Ch.2: Basic Chemistry Flashcards
1
Q
Matter
A
• Anything that occupies space and has mass
• Matter may exist as one of three states:
*Solid: definite shape and volume
*Liquid: definite volume; shape of container
*Gaseous: neither a definite shape nor volume
2
Q
Matter may be changed:
A
- Physically
* Chemically
3
Q
Physically changed matter
A
- Changes do not alter the basic nature of a substance
* Examples include changes in the state of matter (solid, liquid, or gas)
4
Q
Chemically changed matter
A
Changes alter the chemical composition of a substance
5
Q
Energy
A
- The ability to do work
* Has no mass and does not take up space
6
Q
Kinetic energy
A
Energy is doing work
7
Q
Potential energy
A
Energy is inactive or stored
8
Q
Forms of energy:
A
- Chemical energy is stored in chemical bonds of substances
- Electrical energy results from movement of charged particles
- Mechanical energy is energy directly involved in moving matter
- Radiant energy travels in waves; energy of the electromagnetic spectrum
9
Q
Energy form conversions
A
ATP (adenosine triphosphate) traps the chemical energy of food in its bonds
10
Q
Elements
A
Fundamental units of matter
11
Q
96 percent of the body is made from four elements:
A
- Oxygen (O)—most common; 65% of the body’s mass
- Carbon (C)
- Hydrogen (H)
- Nitrogen (N)
12
Q
Atoms
A
- Building blocks of elements
- Atoms of elements differ from one another
- Atomic symbol is chemical shorthand for each element
13
Q
What are the charges of the basic subatomic particles?
A
- Protons (p+) are positively charged
- Neutrons (n0) are uncharged or neutral
- Electrons (e−) are negatively charged
14
Q
Number of protons equals:
A
- Number of electrons in an atom
* Positive and negative charges cancel each other out
15
Q
Ions
A
Atoms that have lost or gained electrons
16
Q
Electrons determine an atom’s:
A
Chemical behavior and bonding properties
17
Q
To identify an element, we need to know the:
A
- Atomic number
- Atomic mass number
- Atomic weight
18
Q
Atomic number
A
- Equal to the number of protons that the atom contains
- Unique to atoms of a particular element
- Indirectly tells the number of electrons in an atom
19
Q
Atomic mass number
A
Sum of the protons and neutrons contained in an atom’s nucleus
20
Q
Atomic weight
A
Approximately equal to the mass number of the element’s most abundant isotope
21
Q
Isotopes
A
- Atoms that have the same number of protons and electrons but vary in the number of neutrons
- Isotopes have the same atomic number but different atomic masses
22
Q
Radioisotope
A
- Heavy isotope of certain atoms
- Tends to be unstable
- Decomposes to more stable isotope
23
Q
Radioactivity
A
- Process of spontaneous atomic decay
* Used to tag and trace biological molecules through the body
24
Q
Molecule
A
Two or more atoms of the same elements combined chemically
25
Compound
Two or more atoms of different elements combined chemically to form a molecule of a compound
26
Chemical reactions occur when:
Atoms combine with or dissociate from other atoms
27
Chemical bonds
Energy relationships involving interactions among the electrons of reacting atoms
28
Electrons occupy energy levels called:
Electron shells (or energy levels)
29
Electrons closest to the nucleus are most strongly attracted to its:
Positive charge
30
Distant electrons further from the nucleus are likely to interact with:
Other atoms
31
How to fill the atom’s electrons shells:
* Shell 1 can hold a maximum of 2 electrons
* Shell 2 can hold a maximum of 8 electrons
* Shell 3 can hold a maximum of 18 electrons
* Subsequent shells can hold more electrons
32
Bonding involves interactions only between electrons in:
* The outermost (valence) shell
| * Atoms with full valence shells do not form bonds
33
Rule of eights
* The key to chemical reactivity
* Atoms are considered stable when their outermost (valence) shell has 8 electrons
* Atoms with 8 electrons in the valence shell are considered stable and chemically inactive (inert)
* The exception to this rule of eights is shell 1, which can hold only 2 electrons
34
Reactive elements
* Atoms will gain, lose, or share electrons to complete their outermost orbitals when fewer than 8 electrons are in the valence shell
* Chemical bonding helps atoms achieve a stable valence shell
35
Ionic bonds
* Form when electrons are completely transferred from one atom to another
* Allow atoms to achieve stability through the transfer of electrons
36
Ions
Result from the loss or gain of electrons
• Anions have negative charge due to gain of electron(s)
• Cations have positive charge due to loss of electron(s)
Tend to stay close together because opposite charges attract
37
Covalent bonds
* Atoms become stable through shared electrons
* Electrons are shared in pairs
* Single covalent bonds share one pair of electrons
* Double covalent bonds share two pairs of electrons
* Can be described as either nonpolar or polar
38
Nonpolar covalent bonds
* Electrons are shared equally between the atoms of the molecule
* Electrically neutral as a molecule
* Example: carbon dioxide
39
Polar covalent bonds
* Electrons are not shared equally between the atoms of the molecule
* Molecule has a positive and negative side, or pole
* Example: water
40
Hydrogen bonds
* Extremely weak chemical bonds
