and sex hormones are both: A) polysaccharides B) proteins C) nucleic acids D) enzymes E) steroids Answer: E 28) Glucose and starch are examples of: A) carbohydrates B) triglycerides C) phospholipids D) steroids E) proteins Answer: A 29) Which of the following groups of chemicals includes ONLY monosaccharides: A) glucose, fructose, galactose B) glucose, fructose, maltose C) fructose, maltose, sucrose D) fructose, maltose, lactose E) maltose, sucrose, lactose Answer: A 30) The organic compounds that function in building tissues and acting as enzymes are the: A) nucleic acids B) carbohydrates C) salts D) lipids E) proteins Answer: E 31) Triglycerides: A) include lipoid substances such as fat-soluble vitamins (e.g., vitamins A, E, and K), prostaglandins, and lipoproteins B) include cholesterol, bile salts, vitamin D, sex hormones, and adrenal cortical hormones C) are found in the cell membrane and participate in the transport of lipids in plasma; they are also abundant in the brain and in nervous tissue where they help to form insulating white matter D) are found in fat deposits (e.g., subcutaneous tissue around organs), and serve to protect and insulate body organs; they are the major source of stored energy in the body E) have a three-dimensional structure that can be easily destroyed by heat, causing them to be denatured and no longer capable of performing their physiological roles Answer: D 32) Vitamin D can be described as: A) a constituent of orange-pigmented vegetables (carrots) and fruits (tomatoes), and part of the photoreceptor pigment involved in vision B) taken in via plant products such as wheat germ and green leafy vegetables; may promote wound healing and contribute to fertility (though not proven in humans) C) made available largely by the action of intestinal bacteria; also prevalent in a wide variety of foods, and necessary for the proper clotting of blood D) produced in the skin on exposure to UV radiation; necessary for normal bone growth and function E) derivatives of fatty acids found in cell membranes; various functions include the stimulation of uterine contractions, the regulation of blood pressure, and the control of motility of the gastrointestinal tract Answer: D 33) Which one of the following DNA bases are complementary: A) adenine and guanine B) guanine and uracil C) thymine and guanine D) cytosine and adenine E) adenine and thymine Answer: E 34) Enzymes: A) are essential to virtually every biochemical reaction in the body B) help regulate growth and development C) are highly specialized proteins that recognize, bind with, and inactivate bacteria, toxins, and some viruses D) increase the rates of chemical reactions by at least a millionfold E) when absent or destroyed, cause all biochemical reactions to cease Answer: D 35) Which of the following statements about enzymes is true: A) they are carbohydrates B) they are stable at high temperatures C) they are biological catalysts D) they are not reuseable E) they are required in large amounts in order to be effective Answer: C 36) Saturated fats: A) have two fatty acid chains B) exist as solids at room temperature C) are formed from 4 interlocking carbon rings D) contain many double bonds E) exist as liquids and are derived from plants Answer: B 37) Which of the following substances below is matched with its correct organic group: A) monosaccharides - nucleic acids B) DNA - lipids C) steroids - carbohydrates D) glycerol - proteins E) enzymes - proteins Answer: E 38) Enzymes are classified as: A) antibodies B) hormones C) triglycerides D) structural proteins E) functional proteins Answer: E 39) Which of the following statements about RNA is true: A) RNA is single stranded B) RNA is composed of cytosine, guanine, adenine, and thymine C) RNA is found only in the nucleus of the cell D) RNA contains deoxyribose E) RNA is a double helix Answer: A 40) Carbohydrates are built up from their basic building blocks by the: A) addition of a water molecule between each unit B) removal of a water molecule between every two units C) addition of a carbon atom D) removal of a carbon atom E) process termed "hydrolysis" Answer: B 41) The nucleotide chains of DNA are held together by: A) carbon bonds B) hydrogen bonds C) ionic bonds D) nonpolar covalent bonds E) polar covalent bonds Answer: B 42) Which of the following statements about ATP is false: A) it drives the transport of certain solutes (e.g., amino acids) across cell membranes B) it activates contractile proteins in muscle cells so that cells can shorten and perform mechanical work C) it provides the energy needed to drive energy-absorbing chemical reactions D) it is a modified nucleotide E) its energy is captured in high-energy hydrogen bonds Answer: E 43) Glycogen is the storage form of __________ in animals. A) protein B) lipids C) amino acids D) glucose E) DNA Answer: D 44) __________ are simple sugars containing between 3 and 7 carbon atoms. A) Proteins B) Monosaccharides