Chapter 2 Flashcards
1
Q
Matter
A
Anything that occupies space and has mass.
2
Q
Mass
A
Is the amount of matter in any object, which does not change.
3
Q
Weight
A
The force of gravity acting on matter, which does change. When objects are farther from Earth, the pull of gravity is weaker.
4
Q
Chemical elements
A
Building blocks that all forms of matter, both living and non-living, are made out of. Each element is a substance that cannot be split into a simpler substance by ordinary chemical means.
5
Q
Chemical symbol
A
One or two letters of the element’s name in English, Latin, or another language. Eg. H for hydrogen, C for carbon, etc.
6
Q
Major elements
A
4 elements that constitute about 96% of the body’s mass. The major elements are oxygen (65%), carbon (18.5%), hydrogen (9.5%), and nitrogen (3.2%).
7
Q
Oxygen
A
Part of water and many organic (carbon-containing) molecules; used to generate ATP; a molecule used by cells to temporary store chemical energy.
8
Q
Carbon
A
Forms backbone chains and rings of all organic molecules; carbohydrates, lipids (fats), proteins, and nucleic acids (DNA and RNA).
9
Q
Hydrogen
A
Constituent of water and most organic molecules; ionized form (H+) makes body fluids more acidic. Component of all proteins and nucleic acids.
10
Q
Nitrogen
A
Component of all proteins and nucleic acids.
11
Q
Lesser elements
A
8 elements that constitute about 3.6% of the body’s mass. The lesser elements are calcium (1.5%), phosphorus (1.0%), potassium (0.35%), along with 5 others (don’t need to memorize others).
12
Q
Trace elements
A
14 elements that are present in tiny amounts. Constitute about 0.4% of the body’s mass. Have important functions in the body.
13
Q
Atoms
A
The smallest units of matter that retain the properties and characteristics of an element. Atoms are extremely small!
14
Q
Subatomic particles
A
Are composed of individual atoms; protons, neutrons, and electrons.
15
Q
Nucleus
A
The dense central core of an atom.
16
Q
Protons
A
Positively charged. In the nucleus.
17
Q
Neutrons
A
Uncharged. In the nucleus.
18
Q
Electrons
A
Negatively charged. In the nucleus.
19
Q
Electron shells
A
Simple circles around the nucleus. The first electron shell (nearest to the nucleus) holds a maximum of 2 electrons. The second shell holds a maximum of 8 electrons, and the third can hold up to 18 electrons. The electron shell fills with electrons in a specific order, beginning with the first shell.
20
Q
Atomic number
A
The number of protons in the nucleus of an atom.
21
Q
Mass number
A
Is the sum of an atom’s protons and neutrons. Eg. Because sodium has 11 protons and 12 neutrons, its mass number is 23.
22
Q
Isotopes
A
Atoms of an element that have different numbers of neutrons and therefore different mass numbers. Are stable. Have the same number of electrons, therefore have identical chemical properties because number of electrons determines chemical properties.
23
Q
Radioactive isotopes
A
Are unstable. Their nuclei decay into a stable configuration. As they decay, these atoms emit radiation, either subatomic particles or packets of energy, and in the process often transform into a different element. Eg. The radioactive isotope of carbon, C-14, decays to N-14.
24
Q
Half-life (of an isotope)
A
The half-life of an isotope is the time required for half of the radioactive atoms in a sample of that isotope to decay into a more stable form. Eg. The half-life of C-14 is about 5730 years.
25
Atomic mass (atomic weight)
Average mass of all the naturally occurring isotopes in an element.
26
If an atom either gives up or gains electrons, it becomes an ______.
Ion
27
Ionization
The process of giving up or gaining electrons.
28
Molecule
When two or more atoms share electrons. May consist of two atoms of the same kind, such as an oxygen molecule.
29
Compound
Substance that contains atoms of two or more different elements. Most of the atoms in the body are joined into compounds. Eg. Water (H2O) and sodium chloride aka table salt (NaCl) are compounds vs. a molecule of oxygen (O2) is not a compound because it consists of atoms of only one element.
30
Free radical
An atom or group of atoms with an unpaired electron in the outermost shell. Having an unpaired electron makes a free radical unstable, highly reactive, and destructive to nearby molecules. Free radicals become stable by either giving up their unpaired electron to, or taking on an electron from another molecule from, another molecule. In doing so, free radicals may break apart important body molecules.
