Force of gravity acting on a mass (can change depending on gravity).
The elements Oxygen, Carbon, Hydrogen and Nitrogen make up what percentage of living matter?
96%
What does the other 4% come from?
3.9% Calcium (Ca), Phosphorus (P), Potassium (K), Sulfur (S), Sodium (Na), Chlorine (Cl), Magnesium (Mg), Iodine (I), and Iron (Fe).0.01% trace and ultratrace elements.
What is an atom?
An electrically neutral unit of matter of all elements.
What is the nucleus comprised of?
protons and neutrons
How are the electrons positioned?
In energy level orbitals
If the number of protons equals the number of electrons, the atom is
electrically neutral
What is an element?
a substance that is made entirely from one type of atom. (ex, hydrogen, gold, silver, copper, carbon)
The atomic number is
is the number of protons found in the nucleus of an atom and therefore identical to the charge number of the nucleus
The mass number is
The total number of protons and neutrons in the nucleus
The atomic weight is
the average mass number of all natural isotopes.
What are bonds?
Links that attach atoms together
What are molecules
Electrically neutral group of at least two atoms in a
definite arrangement held together by very strong (covalent) chemical bonds.
What are ions?
an atom or molecule
in which the total number of electrons
is not equal to the total number of protons,
giving it a net positive or negative electrical charge. (Atoms that have gained or lost an electron)
What is a cation?
an ion with more protons than electrons, giving it a positive charge. (written: Na+)
What is an anion?
an ion with more electrons than protons, giving it a net negative charge
(since electrons are negatively charged and protons are positively
charged).
What is an isotope?
different types of atoms of the same chemical element (same number of protons), each having a different number of neutrons.
What is a radioisotope?
an atom
with an unstable nucleus, which is a nucleus characterized by
excess energy which is available to be imparted either to a
newly-created radiation particle within the nucleus, or else to an
atomic electron. The radioisotope, in this process,
undergoes radioactive decay, and emits a gamma ray(s) and/or subatomic particles. These particles
constitute ionizing. Radioisotopes may
occur naturally, but can also be artificially produced.
What is a half-life?
The time for a radioisotope to lose half of its activity (from hours to centuries)
Al radioactivity is damaging to _______
tissues
What are the atomic radiation rays from low to high penetrating power?
Alpha, beta, gamma
How many electrons are in the first 4 shells of an atom?
The outermost shell (these electrons determine bond formation)
What does it mean when the valence (outermost) shell is full?
The compound is inert (cannot form bonds)
What is the octect rule (rule of eights)?
atoms tend to combine in such a way that they
each have eight electrons in their valence shells.
When atoms of different elements combine, they form what?
a compound
What is a molecular formula?
Shoes the number of atoms in each element (ex H20)
The amount of molecule dissolved in solution is what?
concentration
What is a mixture?
compound physically blended together but not chemically bound
A solvent dissolves a solute to create a what?
solution
What is a colloid/emulsion?
particles are large enough to scatter light (can't see through it, ex: milk)
What is a suspension?
When materials mix but eventually settle out. (Ex: sand in water)
What are ionic bonds?
Positively and negatively charged ions that are attracted to one another.
Ionic compounds that exist as solids, but dissociate into solution are called
electrolytes
What is a covalent bond?
A chemical bond formed by the sharing of one or more electrons to create molecules. They are the most common and strongest bonds in the body.
What makes a covalent bond nonpolar?
the electrons shared by the adjacent atoms in the bonds
are shared equally.These bonds create molecules that are linear and symmectrical (ex: CO2)
What is a polar covalent bond?
The electrons shared by the adjacent atoms in the bonds are unequally shared.These bonds create molecules that are bent where one end is more positive and the other end is more negative (ex: H20)
What are some characteristics of hydrogen bonds?
They are weak, support large molecular shapes, create water surface tension and ice cubes
What are some characteristics of free radicals?
1) They are bad!2) They are formed when an atom has an unpaired electron in the outermost shell3) Unstable and highly reactive4) Become stable by taking an electron from another molecule5) Break apart important body molecules6) Produced by sunlight, x-rays, detoxification and metabolic reactions7) Linked to many diseases such as cancer, diabetes, Alzheimer's, atherosclerosis, and arthritis
What are antioxidants?
They inactivate oxygen-derived free radicals (prevent FR from stealing electrons).Examples: Vitamins C & E, selenium, beta-carotene (precursor to vitamin A)
Metabolism is
the sum of ALL chemical reactions in the body
Reactants are
the starting substances of a chemical reaction
Products are
the ending substances of a chemical reaction
The law of conservation of mass states
mass of reactants equals the mass of products
A combination (synthesis) reaction is
when two or more reactants are chemically bonded together to produce a single productA + B --> AB
A decomposition reaction is when
a more complex substance breaks down into
its more simple parts. One reactant yields 2 or more products.AB --> A + B
What are exchange reactions?
