Chapter 2 — Chemistry of Life Flashcards
Introduction
biochemistry
the study of the molecules that compose living organisms
Introduction
biochemistry is useful for understanding…
cellular structures, basic physiology, nutrition, and health
Introduction
4 types of macromolecules
carbohydrates
lipids
proteins
nucleic acids
Atoms, Ions, and Molecules
element
simplest form of matter with unique chemical properties
Atoms, Ions, and Molecules
atomic number
the number of protons in the nucleus of an atom
Atoms, Ions, and Molecules
the periodic table is arranged by…
atomic number
Atoms, Ions, and Molecules
__ elements have a biological role
24
Atoms, Ions, and Molecules
name the 6 elements that makeup 98.5% of body weight
oxygen carbon hydrogen nitrogen calcium phosphorus
Atoms, Ions, and Molecules
nucleus
center of an atom; contains protons and neutrons
Atoms, Ions, and Molecules
electron shells
surround the nucleus
Atoms, Ions, and Molecules
protons
positive charge (+)
Atoms, Ions, and Molecules
neutrons
no charge (neutral)
Atoms, Ions, and Molecules
electrons
negative charge (-)
Atoms, Ions, and Molecules
__ determine the chemical properties of an atom
electrons
the atom is electrically neutral because…
the number of electrons is equal to the number of protons
Atoms, Ions, and Molecules
electrons occupy an orderly series of __
electron shells (energy levels)
Atoms, Ions, and Molecules
the 1st electron shell holds __ electrons, the 2nd holds __, and the 3rd holds __
2; 8; 8
Atoms, Ions, and Molecules
an atom with a full outer energy level is __/__ and referred to as a __
very stable/unreactive; inert/noble gas
Atoms, Ions, and Molecules
examples of noble gases
helium (He), neon (Ne), argon (Ar)
Atoms, Ions, and Molecules
atoms with unfilled outer energy levels are relatively __/__
unstable/reactive
Atoms, Ions, and Molecules
unstable atoms __ bond with other atoms
will
Atoms, Ions, and Molecules
stable atoms __ bond with other atoms
will not
Atoms, Ions, and Molecules
unstable atoms can achieve stability by…
sharing, gaining, or losing electrons
Atoms, Ions, and Molecules
valance electrons
located in the outermost shell; interact with other atoms; determine the chemical bonding properties of an atom
Atoms, Ions, and Molecules
atomic mass = __ + __
protons + neutrons
Atoms, Ions, and Molecules
isotope
atom with a different number of protons and neutrons
Atoms, Ions, and Molecules
isotopes of an element exhibit the same __ behavior, but differ in __ behavior because…
chemical; physical; extra neutrons increase the atomic weight but do not change the charge because they are neutral
Atoms, Ions, and Molecules
many isotopes are unstable and decay to more stable isotopes by…
giving off radiation
Atoms, Ions, and Molecules
radioisotopes
unstable isotopes that give off radiation
Atoms, Ions, and Molecules
every element has at least one __
radioisotope
Atoms, Ions, and Molecules
radioactivity
radioisotopes decay to stable isotopes by releasing radiation
Atoms, Ions, and Molecules
we are all mildly __
radioactive
Atoms, Ions, and Molecules
madame curie
- first woman to receive nobel prize (1903)
- first woman in world to receive a ph.d.
