Chapter 2: Chemical Basis of Life – Flashcards

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The study of chemistry is essential for the study of physiology because
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because body functions depend on cellular functions that, in turn, result from chemical changes.
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Biochemistry
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is the study of chemistry in living organisms
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Matter
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anything that has weight and takes up space
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All matter is composed of
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elements
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Examples of elements are
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are iron, copper, silver, gold, aluminum, carbon, hydrogen, and oxygen.
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Compounds are
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chemical combinations
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Elements needed by the body in large amounts are called
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bulk elements
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. Six examples of bulk elements are
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are carbon, hydrogen, oxygen, nitrogen, sulfur, and phosphorus.
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Elements needed by the body in small amounts are called
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trace elements
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Trace elements are used by the body for parts of
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enzymes
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Ultratrace elements are
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elements needed by the body in very small amounts and are toxic in large amounts
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Elements are composed of particles called
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atoms.
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Atoms that make up elements are chemically identical to one another, but
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they differ from the atoms that make up other elements
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. The central portion of an atom is called the
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the nucleus
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The nucleus contains
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protons and usually neutrons
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Electrons carry a ___________charge
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negative
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Electrons are located around the
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nucleus
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Protons carry a ___________charge
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positive
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. Neutrons are electrically__________
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neutral
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nucleus of an atom is _______charged
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positively
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A complete atom is electrically___________
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neutral
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The atoms of different elements contain different numbers of ___________
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protons
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An atomic number is the
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number of protons in the atoms of a particular element.
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Carbon has an atomic number of
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six
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One atom of carbon contains ______ protons
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six
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The weight of an atom is primarily due to the
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weight of protons and neutrons.
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The atomic weight of an atom is the
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number of protons plus the number of neutrons in each of an element's atoms
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The atomic weight of carbon is________.
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twelve
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One carbon atom has ___ protons and___neutrons.
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six, six
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Atoms of the same element can vary in atomic weights because.
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their number of neutrons may vary
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An oxygen atom with an atomic weight of 17 has
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eight protons and nine neutrons
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Isotopes are
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atoms that have the same atomic numbers but different atomic weights
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The number of electrons in an atom equals
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the number of protons
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Radioactive isotopes release
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atomic radiation.
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Examples of radioactive isotopes are isotopes of
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oxygen, iodine, iron, phosphorus, and cobalt
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Three common forms of atomic radiation are
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alpha, beta, and gamma radiation
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Alpha radiation consists of particles from atomic nuclei, each of which includes
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two protons and two neutrons.
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Beta radiation consists of
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electrons.
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The most penetrating type of atomic radiation is
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gamma radiation.
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Two or more atoms may combine to form a
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molecule.
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A molecular formula depicts the
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numbers and kinds of atoms in a molecule
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The subscripts in a molecular formula indicate
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how many atoms of each element are present.
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When atoms of different elements combine molecules of substances called ______ form.
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compounds
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Bonds form when __________ combine
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atoms
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Electrons of an atom are found in
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energy shells
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The first electron shell can hold
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two electrons
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The second electron shell can hold
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eight electrons.
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The third electron shell of an atom with an atomic number 18 will hold
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eight electrons
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________electron shells are filled first.
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Innermost
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An atom will react with another atom if its outermost shell
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is not completely full of electrons.
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Inert atoms are
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atoms that have completely full outermost electron shells.
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Atoms with________filled outer shells tend to lose, gain, or share electrons in ways that empty or fill their outer shells to become stable.
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incompletely
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Ions are
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atoms that gain or lose electrons and become electrically charged
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A sodium atom loses_____electron to become stable.
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one
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A chlorine atom gains ______electron to become stable
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one
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If an atom loses an electron, it becomes __________ charged.
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positively
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If an atom gains an electron, it becomes ________ charged.
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negatively
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Positively charged ions are called
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cations
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Negatively charged ions are called
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anions
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An ionic bond forms when
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oppositely charged ions attract.
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A covalent bond forms
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when atoms share electrons.
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When one pair of electrons is shared between atoms, ___________bond is formed
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a single covalent
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When two pairs of electrons are shared between atoms, a ________ bond is formed.
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double covalent
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When three pairs of electrons are shared between atoms, a__________ bond is formed.
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triple covalent
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A structural formula
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shows how atoms bond and are arranged in a molecule
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When electrons are not shared equally in a covalent bond, a _____ forms.
