Human Biology Chapter 2 (Chemistry of Life) – Flashcards
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The smallest unit of an element that still retains the chemical and physical properties of that element is called an isotope. a nucleus. an atom. a molecular bond. a neutrino.
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atom
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In an atom, the number of protons always equals the number of electrons. of neutrons. of neutrons and protons. of quarks. of neutrinos.
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electrons
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How many elements occur naturally? 112 92 64 32 6
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92
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The atomic number of an atom is determined by the number of protons. neutrons. electrons. protons and neutrons. protons and electrons.
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protons
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An element cannot be broken down by chemical means. True False
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True
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Why is He positioned above Ne in the periodic table? They both have the same atomic mass. They both have the same number of electrons in their outermost orbital. They both have a full outermost orbital. They both have the same atomic number. They both have the same number of protons in their nuclei.
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They both have a full outermost orbital.
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Be has an atomic number of 4 and an atomic mass of 9. How many protons does it have? 4 5 9 13 7
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4
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What is the symbol for sodium? Na S So N Dm
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Na
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Which of the following elements will have more than 2 electrons and have a full outer orbital? He Ne C N O
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Ne
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Isotopes of an element differ due to the number of protons. neutrons. electrons. both protons and electrons. neutrinos.
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neutrons
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Carbon dating is a common method employed in dating certain kinds of fossils. It is based upon the radioactive decay of an isotope of carbon (C14). Referring to the atomic number of carbon attained from the periodic table, how many neutrons does C14 have? 2 4 8 12 14
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8
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What substance is used in medicine to produce various images of organs and tissues? A mixture A tracer An emulsion A colloid A sensor
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A tracer
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Radiation can produce both positive and negative effects for humans. True False
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True
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A combination of two or more atoms of the same type is called an atomic unit. a molecule. a compound. an isotope. an ion.
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molecule
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Ca3(PO4)2 represents a/an element. mixture. compound. isotope. atom.
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compound
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Atoms that share electrons have what type of bonds? covalent neutral hydrogen colloidal ionic
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covalent
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CaCl2 is a salt that forms as the result of what type of bond? covalent hydrogen polar non-polar ionic
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ionic
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Water makes up 60-70% of total body weight. True False
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True
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Which type of bond is responsible for holding two water molecules together creating the properties of water? hydrogen covalent ionic polar double covalent
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hydrogen
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Hydrogen bonds result from the loss of neutrons by an atom. result in the formation of salts. involve the loss and gain of electrons. involve the sharing of electrons. are relatively weak and can be broken rather easily.
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are relatively weak and can be broken rather easily.
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The reason water is polar is because in polar molecules atoms share electrons evenly. the oxygen atom is larger than the hydrogen atom. hydrophilic molecules interact with water. hydrophobic molecules do not interact with water. there is a transfer of electrons from the hydrogen to the oxygen.
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the oxygen atom is larger than the hydrogen atom.
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Which of the following characteristics of water is most responsible for the sinking of the Titanic? Water is liquid at room temperature. Water has a high heat of vaporization. The temperature of liquid water rises and falls slowly. Frozen water is less dense than liquid water. Water molecules are cohesive.
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Frozen water is less dense than liquid water.
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On a warm day in April, Tina jumped into the swimming pool. To her surprise the water was really cold. Which property of water did she discover? Water molecules are cohesive. The temperature of liquid water rises and falls slowly. Water possesses hydrogen bonds. Water is a polar molecule. Frozen water is less dense than liquid water.
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The temperature of liquid water rises and falls slowly.
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William noticed water mysteriously climbing up a capillary tube. This is an example of which property of water? Frozen water is less dense than liquid water. The temperature of liquid water rises and falls slowly. Water molecules are cohesive. Water has a high heat of vaporization. Water is a solvent.
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Water molecules are cohesive.
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In an acidic solution the number of H+ is less than the number of OH-. the number of H+ is greater than the number of OH-. the number of H+ is equal to the number of OH-. the number of H+ is 3 times less than the number of OH-. the number of H+ is 10 times less than the number of OH-.
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the number of H+ is greater than the number of OH-.
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A solution with a pH of 7 has 10 times as many H+ as a pH of 6. True False
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False
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A solution containing 0.00001 moles of H+ has a pH of 3. 5. 7. 9. 11.
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5
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The presence of a buffer in our blood is an example of homeostasis. True False
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True
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Joining small molecules (monomers) together to form longer chains (polymers) requires a process called a hydrolysis reaction. a dehydration reaction. monomerization. emulsification. disassembly.
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dehydration reaction
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Which of the following is not one of the four classes of organic molecules found in cells? vitamins lipids proteins carbohydrates nucleic acids
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vitamins
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In biology, calling something organic means that it was grown without the use of any type of herbicide. True False
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False
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NaCl is not an organic molecule. True False
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False
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After lunch our digestive system will use the process of hydrolysis to break the food down into smaller subunits. True False
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True
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A hydrolysis reaction involves the loss of water. True False
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hydrolysis
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Which grouping of elements is found in carbohydrates? C - H - O C - H - P H - O - Cl N - S - O Ca - H - O
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C - H - O
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Sugars with three to seven carbon atoms are called monosaccharides. disaccharides. trisaccharides. polysaccharides. steroids.