- coined term radioactivity
- discovered radioactivity of polonium and radium
- trained physicians in use of x-rays and pioneered radiation therapy as cancer treatment
- died of radiation poisoning at age 67
Atoms, Ions, and Molecules
ions
charged particles with an unequal number of protons and electrons
Atoms, Ions, and Molecules
ionization
transfer of electrons from one atom to another, which increases the stability of the valence shell
Atoms, Ions, and Molecules
anion
atom that gained electrons and has a net negative charge
Atoms, Ions, and Molecules
cation
atom that lost electrons and has a net positive charge
Atoms, Ions, and Molecules
ions with __ charges are attracted to each other
opposite
Atoms, Ions, and Molecules
electrolytes are important for…
- chemical reactivity
- osmotic effects (influence water movement)
- electrical effects on nerve and muscle tissue
Atoms, Ions, and Molecules
__ is one of the most important considerations in patient care
electrolyte balance
Atoms, Ions, and Molecules
possible effects of electrolyte imbalance
muscle cramps, brittle bones, coma, cardiac arrest
Atoms, Ions, and Molecules
free radicals
unstable chemical particles with an odd number of electrons that can damage cells, causing illness and aging
Atoms, Ions, and Molecules
free radicals are produced by…
normal metabolic reactions, radiation, and chemicals
Atoms, Ions, and Molecules
antioxidants __ free radicals and are present in our diet in things such as…
neutralize; selenium, vitamin e, vitamin c, and carotenoids
Atoms, Ions, and Molecules
molecule
two or more atoms held together by a chemical bond; example: N2
Atoms, Ions, and Molecules
compound
molecules composed of two or more different elements; example: CO2
Atoms, Ions, and Molecules
molecular formula
shows elements and how many atoms of each are present; example: C2H6O
Atoms, Ions, and Molecules
structural formula
shows the location of each atom and reveals structural isomers; example:
H | H - C - H | H
Atoms, Ions, and Molecules
isomer
molecules with identical molecular formulae but different arrangement of their atoms (structural formula); example: ethanol and ethyl ether
Atoms, Ions, and Molecules
chemical bonds
forces that hold molecules together, or attract one molecule to another
Atoms, Ions, and Molecules
3 types of chemical bonds
hydrogen (weakest)
ionic
covalent (strongest)
Atoms, Ions, and Molecules
ionic bond
the attraction of oppositely charged ions; an electron is donated by one and received by the other; example: sodium chloride
ionic bonds are __ because…
weak; easily dissociate in water
Atoms, Ions, and Molecules
covalent bond
formed by sharing of valence electrons
Atoms, Ions, and Molecules
types of covalent bonds
single
double
nonpolar
polar
Atoms, Ions, and Molecules
single covalent bond
one pair of electrons are shared; example: H2
Atoms, Ions, and Molecules
double covalent bond
two pairs of electrons are shared; example: CO2
Atoms, Ions, and Molecules
nonpolar covalent bond
electrons are shared equally between two atoms; strongest of all bonds
Atoms, Ions, and Molecules
polar covalent bond
electrons are shared unequally between atoms
Atoms, Ions, and Molecules
hydrogen bond
a weak attraction between a slightly positive hydrogen atom in one molecule and a slightly negative oxygen or nitrogen atom in another
Atoms, Ions, and Molecules
hydrogen bonds occur in…
water molecules, DNA, proteins
Energy and Chemical Reactions
energy
capacity to do work
Energy and Chemical Reactions
work
to move something; all body activities are a form of work
Energy and Chemical Reactions
potential energy
stored energy; not doing work at the time; example: water behind a dam
Energy and Chemical Reactions
chemical energy
potential energy stored in the molecular bonds
Energy and Chemical Reactions
kinetic energy
the energy of motion; actively doing work; example: moving water flowing through a dam
Energy and Chemical Reactions
heat
kinetic energy of molecular motion
Energy and Chemical Reactions
chemical reaction
a process in which a covalent or ionic bond is formed or broken
Energy and Chemical Reactions
chemical equation
symbolizes the course of a chemical reaction; reactants –> products
Energy and Chemical Reactions
classes of chemical reactions
decomposition reactions
synthesis reactions
exchange reactions
Energy and Chemical Reactions
decomposition reactions
large molecules broken down into smaller ones; AB –> A + B; example: carbohydrate metabolism (starch molecule broken into individual glucose molecules)
Energy and Chemical Reactions
during decomposition reactions, a chemical bond is __ and energy is __, which is called a __ reaction
broken; released; exergonic
*our cells use this energy
Energy and Chemical Reactions
synthesis reactions
two or more small molecules combine to form a larger one; A + B –> AB; example: protein synthesis (amino acids form a protein molecule)
Energy and Chemical Reactions
synthesis reactions need __ to form their bonds and are therefore called __ reactions
energy; endergonic
Energy and Chemical Reactions
