Chapter 2: The Chemical Foundation of Life Flashcards
1
Q
What are the four elements common to all living things?
A
Oxygen, carbon, hydrogen and nitrogen
2
Q
radioisotopes
A
isotopes that decay into more stable forms
3
Q
carbon dating
A
using carbon-14 to determine the age of something
4
Q
Why is carbon-14 used in carbon dating?
A
It is radioactive
5
Q
half life
A
time taken for half of a radioactive substance to decay
6
Q
How does carbon dating work?
A
By comparing amount of carbon-14 in object and atmosphere
7
Q
How are electron orbitals represented?
A
With a number and symbol “n”
8
Q
octet rule
A
atoms are most stable with eight valence electrons
9
Q
electron subshell
A
smaller electron shells inside of electron shells
10
Q
What are the four types of subshells?
A
s, p, d and f
11
Q
What subshells are in 1n?
A
There is one s shell
12
Q
What subshells are there in 2n?
A
There is one s shell and three p shells
13
Q
How many electrons can 2ns hold?
A
Two electrons
14
Q
How many electrons can 2np hold?
A
Two electrons
15
Q
How do electrons fill 2n?
A
Two electrons fill 2ns first then each 2np takes one electron each, then another
16
Q
How is electron configuration represented?
A
The electron subshell then the number of electrons in that subshell superscripted
17
Q
law of mass action
A
rate of reaction is proportional to the masses of the reactants
18
Q
electrolytes
A
ions that help regulate the body
19
Q
Why is nitrogen difficult for organisms to use?
A
It is triple bonded
20
Q
What are the two types of covalent bonds?
A
Polar and nonpolar
21
Q
polar covalent bond
A
electrons are not shared equally among atoms and partial charge forms
22
Q
How is a partial charge represented?
A
With lower case delta sign and a + or -
23
Q
electronegativity
A
ability to attract electrons more than other atoms
24
Q
What type of covalent bond does water use?
A
Polar covalent bond
25
Why does water use a polar covalent bond?
Oxygen has a high electronegativity
26
nonpolar covalent bond
covalent bond where electrons are shared equally
27
Where do nonpolar covalent bonds commonly form?
Between atoms of the same element and different elements that share electrons equally
28
What two factors determine if a molecule is polar or nonpolar?
Bond type and molecule shape
29
What are two common weak bonds?
Hydrogen bonds and Van der Waals interactions
30
hydrogen bond
hydrogen atoms in a polar covalent bond have a partial positive charge and are attracted to partially negative atoms
31
Where do hydrogen bonds commonly occur?
In water
32
Van der Waals interactions
weak attractions between molecules due to fluctuations of electron densities
33
How does distance affect Van der Waals interactions?
The closer two molecules are, the stronger the force
34
hydrophilic
readily interacting with or dissolving in water
35
hydrophobic
not interacting with or dissolving well in water
36
water's polarity
water's partial positive and negative charge
37
Why is ice less dense than water?
Hydrogen bonds between water molecules create less dense crystalline structure
38
specific heat capacity
amount of heat one gram of substance must absorb to change by one degrees Celsius
39
Which liquid has the highest specific heat capacity?
Water
40
heat of vaporisation
amount of energy required to change one gram of liquid to a gas
41
sphere of hydration
when water molecules surround polar molecules and keeps them dissolved
42
dissociation
when ionic bonds are broken in an ionic compound to form ions
43
cohesion
same molecules are attracted to each other
44
surface tension
the capacity to withstand rupturing under stress or tension
45
adhesion
different molecules are attracted to each other
46
capillary action
when water is attracted to the sides of a tube-like structure and climbs up slightly
47
How do water's cohesive and adhesive properties help life?
Plants take water from their roots to their leaves through cohesion and adhesion
48
hydronium
H3O+
49
hydroxide
OH-
50
What happens naturally and spontaneously in water?
Small amounts of water molecules dissociate into H+ and OH-
51
What happens to H+ in water after it dissociates?