They involve chemical components being exchanged between phases, so
compositions change, but modes remain the same (no phases disappear and
no new phases are produced)AB + C --> AC + B
Oxidation-reduction (redox) reactions are
the basis for food fuels to be catabolized (broken down) for energy. A reactant losing an electron is oxidized whereas a reactant gaining an electron is reduced.
Energy is
the capacity to do work.
What is kinetic energy?
The energy of motion.
What is potential energy?
The stored energy of position.
Describe an exergonic reaction.
Energy is released, usually as heat. Involved in the catabolism of food.
Describe an endergonic reaction.
Requires energy be added (usually from ATP), forms bonds, and involved in the formation of body proteins.
The law of conservation of energy states
energy present at start and end of a chemical reaction are equal.Energy can neither be created or destroyed, although it may be converted from one form to another.
Describe a catalyst
A catalyst itself is unchanged at the end of a reaction.Often re-used many times.Increase frequency of collisions.Lower activation energy.Properly orient colliding molecules.Chemically specific.Names usually end in -ase.Speed up reactions up to 10 billion times faster.
Activation energy is
energy needed to break bonds and begin reactions.high temperature, small particles, high concentration and catalysts create faster reations.
Inorganic compounds usually lack ______ and are simple molecules.
Carbon. Usually dissociate in water to produce ions (electrolyte solutions).
Organic compounds contain ____, hydrogen and usually oxygen and have ________ bonds.
Carbon, covalent
Salts are made up of
ions and electrolytes (current)
What are some characteristics of water?
High heat capacity and and heat of vaporization.Universal solvent and body's major transport medium.Found wherever friction needs to be reduced or eliminated in the body.Most important and abundant inorganic compound in all living systems.
Hydrophilic means
polar covalent bonds and dissolve in water
Hydrophobic means
non-polar bonds and do not dissolve in water
Water's role as a solvent makes it essential for
health and survival
Acids and bases react in body to form
salts
Salts _____ in water and dissociate into cations and anions.
dissolve
Solutions that are _____ have a high H+ and low pH
acidic
______ solutations have a low H+ and high pH.
Alkaline
Solutions that have equal H+ and OH- are
neutral
Buffers resist large _____ in pH
swings
pH 0-6.99pH 7.01-14pH 7.00
AcidicBasicNeutral
pH# represents a _____ difference in H ion concentration.
Most of the energy needed for life.Build structures, generate ATP and energy reserves.
Examples of monosaccharides are
glucose, fructose, galactose
Examples of disaccharides are
sucrose, maltose, lactose
Examples of polysaccharides are
glycogen, starch, cellulose-fiber
Polymers are
chain-like arrangements of similar molecules
Some characteristics of lipids are
1) hydrophobic and mostly insoluble in water2) combine with protein (lipoproteins) for transport in blood3) Triglycerides/triacyglycerols (TAGS) - glycerol + 3 fatty acides4) fats (solid)/oils (liquid)5) Contain 2x as much energy as CHO (carbs) or protein6) Storage is virtually unlimited7) Excess dietary CHO, protein, fat & oil creates adipose (fat) tissue8) Saturated fats (solid fat/lard) increases cholesterol BAD9) Unsaturated (oil/safflower, corn) and polyunsaturated (oil/olive,peanut) GOOD10) Essential fatty acids - cannot be made by body, must be obtained from food (ex: avocados, fish)11) Coconut & Palm oils are high in saturated fat12) Hydrogenation (man-made) = "trans fat" which leads to heart disease**steroids are a lipid
Describe proteins and their functions
1) Structural material of the body2) Needed for muscle contraction3) Transport substances4) Needed for enzymes and hormones5) Made of amino acids (20)6) Shape greatly influences function7) Types-dipeptide, tripeptide, polypeptide8) Heat, acid and salt cause proteins to denature (break apart or misshape)9) Protein misfolding leads to disease (cystic fibrosis, mad cow, Alzheimer's)
What are nucleic acids?
Deoxyribonucleic acid (DNA) forms genetic codes inside each cellGuide cell's assembly of amino acids into proteins by ribosomesadenine (A), guanine (G), cytosine (C), thymine (T) and uracil (U)each gene is a piece of DNA that controls synthesis of a protein
Describe DNA
double-stranded helixlocated in the nucleusinstructions for protein synthesisdirects human growth and development"blue prints"
Describe RNA
single-stranded helixcarries out DNA orders for protein synthesislocated in the nucleus and cytoplasmuses uracil instead of thyminedifferent types of RNA-messenger, transfer, ribosomal"reads the blue prints"
ATP (adensine triphosphate) is a source of ______ for the cell
energy
1 glucose molecule creates _____ molecules of ATP
36-38
If the atomic number of Ca2+ is 20 and the mass number is 22, how many electrons does Ca2+ have?
18 (20-2=18)
A ______ is an example of a catalyst.
enzyme
When you row a boat, your arms provide _______ energy