exchange reactions
two molecules exchange atoms or a group of atoms; AB + CD –> ABCD –> AC + BD
*molecules cannot be lost, only rearranged
Energy and Chemical Reactions
reversible reactions
can go in either direction; CO2 + H20 <=> H2CO3 <=> HCO3- + H+
Energy and Chemical Reactions
during oxidation, the molecule __ and __ energy
the molecule becomes __ in this process
the accepting molecule is the __, and is often __
gives up electrons; releases
oxidized
oxidizing agent; oxygen
Energy and Chemical Reactions
during reduction, the molecule __ and __
the molecule is __ when it accepts electrons
the donating molecule is the __
gains electrons and energy
reduced
reducing agent
Energy and Chemical Reactions
during redox reactions, electrons are often transferred as __ atoms; each atom is equal to one __
hydrogen; electron
Energy and Chemical Reactions
catabolism
the sum of all decomposition reactions in the body; exergonic
Energy and Chemical Reactions
anabolism
the sum of all synthesis reactions in the body; endergonic
Inorganic Compounds
inorganic compound
does not contain carbon and hydrogen as their primary structural ingredients
Inorganic Compounds
list the four inorganic compounds
water
acids
bases
salt
acid
a solute that dissociated to release hydrogen ions and shift pH toward acidity
Inorganic Compounds
base
a solute that removes hydrogen ions from a solution shifting the pH to basic or alkaline
Inorganic Compounds
salt
reaction of an acid with a base
Inorganic Compounds
a mixture consists of substances that are __ blended but not __ combined
physically; chemically
Inorganic Compounds
our body fluids are complex mixtures of __ and __
chemicals; water
Inorganic Compounds
water is __-__% of body weight
50-75%
Inorganic Compounds
structure of water
atoms joined by polar covalent bonds; molecule is v-shaped
Inorganic Compounds
solvency
ability to dissolve other chemicals
Inorganic Compounds
solution = __ + __
solvent + solute
Inorganic Compounds
solvent
liquid in which a solute is dissolved
Inorganic Compounds
solute
what is being dissolved in the solvent
Inorganic Compounds
hydrophilic
charged substances that dissolve easily in water; water loving
Inorganic Compounds
hydrophobic
neutral substances that do not easily dissolve in water; water fearing
Inorganic Compounds
water is a __
universal solvent
Inorganic Compounds
chemical reactivity of water
the ability to participate in chemical reactions
Inorganic Compounds
water ionizes into __ and __
H+ and OH-; water also ionizes other chemicals (acids and bases)
Inorganic Compounds
water is involved in __ and __ reactions
hydrolysis; dehydration synthesis
Inorganic Compounds
solutions
a mixture of a solute into a solvent; small solute particles pass through cell membranes; the solution is transparent and remains mixed
Inorganic Compounds
colloids
a mixture of protein and water; solidifies within and between cells; the particles are too large to pass through cell membranes; the solution is cloudy and remains mixed
Inorganic Compounds
blood is thicker than water because of __
proteins
Inorganic Compounds
an acid is a proton __
donor (releases H+ ions)
Inorganic Compounds
a base is a proton __
acceptor (accepts H+ ions)
Inorganic Compounds
a pH of less than 7 is…
an acidic solution (H+ > OH-)
Inorganic Compounds
a pH greater than 7 is…
a basic solution (OH- > H+)
a pH of 7 is…
neutral (H+ = OH-)
our body uses __ to prevent changes in pH
buffer systems (mixture of chemicals that resist change)
Inorganic Compounds
pH of blood ranges from __ to __
7.35 to 7.45
Inorganic Compounds
OH- = __
hydroxyl
more H+ = more __
more OH- (hydroxyls) = more __
acidic
basic
Organic Compounds
organic compounds
contains carbon and hydrogen and usually oxygen; carbon is the primary structural atom
Organic Compounds
organic chemistry
study of compounds containing carbon
4 categories of carbon compounds
carbohydrates
lipids (fats)
proteins
nucleotides and nucleic acids
Organic Compounds
carbon
the atomic number of 6; has 4 valence electrons (binds with other atoms that give it 4 electrons to be stable); forms long chains, branched molecules, and rings (serves as the backbone for organic molecules); carries a variety of functional groups
Organic Compounds
functional groups
atoms attached to carbon backbone; determines chemical properties; examples: hydroxyl, carboxyl, amino, phosphate
Organic Compounds
since carbon can form long chains, some organic molecules are…
very large macromolecules, such as starch, proteins, and DNA
Organic Compounds
polymer
molecules made of multiple monomers; example: ººººº
Organic Compounds
monomer
small subunit; example: º
Organic Compounds
a polymer of glucose is a __
starch/carbohydrate
Organic Compounds
a polymer of amino acids is a __
protein molecule
Organic Compounds
polymerization
joining monomers to form a polymer
Organic Compounds
dehydration synthesis
monomers covalently bond together to form a polymer with the removal of a water molecule; a hydroxyl group is removed from one monomer and a hydrogen from the next