* Formed when a hydrogen atom is attracted to the negative portion, such as an oxygen or nitrogen atom, of a polar molecule
* Responsible for the surface tension of water
* Important for forming intramolecular bonds, as in protein structure
41
Synthesis reaction
* Atoms or molecules combine to form a larger, more complex molecule
* Energy is absorbed for bond formation
* Underlies all anabolic (building) activities in the body
42
Decomposition reaction
* Molecule is broken down into smaller molecules
* Chemical energy is released
* Underlies all catabolic (destructive) activities in the body
43
Exchange reaction
* Involves simultaneous synthesis and decomposition reactions as bonds are both made and broken
* Switch is made between molecule parts, and different molecules are made
44
Reversibility is indicated by a:
* Double arrow
* When arrows differ in length, the longer arrow indicates the more rapid reaction or major direction of progress
* Most chemical reactions are reversible
45
Factor: ↑ temperature
↑ the kinetic energy of the molecules, which in turn move more rapidly and collide more forcefully
46
Factor: ↑ concentration of reacting particles
↑ the number of collisions because of increased numbers of reacting particles
47
Factor: ↓ particle size
Smaller particles have more kinetic energy and move faster than larger ones, hence they take part in more collisions
48
Factor: Presence of catalysts
↓ the amount of energy the molecules need to interact by holding the reactants in the proper positions to interact
49
Inorganic compounds
* Lack carbon
* Tend to be small, simple molecules
* Include water, salts, and many (not all) acids and bases
50
Organic compounds
* Contain carbon
* All are large, covalent molecules
* Include carbohydrates, lipids, proteins, and nucleic acids
51
What is the most abundant inorganic compound in the body?
```
• Water
• Accounts for two-thirds of the body’s weight
• Vital properties include:
*High heat capacity
*Polarity/solvent properties
*Chemical reactivity
*Cushioning
```
52
High heat capacity
* Water absorbs and releases a large amount of heat before it changes temperature
* Prevents sudden changes in body temperature
53
Polarity/solvent properties
* Water is often called the “universal solvent”
* Solvents are liquids or gases that dissolve smaller amounts of solutes
* Solutes are solids, liquids, or gases that are dissolved or suspended by solvents
* Solution forms when solutes are very tiny
* Colloid forms when solutes of intermediate size form a translucent mixture
54
Chemical reactivity
* Water is an important reactant in some chemical reactions
* Reactions that require water are known as hydrolysis reactions
* Example: water helps digest food or break down biological molecules
55
Cushioning
* Water serves a protective function
| * Examples: cerebrospinal fluid protects the brain from physical trauma, and amniotic fluid protects a developing fetus
56
Salts
• Ionic compound
• Contain cations other than H+ and anions other than O H−
• Easily dissociate (break apart) into ions in the presence of water
• Vital to many body functions
*Example: sodium and potassium ions are essential for nerve impulses
57
All salts are:
* Electrolytes
| * Electrolytes are ions that conduct electrical currents
58
Acids
* Electrolytes that dissociate (ionize) in water and release hydrogen ions (H+)
* Proton (H+) donors
* Strong acids ionize completely and liberate all their protons
* Weak acids ionize incompletely
59
Bases
* Electrolytes that dissociate (ionize) in water and release hydroxyl ions (O H−)
* Proton (H+) acceptors
60
Neutralization reaction
Type of exchange reaction in which acids and bases react to form water and a salt
61
p H measures relative concentration of:
* Hydrogen (and hydroxide) ions in body fluids
* p H scale is based on the number of protons in a solution
* p H scale runs from 0 to 14
* Each successive change of 1 p H unit represents a tenfold change in H+ concentration
62
Buffers
Chemicals that can regulate p H change
63
Acidic solutions have a pH below
* 7
| * More H+ than O H−
64
Basic solutions have a p H above
* 7
| * Fewer H+ than O H−
65
Polymer
* Chainlike molecules made of many similar or repeating units (monomers)
* Many biological molecules are polymers, such as carbohydrates and proteins
66
Dehydration synthesis
* Monomers are joined to form polymers through the removal of water molecules
* A hydrogen ion is removed from one monomer while a hydroxyl group is removed from the monomer it is to be joined with
* Water is removed at the site where monomers join (dehydration)
67
Hydrolysis
* Polymers are broken down into monomers through the addition of water molecules
* As a water molecule is added to each bond, the bond is broken, and the monomers are released
68
Carbohydrates
```
• Contain carbon, hydrogen, and oxygen
• Include sugars and starches
• Classified according to size and solubility in water:
*Monosaccharides
*Disaccharides
*Polysaccharides
```
69
Monosaccharides
* Simple sugars and the structural units of the carbohydrate group
* Single-chain or single-ring structures
* Contain three to seven carbon atoms
* Examples: glucose (blood sugar), fructose, galactose, ribose, deoxyribose
70
Disaccharides
* Two simple sugars joined by dehydration synthesis
