Chapter 2: Chemical Basis Of Life Flashcards
1
Q
what is an element?
A
a pure substance of 1 kind of atom
2
Q
what is an atom?
A
the smallest functional unit of matter
3
Q
what are the parts of an atom?
A
protons, neutrons, electrons
4
Q
what are protons?
A
positive charge
5
Q
what are neutrons?
A
no charge
6
Q
what are electrons?
A
negative charge
7
Q
how is an atom arranged?
A
the protons and neutrons are in the center of the nucleus. the electrons are arranged in orbitals around the nucleus. The first 2 electrons are in the first orbital and the rest are in the second
8
Q
are the nucleus of a cell and atom different?
A
yes. the cell is a physical structure where the atoms is not
9
Q
what makes up most of the weight of an atom?
A
the protons and neutrons because they both have an atomic mass of 1. The electrons have an atomic mass way less than 1 so they don’t weigh much
10
Q
elements in the same column on the periodic table have similar…
A
properties
11
Q
how are elements arranged?
A
by atomic number
12
Q
what is the net charge of an atom?
A
it is zero or uncharged because the protons equal the electrons canceling each other.
13
Q
what is atomic mass?
A
it is mainly based on #protons and neutrons
14
Q
electrons are involved in what but have very little…
A
bonding
mass
15
Q
what is electronegativity?
A
the ability of an atom to attract/ gain electrons
16
Q
electronegativity increases which way on the periodic table?
A
left-right
17
Q
when atoms lose an electron, what charge do they have?
A
positive charged ion
18
Q
when atoms gain an electron, they have what charge?
A
a negative charged ion
19
Q
noble gases are nonreactable because…
A
their outer most orbital is full
20
Q
how do elements become the most stable?
A
have a full outer orbital or be completely empty
21
Q
what are ions?
A
atoms that have gained or lost electrons
22
Q
what are ions?
A
atoms that have gained or lost electrons
23
Q
are ions charged particles?
A
yes. they can either be negative or positive
24
Q
what do ions have to add up to in an ionic bond?
A
zero
25
when do opposites attract?
with ionic bonds
26
what are molecules?
made up of 2 or more atoms that are connected together by bonds. they can either be the same atom or different atoms (compound).
27
a molecule has a net charge of…
zero
28
ionic bonds are always charged and is between…
ions
29
what is a covalent bond?
when the electrons are shared between the atoms so there is no charge because there are no electrons.
30
why do they want to share a pair of electrons?
to become more stable
31
what is a type of covalent bond?
disulfide bonds
32
electrons are shared between two atoms
covalent bonds
33
hydrogen bonds are very…
weak
34
bond formed between a positively charged ion and a negatively charged ion
ionic bonds
35
what bond? Na+Cl-
C-C, C-H
ionic
covalent
36
what is a nonpolar covalent bond?
electrons are shared evenly between 2 atoms
37
what is a polar covalent bond ?
electrons are shared between 2 atoms, but they spend more time near one atom than the other. one end is partially positive and the other is negative
38
what type of atoms are electron hogs?
electronegative atoms
39
electrons spend more time near what?
the electronegative atoms than near other atoms
40
what is a polar molecule?
has a partial positive or partial negative charge at one end of molecule.
41
electronegative atoms in biological molecules are
O and N
42
what is a single bond?
a covalent bond that one pair of electrons is shared between atoms
43
what is a double bond?
a covalent bond that two pairs of electrons are shared between atoms
44
what is a triple bond?
a covalent bond where three pairs of electrons are shared between atoms
45
what is a disulfide bonds?
a covalent bond between two sulfur atoms S-S
46
what is a hydrogen bond?
a very weak bond that can break easily that is formed when a H atom is electrically attracted to an electronegative atom (O or N)
47
how many H bonds can there be in a molecule?
100s or 1000s
48
what are valence electrons?
the electrons in the outermost shell
49
what is ignored in calculations of atomic mass?
electrons
50
what are cations?
ions that have a net positive charge
51
what are anions?
ions with a negative charge
52
what is a free radical?
a molecule containing an atom with a single unpaired electron in its outer shell
53
what type of molecule is water?
polar
54
in a water molecule, the o and h have what charges and why?
the o has a partial negative charge because it is electronegative
the h has a partial positive charge because it’s electrons spend more time near the O
55
how can a molecule dissolve in water?
