CH.2 Flashcards

1
Q

Matter

A

—anything that has mass and

occupies space

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2
Q

3 states of matter

A

solid, liquid, gas

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3
Q

Energy

A

capacity to do work

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4
Q

kinetic

A

energy in action

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5
Q

potential

A

stored energy

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6
Q

chemical energy

A

stored in bonds of chemical substances

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7
Q

Electrical energy

A

– Results from movement of charged particles

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8
Q

Mechanical energy

A

Directly involved in moving matter

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9
Q

• Radiant or electromagnetic energy

A

Travels in waves (e.g., visible light, ultraviolet

light, and x-rays)

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10
Q

Elements

A

– Matter is composed of elements
– Elements cannot be broken into simpler
substances by ordinary chemical methods
– Each has unique properties

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11
Q

• Atoms

A
Unique building blocks for each element
– Give each element its physical & chemical 
properties
– Smallest particles of an element with 
properties of that element
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12
Q

Atomic symbol

A

One- or two-letter chemical shorthand for

each element

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13
Q

Four elements make up 96.1% of body mass

A
Element
Carbon
Hydrogen
Oxygen
Nitrogen
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14
Q

9 elements make up 3.9% of body mass

A
Element
Calcium
Phosphorus
Potassium
Sulfur
Sodium
Chlorine
Magnesium
Iodine
Iron
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15
Q

11 elements make up < 0.01% of body mass

A
Element
Chromium
Copper
Fluorine
Manganese
Silicon
Zinc
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16
Q

Atoms

A
composed of subatomic 
particles
– Protons, neutrons, electrons
• Protons and neutrons found in nucleus
• Electrons orbit nucleus in an electron 
cloud
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17
Q

Nucleus of atoms

A
Almost entire mass of the atom
• Neutrons
• Carry no charge
• Mass = 1 atomic mass unit (amu)
• Protons
• Carry positive charge
• Mass = 1 amu
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18
Q

Electrons in orbitals within electron cloud

A

• Electrons in orbitals within electron cloud
– Carry negative charge
– 1/2000 the mass of a proton (0 amu)
– Number of protons and electrons always
equal

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19
Q

Different elements contain different

numbers of subatomic particles

A

Hydrogen has 1 proton, 0 neutrons, and 1
electron
– Lithium has 3 protons, 4 neutrons, and 3
electrons

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20
Q

Atomic number

A

Number of protons in
nucleus
– Written as subscript to left of atomic symbol Ex. 3Li

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21
Q

Mass number

A
Total number of protons and neutrons in 
nucleus
• Total mass of atom
– Written as superscript to left of atomic symbol
• Ex. 7Li
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22
Q

• Isotopes

A

– Structural variations of atoms
– Differ in the number of neutrons they contain
– Atomic numbers same; mass numbers
different

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23
Q

Atomic weight

A

Average of mass numbers (relative weights)

of all isotopes of an atom

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24
Q

Radioisotopes - Heavy isotopes decompose to more stable forms

A

Spontaneous decay called radioactivity
– Similar to tiny explosion
– Can transform to different element
Can be detected with scanners

