Chapter 2 Flashcards
Electrons
the lightest subatomic particle
Atomic Number
number of protons in an atom
Isotopes
- have a different number of neutrons in the nucleus
- are different from one another by their mass number only.
unstable isotopes are
radioactive- spontaneously emit radioactive particles
atomic mass number
tell us the number of protons and neutrons
atomic weight
the average mass of an elements atoms
what makes an atom unstable?
having an unfilled outer electron shell
first electron shell
2 electrons
second electron shell
8 electrons
atoms with unfilled outer electron shells can achieve stability by
sharing gaining or losing electrons through chemical reactions w/ other atoms
chemical bonds
hold the participating atoms together once the reaction has ended
- produces molecules and compounds
molecules
chemical structures that contain more than one atom bonded together by shared electrons
compound
any chemical substance made up of atoms of 2 or more elements
- is a new chemical substance w/ properties that can be different from those of its component elements
ionic bonds
chemical bonds created by the electrical attraction between anions and cations
cations
ions with a positive charge
anions
ions with a negative charge
covalent bonds
when atoms share electrons with other atoms
single covalent bond
sharing of one pair of electrons
double covalent bond
sharing of 2 pairs of electrons
non polar covalent bonds
electrons are shared equally, remain electrically neutral, make up most of the human body
polar covalent
has an unequal sharing between atoms one end is slightly neg/ one is slightly positive
ex: water
hydrogen bond
attraction between a slight positive charge of the hydrogen atom of one polar covalent bond and a weak negative charge on an oxygen or nitrogen atom of another polar covalent bond
water molecules attract because of what?
hydrogen bonding
surface tension
acts as a barrier that keeps small objects from entering the water
chemical notation
complex chemical compounds and reactions that are most easily described with a simple form of “chemical shorthand”
Chemical reactions
new chemical bonds form between atoms or existing bonds between atoms are broken
work
is movement or a change in the physical structure of matter
ex: running, walking, water to water vapor
energy
is the capacity to perform work
kinetic energy
energy of motion
potential energy
is stored energy
decompositon
breaks a molecule into smaller fragments
ex: digestion
hydrolisis
one of the bonds in a complex molecule are broken, and the components of a water molecule are added to the resulting fragments
catabolism
refers to the decomposition reactions of complex molecules within cells. cells harness energy from broken covalent bonds
synthesis
assembles larger molecules from smaller components
dehydration synthesis
condensation, formation of a complex molecule by the removal of water
opposite of hydrolysis
anabolism
is the synthesis of new compounds in the body
exchange reaction
parts of the reacting molecules are shuffled around
equilibrium
the rates of 2 reactions are in balance
activation energy
amount of energy required to start a reaction
enzymess
are used to speed up the reactions that support life
catalysts
compounds that accelerate chemical reactions without themselves being permanently changed
exergonic
reactions that release energy/ the energy released is greater than the activation energy
endergonic
more energy is required to begin the reaction than is released as it proceeds/ the reaction as a whole will absorb energy
nutrients
the essential elements and molecules obtained from the diet
metabolites
include all of the molecules synthesized or broken down by chemical reactions inside our bodies
inorganic compounds
small molecules that do not contain carbon and hydrogen atoms
organic compounds
are primarily composed of carbon and hydrogen atoms, can be much larger and more complex than inorganic compounds
3 properties of water
- water is a good solvent
- water has a very high heat capacity
- water is an essential reactant in the chemical reactions of living systems
solution
consists of a uniform mixture of a fluid solvent and dissolved solutes
ionization
inorganic compounds held together by ionic bonds/ ionic bonds are broken down and surrounded by water
an aqueous solution containing anions and cations can do what?
conduct electrical current
acid
any substance that breaks apart in solution to release hydrogen ions
base
substance that removes hydrogen ions from a solution
pH
a number between 0 and 14, pure water is 7(neutral) below 7 is acidic, above 7 is basic or alkaline
buffers
compounds that stabilize pH by removing or replacing hydrogen ions
salt
ionic compound consisting of any cation except a hydrogen ion and any anion except a hydroxide ion
electrolytes
inorganic compounds whose ions can conduct an electrical current in solution
steroids
are large lipid molecules composed of four connected rings of carbon atoms
cholesterol
is the best known steroid
phospholipids
consist of glycerol and 2 fatty acids, linked to a nonlipid group by a phosphate group
structural poteins
create 3 dimensional framework for the body, provides strength support and organizationSUPPORT
contractile proteins
responsible for muscular contraction MOVEMENT
transport proteins
TRANSPORT insoluble liquids, respiratory gases, minerals such as iron, and several hormones are carried in the blood attacted to this
protein hormones
can influence the metabolic activities of every cell in the body or affect the function of specific organs or organ systems
antibodies
protect us from disease
clotting proteins
restrict bleeding following an injury to the cardiovascular system
amino acids
20, are the bilding blocks of proteins
peptide bond
amino acids are strung together like beads on a string, with the carboxylic acid group of one amino acid attached to the amino group of another
peptides
molecules made up of amino acids held together by peptide bonds
denaturation
a change in their 3-D shape