It has to be ellectrically attracted to the water molecule ( polar or charged)
56
inside a water molecule how are they connected?
by covalent bonds and then there are hydrogen bonds between the molecules
57
if one end of a polar molecule has a partial positive charge it will be attracted so what?
the partial negative end on the o of the water
58
if one end of a polar molecule has a partial negative charge, it will be attracted to what?
the partial positive on the h of water
59
what kind of molecules dissolve in water?
charged ions
charged molecules
polar molecules
60
NA+ is attracted to what in water?
the partial negative on the O in water
61
Cl- is attracted to the what in water?
the partial positive charge on the H in water
62
the water surrounds the molecules to…
dissolve them
63
what are hydrophilic molecules?
molecules that can dissolve in water
64
what does hydrophilic mean?
water loving
65
hydrophilic molecules are usually
charged or polar
66
in a cell, where do hydrophilic molecules usually dissolve?
the cytoplasm because it is mainly water
67
are hydrophilic molecules soluble?
yes
68
what are hydrophobic molecules?
molecules that can’t dissolve in water
69
what does hydrophobic mean?
water fearing
70
hydrophobic molecules are normally
nonpolar, uncharged, and large
71
where does hydrophobic molecules usually dissolve in?
nonpolar solvents
72
in a cell, hydrophobic molecules usually dissolve in the
lipid bilayer of a membrane (fatty layer)
73
what is an amphipathic molecule?
has one polar/charged end and one nonpolar/hydrophobic end
74
why do hydrophobic parts of the molecule cluster together in an amphipathic molecule?
so they minimize exposure to water
75
hydrophilic parts of the amphipathic molecule are attracted to
water
76
each end of an amphipathic molecule has different
Properties
77
what is a solute?
substances dissolved in a liquid
78
what is a solvent?
the liquid in which the substance is dissolved
79
what is a solution?
a liquid (solvent) containing dissolved substances (solute)
80
what is an aqueous solution?
a solution made with water
81
what type of solution is in a cytoplasm?
aqueous
82
salt is the solute
water is the solvent
saline solution
83
what is cohesion?
water molecules are attracted to other water molecules
84
what is adhesion?
water molecules are attracted to charged surfaces
85
cohesion and adhesion will cause what in the surface of water?
a curve
86
why can water interact with charged surfaces?
it has a partial negative and positive
87
water can partially dissolve into
ions
88
when water partially dissolves, what form are the particles in?
ionized and hydroxide ions
89
what is an acid?
a substance that releases H+ ions when it dissolves in water
90
what is a strong acid?
completely dissolves into its ions (HCl->H+,Cl-
91
what is a weak acid?
partially dissociates into its ions and some stays in its neutral form ( H2CO3-> H+, HCO3)
92
what increases the H+ concentration of a solution?
an acid
93
acids solution have a what concentration of H+?
high which results in low ph
94
what is a low ph?
<7
95
what is a base?
a substance that releases OH- ions when it dissolves in water
96
what is a strong base?
completely dissociates into its ions (NaOH-> Na+, OH-)
97
what is a weak base?
will partially dissociate in water (NH3+H2O <-> NH4+OH-
98
a weak base is normally an
organic base
99
there is an always an uncharged form and charged form in what?
weak bases and acids
100
what decreases the H+ concentration of a solution?
base
101
H+ from water binds to the substance to make what?
a positive charged ion
102
basic solutions have what type of concentration of H+
low which results in high ph
103
what is a high ph?
>7
104
what is a ph scale?
a measure of how acidic or basic a substance is
105
A ph scale is expressed as what?
the negative logarithm of the H+ concentration
106
what ph does pure water have?
7
107
do alkaline and basic mean the same thing?
yes
108
the higher the H+ concentration, what happens to the ph?
lower
109
acidic solutions have what type of ph?
low (<7)
110
the lower the H+ concentration, what happens to the ph?
higher
111
what ph do alkaline or basic solutions have?
High (>7)
112
the row on the periodic table shows what?
#of electrons shells
113
the column on the periodic table shows what?
# of electrons in the outer shell
114
can a substance be a molecule and an compound?
yes
NaCl, CO2
115
explain the trend of electronegatity
less-> more
more
^
less
more
/
less
116
what is nonpolar?
less than 0.4
117
what is polar?
0.4-0.8
118
what is ionic?
more than 0.8
119
what can’t denature an enzyme?
cold
120
NaCl is what type of bond
Ionic
121
LiF are connected by what bond?
Ionic
122
NH3 is a molecule connected by which bond as is H2O. Can these two molecules create H bonds between one another?
polar covalent, yes
123
Phosphate groups have what charge?
negative
124
is amino group acidic or basic?
Basic
125
Is carboxyl an acid or base?
Acid
126
Why is carbon a great component of organic molecules?
forms polar bonds, forms nonpolar bonds, has 4 electrons in the outer shell
127
is hydraphilic charged or uncharged?
charged
