Chapter 2; The Chemistry Of Life Flashcards
Biochemistry
study of the molecules that compose living organisms
Element
simplest form of matter to have unique chemical properties
Atomic Number
number of protons in the nucleus
Trace Elements
element that does not account for more than 0.02%
Minerals
inorganic elements extracted from the soil by plants and passed up the food chain to humans and other organisms
Atoms
particles so small that are not visible to the human eye
Protons
single positive charge
Neutrons
no charge
atomic mass
total number of protons and neutrons
Electrons
tiny particles with a single negative charge and very low mass
Electron levels
electrons swarm about the nucleus in concentric regions
valence electrons
electrons on the outermost shell that determine the chemical bonding properties of an atom
isotopes
each of two or more forms of the same element that contain equal numbers of protons but different numbers of neutrons in their nuclei
Deuterium
one proton and one neutron
Tritium
one proton and two neutrons
atomic weight (relative atomic mass)
mixture of isotopes
radioisotopes
unstable isotopes
radioactivity
process of decay
Ionizing radiation
destroys molecules and produces dangerous free radicals and ions in human tissues
mutagenetic
causing mutations in DNA
carcinogenic
triggering cancer as a result of mutation
alpha particles
consists of two protons and two neutrons
beta particle
free electron
gamma rays
very dangerous even when emitted by sources outside the body
physical half-life
the time required for 50% of its atoms to decay to a more stable state
biological half-life
time required for half of it to disappear from the body
ions
charged particles with unequal numbers of protons and electrons
background radiation
measure of the level of ionizing radiation present in the environment at a particular location
radon
a gas produced by the decay of uranium in the earth
anion
particle that gains electrons acquires a negative charge
cation
particle that loses electrons acquires a positive charge
Electrolytes
substances that ionize in water and form solutions capable of conducting electricity
Free radicals
chemical particles with an odd number of electrons
superoxide anion
when an additional electron is added, it becomes a free radical
antioxidant
a chemical that neutralizes free radicals
Superoxide dismutase (SOD)
enzyme that alternately catalyzes the dismutation of the superoxide radical into ordinary molecular oxygen and hydrogen peroxide
Molecules
chemical particles composed of two or more atoms united by a chemical bond
compounds
molecules composed of two or more elements
molecular formulae
represents molecules that identify their elements and show how many atoms of each are present
isomers
molecules with identical molecular formulae but different arrangements of their atoms
structural formulae
shows the location of each atom
molecular weight
sum of the atomic weights of its atoms
chemical bonds
a molecule that is held together and molecules are attached to one another by forces
ionic bond
relatively weak attraction between an anion and a cation
covalent bond
sharing of one or more pairs of electrons between nuclei
single covalent bond
sharing one electron pair
double covalent bond
sharing of two electron pairs
nonpolar covalent bond
covalent bond in which electrons are equally attracted to both nuclei
Polar covalent bond
covalent bond in which electrons are more attracted to one nucleus than to the other, resulting in slightly positive and negative regions in one molecule
Hydrogen bond
weak attraction between polarized molecules or between polarized regions of the same molecule
Van der Waals Force
weak, brief attraction due to random disturbances in the electron clouds of adjacent atoms (weakest bond)
mixture
consists of substances that are physically blended but not chemically combined
solvency
ability to dissolve other chemicals
universal solvent
water
hydrophilic
substances that dissolve in water
hydrophobic
substances that do not dissolve in water
hydration sphere
cluster of water molecules
adhesion
the tendency of one substance to cling to another
cohesion
tendency of molecules of the same substances to cling to each other
surface film
an elastic layer of water cohensed
chemical reactivity
ability to participate in chemical reactions
hydrolysis
ions that are incorporated into other molecules in the chemical reactions
thermal stability
helps to stabilize the internal temperature of the body
heat capacity
the amount of heat required to raise the temperature
calorie
base unit of heat
solution
mix of solutes and solvents
solute
particles of matter
solvent
more abundant substance
colloids
body are mixtures of protein and water
emulsion
a suspension of one liquid in another
acid (proton donor)
a molecule that releases a proton in water
base
proton accepter
pH
measure derived from the molarity of H+
neutral pH
7.0
acidic
pH below 7
basic (alkaline)
pH above 7
buffers
chemical solutions that resist changes in pH
weight per volume
weight of solute in a given volume of solution
percentage
weight of solute as a percentage of solution volume or volume of a liquid as a percentage of total solution volume
molarity
measure of the number of moles of solute per liter of solution
milliequivalents per liter
the unit of measure is used to express electrolyte to concentrations
energy
capacity to do work
work
to move something
potential energy
energy contained in an object because of its position or internal state but that is not doing work at the time
kinetic energy
energy of motion
chemical energy
potential energy stored in the bonds of molecules
heat
kinetic energy of molecular motion
electromagnetic energy
kinetic energy of moving “packets” of radiation called photons
electrical energy
both potential and kinetic energy
free energy
potential energy available in a system to do useful work
chemical reaction
process in which a covalent or ionic bond is formed or broken
chemical equation
shows the reactants on the left, the products on the right, and an arrow pointing from the reactants to the products
decomposition reactions
a large molecule breaks down into two or more smaller ones
synthesis reactions
two or more small molecules combine to form a larger one
exchange reactions
two molecules exchange atoms or groups of atoms
reversible reactions
can go in either direction under different circumstances
law of mass action