* Examples include sucrose, lactose, and maltose
* Too large to pass through cell membranes
71
Polysaccharides
* Long, branching chains of linked simple sugars
* Large, insoluble molecules
* Function as storage products
* Examples include starch and glycogen
72
Lipids are insoluble in water, but soluble in:
• Other lipids
• Most abundant are the triglycerides, phospholipids, and steroids
• Contain carbon, hydrogen, and oxygen
*Carbon and hydrogen outnumber oxygen
73
Triglycerides, or neutral fats
```
• Found in fat deposits
• Source of stored energy
• Composed of two types of building blocks—fatty acids and one glycerol molecule
*Saturated fatty acids
*Unsaturated fatty acids
```
74
Saturated fats (Fatty acid chains of triglycerides)
* Contain only single covalent bonds
* Chains are straight
* Exist as solids at room temperature since molecules pack closely together
75
Unsaturated fats (Fatty acid chains of triglycerides)
* Contain one or more double covalent bonds, causing chains to kink
* Exist as liquid oils at room temperature
* “Heart healthy”
76
Trans fats
* Oils that have been solidified by the addition of hydrogen atoms at double bond sites
* Increase risk of heart disease
77
Omega-3 fatty acids
* Found in cold-water fish and plant sources, including flax, pumpkin, and chia seeds; walnuts and soy foods
* Appear to decrease risk of heart disease
78
Phospholipids
* Contain two fatty acids chains rather than three; they are hydrophobic (“water fearing”)
* Phosphorus-containing polar “head” carries an electrical charge and is hydrophilic (“water loving”)
* Charged “head” region interacts with water and ions while the fatty acid chains (“tails”) do not
* Form cell membranes
79
Steroids
* Formed of four interlocking rings
* Include cholesterol, bile salts, vitamin D, and some hormones
* Some cholesterol is ingested from animal products; the liver also makes cholesterol
* Cholesterol is the basis for all steroids made in the body
80
Proteins
* Account for over half of the body’s organic matter
* Provide for construction materials for body tissues
* Play a vital role in cell function
* Act as enzymes, hormones, and antibodies
* Contain carbon, oxygen, hydrogen, nitrogen, and sometimes sulfur
* Built from building blocks called amino acids
81
Amino acid structure
* Contain an amine group (N H2)
* Contain an acid group (C O O H)
* Vary only by R-groups
82
Protein structure
* Polypeptides contain fewer than 50 amino acids
* Proteins contain more than 50 amino acids
* Large, complex proteins contain 50 to thousands of amino acids
* Sequence of amino acids produces a variety of proteins
83
Structural levels of proteins
```
• Primary structure
• Secondary structure
*Alpha helix
*Beta-pleated sheet
• Tertiary structure
• Quaternary structure
```
84
Primary structure
Strand of amino acid “beads”
85
Secondary structure
* Chains of amino acids twist or bend
* Alpha helix resembles a metal spring
* Beta-pleated sheet resembles pleats of a skirt or sheet of paper folded into a fan
86
Tertiary structure
Compact, ball-like (globular) structure
87
Quaternary structure
Result of a combination of two or more polypeptide chains
88
Fibrous (structural) proteins
* Appear in body structures
* Exhibit secondary, tertiary, or even quaternary structure
* Bind structures together and exist in body tissues
* Stable proteins
* Examples include collagen and keratin
89
Globular (functional) proteins
* Function as antibodies, hormones, or enzymes
* Exhibit at least tertiary structure
* Hydrogen bonds are critical to the maintenance of structure
* Can be denatured and no longer perform physiological roles
* Active sites “fit” and interact chemically with other molecules
90
Enzymes
• Act as biological catalysts
• Increase the rate of chemical reactions
• Bind to substrates at an active site to catalyze reactions
• Can be recognized by their –ase suffix
*Hydrolase
*Oxidase
91
Nucleic acids
* Form genes
* Composed of carbon, oxygen, hydrogen, nitrogen, and phosphorus atoms
* Largest biological molecules in the body
* Two major kinds are DNA and RNA
92
Nucleic acids are built from building blocks called:
Nucleotides
93
Nucleotides contain three parts:
* A nitrogenous base
* Pentose (five-carbon) sugar
* A phosphate group
94
Deoxyribonucleic acid (DNA)
* The genetic material found within the cell’s nucleus
* Provides instructions for every protein in the body
* Organized by complementary bases to form a double-stranded helix
* Contains the sugar deoxyribose and the bases adenine, thymine, cytosine, and guanine
* Replicates before cell division
95
Ribonucleic acid (RNA)
* Carries out DNA’s instructions for protein synthesis
* Created from a template of DNA
* Organized by complementary bases to form a single-stranded helix
* Contains the sugar ribose and the bases adenine, uracil, cytosine, and guanine
* Three varieties are messenger, transfer, and ribosomal RNA
96
Adenosine triphosphate (ATP)
* Composed of a nucleotide built from ribose sugar, adenine base, and three phosphate groups
* Chemical energy used by all cells
* Energy is released by breaking high-energy phosphate bond
97
ADP (adenosine diphosphate) accumulates as ATP is used for:
Energy
98
A T P is replenished by oxidation of:
Food fuels