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25
Radioisotopes
``` Valuable tools for biological research and medicine – Share same chemistry as their stable isotopes – Most used for diagnosis • All damage living tissue – Some used to destroy localized cancers – Radon from uranium decay causes lung cancer ```
26
Molecule
• Two or more atoms bonded together (e.g., H2 or C6H12O6 ) • Smallest particle of a compound with specific characteristics of the compound
27
Compound
Two or more different kinds of atoms bonded together (e.g., C6H12O6 , but not H2)
28
Three types of mixtures
– Solutions – Colloids – Suspensions
29
Solvent
– Substance present in greatest amount | – Usually a liquid; usually water
30
Solute
– Present in smaller amounts • Ex. If glucose is dissolved in blood, glucose is solute; blood is solvent
31
Colloids
Heterogeneous mixtures, e.g., cytosol – Large solute particles do not settle out – Some undergo sol-gel transformations • e.g., cytosol during cell division
32
Suspensions
Heterogeneous mixtures, e.g., blood | – Large, visible solutes settle out
33
• Mixtures
No chemical bonding between components – Can be separated by physical means, such as straining or filtering – Heterogeneous or homogeneous
34
Compounds
Chemical bonding between components – Can be separated only by breaking bonds – All are homogeneous
35
• Chemical bonds
are energy relationships | between electrons of reacting atoms
36
• Electrons in valence shell (outermost electron | shell)
Have most potential energy | – Are chemically reactive electrons
37
Chemically Reactive Elements
• Valence shell not full • Tend to gain, lose, or share electrons (form bonds) with other atoms to achieve stability
38
Types of Chemical Bonds
– Ionic bonds – Covalent bonds – Hydrogen bonds
39
Ions
Atom gains or loses electrons and becomes charged • # Protons ≠ # Electrons • Transfer of valence shell electrons from one atom to another forms ions – One becomes an anion (negative charge) • Atom that gained one or more electrons – One becomes a cation (positive charge) • Atom that lost one or more electrons • Attraction of opposite charges results in an ionic bond
40
Ionic Compounds
• Most ionic compounds are salts – When dry salts form crystals instead of individual molecules – Example is NaCl (sodium chloride)
41
Covalent Bonds
• Formed by sharing of two or more valence shell electrons • Allows each atom to fill its valence shell at least part of the time
42
Nonpolar Covalent Bonds
Electrons shared equally • Produces electrically balanced, nonpolar molecules such as CO2
43
Polar Covalent Bonds
``` • Unequal sharing of electrons produces polar (AKA dipole) molecules such as H2O – Atoms in bond have different electronattracting abilities • Small atoms with six or seven valence shell electrons are electronegative, e.g., oxygen – Strong electron-attracting ability • Most atoms with one or two valence shell electrons are electropositive, e.g., sodium ```
44
Hydrogen Bonds
Attractive force between electropositive hydrogen of one molecule and an electronegative atom of another molecule – Not true bond – Common between dipoles such as water – Also act as intramolecular bonds, holding a large molecule in a three-dimensional shape
45
Chemical Reactions
• Occur when chemical bonds are formed, rearranged, or broken • Represented as chemical equations using molecular formulas – Subscript indicates atoms joined by bonds – Prefix denotes number of unjoined atoms or molecules • Chemical equations contain – Reactants • Number and kind of reacting substances – Chemical composition of the product(s) – Relative proportion of each reactant and product in balanced equations
46
Patterns of Chemical Reactions
* Synthesis (combination) reactions * Decomposition reactions * Exchange reactions
47
Decomposition Reactions
``` AB  A + B – Molecule is broken down into smaller molecules or its constituent atoms • Reverse of synthesis reactions – Involve breaking of bonds – Catabolic ```
48
Exchange Reactions
AB + C  AC + B – Also called displacement reactions – Involve both synthesis and decomposition – Bonds are both made and broke
49
Oxidation-Reduction (Redox) Reactions
Are decomposition reactions – Reactions in which food fuels are broken down for energy • Are also exchange reactions because electrons are exchanged between reactants – Electron donors lose electrons and are oxidized – Electron acceptors receive electrons and become reduced • C6H12O6 + 6O2  6CO2 + 6H2O + ATP • Glucose is oxidized; oxygen molecule is reduced
50
Exergonic reactions
