atomic number
the number of protons
mass number
the sum of protons plus
isotopes
two atoms of an element that differ in number of neurons
radioactive isotopes
isotopes that give off particle and energy
Help with : dating fossils, tracing atoms through metabolic processes, Diagnosing medical disorders
Energy
the compactly to cause change
Potential Energy
the energy that matters has because of its location or structure
Energy level (electrons shell)
an electron's state of potential energy
covalent bonds
the sharing of a pair of valence electrons by two atoms
polar covalent bond
one atom is more electronegative and the atoms do not share the electrons equally (ex. water oxygen have a stronger electronegativity than the hydrogen so it pulls them together)
ionic bonds
an attraction between an anion and a cation
anion
a negatively charged ion
cation
a positively charged ion
ion
a charged atom or molecule
hydrogen bond
forms when a hydrogen atom covalently bonded to one electronegative atom is also attracted to another electronegative atom
(in living cells, the electronegative partners are usually oxygen or nitrogen atoms)
Biological molecules
recognize the interaction with each other with a specificity based on molecular shape (which is usually very important to its function)
molecules with similar shapes can have similar biological effects
chemical equilibrium
is reached when the forward and reverse reaction rates are equal
polarity
the water molecule is a polar molecule: the opposite ends have opposite charges. It allows water molecules to form hydrogen bonds with each other.
surface tension
a measure of how hard it is to break the surface of a liquid
Also, is the resistance to being stretched and is due to hydrogen bonding
Cohesion
a phenomenon when hydrogen bonds hold water molecules together
(helps transport of water against gravity in plants [up through the tubes of plants]
Adhesion
the ability of water to stick to other molecules
(sticks to plant cell walls which helps to counter gravity)
Specific heat of a substance
the amount of heat that must be absorbed or lost for 1 gram of that substance to change its temperature by 1C
Water
a versatile solvent due to its polarity and its ability to readily form hydrogen bonds
Carbon Chains
form the skeletons of most organic molecules (vary in length and shape)
Hydrocarbons
are organic molecules consisting of only carbon and hydrogen (ex. fats have hydrocarbon components). This can undergo reactions that release a large amount of energy
Functional Groups
distinctive properties of organic molecules depend not only on the carbon skeleton but also on the molecular components attached to it
Adenosine Triphosphate (ATP)
the primary energy-transferring molecule in the cell (consists of adenosine attached to a string of three phosphate groups)
polymer
a long molecule consisting of many similar building blocks caled monomer (ex. carbohydrates, proteins, Nucleic acids)
dehydration reactions
monomers form large molecules by condensation reactions
hydrolysis
the disassemblement of polymers to monomers
Carbohydrates
include sugars and the polymers of sugars
monosaccharides
are the simplest form of carbohydrates, or single sugars . Also, they serve as a major fuel for cells and as raw material for building molecules
disaccharide
is formed when a dehydration reactions joins two monosaccharides
glycosidic linkage
the covalent bond that is formed with a dehydration reactions joins two monosaccharides
polysaccharides
Carbohydrate macromolecules, polymers composed of many monosaccharides
They have storage and structural rules
The structure and function of this are determined by its sugar monomers and the positions of glycosidic linkages
Starch
s storage polysaccharide of plants, consists entirely of glucose monomers
(plants store surplus starch as granules within chloroplasts and other plastids)
Glycogen
is a storage polysaccharide in animals
(humans and other vertebrates store glycogen mainly in liver and muscle cells)
Cellulose
a major component of the tough wall of plant cells (polymer of glucose and is not digestible due to the bonds formed)
alpha and beta
the difference between starch and cellulose is based on two ring forms for glucose
Chitin
another structural polysaccharide, is found in the exoskeleton of arthropods
Provides structural support for the cell walls of many fungi
Can be used as surgical thread
Lipids
the one class of large biological molecules that do not form polymers (glucose, fructose, repeat)
They are hydrophobic because they consist mostly of hydrocarbons, which form non polar covalent bonds
(ex. fats, phospholipids and steroid)
Fats
are constructed from two types of smaller molecules: glycerol and fatty acids
Glycerol
is a three-carbon alcohol with a hydroxyl group attached to each carbon
fatty acid
repeating sub unit of long carbons, but not a polymer because its not attached with each other in a certain way) consists of a carboxyl group attached to a long carbon skeleton
triacylglycerol/ triglyceride
created by the joining of three fatty acids to glycerol by an ester linkage
Ester Linkage
covalent bond that forms lipids