31
Chemical bonds
The forces that hold together the atoms of a molecule or a compound.
32
Valence shell
The outermost shell of an atom.
33
What influences the likelihood that an atom will form a chemical bond?
The number of electrons in its valence shell (outermost shell). An atom with a valence shell holding 8 electrons is chemically stable, which means it is unlikely to form chemical bonds with other atoms. This chemical principal is known as the octet rule.
34
Ionic bond
The force of attraction that holds together ions with opposite charges.
35
Cation
A positively charged ion; when the total number of protons exceeds the number of electrons the atom becomes a cation.
36
Anion
A negatively charged ion; when the total number of electrons exceeds the number of protons the atom becomes an anion.
37
Electrolyte
An ionic compound that breaks apart into positive and negative ions in a solution.
38
Covalent bond
Two or more atoms share electrons rather than gaining or losing them. Atoms form a covalently bonded molecule by sharing one, two, or three pairs of valence electrons. The larger the number of electron pairs shared between two atoms, the stronger the covalent bond. Covalent bonds may form between atoms of the same element or between atoms of different elements. They are the most common chemical bonds in the body, and the compounds that result from them form most of the body’s structures.
39
Single covalent bond
When two atoms share one electron pair.
40
Double covalent bond
When two atoms share two pairs of electrons.
41
Triple covalent bond
Occurs when two atoms share three pairs of electrons.
42
Non-polar covalent bond
When two atoms share the electrons equally; one atom does not attract the shared electron more strongly than the other atom.
43
The bonds between 2 identical atoms and the bond between carbon and hydrogen atoms are always ______.
Non-polar
44
Polar covalent bond
When 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.
45
Electronegativity
The power to attract electrons to itself. Eg. in the bond between oxygen and hydrogen in a molecule of water, the nucleus of the oxygen atom attracts the electrons more strongly than do the nuclei of the hydrogen atoms, so the oxygen atom is said to have a greater electronegativity.
46
Hydrogen bond
Form when a hydrogen atom with a partial positive charge attracts the partial negative charge of neighbouring electronegative atoms, most often larger oxygen or nitrogen atoms. Hydrogen bonds establish important links between molecules or between different parts of a large molecule, such as a protein or a nucleic acid. The hydrogen bonds that link neighbouring water molecules give water considerable cohesion.
47
How do hydrogen bonds differ from ionic or covalent bonds?
Hydrogen bonds result from attraction of oppositely charged parts of molecules rather than from sharing of electrons as in covalent bonds, or the loss or gain of electrons as in ionic bonds. Additionally, hydrogen bonds are weak compared to ionic and covalent bonds. Thus, they cannot bind atoms into molecules.
48
Surface tension
A measure of the difficulty of stretching or breaking the surface of a liquid
49
Chemical reaction
Occurs when new bonds form or old bonds break between atoms. Chemical reactions are foundations of all life processes, and the interaction of valence electrons are the basis of all chemical reactions.
50
Reactants
The starting substances
51
Products
The ending substances.
52
Metabolism
All the chemical reactions occurring in the body.
53
Energy
Is the capacity to do work. Each chemical reaction involves energy changes.
54
Potential energy
The energy stored in matter due to its position.
55
Kinetic energy
The energy associated with matter in motion.
56
Chemical energy
A form of potential energy stored in the bonds of compounds and molecules.
57
Activation energy
The collision energy needed to break the chemical bonds of the reactants.
58
What 2 factors influence the chance that a collision will occur and cause a chemical reaction?
Concentration and temperature
59
How does concentration influence chance of collision occurring and causing a chemical reaction?
The more particles of matter present in a confined space, the greater the chance that they will collide. The concentration of particles increases when more are added to a given space or when the pressure on the space increases, which forces the particles closer together so that they collide more often.
60
How does temperature influence chance of collision occurring and causing a chemical reaction?
As temperature rises, particles of matter move about more rapidly. Thus, the higher the temperature of matter, the more forcefully particles will collide, and the greater the chance that a collision will produce a reaction.
61
Catalyst
Speed up chemical reactions by lowering the activation energy needed for a reaction to occur.
62
Exergonic reactions
Release more energy than they absorb.
63
Endergonic reactions
Absorb more energy than they release.
64
Synthesis reactions/anabolism
When two or more atoms, ions, or molecules combine to form new and larger molecules. Overall, anabolic reactions are usually endergonic because they absorb more energy than they release. Eg. Combining simple molecules like amino acids to form large molecules such as proteins.
