Chapter 2: Chemical Compositions in the Body Flashcards
1
Q
Matter
A
anything that occupies space, all living and non-living things consist of matter
exists in 3 states
1) solid (ex. bones)
2) liquid (ex. blood plasma)
3) gas (ex. oxygen)
2
Q
Mass
A
amount of matter in any object, which DOES NOT change
3
Q
weight
A
the force of gravity acting on matter
DOES change
4
Q
Atom
A
is the smallest stable unit of matter – they are extremely small
5
Q
chemical symbol
A
each element is designated by one or two letters of the elements name in English
6
Q
Major elements
A
oxygen, carbon, hydrogen, nitrogen (96%)
7
Q
Nucleus
A
dense central core of an atom
8
Q
Oxygen (O)
A
body mass: 65%
- part of water and many organic (carbon containing) molecules
- used to generate ATP
9
Q
Carbon (C)
A
body mass: 18.5%
- forms backbone chains and rings of all organic molecules: carbs, lipids, proteins
(DNA & RNA)
10
Q
Hydrogen (H)
A
body mass: 9.5%
- Constituent of water and most organic molecules
- In ionized form (H+) makes body fluids more acidic
11
Q
Nitrogen (N)
A
body mass: 3.2%
- Component of all proteins and nucleic acids
12
Q
Electron Shells
A
- depicted as simple circles around the nucleus
- each electron shell can hold a specific number of electrons, the electron shell model best conveys this aspect of atom structure
13
Q
how many electrons in each shell
A
*The first electron shell (the one nearest the nucleus) never holds more than 2 electrons
*The second shell holds a maximum of 8 electrons
*The third can hold up to 18 electrons
14
Q
Atomic number:
A
number of protons in the nucleus of an atom
ex. oxygen has an atom # of 8 because its nucleus has 8 protons
15
Q
Mass number:
A
is the sum of its protons and neutrons
ex. sodium has 11 protons and 12 neutrons, mass number = 23
16
Q
Isotopes
A
are atoms of an element that have different numbers of neutrons and therefore different mass numbers
17
Q
Radioactive isotopes
A
are unstable; their nuclei decay (spontaneous change) into a stable configuration
Ex. H-3, O-15, C-14
18
Q
Half-life of an isotope
A
is the time required for half of the radioactive atoms in a sample of that isotope to decay into a more stable form
19
Q
Dalton
A
standard unit for measuring the mass of atoms and their subatomic particles, also known as an atomic mass unit (amu)
20
Q
Atomic mass
A
also called the atomic weight of an element is the average mass of all of its naturally occurring isotopes
21
Q
Ion
A
an atom that has a positive or negative charge because it has unequal numbers of protons and electrons – symbolized by writing its chemical structure follow by a positive or negative charge (+ or -)
22
Q
Ionization
A
is the process of giving up or gaining electrons
23
Q
Molecule
A
when two or more atoms share electrons, the resulting combination – may consist of two atoms of the same kind, such as an oxygen molecule
24
Q
Molecular formula
A
indicates the elements and the number of atoms of each element that make up a molecule
25
Compound
is a substance that contains atoms of two or more different elements
Ex. Water H20
26
Free radical
is an atom or molecule with an unpaired electron in the outermost shell
Ex. superoxide, which is formed by the addition of an electron to an oxygen molecule
27
Chemical bonds
the forces that hold together the atoms of a molecule or a compound
28
Chemically stable
an atom with a valence shell holding eight electrons (outermost shell)
29
Ionic Bound
the force of attraction that holds together ions with opposite charges
30
cation & anion
Cation: total number of protons exceeds number of electrons = positively charged
Anion: total number of electrons exceeds number of protons = negatively charged
31
Covalent Bond
strongest type of chemical bond, two or more atoms share electrons rather than gaining or losing them
- form between atoms of same or different
- most common chemical bond
- sharing of 1, 2 or 3 pairs of valence electrons
32
single, double, triple covalent bond
Single covalent bond: results when two atoms share one electron pair
Double covalent bond: results when two atoms share two pairs of electrons
Triple covalent bond: occurs when two atoms share three pairs of electrons
33
Nonpolar covalent bond
two atoms share the electrons equally, one atom does not attract the shared electron more strongly than the other atom
- The bonds between two identical atoms are always nonpolar covalent
34
Polar covalent bond
