Chapter 2 Flashcards
Four elements make up how much of the body?
96%
What are the four elements that make up the body?
carbon, oxygen, hydrogen, and nitrogen
Orbital model
current model used that depicts orbitals, probable regions where an electron is most likely to be located
- shading in regions of greatest electron density results in an electron cloud around nucleus
- useful for predicting behavior of atoms
Atomic number
number of protons in nucleus
Mass number
total number of protons and neutrons in nucleus
Isotopes
structural variations of same element due to different number of neutrons but same number of protons
Atomic weight
average of mass numbers of all isotope forms of an atom
homogeneous mixture
particles are evenly distributed throughout
Solvent
substance present in greatest amount
Solute
substance dissolved in solvent
Colloids
also know as emulsions and are heterogeneous mixtures, meaning that particles are not evenly distributed throughout mixture
Suspensions
heterogeneous mixtures that contain large, visible solutes that do settle out
What is the outermost electron shell called?
valence shell
Ionic bonds
involve the transfer of valence shell electrons from one atom to another
Anion
negative charge and atom has gained one or more electron
Cation
positive charge and atom that has lost one or more electrons
Attraction of opposite charges created what kind of bond?
ionic
What are most ionic compounds?
salts
Covalent bonds
formed by sharing of two or more valence shell electrons between two atoms
Two types of covalent bonds
polar and non polar
Nonpolar covalent bonds
equal sharing or electrons between atoms
Polar covalent bonds
unequal sharing of electrons between 2 atoms
Electronegative
atoms with greater electron-attracting ability
Electropositive
with less electron-attracting ability
Hydrogen bonds
attractive force between electropositive hydrogen of one molecule and an electronegative atom of another molecule
not true bond, more of a weak magnetic attraction
Water
most abundant inorganic compound
Water properties
high heat capacity high heat of vaporization polar solvent properties reactivity cushioning salts
Salts
ionic compounds that dissociate into separate ions in water
All ions are called what?
electrolytes
Electrolytes
can conduct electrical currents in solutions
What balance is vital for homeostasis?
ionic balance
Common salts in body
NaCl, CaCO3, KCl, calcium phosphates
Acids
proton donors
Proton donors
release hydrogen ions,
Bases
proton acceptors
Proton acceptors
pick up H+ ions in solution
pH
acid-base concentration
Normal blood pH
7.35-7.45
Monosaccharides
simple sugars containing three to seven carbon atoms
Important monosaccharides
pentose and hexose sugars
Pentose sugars
ribose and deoxyribose
Hexose sugars
glucose (blood sugar)
Disaccharides
double sugars and too large to pass through cell membranes
Important disaccharides
sucrose, maltose, lactose
What is formed by dehydration synthesis
water and energy
Polysaccharides
polymers of monosaccharides by dehydration synthesis of many monomers
Triglycerides or neutral fats
composed of three fatty acids bonded to a glycerol molecule
Saturated fatty acids
all carbons are linked via single covalent bonds, resulting in a molecule with the maximum number of H atoms
Unsaturated fatty acids
one or more carbons are linked via double bonds, resulting in reduced H atoms
liquid at room temperature
Trans fat
modified oils, unhealthy
Omega-3 fatty acids
“heart healthy”
Phospholipids
glycerol and two fatty acids plus a phosphorus-contain group
Steroids
consist of four interlocking ring structures
Most important steroid
cholesterol
Eicosanoids
derived from a fatty acid found in cell membranes
Most important eicosanoids
prostaglandins
Prostaglandins role
blood clotting, control of blood pressure, inflammation and labor contractions
Polymers of amino acids monomers are held together by what?
peptide bonds
Shape and function of proteins due to what?
four structural levels
How many different types of amino acids make up proteins?
20
How are amino acids joined?
by covalent bonds called peptide bonds
What do amino acids contain?
amine group and acid group
Primary structure level
linear sequence of amino acids
Secondary structure level
how primary amino acids interact with each other
alpha helix and beta pleated sheets
Tertiary structure level
how secondary structures interact
Quaternary structure level
how 2 or more different polypeptides interact with each other
Enzymes
globular proteins that act as biological catalysts
Holoenzymes
most functional enzymes
Two parts of holoenzymes
apoenzyme and cofactor or coenzyme
Apoenzyme
protein portion
Cofactor
metal ion
Coenzyme
organic molecule, often a vitamin
Are enzymes unspecific?
No, they act on a very specific substrate
Enzyme action
lower activation energy, which is the energy needed to initiate a chemical reaction
-“prime” the reaction
Nucleic acids
composed of C, H, O, N, and P, are the largest molecules in the body
DNA nucleotides
purines and pyrimidines
Purines
adenine and guanine
Pyrimidines
cytosine and thymine
Complementary base-pairing rules
A always pairs with T
G always pairs with C