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polar molecule
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An important example of a polar molecule is
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water
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A hydrogen bond is
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the weak attraction between the positive hydrogen end of a polar molecule to the negative nitrogen or oxygen end of another polar molecule.
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Reactants of a chemical reaction are
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substances being changed.
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Products of a chemical reaction are
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substances formed at the end of a chemical reaction.
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A synthesis reaction occurs when
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two or more atoms, ions, or molecules bond to form a more complex structure.
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A decomposition reaction occurs when .
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the bonds of a reactant molecule break to form simpler molecules
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An exchange reaction occurs when
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parts of two different kinds of molecules trade positions
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In reversible reactions,
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products can change back to the reactant or reactants
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Catalysts are
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molecules that influence the rates of chemical reactions but are not consumed in the reactions
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Catalysts are
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molecules that influence the rates of chemical reactions but are not consumed in the reactions
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When salts are put into water, they dissolve into
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positive ions (cations) and negative ions (anions).
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Substances that release ions in water are called
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electrolytes.
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Acids are
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electrolytes that dissociate to release hydrogen ions in water.
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Bases are
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substances that combine with hydrogen ions.
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A salt is a substance formed by the reaction between
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an acid and a base.
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Hydrogen ion concentration is typically measured in
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grams of ions per liter of solution.
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The pH scale is a shorthand system used to indicate
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the concentration of hydrogen ions.
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A solution with a hydrogen ion concentration of 0.1 grams per liter has a pH value of
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1.0.
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A solution with a hydrogen ion concentration of 0.001 grams per liter has a pH value of
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3.0.
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The pH scale ranges from
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0 to 14.
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Each whole number on the pH scale represents a tenfold difference in .
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hydrogen ion concentration
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As the hydrogen ion concentration increases,
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the pH decreases.
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A neutral pH is
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7.0.
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________have pH values that are less than 7.0.
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Acidic solutions
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___________ have pH values that are more than 7.0.
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Alkaline solutions
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Solutions with more hydrogen ions than hydroxide ions are
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acidic.
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Solutions with more hydroxide ions than hydrogen ions are _______or_____.
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basic or alkaline.
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Solutions with equal numbers of hydrogen ions and hydroxide ions are neutral
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neutral
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The normal pH of blood is
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7.35 - 7.45.
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Alkalosis is
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a rise in blood pH
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Acidosis is
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a fall in blood pH.
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Buffers are
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chemicals that resist pH change
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Chemicals that contain carbon and hydrogen are organic.
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organic.
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Chemicals that generally do not contain carbon and hydrogen are
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inorganic
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Many organic chemicals have long chains or ring structures that can be formed because of a.
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carbon atom's ability to form four covalent bonds
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Inorganic chemicals usually dissociate _in__ ______
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water.
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Organic chemicals usually dissolve in ___________ ________
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organic liquids.
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____________ are compounds that do not release ions when dissolved in water.
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Nonelectrolytes
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Four common inorganic substances in cells are .
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water, oxygen, carbon dioxide, and inorganic salts
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The most abundant compound in living material is
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water.
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Most metabolic reactions occur in ________because when substances dissolve in water, the polar water molecules cause molecules of the substance to separate from each other or to break up into ions. These particles are then much more likely to take part in chemical reactions.
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water
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In the body, _____ transports chemicals, waste materials and heat
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water
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Organelles use _____ to release energy from nutrient molecules.
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oxygen
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A continuing supply of_________ is necessary for cell survival
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oxygen
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______ _______is produced when energy is released during certain metabolic processes.
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Carbon dioxide
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As ______ _______moves into body fluids and blood, it reacts with water to form a weak acid (carbonic acid).
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carbon dioxide
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Inorganic salts are sources of many necessary
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ions
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______ _________ is the condition of having electrolytes in correct concentrations, both inside and outside cells
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Electrolyte balance
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Four groups of organic substances in cells are
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carbohydrates, lipids, proteins, and nucleic acids.
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Three things _________ supply to cells are energy, materials to build certain cell structures, and a reserve energy supply.
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carbohydrates
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Three elements always found in carbohydrates are
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carbon, hydrogen, and oxygen.
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The ratio of hydrogen to oxygen in carbohydrates is close to
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2:1.
