Chapter 2: Chemistry of Life Flashcards
matter
anything that has mass and takes up space
atom
smallest particle of matter. composed of subatomic particles: protons, neutrons, and electrons
element
substance that cannot be broken down into simpler substances by chemical means
4 major elements found in human body
hydrogen, oxygen, carbon, and nitrogen
isotopes
atoms with the same atomic number but different mass numbers
mixtures
physical combinations of matter
3 types of mixtures
suspensions, colloids, and solutions
solution
contains a solvent that dissolves a solute. The amount of solute present in a _____ is the “concentration”
chemical bonds
atoms united chemically to form molecules or compounds.
valence electrons
the electrons in an atom’s outermost shell
ionic bond
forms when a metal and nonmetal transfer electrons to form cations and anions. The ______ results from the attraction of the pos. charged metal cation and the neg. charged nonmetal anion.
covalent bond
forms when two or more atoms share electrons so that each atom obeys the octet rule
octet rule
the tendency of atoms to prefer to have eight electrons in the valence shell. When atoms have fewer than eight electrons, they tend to react and form more stable compounds.
nonpolar covalent bonds
type of chemical bond that is formed when electrons are shared equally between two atoms.
polar covalent bonds
unequal sharing of electrons between two nonmetals. The electrons are pulled more strongly by the more electronegative atom, and a dipole results.
dipole
a partially positive and partially negative pole that forms as a result of a polar covalent bond
hydrogen bonds
bond formed b/w partially (+) hydrogen atom and another partially or fully (-) electronegative atom (nitrogen, oxygen, fluorine)
chemical reactions
Any time chemical bonds are formed, broken, or rearranged, or electrons are transferred between atoms
energy
the capacity to do work. There are two types of _____ : potential energy and kinetic energy
potential energy
energy that is stored
kinetic energy
energy in motion
3 forms of potential/kinetic energy in the body
chemical energy, electrical energy, and mechanical energy
exergonic reaction
reaction that releases energy
endergonic reaction
reaction that consumes energy
3 types of reactions in human body
catabolic, exchange, and anabolic (aka synthesis).
Catabolic (aka decomposition) reactions
break larger molecules into smaller ones (collapse = break down)
exchange reaction
one or more atoms from the reactants are exchanged for another
anabolic (aka synthesis) reaction
form larger molecules from smaller ones (anabolic = add more)
factors for rate of reactions
reactants concentration, temperature, size and phase of the reactants, and presence/absence of a catalyst.
enzymes
biological catalysts that increase the speed of a reaction
water
acts as a solvent for substances with polar covalent and ionic bonds, which are hydrophilic, but not for those with nonpolar covalent bonds, which are hydrophobic.
hydrophilic
having a tendency to dissolve in water
hydrophobic
tending to repel to mix/dissolve in water
acid
a molecule or other entity that can donate a proton or accept an electron pair in reactions
base
a substance that can accept hydrogen ions in water and can neutralize an acid
pH scale
logarithmic scale that represents the hydrogen ion concentration of a solution
pH less than 7
acidic; as the pH decreases the number ____, the solution becomes more acidic.
pH of 7
neutral pH level
pH greater than 7
basic (alkaline); as pH increases, solution becomes more basic
buffer
system of chemicals that resist a change in pH
salt
metal cation bonded ionically to a nonmetal anion. _____ are electrolytes
monomer
atoms or small molecules that bond together to form more complex structures such as polymers
polymer
a long chain molecule that’s formed from small molecules (monomers) linked together
carbohydrates
primarily functions as fuel in the body but also plays a structural role
monosaccharides
carbohydrate monomers
most abundant monosaccharides in the body
glucose, fructose, galactose, ribose, and deoxyribose
disaccharides
formed from the union of two monosaccharides by dehydration synthesis
polysaccharides
consist of many monosaccharides. Glycogen is the body’s main polysaccharide
lipids
stores energy, forms structural components of cell membrane, and functions as signaling molecules.
fatty acid
monomer of fats. the building blocks of the fat in our bodies and in the food we eat
triglyceride
3 fatty acids joined to glycerol
phospholipid
contains two fatty acids and a phosphate group bonded to glycerol
It is an amphiphilic molecule
steroids
a class of lipids based upon a four-ring hydrocarbon steroid nucleus
Any of a group of lipids (fats) that have a certain chemical structure.
proteins
function as enzymes, play structural roles, are involved in movement, function in the body’s defenses, can be used as fuel, and more
polypeptide
chain of amino acids (protein)
How many levels of organization does protein have?
4 levels: primary, secondary, tertiary, and possible quaternary structures
denature
molecule permanently loses its shape and therefore its function
causes of denaturing
heat, pH changes, and certain chemicals
nucleotide
a monomer composed of a nitrogenous base, a sugar, and a phosphate group
2 types of nitrogenous bases
Purines= adenine (A) and guanine (G)
Pyrimidines= cytosine (C), thymine (T), and uracil (U)
adenosine triphosphate
(ATP) the body’s main source of chemical energy. ATP is synthesized from adenosine diphosphate (ADP) and a phosphate group.
nucleic acids
DNA & RNA
deoxyribonucleic acid
aka DNA, only found in cell nucleus. has 2 strands of nucleotides (double helix) joined by hydrogen bonds
DNA
contains genes that provide the “recipe” or code for every protein in the body
ribonucleic acid
aka RNA, single strand of nucleotides that move between cell’s nucleus and cytosol. helps assemble amino acids into a protein outside the nucleus.