the sharing of electrons between two atoms is unequal – the nucleus of one atom attracts the shared electrons more strongly than the nucleus of the other atom
- resulting: partial negative charge
35
Electronegativity
the power to attract electrons to itself
36
Hydrogen bonds
forms when a hydrogen atom with a partial positive charge attracts the partial negative charge of a neighbouring electronegative atom, most often an oxygen or nitrogen atom
* Result from attraction of oppositely charged parts of molecules rather than from sharing of electrons
37
reactants
starting materials in a chemical reaction – substances that change or combine
Ex. ingredients in a recipe
38
products
substances that are formed as a result of the chemical reaction
Ex. final dish made
39
Irreversible reactions
proceed in only one direction, from reactants to products
40
reversible reactions
the products can revert to the original reactants. Indicated by two half arrows
41
Chemical equilibrium
the rate of the forward reaction is equal to the rate of the reverse reaction
42
Law of mass action
relationship between the net direction of a reversible reaction and the concentrations of the reactants and products
43
Inorganic compounds
usually lack carbon and are structurally simple – include many salts, acids and bases
44
Organic compounds
always contain CARBON, usually contain hydrogen and always have covalent bonds
45
hydrophilic
solutes that are charged or contain polar covalent bonds (hydro = water philic = loving)
- dissolve easily in water
46
hydrophobic
molecules that contain mainly nonpolar covalent bonds (phobic = fearing)
- NOT water soluble
47
mixture
is a combination of elements and compounds that are physically blended together but not bound by chemical bonds
48
colloid
is a mixture where very tiny particles are spread out evenly but don’t fully dissolve, like they would in a solution
ex. milk
49
Suspension
is a type of mixture where the particles are large enough that they don’t stay evenly mixed for long - Over time, the particles settle to the bottom of the container because they are too heavy to stay floating
ex. blood
50
molarity
refers to the number or moles of solute per liter or solution “how many groups of a certain size are in a liquid”
51
mole
is the amount of any substance that has a mass in grams equal to the sum of the atomic masses of all its atoms
52
equivalents
measures amount of solute based on its ability to interact in chemical reactions
- useful for things like acids, bases or electrolytes
53
Mass per volume
tells you how much the solute weighs (in grams for ex) compared to how much liquid there is (in litres for ex)
54
proton donor
is something that gives away hydrogen ions (H⁺) when it dissolves in water
55
proton acceptor
is something that takes in hydrogen ions (H+) from a solution
56
pH scale
solutions acidity or alkalinity is expressed on this scale, extends from 0-14
57
pH
defined as the negative logarithm of the hydrogen ion concentration in moles
58
acidic solution
solution that has more H+ than OH- and has a pH below 7
59
basic (alkaline) solution
that has more OH- than H+ and has a pH above 7
60
pH of blood between: is homeostatic
Homeostatic mechanisms maintain the pH of blood between 7.35 and 7.45 (average = 7.4), which is slightly more basic than pure water
61
Acidosis
occurs if pH falls below 7.35
62
Alkalosis
if pH rises above 7.45
63
Buffers
chemical compounds that can convert strong acids or bases into weak ones (by removing or adding protons)
64
dehydration synthesis
reaction that joins two monomers, hydrogen atom is removed from one monomer and a hydroxyl group is removed from the other to form a molecule of water
65
Hydrolysis
polymers can be brown down into monomers by the addition of water molecules
(hydro = water) (lysis = to break down) – it is the reverse of dehydration synthesis
66
Carbohydrates
include sugars, glycogen, starches and cellulose
*Represent only 2-3% of your total body mass
*In humans and animals
67
Monosaccharides
contain three to seven carbon atoms
*Designated by names ending in -ose
*Ex. Glucose and fructose
68
Disaccharide
is a molecule formed from the combination of two monosaccharides by dehydration synthesis
* Examples include: sucrose, lactose, maltose
* Sucrose = fructose + glucose
69
Polysaccharides
- Each contains hundreds to thousands monosaccharides joined through dehydration synthesis reactions
- Main polysaccharide in the human body is glycogen
70
Lipids
make up 18-25% of body mass in lean adults
