chapter 2 Flashcards
DNA
is described like a double helix, organized into 46 chromosomes, attached by hydrogen bonds
elements found in the body
nitrogen, hydrogen, carbon, oxygen
isotopes
forms of the same element that have an equal number of protons but a different number of neutrons, unstable, emit radioactive waves, isotopes DONATE
PET scan
uses isotopes, highlights areas in the body that are high in glucose to show cancer,
electron shells
must fill the outermost shell to be considered stable, all elements make an effort to reach stability
types of chemical bonding
ionic, covalent, hydrogen
ionic bonds
when an element donates an electron to fill the outer shell of another element, attraction of many sodium and chloride ions result in the formation of a large group called a crystal
covalent bonding
sharing of pairs of electrons between atoms, goal is for the outer shell to be filled so they reach stability
covalent bonds in water
water forms a covalent bond with the hydrogen and oxygen atoms, the oxygen atom “wants” the electrons more than the hydrogen atoms do
hydrogen bonds
hydrogen bonds are weak, they are indicated with a dotted line rather than solid, between a weak negative and positive charge
enzymes
substrate -> enzyme-substrate complex-> products, reduce activation energy so increasing the rate of reaction
how enzymes help
less energy is needed for a reaction to begin
monomers
the basic units for building larger molecules, form polymers
polymers
two or more chemically bonded monomers
dehydration synthesis
two monomers are covalently bonded in a reaction in which one gives up a hydroxyl group and the other a hydrogen atom. a molecule of water is released as a byproduct
hydrolysis
the covalent bond between two monomers is split by the addition of a hydrogen atom to one and a hydroxyl group to the other, this requires the gaining of one molecule of water
dissociation of sodium chloride in water
the crystals of sodium chloride dissociate NOT into molecules of NaCl, but into Na+ cations and Cl- anions, each completely surrounded by water molecules
acids
dissociates into hydrogen ions and anions. nearly every molecule of a strong acid dissociates producing a high concentration of H+
bases
dissociates into hydroxyl ions and cations, nearly every molecule of a strong base dissociates producing a high concentration of OH-
types of macromolecules
carbohydrates, lipids, proteins, nucleic acids
types of monosaccharides
glucose, fructose, galactose, deoxyribose, ribose
how disaccharides form
dehydration synthesis to form glycosidic bonds
types of polysaccharides
starch, glycogen, cellulose
types of disaccharides
sucrose, lactose, maltose
what are triglycerides
three fatty acid chains are bound to glycerol by dehydration synthesis
what are triglycerides composed of
glycerol attached to three fatty acids via dehydration synthesis, glycerol gives up a hydrogen atom, and the carboxyl groups on the fatty acids each give up a hydroxyl group
what do saturated fatty acid chains look like
straight
what do unsaturated fatty acid chains look like
kinked
phospholipids
composed of two fatty acids, glycerol, and a phosphate group
sterols
ring- shaped lipids
prostaglandins
derived from unsaturated fatty acids. PGE2 includes hydroxyl and carboxyl groups
amino acids
central carbon atom bonded to hydrogen atoms, amide group, carboxyl group, R- group (20 naturally occurring)
peptide bonds
different amino acids join together to form peptides, polypeptides, or proteins via dehydration synthesis. The bonds between amino acids are peptide bonds
protein primary structure
the sequence of amino acids that make up a polypeptide chain
protein secondary structure
can take form of an alpha- helix or beta- pleated sheet, is maintained by hydrogen bonds between amino acids in different regions of the original polypeptide strand
protein tertiary structure
occurs as a result of further folding and bonding of the secondary structure
protein quaternary structure
occurs as a result of interactions between two or more tertiary subunits
nucleotides building blocks
one or more phosphate groups, a pentose sugar, and a nitrogen containing base
ATP
a derivative of the nucleotide adenine, the energy currency of all cells
mass number
the weight of neutrons and protons
protons and electrons are ______ in number
equal
polar
charged
non-polar
no charge