65
Decomposition reactions/catabolism
Split up large molecules into smaller atoms, ions, or molecules. Overall, catabolism reactions are usually exergonic because they release more energy than they absorb.
66
Exchange reactions
Consist of both synthesis and decomposition reactions.
67
Reversible reactions
Reaction in which the products can revert to the original reactants.
68
Oxidation
Refers to the loss of electrons. In the process, the oxidized substance releases energy.
69
Reduction
Refers to the gain of electrons; in the process, the reduced substance gains energy.
70
Oxidation-reduction reactions
Always parallel; when one substance is oxidized, another is reduced at the same time. Eg. When a food molecule, such as glucose, is oxidized, the energy produced is used by a cell to carry out its various functions.
71
Inorganic compounds
Lack carbon and are structurally simple.
72
Organic compounds
Always contain carbon, usually contain hydrogen, and always have covalent bonds.
73
Water
Is the most important and abundant inorganic compound in all living systems.
74
What property makes water an excellent solvent?
Its polarity gives water molecules cohesion (the tendency to stick together) and allows water to resist temperature changes.
75
In a ______, and substance called the ______ dissolves another substance called the ______.
Solution, solvent, solute
76
Hydrophilic
Solutes that are charged or contain polar covalent bonds; dissolve easily in water. Eg. sugar and salt.
77
Hydrophobic
Molecules that contain mainly non-polar covalent bonds; are not very water-soluble. Eg. animal fats and vegetable oils.
78
Hydrolysis
Break down large nutrient molecules into smaller molecules by the addition of water molecules. Enable dietary nutrients to be absorbed into the body.
79
Dehydration synthesis reaction
When two smaller molecules join to form a larger molecule. A water molecule is one of the products formed.
80
What are the 2 thermal properties of water?
Water can absorb or release a relatively large amount of heat with only modest change in its own temperature. For this reason, water is said to have a high heat capacity. Water also requires a large amount of heat to change from a liquid to a gas, so its heat of vaporization is high.
81
How is water a lubricant? Why is this necessary?
Water is a major component of mucus and other lubricating fluids throughout the body. Lubrication is especially necessary in the chest (pleural and pericardial cavities) and abdomen (peritoneal cavity), where internal organs touch and slide over one another. It is also needed at joints, where bones, ligaments, and tendons rub against one another. Inside the gastrointestinal tract, mucus and other watery secretions moisten foods, which aids their smooth passage through the digestive tract.
82
Mixture
A combination of elements or compounds that are physically blended together but not bound by chemical bonds. Eg. the air you breathe is a mixture of gases that include nitrogen, oxygen, argon, and carbon dioxide. The 3 common liquid mixtures are solutions, colloids, and suspensions.
83
Colloid
The solute particles in a colloid are large enough to scatter light, just as water droplets in fog scatter light from a car’s headlight beams. For this reason, colloids usually appear translucent or opaque. Eg. Milk.
84
Suspension
The solutes in both solutions and colloids do not settle out and accumulate on the bottom of the container. In a suspension, by contrast, the suspended material may mix with the liquid or suspending medium for some time, but eventually it will settle out. Eg. Blood - when it is freshly drawn it is red. However, after it sits for awhile, it settles out and there is an upper layer of blood plasma.
85
Concentration
The concentration of a solution may be expressed in several ways. One way could be percentage (mass per volume). Another way could be molarity (moles (mol) per liter).
86
Dissociate
When inorganic acids, bases, or salts dissolve in water, and they separate into ions and become surrounded by water molecules.
87
Acid
A substance that dissociates into one or more hydrogen ions (H+) and one or more anions.
88
Because H+ is a single proton with one positive charge, an acid is also referred to as a ______.
Proton donor
89
Base
Removes hydrogen ions (H+). Many bases dissociate into one or more hydroxide ions (OH-) and one or more cations.
90
Because a base removes hydrogen ions (H+) from a solution it is a ______.
Proton acceptor
91
Salt
When dissolved in water dissociates into cations and anions, neither of which is hydrogen ions (H+) or hydroxide ions (OH-). The ions of salts provide many essential chemical elements in intracellular and extracellular fluids (such as blood, lymph, and the interstitial fluid of tissues).
92
pH
To ensure homeostasis, intracellular and extracellular fluids must contain almost balanced quantities of acids and bases.