Organic Compounds
hydrolysis
splitting a polymer by the addition of a water molecule
Organic Compounds
carbohydrates are __ and contain carbon, hydrogen, and oxygen in a __ ratio
hydrophilic; 1:2:1
Organic Compounds
all digested carbohydrates are converted to __ and oxidized to make __
glucose; ATP
Organic Compounds
monosaccharide
simple sugar; produced by digestion of complex carbohydrates
Organic Compounds
major monosaccharides
glucose (the body’s most important source of energy [metabolic fuel]), galactose, fructose
*these are all isomers
Organic Compounds
disaccharides
sugar molecule composed of 2 monosaccharides
Organic Compounds
major disaccharides
sucrose (table sugar), lactose (milk sugar), maltose (grain)
Organic Compounds
polysaccharides
chains of glucose subunits
Organic Compounds
starch
energy storage in plants; most commonly digested carbohydrate; digestible by humans for energy
Organic Compounds
cellulose
structural molecule of plant cell walls; fiber in human diet
Organic Compounds
glycogen
energy storage in animals; stored glucose; found in liver and muscle tissue; if energy is needed, can be broken back down into glucose; liver synthesizes after a meal and breaks down between meals
Organic Compounds
lipids are __ and composed of carbon, hydrogen, and oxygen in __ ratio
hydrophobic; no
Organic Compounds
five primary types of lipids in humans
fatty acids triglycerides phospholipids eicosanoids* steroids (cholesterol)
Organic Compounds
primary function of triglycerides
energy storage, insulation, and shock absorption (adipose tissue)
Organic Compounds
phospholipids are the structural foundation of a __ __
cell membrane
Organic Compounds
HDL
high-density lipoprotein; “good” cholesterol; makes up cell membranes and hormones; heart does like
Organic Compounds
LDL
low-density lipoprotein; “bad” cholesterol; high ratio of lipid to protein; contributes to cardiovascular disease
Organic Compounds
__ are the most abundant and important organic molecule
proteins
Organic Compounds
five components of amino acid structure
central carbon atom hydrogen atom amino group carboxyl group R group/variable side chain
Organic Compounds
__ amino acids are used to make proteins; they are all identical except for the __
20; radical (R) group
Organic Compounds
properties of an amino acid are determined by __
R group
Organic Compounds
primary protein structure
sequence of amino acids
Organic Compounds
secondary protein structure
H bonding causes spiral, coiling, or folded effect; can be either alpha helix (spiral) or beta-sheet shape
Organic Compounds
tertiary protein structure
further coiling and folding and bending into globular and fibrous shapes
Organic Compounds
quaternary protein structure
final protein shape; several tertiary structures together
Organic Compounds
major protein functions
support movement transport buffering metabolic regulation coordination and control defense
Organic Compounds
enzymes
proteins that speed up a reaction by lowering the activation energy (energy needed to get a reaction started); act as biological catalysts
Organic Compounds
examples of enzymes
pepsin, trypsin, amylase
*all digestive
Organic Compounds
a __ acts upon an __ on the enzyme forming a __
substrate; active site; product
Organic Compounds
temperature and pH can effect enzyme performance by changing its __, therefore altering ability to __
shape; bind
Organic Compounds
steps of enzyme reaction
- enzyme and substrate
- substrate binds to active site, forming an enzyme-substrate complex (highly specific)
- enzyme breaks bond
- products released
Organic Compounds
3 components of a nucleotide
nitrogenous base
sugar (monosaccharide)
one or more phosphate groups
Organic Compounds
physiologically important nucleotides
ATP, DNA, RNA
Organic Compounds
ATP contains…
adenine, ribose, and 3 phosphate groups
Organic Compounds
what is the significance of ATP’s three phosphate groups?
it takes a lot of energy to bring 3 phosphate groups together, so there is a lot of potential energy stored in the bonds of the 2nd and 3rd groups, so when the bonds are broken, energy is released (exergonic) and becomes ADP + P + energy
Organic Compounds
ATP is consumed within __ and continually __
60 seconds; replenished
Organic Compounds
2 types of nucleic acids
DNA and RNA
Organic Compounds
DNA
deoxyribonucleic acid
double-stranded and held together by hydrogen bonding
backbone is made of deoxyribose (sugar) and phosphate
nitrogenous bases
100 million to 1 billion nucleotides long
contains genetic code
Organic Compounds
RNA
ribonucleic acid
single-stranded
backbone is made of ribose (sugar) and phosphate
nitrogenous bases
three types
70 to 10,000 nucleotides long
involved in protein synthesis coded for by DNA
Organic Compounds
DNA nitrogenous bases
adenine
thymine
guanine
cytosine
Organic Compounds
RNA nitrogenous bases
adenine
uracil
guanine
cytosine
Organic Compounds
law of complementary base pairing
one strand determines the base sequence of the other; A–T, C–G
Organic Compounds
nitrogenous bases united by __
hydrogen bonds