Chapter 2 Flashcards
Ionic bond
An atom with an electric charge
One atom is the electron donor (loses electron), one an electron acceptor
Cation (lost negative electron) = POSITIVE charge
Anion (gained negative electron =more negative) = Negative charge
Example is sodium chloride
Opposites attract
Covalent bond
Strong bond involving shared electrons
If sharing one pair of electrons =single
If sharing two pair= double. Etc
Polar =unequal sharing of electrons, one atom has a stronger electronegativity (water)
Nonpolar= equal sharing of electrons between atoms that have equal pull
Hydrogen bond
Weak polar bond
In water causes surface tension (cohesion)
Matter exists in 3 states …
Solids, liquids, gases
Elements in the body
26 different chemical elements are normally found in the body.
Only four of those are considered “major elements” and constitute 96% of the body’s mass.
Oxygen, carbon, hydrogen, and nitrogen
8 others the “lessers” =3.6%
Calcium, phosphorus, potassium, sultry, sodium, chlorine, magnesium, and iron.
Atom
Smallest units of matter. Hydrogen atoms are the smallest atoms.
How many electrons can each shell hold?
First shell: 2
Second shell: 8
Third shell: 18
How do you determine the atomic number of an element?
By the amount of protons in its nucleus.
How do you determine the mass number of an atom?
It’s the sun of protons and neutrons.
Isotopes
Have a different number of neutrons than protons.
For example. In a sample of oxygen. Some atoms have 9 or 10 neutrons- but ALL HAVE 8 electrons and protons. The mass number determines the name of the isotope. For example (oxygen) O16 O17 O18
Ion
Is an atom that has a positive or negative charge because it has an uneven number of protons and electrons.
Molecule
When two or more atoms share electron(s). A molecule may include two atoms of the same kind. For example oxygen O2
Compound
Is a substance that contains atoms of two or more different elements. Most of the atoms in the body are joined into compounds.
Free radical
Is an atom or group of atoms with an unpaired electrons in the outer most shell. Example is superoxide which is the addition of an electron to an oxygen molecule.
Having an unpaired electron makes a free radical unstable, highly reactive, and destructive to nearby molecules.
Free radicals become stable by giving up their extra electron or pairing with an electron from another molecule, making them able to break apart important body molecules.
Octet rule
One atom is more likely to interact with another atom if it leaves both atoms with eight valence electrons.
Where are ionic bonds mostly found in the body?
Teeth and bones. Where they give great strength.
Electrolyte
An ionic compound that breaks apart into positive and negative ions in a solution.
Ions
Have a charge associated with them. For example if written as H+ (it’s because it donated its electron and gave up negativity)
Electonegativity
The power to attract electrons to itself (atom)
Polar covalent bond
Sharing of electrons between two atoms is unequal. The nucleus of one atom attracts the shared electrons more strongly than the other.
The molecule will have have a partial negative charge closer to the atom that attracts electrons more strongly (gaining negativity)
Cohesion
The tendency of like particles to stay together.
Energy
Capacity to do work
Potential energy
Energy stores by matter due to its position
Kinetic energy
The energy associated with matter in motion
For example the energy stored in water behind a dam, or stored in a person prepared to jump is potential energy. When the damn opens, or the person jumps potential energy is converted to kinetic energy.
Chemical energy
Is a form of potential energy that is stored in the bonds of of compounds and molecules.
Law of conservation of energy
Energy can not be created or destroyed, it may be converted from one form to another.
Generally releases heat.
For example energy from food can be converted to walking or talking.
Exergonic energy
Releases more energy than absorbs
I’m general usually occur as nutrients. Such as glucose. If a molecule of glucose is completely broken down. It can be used to make 32 ATP.
Endergonic reactions
Absorb for energy than they release.
Activation energy
Collision energy needed to break the chemical bonds of reactants. Needed to start a reaction.
Temperature and concentration are factors.
The more particles of matter present in a confined space, the greater chance they will collide.
As temperature rises, particles move about more rapidly. The higher the temp. The more forcefully particles will collide=greater chance of reaction.
Catalysts
Speed chemical reactions by lowering the amount of activation energy needed. Most important catalysts are enzymes.
Just lowers amount of energy needed to start the reaction.
Anabolism
Building
Synthesis reaction
Enderogenic (absorb more than they release)
Catabolism
Decomposition reactions
Exerogrnic (release energy)
Oxidation-Reduction reactions
Essential to life, break down food molecules.
Oxidation refers to loss of electrons.
Reduction refers to the gain of electrons.
Inorganic compounds
Lack carbon
Structurally simple
Molecules only have a few atoms
Cannot be used by cells to carry out complicated biological functions.
Water and many salts.
Ionic or covalent bonds
Inorganic compounds that contain carbon are: CO2, HCO-3, H2CO3
Organic compounds
Always contain carbon
Usually contain hydrogen
Always have covalent bonds
Most are large molecules made up of long carbon atom chains.
Solvent
Solution that Dissolves another substance called a solute.
Your sweat (solvent) and small amounts of salts (solute)
Hydrophilic
Water loving
Solutes that are charged or contain polar covalent bonds are hydrophilic. Which means these solutes dissolve easily in water.
Hydrophobic
Molecules with Non polar covalent bonds
Water fearing
Water
Most important and abundant inorganic compound in all living systems.
-Universal solvent
-Serves as a medium for most chemical reactions
-Hydrolysis : helps break down molecules by adding water.
-Water can absorb or release a large amount of heat
-important component of mucus and other lubricating fluids.
Mixture
Combination of elements or compounds that are physically blended together. But not bound by chemical bonds. For example air
Colloid
Differs from a solution largely because the size of particles.
Colloids particles are large enough to scatter light. Usually appear translucent, or opaque.
Solution
Once mixed together solutes in a solution remain evenly dispersed.
Because the particles are very small. The solution looks transparent.
Suspensions
Suspended materials may mix with liquid or medium for some time, but eventually it will settle out.
Blood is an example.
Colloids and solutions don’t settle.
Mole
A unit of measurement that is equal to the sum of atomic mass(es) for a given element or compound.
Acid
Is a substance that dissociates into one or more hydrogen ions, and one or more anions.
Because H+ is a single proton with one positive charge (gave away negativity) … An acid is a proton donor.
Base
Removes H+ from solutions. And is therefore a proton acceptor.
Dissociate into one or more hydroxide (OH-) ions.
Acid Base balance
Intracellular and extracellular fluids must contain almost balanced quantities of acids and bases. The more hydrogen ions in a solution the more acidic. The more hydroxide ions the more basic.
Ph is used to measure acidity.
A pH of 6 denotes 10 times more H+ than a pH of 7. A pH of 7 (such as water) is neutral
A pH below 7 =acidic
A pH above 7 =basic
Buffer system
Functions to convert strong acids or bases into weak acids or bases.
Strong acids and bases ionize easily and can disrupt pH quickly and drastically. Where as weaker acids and bases can not.
Carbonic acid-bicarbonate buffer system
Carbonic acid (H2CO3) can act as a weak acid, and bicarbonate (HCO3-) can act as a weak base. So this buffer system can compensate for either an excess or shortage of H+.
In example : for excess H+
H+ + HCO3- ->. H2CO3
If there is a shortage of H+ carbonic acid can function as a weak acid and provide hydrogen ions.
H2CO3 -> H+ + HCO3-