93
The more hydrogen ions (H+) dissolved in a solution, the more ______ the solution.
Acidic
94
The more hydroxide ions (OH-) dissolved in a solution, the more ______ the solution.
Basic
95
pH scale
How a solutions acidity or alkalinity is expressed. Extends from 0-14. This scale is based on the concentration of hydrogen ions (H+) in moles per litre.
96
Buffer system
Functions to convert strong acids or bases into weak acids or bases.
97
Buffers
The chemical compounds that can convert strong acids or bases into weak ones are called buffers. They do so by removing or adding protons (H+).
98
Macromolecules
Small organic molecules that combine into very large molecules. Are usually polymers. Eg. Carbohydrates, lipids, proteins, and nucleic acids are macromolecules.
99
Polymers
A large molecule formed by the covalent bonding of many identical or similar monomers.
100
Monomers
Small building block molecules.
101
Isomers
Molecules that have the same molecular formula but different structures. Eg. the molecular formulas for the sugar's glucose and fructose are both C6H12O6. The individual atoms, however, have different chemical properties.
102
Monosaccharides
Known as a simple sugar; contain between 3-7 carbon atoms.
103
Disaccharides
Known as a simple sugar; a molecule formed from the combination of two monosaccharides by dehydration synthesis.
104
Polysaccharides
Contains tens or hundreds of monosaccharides joined through dehydration synthesis reactions. Unlike simple sugars, polysaccharides usually are insoluble in water and do not taste sweet.
105
Glycogen
The main polysaccharide in the human body; made entirely of glucose monomers linked to one another in branching chains. A limited amount of carbohydrates is stored as glycogen in the liver and skeletal muscles. This is where we store carbohydrate energy.
106
Starches
Polysaccharides formed by glucose by plants. They’re found in foods like pasta and potatoes and are the major carbohydrate in the diet.
107
Cellulose
A polysaccharide formed from the glucose by plants that cannot be digested by humans but does provide bulk to help eliminate feces.
108
Carbohydrates
Include sugars, glycogen, starches, and cellulose. Even though they are a large and diverse group of organic compounds and have several functions, carbohydrates represent only 2-3% of your total body mass. In humans and animals, carbohydrates function mainly as a source of chemical energy for generating ATP needed to drive metabolic reactions. Only a few carbohydrates are used for building structural units. Carbon, hydrogen, and oxygen are the elements found in carbohydrates.
109
Fatty acid
Consists of a carboxyl group and a hydrocarbon chain
110
Saturated fatty acid
Contains only single covalent bonds between the carbon atoms of the hydrocarbon chain. Because they lack double bonds, each carbon atom of the hydrocarbon chain is saturated with hydrogen atoms.
111
Unsaturated fatty acid
Contains one or more double covalent bonds between the carbon atoms of the hydrocarbon chain. Thus, the fatty acid is not completely saturated with hydrogen atoms.
112
Triglycerides
Three fatty acid chains connected to glycerol; the most plentiful lipid in the human diet.
113
Glycerol
A three-carbon molecule that forms the backbone of a triglyceride.
114
Saturated fat
A fat that mainly consists of saturated fatty acids. Are found mostly in meats (especially red meats) and non-skim dairy products (whole milk, cheese, and butter).
115
Monounsaturated fats
Contain triglycerides that mostly consist of monounsaturated fatty acids. Eg. olive oil, peanut oil, canola oil, most nuts, and avocados.
116
Polysaturated fats
Contain triglycerides that mostly consist of poly-unsaturated fatty acids. Eg. corn oil, safflower oil, sunflower oil, soybean oil, and fatty fish (salmon, tuna, and mackerel).
117
______ are the body’s most highly concentrated form of chemical energy.
Triglycerides
118
Phospholipids
Like triglycerides, except instead of three fatty acids its two, with the addition of a phosphate group; is amphipathic, meaning it has both polar and non-polar parts.
119
Steroids
Steroids have four rings of carbon atoms. In the body, the commonly encountered steroids are cholesterol, estrogens, testosterone, cortisol, bile salts, and vitamin D.
120
Eicosanoids
Lipids derived from a 2-carbon fatty acid called arachidonic acid. The two principal subclasses of eicosanoids are prostaglandins and leukotrienes.
121
Prostaglandins
Modify responses to hormones, contribute to the inflammatory response, prevent stomach ulcers, dilate (enlarge) airways to the lungs, regulate body temperature, and influence formation of blood clots.