net release of energy • Products have less potential energy than reactants • Catabolic and oxidative reactions
51
Endergonic reactions
``` net absorption of energy • Products have more potential energy than reactants • Anabolic reactions ```
52
Rate of Chemical Reactions
``` Affected by –  Temperature   Rate –  Concentration of reactant   Rate –  Particle size   Rate – Catalysts:  Rate without being chemically changed or part of product • Enzymes are biological catalysts ```
53
Biochemistry
Study of chemical composition and reactions of living matter • All chemicals either organic or inorganic
54
• Inorganic compounds
Water, salts, and many acids and bases | • Do not contain carbon
55
Organic compounds
Carbohydrates, fats, proteins, and nucleic acids • Contain carbon, usually large, and are covalently bonded
56
Polar solvent properties of water
– Dissolves and dissociates ionic substances – Forms hydration layers around large charged molecules, e.g., proteins (colloid formation) – Body’s major transport medium
57
Salts
Ionic compounds that dissociate into ions in water – Ions (electrolytes) conduct electrical currents in solution – Ions play specialized roles in body functions (e.g., sodium, potassium, calcium, and iron) – Ionic balance vital for homeostasis • Contain cations other than H+ and anions other than OH– • Common salts in body – NaCl, CaCO3 , KCl, calcium phosphates
58
Acids
``` s are proton donors – Release H+ (a bare proton) in solution – HCl  H+ + Cl– is a electrolyte ```
59
Bases
``` proton acceptors – Take up H+ from solution • NaOH  Na+ + OH– – OH– accepts an available proton (H+ ) – OH– + H+  H2O electrolyte ```
60
Important acids
– HCl, HC2H3O2 | (HAc), and H2CO
61
• Important bases
– Bicarbonate ion (HCO3–) and ammonia (NH3
62
pH: Acid-base Concentration
``` – Relative free [H+ ] of a solution measured on pH scale – As free [H+ ] increases, acidity increases • [OH– ] decreases as [H+ ] increases • pH decreases – As free [H+ ] decreases alkalinity increases • [OH– ] increases as [H+ ] decreases • pH increases ```
63
pH: Acid-base Concentration
``` Acidic solutions   [H+ ],  pH – Acidic pH: 0–6.99 • Neutral solutions – Equal numbers of H+ and OH– – All neutral solutions are pH 7 – Pure water is pH neutral • pH of pure water = pH 7: [H+ ] = 10–7 m • Alkaline (basic) solutions   [H+ ],  pH – Alkaline pH: 7.01–14 ```
64
Buffers
Acidity reflects only free H+ in solution – Not those bound to anions • Buffers resist abrupt and large swings in pH – Release hydrogen ions if pH rises – Bind hydrogen ions if pH falls • Convert strong (completely dissociated) acids or bases into weak (slightly dissociated) ones • Carbonic acid-bicarbonate system (important buffer system of blood):
65
Organic Compounds
Molecules that contain carbon – Except CO2 and CO, which are considered inorganic – Carbon is electroneutral • Shares electrons; never gains or loses them • Forms four covalent bonds with other elements • Unique to living systems • Carbohydrates, lipids, proteins, and nucleic acids Many are polymers – Chains of similar units called monomers (building blocks) • Synthesized by dehydration synthesis • Broken down by hydrolysis reactions
66
Carbohydrates
``` • Sugars and starches • Polymers • Contain C, H, and O [(CH20)n ] • Three classes – Monosaccharides – one sugar – Disaccharides – two sugars – Polysaccharides – many sugars Functions of carbohydrates – Major source of cellular fuel (e.g., glucose) – Structural molecules (e.g., ribose sugar in RNA) ```
67
Monosaccharides
``` Simple sugars containing three to seven C atoms • (CH20)n – general formula; n = # C atoms • Monomers of carbohydrates • Important monosaccharides – Pentose sugars • Ribose and deoxyribose – Hexose sugars • Glucose (blood sugar) ```
68
Disaccharides
Double sugars • Too large to pass through cell membranes • Important disaccharides – Sucrose, maltose, lactose
69
Polysaccharides
• Polymers of monosaccharides • Important polysaccharides – Starch and glycogen • Not very soluble
70
Lipids
``` Contain C, H, O (less than in carbohydrates), and sometimes P • Insoluble in water • Main types: – Neutral fats or triglycerides – Phospholipids – Steroids – Eicosanoids ```
71
Neutral Fats or Triglycerides
• Called fats when solid and oils when liquid • Composed of three fatty acids bonded to A glycerol molecule • Main functions – Energy storage – Insulation – Protection
72
Saturation of Fatty Acids