C) Polysaccharides D) Saturated fats E) Steroids Answer: B 45) Shell 1 of an atom can hold a maximum of __________ electron(s). A) 1 B) 2 C) 4 D) 8 E) 18 Answer: B 46) Trans fats are oils that have been solidified by the addition of: A) oxygen atoms B) carbon atoms C) hydrogen atoms D) nitrogen atoms E) phosphorus-containing groups Answer: C Figure 2.3 47) What type of chemical bond is pictured in Figure 2.3: A) nonpolar covalent bond B) polar covalent bond C) ionic bond D) single covalent bond E) double covalent bond Answer: C 48) The sugar found in DNA is: A) ribose B) sucrose C) deoxyribose D) lactose E) starch Answer: C 49) Which of these substances is an enzyme: A) glucose B) triglyceride C) oxidase D) nucleotide E) omega-3 fatty acid Answer: C 50) Which of these factors will not the rate of a chemical reaction: A) increased temperature B) increased concentration of reacting particles C) presence of catalysts D) decreased temperature E) decrease in particle size Answer: D True/False 1) Inactive or stored energy is called kinetic energy. Answer: FALSE 2) Stored energy is called potential energy. Answer: TRUE 3) Negatively charged atoms are called cations. Answer: FALSE 4) Atoms are the smallest particles of a compound that still retain the properties of that compound. Answer: FALSE 5) Calcium is one of the major elements composing the human body. Answer: FALSE 6) Every atom in a molecule has a full valence shell. Answer: TRUE 7) Water is the single most abundant inorganic compound in the human body. Answer: TRUE 8) The lower the pH, the greater the number of hydrogen ions. Answer: TRUE 9) Compounds that ionize completely, producing large numbers of hydrogen ions (protons), are termed . Answer: FALSE 10) Carbon is found in all inorganic compounds. Answer: FALSE 11) When a solution produces equal numbers of hydrogen and hydroxyl ions, it is said to be neutral. Answer: TRUE 12) The normal pH of blood occupies a narrow range around 7.35-7.45. Answer: TRUE 13) Estrogen and cholesterol are both steroids. Answer: TRUE 14) Enzymes decrease the rates of chemical reactions. Answer: FALSE 15) Disruption of the hydrogen bonds of functional proteins leads to their denaturation. Answer: TRUE Matching 1) A bond in which electrons are completely lost or gained by the atoms involved A) single covalent bond B) hydrogen bond C) covalent bond 2) A bond in which electrons are shared unequally D) polar covalent bond E) nonpolar covalent bond 3) A type of bond important in holding different parts of the same molecule together in three-dimensional structure F) ionic bond G) double bond 4) A type of covalent bond formed when atoms share two pairs of electrons 5) Type of bond exhibited by carbon dioxide 1) F 2) D 3) B 4) A 5) E 6) The particle(s) contributing to the atomic mass A) neutron(s) B) electron(s) 7) The particle(s) contributing to the atomic number C) proton(s) D) protons and neutrons 8) The particle(s) shared during covalent bond formation 9) The particle(s) that differ between isotopes 10) The particle(s) located within the nucleus 11) The particle(s) lost during cation formation 12) The number of protons is equal to the number of these subatomic particles 6) D 7) C 8) B 9) A 10) D 11) B 12) B 13) Building block is the monosaccharide A) proteins B) nucleic acids 14) DNA, RNA, and ATP are types of these organic compounds C) lipids D) carbohydrates 15) Triglycerides, steroids, and fat-soluble vitamins are types of these organic compounds 16) Antibodies, some hormones, and enzymes are types of these organic compounds 17) Building blocks of these organic compounds are amino acids 18) Nucleotides form the building blocks of these organic compounds 19) Glycogen, glucose, and lactose are examples of these organic compounds 20) Most of this organic compound group are water insoluble 13) D 14) B 15) C 16) A 17) A 18) B 19) D 20) C Essay 1) Describe the role of the electron in chemical bond formation. Answer: When the valence shell of an atom contains fewer than 8 electrons, an atom will tend to gain, lose, or share electrons with other atoms to reach a stable state. As a result, chemical bonds such as covalent bonds or ionic bonds are formed. 2) Compare DNA and RNA from the standpoint of their location, role(s), number of chains, arrangement of nucleotides, and sugars and bases present. Answer: 1. Location—DNA is located inside the nucleus of the cell; RNA is located inside and outside the nucleus of the cell. 2. Role(s)—DNA undergoes replication prior to cell division to pass on heredity information, and provides instructions for the building of all protein; RNA carries out the orders for protein synthesis issued by DNA. 3. Number of chains—DNA consists of a double chain of nucleotides in the form of a double helix; RNA is a single chain of nucleotides. 4. Arrangement of nucleotides—DNA consists of sugar and phosphate molecules that form uprights of a ladder-like structure, and each rung is formed by two joined bases; in RNA, a base projects from each sugar-phosphate unit in the chain of nucleotides. 