Bio152 Ch. 3
in the stable form of protein, what is generally oriented to the interior of the protein molecule?
hydrophobic portions
when phospholipid molecules are mixed with water, they can spontaneously organize into a bilayer with the "heads" located __________ of the bilayer.
on the surface
when an egg is fried, what happens to the protein in the egg?
the protein is denatured
the fatty acid of a triglyceride need not be identical, and often they are very different from one another
true
when proteins are denatured, which type of bond is not disturbed?
covalent bonds
Ala-Gly-Try-Lys-Met-Trp-Phe
Primary structure
The sequence of amino acids in the polypeptide chains
Primary structure
In a phospholipid molecule, ________ usually binds to a charged organic molecule, such as choline or the amino acid serine.
a phosphate group
polar soluble, can act as a weak base and accept a proton, found in proteins and nucleic acids
amino group
lipid bilayers form the basic framework of _____________.
biological membranes
polar, soluble, protons can dissociate from this group and it has acidic properties
carboxyl group
a molecule of glycogen is formed by linking glucose molecules through this process.
dehydration synthesis
monomers are linked together through this process
dehydration synthesis
this process removes water to link two or more amino acids
dehydration synthesis
the change to the color and consistency of an egg during cooking is an example of this process.
denaturation
this process does not involve breaking peptide bonds, bit it does involve unfolding protein structure
denaturation
using acids to cook raw fish is an example of this process
denaturation
a protein that has many hydrophobic R-groups pointing to the outside of the protein would be found?
embedded within the membrane
a fatty acids consists of a hydrocarbon chain joined to a hydroxyl group
false
a saturated fatty acid has the maximum number oxygen atoms bonded to its hydrocarbon chain
false
a tricylglycerol is composed of 3 glycerol molecules joined to a fatty acid
false
denatured proteins are usually biologically active
false
fats containing unsaturated fatty acids have high melting points because their fatty acid chains bend at the double bonds, preventing them from packing closely together
false
glycerol is a three-carbon alcohol, in which each carbon bears a carboxyl group
false
if a proteins environment is altered, the protein may change its shape or even unfold completely, a process called dissociation.
false
proteins have a narrow range of conditions in which they fold, outside that range, proteins tend to renature
false
the final 3-D shape of a protein is determined entirely by its primary structure
false
when normal environmental conditions are reestablished after protein denaturation, almost all proteins can spontaneously refold back into their natural shape.
false
In a phospholipid molecule, _____ binds to two fatty acids
glycerol
breaking DNA into nucleotides involves this process
hydrolysis
the addition of water to break proteins into amino acids is an example of the process.
hydrolysis
the separation of polymers into smaller units makes use of this process.
hydrolysis
in a phospholipid molecule, the "head" is ________.
hydrophilic
in a phospholipid molecule, the fatty acid "tails" are______.
hydrophobic
polar, soluble, forms H bonds, forms alcohol
hydroxyl group
when phospholipid molecule are mixed with water, they can spontaneously organize into bilayer with the "tails" located _________ of the bilayer
in the center
nonpolar, hydrophobic, found in hydrocarbon chains
methyl group
what type of bonds link individual amino acids together?
peptide bonds
polar, soluble, found in nucleic acids, can be acidic if it loses protons
phosphate group
what levels of protein structure would be affected if all hydrogen bonding interactions were prevented.
primary secondary
only found in proteins composed of more than one polypeptide chain
quaternary
refers to the way several different polypeptide chains fit together to form the final protein
quaternary structure
Alpha- helix and beta-pleated sheets
secondary structure
repeated pattern of coiling or folding within a polypeptide chain
secondary structure
results from hydrogen bonds between polar groups in the polypeptide backbone
secondary structure
results from the bending and folding of a polypeptide chain that occurs due to a variety of interactions between the amino acid side chains
tertiary structure
the overall 3-D shape of polypeptide or protein
tertiary structure
a hydro carbon chains of fatty acids vary in length as well as in the number and location of double bonds between the carbon atoms
true
cells use chaperones both to accomplish the original folding of some proteins and to restore the structure of incorrectly folded ones
true
during a process called dissociation, the polypeptides of a protein with quaternary structure separate and unfold, losing their individual tertiary structure
true
fatty acids with one double bond in their hydrocarbon chain are called monounsaturated, while those with more than one double bond are called polyunsaturated
true
if the 3-D structure of a protein depends only on its primary structure and the surrounding environment conditions, then when the protein is denatured and subsequently returned to its native conditions it will spontaneously refold back to its native structure.
true
most plant fats are partially hydrogenated industrially, this can produce trans fats which have been linked to elevated levels of low-density lipoprotein (LDL) "bad cholesterol" and lowered levels of high-density lipoprotein (HDL) "good cholesterol"
true
proteins can denature when the pH, temperature, or ionic concentration of surrounding solution changes
true
some diseases may occur because a protein with the correct amino acid sequence fails to correctly fold into its final functional form
true
some proteins require other proteins called chaperones in order to correctly fold into their normal 3-D shape
true
when forming a semi-solid gel such as gelatin, which molecule does the process of protein coagulation entrap?
water molecules