122
Leukotrienes
Participate in allergic and inflammatory responses.
123
Lipids
Make up 18-25% of body mass in lean adults. Like carbohydrates, lipids contain carbon, hydrogen, and oxygen.
124
Lipoproteins
The result of lipid molecules joining with hydrophilic protein molecules.
125
Proteins
Large molecules that contain carbon, hydrogen, oxygen, and nitrogen. Some proteins also contain sulfur. A normal, lean adult body is 12-18% protein.
126
Amino acids
Each of the 20 different amino acids has a hydrogen (H) atom and three important functional groups attached to a central carbon atom.
127
Peptide bond
The covalent bond joining each pair of amino acids. It always forms between the carbon of the carboxyl group (-COOH) of one amino acid and the nitrogen of the amino group (-NH2) of another.
128
As a peptide bond is formed, a molecule of ______ is ______, making this a ______ reaction. Breaking a peptide bond, as occurs during digestion of dietary proteins, is a ______ reaction.
water, removed, dehydration synthesis, hydrolysis
129
Peptide
Combining between 4-9 amino acids.
130
Polypeptide
Combining between 10-2000+ amino acids. Proteins are formed when polypeptides connect.
131
Denaturation (of proteins)
If a protein encounters an altered environment, it may unravel and lose its characteristic shape. Denatured proteins are no longer functional.
132
Enzymes
Proteins molecules that act as catalysts.
133
Some enzymes consist of two parts - a protein portion, called the ______, and a nonprotein portion, called a ______.
Apoenzyme; cofactor
134
What are three important properties of enzymes?
Enzymes are highly specific, enzymes are very efficient, and enzymes are subject to a variety of cellular controls.
135
Substrate
The reactant molecules on which the enzyme acts; each particular enzyme binds only to specific substrates.
136
Active site
The part of the enzyme that catalyzes the reaction.
137
How do enzymes work?
1. Enzymes and substrate come together at active site of enzyme, forming an enzyme-substrate complex.
2. Enzyme catalyzes reaction and transforms substrate into products.
3. When reaction is complete, enzyme is unchanged and free to catalyze same reaction again on a new substrate.
138
Nucleic acid
Huge organic molecules that contain carbon, hydrogen, oxygen, nitrogen, and phosphorus. Two varieties include DNA and RNA.
139
DNA
Forms the inherited genetic material inside each human cell.
140
Gene
Genes are segments of a DNA molecule. Our genes determine the traits we inherit, and by controlling protein synthesis, they regulate most of the activities that take place in body cells throughout our lives.
141
RNA
Relays instructions from the genes to guide each cell’s synthesis of proteins from amino acids.
142
Nucleotides
Chain of repeating monomers.
143
What 3 parts do nucleotides of DNA consist of?
Nitrogenous base, a pentose sugar, and a phosphate group.
144
Nitrogenous base
Part of a nucleotide; DNA contains 4 different nitrogenous bases, which contain atoms C, H, O, and N. In DNA the 4 nitrogenous bases are adenine (A), thymine (T), cytosine (C), and guanine (G). A and G are larger, double-ring bases called purines. T and C are smaller, single-ring bases called pyrimidines. The nucleotides are named according to the base that is present. Eg. A nucleotide containing T is called a thymine nucleotide.
145
Pentose sugar
Part of a nucleotide; a five-carbon sugar called deoxyribose attaches to each base in DNA.
146
Phosphate group
Part of a nucleotide; phosphate groups alternate with pentose sugars to form the “backbone” of a DNA strand; bases project inward from the backbone chain.
147
Double helix
Model where DNA resembles a spiral ladder. Two strands of alternating phosphate groups and deoxyribose sugars form the uprights of the ladder. Paired bases, held together by hydrogen bonds, form the rungs.
148
ATP
Is the “emergency currency” of living systems.
149
When a water molecule is added to ATP, the third phosphate group (PO43−) is removed, and the overall reaction liberates energy. The enzyme that catalyzes the hydrolysis of ATP is called ______. Removal of the third phosphate group produces a molecule called ______.
ATPase; adenosine diphosphate (ADP)
150
The energy needed to attach a phosphate group to ADP is supplied mainly by the catabolism of glucose in a process called ______.
Cellular respiration
151
Anaerobic phase
Series of reactions that do not require oxygen; glucose is partially broken.
152
Aerobic phase
Series of reactions that require oxygen; glucose is completely broken down.