It bonds with a water molecule to form hydronium
52
What happens to OH- in water after it dissociates?
They stay in the solution due to hydrogen bonds
53
What is the concentration of H+ dissociating in water?
1 x 10^-7 moles per litre of water
54
How much is one mole?
6.022 x 10^23 particles
55
How is pH calculated?
The negative of the base 10 logarithm of the concentration of H+ dissociating in water
56
acid
substance that increases H+ concentration in a solution
57
base
substance that decreases H+ concentration in a solution
58
How do acids increase H+ concentration in a solution?
Usually one of the acid's hydrogen atoms dissociates
59
How do bases decrease H+ concentration in a solution?
They provide OH- ions or other negative ions to bond with H+
60
How do strong and weak bases compare?
Stronger bases readily donate OH- or take up H+ and weaker bases not so much
61
buffer
substances that absorb excess H+ or OH-
62
What are the buffers maintaining blood pH?
Carbonic acid, bicarbonate ion and carbon dioxide
63
What is the fundamental component of most macromolecules?
Carbon
64
Why is carbon such a versatile element in macromolecules?
It has four valence electrons so it can form four covalent bonds
65
hydrocarbons
molecules of only carbon and hydrogen
66
Why are hydrocarbons a good fuel source?
The four covalent bonds in carbon can store a lot of energy
67
How is the shape of methane determined?
By the shape of carbon's electron orbitals
68
What shape is methane?
Tetrahedral
69
How do single carbon-carbon bonds affect a hydrocarbon's geometry?
Single bonds allow rotation along a bond's axis and allows flexibility
70
How do double carbon-carbon bonds affect a hydrocarbon's geometry?
Double bonds lead to a planar configuration
71
How do triple carbon-carbon bonds affect a hydrocarbon's geometry?
Triple bonds lead to a linear configuration
72
eth-
two carbon hydrocarbon
73
pro-
three carbon hydrocarbon
74
but-
four carbon hydrocarbon
75
-ane
single carbon-carbon bond
76
-ene
double carbon-carbon bond
77
-yne
triple carbon-carbon bond
78
aliphatic hydrocarbon
hydrocarbons with linear chains of carbon
79
aromatic hydrocarbon
hydrocarbons with closed rings of carbon
80
How is carbon bonded in aromatic hydrocarbons?
With single and sometimes double bonds
81
How many carbons can form a ring?
Typically five or six
82
isomer
molecules with the same chemical formula but different structure
83
structural isomer
differs in placement of covalent bonds
84
geometric isomer
same covalent bonds but different molecule placement
85
cis configuration
when carbons are bound on the same side of a double bond
86
trans configuration
when carbons are bound on opposite sides of a double bond
87
triglyceride
fat or oil molecule
88
fatty acid
long carbon chain in triglycerides
89
Which configurations can fatty acids be in?
Cis or trans configuration
90
unsaturated fat
fats with at least one double bond
91
What does an unsaturated fat in the cis configuration look like?
It has a bend around the double bond
92
Why do unsaturated fats in the cis configuration remain liquid at room temperature?
Because of their bend, they cannot pack tightly enough to become solid
93
What does an unsaturated fat in the trans configuration look like?
It has a linear shape
94
What happens to trans fats at room temperature?
They pack together to form a solid
95
saturated fat
fats that do not have a double bond and contain all hydrogen atoms available
96
What happens to saturated fats at room temperature?
They pack together to form a solid
97
enantiomer
molecules with the same chemical formula and placement but are non-superimposable mirror images of each other
98
What are the two enantiomers of amino acids?
L-forms and D-forms
99
Which amino acid enantiomers make proteins?
L-forms
100
functional group
groups of atoms that give a macromolecule specific chemical properties
101
Where are functional groups found in a macromolecule?
Along the carbon skeleton
102
substituted hydrocarbon
hydrocarbons with other elements in their carbon skeleton
