exam 1 biological molecules Flashcards
what are cells made from?
a set of carbon-based molecules that are fundamentally the same for all living species
are lipids polymers
no
what are carbohydrates made of
sugar monomers
what do carbohydrates serve as
energy storage and structural support for cells
what are lipids composed of
fatty acids, usually linked to glycerol
what do lipids serve as
energy storage/source and can assemble into hydrophobic membranes
what are proteins made of
amino acids
what do proteins do (basic)
perform most cellular functions
what are nucleic acids built from
nucleotide monomers
what do nucleic acids do
they are the units of info storage and short-term energy storage
how do cells reduce entropy
cells build order, but have to expand energy to do so - cells want to go to disorder
what is the larger unit of the building block, sugar
polysaccharides
what is the larger unit of the building block, fatty acids
fats, lipids, membranes
what is the larger unit of the building block, amino acids
proteins
what is the larger unit of the building block, nucleotides
nucleic acids
what is a condensation reaction
combine two small molecules to make a larger molecules - condensing two molecules into one
what is a dehydration reaction
water molecule is removed from two molecules - dehydrates molecule to make water
what is hydrolysis
add water to break a bond
what is a glycosidic bond between
two sugars
what is a peptide bond between
two amino acids
what is a phosphodiester bond between
two nucleic acids
why are carbohydrates added to proteins and lipids
they’re extremely water soluble, so they provide a surface to bind other dissolved molecules (act as binding surfaces)
what are the chemical features of carbohydrates
can be a linear chain form or a ring form; have several OH groups
what is the distinction between polymer and monomer form
polymers are only in ring form, monomers are ring or linear chain
what is the chemical nature of carbohydrates
highly polar
how do you number carbons of a carbohydrate
clockwise starting with oxygen
what are the positions of OH groups attached to each carbon in a ring called
UP (above the plane of the ring) = beta
DOWN (below the plane of the ring) = alpha
Starch and cellulose are both polymers made up of glucose subunits. why are we able to digest starch but not cellulose
we have enzymes that digest the alpha linkages of starch but not the beta linkages of cellulose
what are the chemical features of lipids
hydrocarbon chains with polar COOH at one end
what is the chemical nature of lipids
amphipathic
how are lipids amphipathic
hydrophobic hydrocarbon tails and hydrophilic carboxylic acid head
what is a triglyceride
energy storage in animals
what is a phospholipid
makes up membranes in cells - tails face each other in center, heads face water
what are gangliosides
similar to phospholipids; have a carbohydrate instead of a phosphate/polar head group
what is the importance of the GM2 ganglioside
involved in cell-cell communication and neuronal plasticity
what are amino acids
building blocks of proteins; can be metabolized for energy
what are the chemical features of amino acids
uniform chemical structure with directionality and side group (R) variability
what charge is the n-terminus (amino terminus)
positive
what charge is the c-terminus (Carboxyl terminus)
negative
what is the net charge of an amino acid
zero, unless R group has a charge
are amino acids hydrophobic or hydophilic
intrinsically hydrophilic, but can be amphipathic if the side chain is hydrophobic
which amino acids are nonpolar (hydrophobic)
9 - glycine alanine valine leucine isoleucine methionine phenylalanine tryptophan proline
which amino acids are polar (uncharged)
6 - serine threonine cysteine tyrosine asparagine glutaminne
which amino acids are acids (negatively charged)
2 -
aspartate
glutamate
which amino acids are basic (positively charged)
3 -
lysine
arginine
histidine
what is pK
the pH at which 50% of a molecule is charged and 50% is uncharged
when are acidic amino acids charged
at pH 7 (below certain pH they are uncharged, above they are charged - opposite for basic)
what happens to acidic amino acids in water
they lose a proton
what happens to basic amino acids in water
they gain a proton
what are nucleotides
building block of nucleic acids; short term energy carriers
what are nucleotides made up of
a pentose sugar, a nitrogenous base, and a phosphate group
what are the charges of the parts of nucleotides
pentose sugar (hydrophilic) nitrogenous base (mainly hydrophobic) phosphate group (negatively charged) AMPHIPATHIC
what is the composition of the outer face of nucleotides
hydrophilic
what is the composition of the inner face of nucleotides
hydrophobic
what are the chemical features of nucleotides
uniform chemical structure with side group variability (from nitrogenous bases)
what is the chemical nature of nucleotides
polar, charged
what is ATP
the major short term energy carrier in the cell
what is the second law of thermodynamics
all processes in the universe are driven in the direction that increases disorder (entropy)
what does the universe tend towards
disorder
what is the first law of thermodynamics
the amount of energy in a system is constant - energy cannot be created or destroyed, but can be converted
when is energy useable
if it’s confineable (stored)
what are characteristics of reactions that decrease the availability of useable energy
they are energetically favorable and will occur spontaneously
what are characteristics of reactions that increase the availability of useable energy
they are NOT energetically favorable and will not occur spontaneously
what is a spontaneous reaction
a reaction that will occur without a net addition of energy
do cells violate the second law of thermo
NO - cells are not isolated system and thermo laws apply only to isolated systems
why are cells not isolated systems
they can exchange energy with their environent
what generates order within a cell
energy input
how do cells build order
by putting energy into the system
how do cells build disorder
the cell converts part of the energy into heat, which is released into the cell’s environment, thereby disordering it and thus also increasing entropy overall