* They contain carbon, hydrogen and oxygen
* Most lipids are insoluble in polar solvents (such as water) : hydrophobic
71
Lipoproteins
lipid/protein complexes
- Soluble because the proteins are on the outside of the molecule and lipids on the inside
72
Fatty acids
used to synthesize triglycerides and phospholipids
- Can be broken down to generate ATP
- consists of a carboxyl group and a hydrocarbon chain
- can be saturated or un saturated
73
Saturated fatty acid
contains only one single covalent bond between the carbon atoms of the hydrocarbon chain
74
Unsaturated fatty acid
contains one or more double covalent bonds between the carbon atoms of the hydrocarbon chain
75
Triglycerides
most plentiful lipid in your body and in your diet
* Consists of two types of building blocks
1. single glycerol molecule
2. three fatty acid molecules
76
Saturated fat
a fat that mainly consists of saturated fatty acids
Present in lard, butter, cheese and most animal meats (especially red meat)
77
Monosaturated fats
contain triglycerides that consists of mostly of monounsaturated fatty acids (ex. Olive oil, peanut oil, canola oil)
78
Polyunsaturated fats
contains triglycerides that consists mostly of polyunsaturated fatty acids (ex. Corn oil, sunflower oil, fish oil)
79
Phospholipids
have a glycerol backbone and two fatty acid chains attached to the first two carbons
- Have both polar and non polar bonds
80
Steroids
are lipids that contain four interconnected hydrocarbon rings
* Ex. Cholesterol, estrogens, testosterone, vitamin d
81
Eicosanoids
lipids derived from a 20 carbon fatty acid called arachidonic acid
Three subclasses:
1. Prostaglandins
2. Thromboxane
3. Leukotrienes
82
Proteins
are large molecules that contain carbon, hydrogen, oxygen and nitrogen
* Some also contain sulfur
* Some proteins are enzymes
83
Amino acids
monomers of proteins
* Each has a hydrogen atom and 3 important functional groups attached to the central carbon atom
84
Peptide bond
the covalent bond joining each pair of amino acids
85
levels of structural organization in proteins:
Primary structure: unique sequence of amino acids that are linked by covalent peptide bonds to form a polypeptide chain
Secondary structure: is the repeated twisting or folding of neighbouring amino acids in the polypeptide chain
Tertiary structure: refers to the 3-dimensional shape of a polypeptide chain
Quaternary structure: if more than one polypeptide chain, the arrangement of the individual polypeptide chains relative to one another
86
Denaturation
If a protein encounters an altered environment (such as a significant change in temperature or pH or the presence of certain chemical agents), it may unravel and lose its characteristic shape (secondary, tertiary, and quaternary structure)
87
Ligand
any molecule or ion that binds to a particular site on a protein through weak, noncovalent interactions (hydrogen bonds, ionic bonds, hydrophobic interactions)
88
Binding site
the region of the protein where the ligand binds
89
properties of ligands - protein binding
specificity - particular 3D shape
affinity - strength
saturation - degree to which they are occupied
competition - if similar they can bind to the same site
90
Modulator
Chemical that binds to a protein and either alters the ligands binding ability or changes the functional activity of the protein
- through allosteric modulation & covalent modulation
91
Nucleic acids
first discovered in the nuclei of cells, are huge organic molecules that contain carbon, hydrogen, oxygen, nitrogen and phosphorus
92
Deoxyribonucleic acid (DNA)
Forms the inherited genetic material inside each human cell
- Each gene is a segment of a DNA molecule
o Genes determine traits we inherit, regulate most activities
93
Ribonucleic acid (RNA)
* Relays instructions from the genes to guide each cells synthesis of proteins from amino acids
* Not double stranded
* Cells contain three different kinds of RNA: messenger RNA, ribosomal RNA, and transfer RNA
94
Adenosine Triphosphate (ATP)
“energy currency” of living systems
- ATP transfers energy from energy releasing reactions to energy requiring actions that maintain cellular activities
- ATP consists of three phosphate groups attached to adenosine, a unit composed of adenine and the five carbon sugar ribose
95
each nucleotide contains 3 parts:
1. nitrogenous base
- arranged in a single or double ring
2. pentose sugar
- 5 carbon sugar
3. phosphate group
- forms the backbone of DNA & RNA
96