``` Saturated fatty acids – Single covalent bonds between C atoms • Maximum number of H atoms – Solid animal fats, e.g., butter • Unsaturated fatty acids – One or more double bonds between C atoms • Reduced number of H atoms – Plant oils, e.g., olive oil – “Heart healthy” • Trans fats – modified oils – unhealthy • Omega-3 fatty acids – “heart healthy” ```
73
Phospholipids
Modified triglycerides: – Glycerol + two fatty acids and A phosphorus (P) - containing group • “Head” and “tail” regions have different properties • Important in cell membrane structure
74
Steroids
Steroids—interlocking four-ring structure • Cholesterol, vitamin D, steroid hormones, and bile salts • Most important steroid – Cholesterol • Important in cell membranes, vitamin D synthesis, steroid hormones, and bile salts
75
Eicosanoids
• Many different ones • Derived from a fatty acid (arachidonic acid) in cell membranes • Most important eicosanoid – Prostaglandins • Role in blood clotting, control of blood pressure, inflammation, and labor contractions
76
Proteins
Contain C, H, O, N, and sometimes S and P • Proteins are polymers • Amino acids (20 types) are the monomers in proteins – Joined by covalent bonds called peptide bonds – Contain amine group and acid group – Can act as either acid or base – All identical except for “R group” (in green on figure)
77
Fibrous (structural) proteins
Strandlike, water-insoluble, and stable – Most have tertiary or quaternary structure (3-D) – Provide mechanical support and tensile strength – Examples: keratin, elastin, collagen (single most abundant protein in body), and certain contractile fibers
78
Globular (functional) proteins
Compact, spherical, water-soluble and sensitive to environmental changes – Tertiary or quaternary structure (3-D) – Specific functional regions (active sites) – Examples: antibodies, hormones, molecular chaperones, and enzymes
79
Protein Denaturation
Globular proteins unfold and lose functional, 3-D shape • Active sites destroyed – Can be cause by decreased pH or increased temperature • Usually reversible if normal conditions restored • Irreversible if changes extreme – e.g., cooking an egg
80
Molecular Chaperones
``` Globular proteins • Ensure quick, accurate folding and association of other proteins • Prevent incorrect folding • Assist translocation of proteins and ions across membranes • Promote breakdown of damaged or denatured proteins • Help trigger the immune response ```
81
• Stress proteins
– Molecular chaperones produced in response to stressful stimuli, e.g., O2 deprivation – Important to cell function during stress – Can delay aging by patching up damaged proteins and refolding them
82
Enzymes
Globular proteins that act as biological catalysts • Regulate and increase speed of chemical reactions – Lower the activation energy, increase the speed of a reaction (millions of reactions per minute!)
83
Characteristics of Enzymes
``` • Some functional enzymes (holoenzymes) consist of two parts – Apoenzyme (protein portion) – Cofactor (metal ion) or coenzyme (organic molecule often a vitamin) • Enzymes are specific – Act on specific substrate • Usually end in -ase • Often named for the reaction they catalyze – Hydrolases, oxidases ```
84
Nucleic Acids
``` Deoxyribonucleic acid (DNA) and ribonucleic acid (RNA) – Largest molecules in the body • Contain C, O, H, N, and P • Polymers – Monomer = nucleotide • Composed of nitrogen base, a pentose sugar, and a phosphate group ```
85
Deoxyribonucleic Acid (DNA)
Utilizes four nitrogen bases: – Purines: Adenine (A), Guanine (G) – Pyrimidines: Cytosine (C), and Thymine (T) – Base-pair rule – each base pairs with its complementary base • A always pairs with T; G always pairs with C • Double-stranded helical molecule (double helix) in the cell nucleus • Pentose sugar is deoxyribose • Provides instructions for protein synthesis • Replicates before cell division ensuring genetic continuity
86
Ribonucleic Acid (RNA)
Four bases: – Adenine (A), Guanine (G), Cytosine (C), and Uracil (U) • Pentose sugar is ribose • Single-stranded molecule mostly active outside the nucleus • Three varieties of RNA carry out the DNA orders for protein synthesis – Messenger RNA (mRNA), transfer RNA (tRNA), and ribosomal RNA (rRNA)
87
Adenosine Triphosphate (ATP)
• Chemical energy in glucose captured in this important molecule • Directly powers chemical reactions in cells • Energy form immediately useable by all body cells • Structure of ATP – Adenine-containing RNA nucleotide with two additional phosphate group
88
• Phosphorylation
Terminal phosphates are enzymatically transferred to and energize other molecules – Such “primed” molecules perform cellular work (life processes) using the phosphate bond energy