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monosaccharides
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If a person is looking to eat a breakfast that will help supply them with energy for the entire course of the day, which of the following foods would they want to include? pancakes with maple syrup bacon, eggs, and toast cup of coffee and a donut bowl of grapes and a glass of milk All of these choices would provide the same potential for all day energy.
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pancakes with maple syrup
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Which of the following is not a monosaccharide? glucose fructose galactose maltose None of these are monosaccharides.
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maltose
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Which polysacccharide is stored as an energy source in the body of animals? glycogen glucose cellulose starch chitin
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glycogen
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What passes through the digestive tract as fiber or roughage? Maltose Glucose Glycogen Starch Cellulose
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Cellulose
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Which of the following foods would be a good source of fiber? All of these are good sources of fiber. peaches whole wheat bread peanuts bran cereal
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All of these are good sources of fiber.
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Which polysaccharide is branched the most? cellulose starch glycogen glucose fructose
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glycogen
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Which polysaccharide is consumed as a source of fiber? cellulose glycogen glucose chitin starch
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cellulose
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The main function of carbohydrates is for long-term energy storage. True False
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False
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Our body is capable of converting starch into glycogen. True False
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True
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Starch, cellulose, and glycogen are alike in that they are all made of glucose. they contain the same number of side chains. they have the same types of bonds between the monomer units. they are all found in animals. they can all be digested by our bodies.
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they are all made of glucose
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A fat contains how many fatty acids? 1 2 3 4 5
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3
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How are fats, phospholipids, and steroids alike? They are all solid at room temperature. They each contain a polar phosphate group. They each contain only 1 fatty acid. They do not dissolve in water. They all contain at least one carbon ring.
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They do not dissolve in water
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A fatty acid that contains only single bonds between the carbon atoms is considered saturated. unsaturated. trans unsaturated. a cholestrol. a steroid.
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saturated
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Fats are usually of animal origin while oils are usually of plant origin. True False
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True
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The sex hormones belong to which category of lipids? steroids fats oils triglycerides phospholipids
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steroids
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The membranes of cells are composed of phospholipids. fats. oils. steroids. triglycerides.
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phospholipids
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Fats and oils function better than other biological molecules as energy-storage molecules because of the carbon they contain. True False
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False
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The monomer unit of a protein is fatty acids. amino acids. monosaccharides. polysaccharides. nucleic acids.
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amino acids
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What makes each amino acid unique? the central carbon the R group the amino group the carboxyl group the carbon ring
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the R group
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Which of the following is not a function of proteins? quick energy support transport enzymes motion
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quick energy
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Why does a protein not function after it has been denatured? The normal bonding between the R groups has been disturbed and the protein loses its normal shape. The normal bonding between the beta sheets has been disturbed and the protein loses its normal shape. The normal bonding between the hydrogens in the alpha helix has been disturbed and the protein loses its normal shape. The R groups form additional bonds causing the structure to become more compact. The normal peptide bonds are ruptured and the individual amino acids are not held together anymore.
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The normal bonding between the R groups has been disturbed and the protein loses its normal shape.
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An alpha helix or a beta sheet are examples of what level of protein structure? secondary primary tertiary quaternary octagon
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secondary
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Which level of protein structure is characterized by alpha and beta sheets in which hydrogen bonding holds the shape in place? secondary structure primary structure tertiary structure quaternary structure pentagonal structure
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secondary structure
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When two amino acids combine via a dehydration reaction, a peptide bond is formed. the R groups are lost. water is added to begin the reaction. the carboxyl group of each join together. the amino group of each join together.
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a peptide bond is formed.
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The primary level of protein structure is composed of amino acids in a linear sequence joined by peptide bonds. True False
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True
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All amino acids are alike in that their R groups are polar. True False
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False
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The sides of the DNA ladder (backbone) are alternating carbons and nitrogens. the R groups. the nitrogenous bases. alternating nitrogens and phosphates. sugars and phosphates.
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sugars and phosphates
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When an ATP molecule is used to supply energy, which of the following occurs? a phosphate bond is added a phosphate bond is broken oxygen is removed oxygen is added an adenine is added
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a phosphate bond is broken
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Which of the following nitrogenous bases is NOT found in DNA? cytosine thymine uracil guanine adenine
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uracil
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Which of the following is not present in a nucleotide? phosphate nitrogenous base 5 ring sugar an R group a pentose
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an R group
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A species has 29% of its DNA composed of the nucleotide containing guanine (G). What percent does the nitrogen base thymine (T) equal? 58% 42% 21% 67% 29%
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21%
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ATP carries energy in the form of high-energy carbohydrate bonds. peptide bonds. lipid bonds. phosphate bonds. hydrogen bonds
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phosphate bonds.
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The function of RNA in the body is to store the genetic information in the nucleus. True False
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False
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ATP is called the energy currency of the body because it is a type of electricity. True False
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False
