BIO 141 Exam 1 Study Guide |120 Questions and
Answers
atoms and their parts - -the smallest unit that retains the properties of an element; has a
positively charged nucleus with with protons and neutrons, and an negatively charged
electron cloud
-ions - -charged atoms/non-neutral atoms; cations are positive and anions are negative
-elements - -A substance that cannot be broken down any further by chemical means
-properties of elements - -all atoms of a particular element have the same number of
protons; the mass of a proton and a neutron is the same and is equal to 1 dalton; the
number of protons is equal to the mass number; atomic numbers are unique to each
element
-compounds - -substances made up of two or more elements
-relationship between an elements structure and its chemical properties - -the chemical
behavior of an atom is determined by the distribution of electrons in the atom's electron
shells
-main elements of life - -carbon, oxygen, hydrogen, and nitrogen
-essential elements - -(20-25% of all elements) elements needed by organisms to live a
healthy life and reproduce; humans need 25 and plants need 17
-trace elements - -elements that are required by organisms in very small quantities
-orbitals vs. shells - -An orbital is the 3-dimensional space that the electrons occupy 90%
percent of the time; a shells is an energy level that refers to the distance away from the
nucleus and is composed of orbitals
-valence - -the number of e- in the outer most shell of an atom or compound
-types of bonds - -ionic bonds (strong), covalent bonds (strong), hydrogen bonds (weak),
and Van der Walls attraction (weak)
-ionic bonds - -when two atoms are joined together through the transfer of e-; form salts
-covalent bonds - -when two atoms are joined together through the sharing of e-; can be
polar or non-polar due to electronegatvitiy
, -hydrogen bonds - -when a bonded hydrogen atom is attracted to a neighboring
electronegative atoms
-Van der Waals interactions - -the sum of the attractive or repulsive forces between
molecules
-relationship between molecular shape and function - -a molecule's shape is determined
by the positions of its atoms' valence orbitals. Covalent bonds result in hybrid orbitals,
which are responsible for the shapes of many complex biological molecules. Shape is the
basis for the recognition of one biological molecule by another. Biological molecules often
bind temporarily to each other by forming weak bonds, but only if their shapes are
complementary
-models of molecular shape - -the positions of the hybrid orbitals determine the shapes of
the molecules
-electronegativity - -the tendency of an atom to draw e- to it (unequal sharing)
-chemical reactions - -breaking and formation of chemical bonds, leading to the
composition of matter
-isotopes - -forms of the same element with different numbers of neutrons
-atomic mass - -the sum of the number of protons and neutrons in an atom
-atomic numbr - -the number of protons
-mass number - -the total number of particles in the nucleus
-hydrogen bonds in water - -due to the partial changes that form from waters polar
covalent bonds, oppositely charged regions of neighboring water molecules are attracted to
each other forming hydrogen bonds
-polarity of water molecules - -water is held together by polar covalent bonds; this
polarity in means that the overall charge is unevenly distributed; the oxygen has a partial
negative charge and the hydrogen have a partial positive charge
-cohesiveness of water - -cohesion is the sticking together of particles of the same kind;
hydrogen bonds in water form links of water molecules. the hydrogen bonds within water
hold the substance together and make it more structured; example: this is why plants are
able to move water from the roots to the leaves
-temperature - -the intensity of heat due to the average kinetic energy
-kinetic energy - -energy of motion
Answers
atoms and their parts - -the smallest unit that retains the properties of an element; has a
positively charged nucleus with with protons and neutrons, and an negatively charged
electron cloud
-ions - -charged atoms/non-neutral atoms; cations are positive and anions are negative
-elements - -A substance that cannot be broken down any further by chemical means
-properties of elements - -all atoms of a particular element have the same number of
protons; the mass of a proton and a neutron is the same and is equal to 1 dalton; the
number of protons is equal to the mass number; atomic numbers are unique to each
element
-compounds - -substances made up of two or more elements
-relationship between an elements structure and its chemical properties - -the chemical
behavior of an atom is determined by the distribution of electrons in the atom's electron
shells
-main elements of life - -carbon, oxygen, hydrogen, and nitrogen
-essential elements - -(20-25% of all elements) elements needed by organisms to live a
healthy life and reproduce; humans need 25 and plants need 17
-trace elements - -elements that are required by organisms in very small quantities
-orbitals vs. shells - -An orbital is the 3-dimensional space that the electrons occupy 90%
percent of the time; a shells is an energy level that refers to the distance away from the
nucleus and is composed of orbitals
-valence - -the number of e- in the outer most shell of an atom or compound
-types of bonds - -ionic bonds (strong), covalent bonds (strong), hydrogen bonds (weak),
and Van der Walls attraction (weak)
-ionic bonds - -when two atoms are joined together through the transfer of e-; form salts
-covalent bonds - -when two atoms are joined together through the sharing of e-; can be
polar or non-polar due to electronegatvitiy
, -hydrogen bonds - -when a bonded hydrogen atom is attracted to a neighboring
electronegative atoms
-Van der Waals interactions - -the sum of the attractive or repulsive forces between
molecules
-relationship between molecular shape and function - -a molecule's shape is determined
by the positions of its atoms' valence orbitals. Covalent bonds result in hybrid orbitals,
which are responsible for the shapes of many complex biological molecules. Shape is the
basis for the recognition of one biological molecule by another. Biological molecules often
bind temporarily to each other by forming weak bonds, but only if their shapes are
complementary
-models of molecular shape - -the positions of the hybrid orbitals determine the shapes of
the molecules
-electronegativity - -the tendency of an atom to draw e- to it (unequal sharing)
-chemical reactions - -breaking and formation of chemical bonds, leading to the
composition of matter
-isotopes - -forms of the same element with different numbers of neutrons
-atomic mass - -the sum of the number of protons and neutrons in an atom
-atomic numbr - -the number of protons
-mass number - -the total number of particles in the nucleus
-hydrogen bonds in water - -due to the partial changes that form from waters polar
covalent bonds, oppositely charged regions of neighboring water molecules are attracted to
each other forming hydrogen bonds
-polarity of water molecules - -water is held together by polar covalent bonds; this
polarity in means that the overall charge is unevenly distributed; the oxygen has a partial
negative charge and the hydrogen have a partial positive charge
-cohesiveness of water - -cohesion is the sticking together of particles of the same kind;
hydrogen bonds in water form links of water molecules. the hydrogen bonds within water
hold the substance together and make it more structured; example: this is why plants are
able to move water from the roots to the leaves
-temperature - -the intensity of heat due to the average kinetic energy
-kinetic energy - -energy of motion