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Two types of simple _______ are monosaccharides and disaccharides
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sugars
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Monosaccharides have __ - ___ carbons
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3-7
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Disaccharides have __ carbons
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12
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Three examples of monosaccharides are glucose, fructose, and galactose
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glucose, fructose, and galactose
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Two examples of _________ are sucrose and lactose.
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disaccharides
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Complex carbohydrates are
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polysaccharides
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__________ are built from simple carbohydrates
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Polysaccharides
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Three examples of ___________are cellulose, starch, and glycogen
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polysaccharides
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Lipids are soluble in _______ solvents.
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organic
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Three examples of_______are fats, phospholipids, and steroids
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lipids
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Three elements found in ______molecules are carbon, hydrogen, and oxygen
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fat
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______have a smaller proportion of oxygen than carbohydrates.
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Fats
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The building blocks of___molecules are fatty acids and glycerol.
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fat
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All fatty acid molecules include a _________group at the end of a chain of carbon atoms
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carboxyl
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Two ways fatty acid molecules differ are in
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the lengths of their carbon atom chains and the way the carbon atoms join together
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A _______________is one in which the carbon atoms are linked by single carbon-carbon bonds.
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saturated fatty acid
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Fatty acids with one double carbon-carbon bond is
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monounsaturated
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Fatty acids with more than one double carbon-carbon bond is
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polyunsaturated.
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A single fat molecule is called a
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triglyceride
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One_________ contains one glycerol molecule and three fatty acid molecules.
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triglyceride
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Saturated fats contain only
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saturated fatty acids.
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_________contain at least one unsaturated fatty acid
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Unsaturated fats
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The number of fatty acid chains in a phospholipid molecule is
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two
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The part of a ______ ______ that is soluble in water is the phosphate containing portion.
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phospholipid molecule
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The part of a phospholipid molecule that is insoluble in water is the
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fatty acid portion.
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______________ are important in cellular structures.
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Phospholipids
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_________contain connected rings of carbon atoms.
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Steroids
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.An important steroid found in all body cells is
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cholesterol
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_______________ is used to synthesize other steroids, sex hormones, and hormones from the adrenal glands.
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Cholesterol
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Three important functions of___________are to serve as structural materials, energy sources, and chemical messengers. _______also function as receptors, antibodies, and enzymes.
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proteins
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____________are catalysts in living systems
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Enzymes
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One element sometimes found in proteins is .
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sulfur
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The building blocks of proteins are
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amino acids
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___________ have an amino group at one end and a carboxyl group at the other end
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Amino acids
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The twenty amino acids differ in their side chains or
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R groups
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Peptide bonds are
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covalent bonds between amino acids
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A ______________is a chain of amino acids.
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polypeptide
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The four levels of protein structure are
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primary, secondary, tertiary, and quaternary
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The primary structure of a ______ is the amino acid sequence of the polypeptide chain.
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protein
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In secondary structure, a _______ chain forms an alpha helix or a beta-pleated sheet.
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polypeptide
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Hydrogen bonding determines
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secondary structure
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The folding of secondary structure is called
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tertiary structure.
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________is determined by its distinct conformation created by its primary, secondary, and tertiary structures.
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Protein function
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When a protein ______, it loses its tertiary or secondary structure.
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denatures
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Four things that cause a protein to denature are
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heat, radiation, pH changes, and certain chemicals
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The _______ structure of a protein forms when several polypeptide chains connect to form a very large protein
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quaternary
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____________carry the instructions that control a cell's activities by encoding the amino acid sequences of proteins in its building blocks.
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Nucleic acids
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The five elements found in nucleic acids are
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carbon, hydrogen, oxygen, nitrogen, and phosphorus
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The building blocks of nucleic acids are
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nucleotides.
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The three parts of a nucleotide are a
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5-carbon containing sugar, a phosphate group, and one of several organic bases
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A _________ is a chain of nucleotides.
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polynucleotide
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Two major types of nucleic acids are
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DNA and RNA
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RNA contains the sugar
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ribose
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DNA contains the sugar
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deoxyribose
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_____is a single polynucleotide chain
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RNA
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_____ is a double polynucleotide chain
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DNA
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The function of ____ is to store information for protein synthesis
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DNA
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The function of RNA is to use the information stored in DNA to construct specific protein molecules. true or false
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true
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______has the unique ability to make copies of itself.
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DNA
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