5. Sugar—the sugar in DNA is deoxyribose; the sugar in RNA is ribose. 6. Bases—in DNA the bases are adenine (A), thymine (T), guanine (G) and cytosine (C); in RNA the bases are adenine (A), uracil (U), guanine (G) and cytosine (C). 3) Discuss the major properties of water that make it so vital to the proper functioning of the body. Answer: 1. It has a high heat capacity, and absorbs and releases large amounts of heat before its temperature changes appreciably. Therefore, it helps maintain homeostatic body temperature. 2. Because of its polarity, it is an excellent solvent in which electrolytes can ionize. Nutrients, respiratory gases, and wastes can dissolve in water, thereby allowing water to act as a transport and exchange medium in the body. Water is also used as a solvent in specialized molecules that lubricate the body, such as mucus that eases the movement of feces in the digestive tube, saliva that moistens food and prepares it for digestion, and synovial fluids that lubricate bone ends. 3. Water is a reactant in some types of chemical reactions, such as digestion and the breakdown of large biological molecules. Water is added to the bonds of the larger molecules in specific reactions termed hydrolysis reactions. 4. Water serves a protective function by forming a watery cushion (e.g., cerebrospinal fluid cushions the brain and amniotic fluid cushions the fetus). 4) Explain how saturated fats are different from unsaturated fats. Answer: Saturated fats: 1. tend to be animal fats 2. have all single bonds between carbon atoms 3. may be solid Unsaturated fats: 1. tend to be plant oils 2. have some double or triple bonds between carbon atoms 3. may be liquid 5) Distinguish between a dehydration synthesis and a hydrolysis reaction. Answer: In a dehydration synthesis reaction, a more complex molecule is formed from two simpler ones, and a water molecule is lost as each bond forms. An example of dehydration synthesis is seen when a disaccharide is formed from two monosaccharides. Hydrolysis is the breakdown of a more complex molecule into its building blocks. A water molecule is added to each bond, the bond is broken, and simpler molecules are formed. In the process, water is split into a hydrogen ion and a hydroxyl ion. An example of hydrolysis is seen when a disaccharide is broken down into two monosaccharides. 6) Explain why ATP is classified as a nucleic acid. Answer: ATP is a modified nucleotide. Nucleotides are the building blocks of nucleic acids. ATP consists of a base (adenine), a sugar (ribose), and three phosphate groups. 7) Explain why hydrolysis (decomposition) reactions require the addition of water. Answer: Water molecules are added to the bonds of large organic molecules. When water is added to each bond, the bond is broken, and the molecule is broken down. 8) Explain why a denatured protein no longer functions. Answer: Denaturation results when the three-dimensional shape of a protein is destroyed. The function of a protein depends on its structure. The presence of an active site on the surface of a protein that interacts with other molecules must be intact for the enzyme to work properly. 9) Explain why enzymes are specific to their substrates. Answer: Exzymes, like other proteins, have active sites on their surfaces that chemically interact with other molecules of complementary shape and charge. These active sites must "fit" with the substrate. Enzymes bind to the reacting substrates and structural changes result in a new product. 10) Differentiate between a molecule and a compound. Answer: Molecules are formed when two or more atoms of the same element combine chemically. Compounds result when two or more different atoms bind together to form a molecule. 11) Name this type of reaction and briefly explain what is happening in this reaction: glucose + fructose ? water + sucrose Answer: Glucose and fructose are two monosaccharides. Sucrose is a disaccharide. Glucose and fructose are combining to form sucrose. This is an example of a dehydration synthesis reaction. A water molecule is lost from the two simple sugars as the bond forms to create the double sugar. 12) List the three parts of a nucleotide. Answer: Nucleotides contain: 1. a nitrogen-containing base 2. a pentose (5-carbon) sugar 3. a phosphate group 13) Describe the difference between a polar and a nonpolar covalent bond. Give and explain an example of each type of bond. Answer: 1. In polar covalent bonds, electrons are not shared equally. For instance, water is an example of a polar covalent bond. The electron pairs shared in water spend more time with the oxygen atom causing that end of the molecule to become slightly negative and the hydrogen end to become slightly positive. 2. In nonpolar covalent bonds, electrons are shared equally. For example, the electron pairs in carbon dioxide orbit the entire molecule.