they proceed from the reactants in greater quantity to the substances with the lesser quantity
equilibrium
the ratio of products to reactants is stable
concentration
reaction rate increases when the reactants are more concentrated
temperature
reaction rate increases as the temperature rises
catalysts
substances that temporarily bind to reactants, hold them in a favorable position to react with each other, and may change the shapes of reactants in ways that make them more likely to react
metabolism
all the chemical reactions in the body
catabolism
consists of energy-releasing decomposition reactions
exergonic reactions
energy-releasing reactions
Anabolism
consists of energy-storing synthesis reactions
endergonic reactions
reactions that require an Energy input
oxidixing agent (electron acceptor)
molecule that takes the electrons
reduction
a chemical reaction in which a molecule gains electrons and energy
reducing agent (electron donor)
a molecule that donates electrons to another
oxidation-reduction (redox) reactions
the oxidation of one molecule is always accompanied by the reduction of another
organic chemistry
the study of compounds of carbon
functional groups
small clusters of atoms that determine many of the properties of an organic molecule
macromolecules
gigantic organic molecules
polymerization
the joining of monomers to form a polymer
dehydration synthesis (condensation)
living cells achieve this by means of a reaction
dimer
the two monomers become joined by a covalent bond
carbohydrate
a hydrophilic organic molecule with the general formula
monosaccharides
the simplest carbohydrates
glucose
the “blood sugar” that provides energy to most of our cells
disaccharides
sugars composed of two monosacharides
sucrose
glucose + fructose
lactose
glucose + galactose
maltose
glucose + glucose
oligosaccharides
short chains of three or more monosaccharides
polysaccharides
long chains
glycogen
an energy-storage polysaccharide made by cells of the liver, muscles, brain, uterus, and vagina
starch
corresponding energy-storage polysaccharide of plants
cellulose
structural polysaccharide that gives strength to the cell walls of plants
glycoproteins
major component of mucus
proteoglycans
macromolecules in which the carbohydrate component is dominant and a peptide or protein forms a smaller component
lipids
a hydrophobic organic molecule
fatty acids
precursor of triglycerides, source of energy
triglycerides (neutral fats)
energy storage; thermal insulation; filling space; binding organs together; cushioning organs
phospholipids
major component of cell membranes; aid in fat digestion
eicosanoids
chemical messengers between cells
steroids
chemical messengers between cells
bile acids
steroids that aid in fat digestion and nutrient absorption
cholesterol
component of cell membranes; precursor of other steroids
fat-soluble vitamins (ADEK)
involved in a variety of functions including blood clotting, wound healing, vision, and calcium absorption
polyunsaturated fatty acids
those with multiple C=C bonds
prostaglandins
five of the carbon atoms are arranged in a ring
radical (R group)
the 20 amino acids used to make proteins are identical except for a third functional group
peptide
any molecule composed of two or more amino acids joined by peptide bonds
peptide bonds
formed by dehydration synthesis, joins the amino group of one amino acid to the carboxyl group of the next
oligopeptides
chains of fewer than 10 or 15 amino acids
polypeptides
chains larger than 15 amino acids
conformation
three-dimensional shape
primary structure
protein’s sequence of amino acids, which is encoded in the genes
secondary structure
a coiled or folded shape held together by hydrogen bonds between the slightly negative -C=O group of one peptide bond and the slightly positive -NH group of another one some distance away
alpha helix
springlike shape
beta sheet
pleated, ribbonlike shape
tertiary structure
formed by the further bending and folding of proteins into various globular and fibrous shapes
alpha helix
spring-like shape
globular proteins
a compact tertiary structure well suited for proteins embedded in cell membranes and proteins that must move around freely
fibrous proteins
used for muscle contractions and providing strength to skin, hair, and tendons
Quaternary Structure
the association of two or more polypeptide chains by noncovalent forces
Denaturation
a more drastic conformational change in response to conditions
conjugated proteins
non-amino acid moiety
Keratin
a tough structural protein gives strength to nails, hair, and skin
collagen
durable protein
ligand
any hormone or molecule that reversibly binds to a protein
molecular motors (motor proteins)
special power that some proteins can change shape repeatedly
enzymes
proteins that function as biological catalysts
substrate
enzyme’s action
amylase
digests starch
carbonic anhydrase
removes water
activation energy
the energy needed to get the reaction started
sucrase
an enzyme that breaks sucrose down to glucose and fructose
active site
a substrate molecule approaches a pocket on the enzyme surface
enzyme-substrate complex
the substrate binds to the enzyme
enzyme-substrate specificity
the substrate slightly changes the shape of the enzyme to create a better fit between the two
cofactor
about two-thirds of human enzymes require a nonprotein partner
coenzymes
organic cofactors usually derived from niacin, riboflavin, and other water soluble vitamins
aerobic respiration
uses energy from electrons to make ATP
metabolic pathway
a chain of reactions with each step usually catalyzed by a different enzyme
nucleotides
organic compounds with three principal components
nitrogenous base
a single or double carbon-nitrogen ring
adenine
double ring
ribose
sugar
adenosine triphosphate (ATP)
the body’s most important energy-transfer molecule
adenosine triphosphatases (ATPases)
enzymes specialized to hydrolyze the third phosphate bond, producing ADP
guanosine triphosphate (GTP)
another nucleotide involved in energy transfers
cyclic adenosine monophosphate (cAMP)
a nucleotide formed by the removal of both the second and third phosphate groups from ATP
nucleic acids
polymers of nucleotides
deoxyribonucleic acid (DNA)
typically 100 million to 1 billion
ribonucleic acid (RNA)
70-10,000 nucleotides long, carry out those instructions and synthesize the proteins, assembling amino acids in the right order to produce each protein “described” by the DNA
