Chapter 19 – Flashcards with Answers

Unlock all answers in this set

Unlock answers
question
are all proteins structurally similar?
answer
yes
question
proteins are polymers consisting of...
answer
chains of amino acids chemically bound to each other
question
an amino acid is a compound that contains both a
answer
amino group and carboxylate group
question
how many amino acids are commonly found in the body?
answer
20
question
what are the amino acids found in proteins called?
answer
alpha amino acids
question
why are they called alpha amino acids>
answer
because they are attached to the alpha carbon
question
what is the alpha carbon?
answer
the carbon next to the carboxylate group
question
what gives an amino acids its unique characteristics
answer
the R group (or side chain)
question
what four categories are amino acids broken up into?
answer
neutral with nonpolar side chains, neutral with polar side chains, basic side chains and acidic side chains
question
acidic side chains contain a (blank) group
answer
carboxylate
question
basic side chains contain an (blank) group
answer
amino group
question
what is the simplest amino acid
answer
glycine
question
with the exception of glycine, what is true of the alpha carbons in amino acids?
answer
they are chiral
question
are most amino acids found in the D or L form?
answer
L
question
what is a zwitterion?
answer
a dipolar ion that carries both a positive and negative charge as a recult of an internal acid-base reaction in an amino acid molecule
question
what is the net charge of a zwitterion?
answer
zero
question
what happens to a zwitterion if an acid is added?
answer
then the COO- picks up a hydrogen
question
what happens to a zwitterion if a base is added?
answer
then the amino group loses a hydrogen
question
what is the isoelectric point?
answer
the pH at which the zwitterion forms
question
what is the only sulfhydryl containing amino acid?
answer
cysteine
question
what chemical property do cysteine have that other amino acids don't?
answer
they are able to be oxidized to form a disulfide bond
question
what is the product of oxidizing a cysteine?
answer
a disulfide compound, cystine
question
what functional group reacts when two amino acids are put together?
answer
the carboxylate group
question
what are dipeptides?
answer
compounds made up of two amino acids
question
what kind of bonds peptide bonds?
answer
amide linkages
question
does the order amino acids are in matter?
answer
yes
question
alyclalamine and alanylglycine are (blank) isomers of each other.
answer
structural
question
peptide
answer
an amino acid polymer of short chain length.
question
polypeptide
answer
an amino acid polymer of intermediate chain length containing up to 50 amino acid residues
question
protein
answer
an amino acid polymer made up of more than 50 amino acids
question
amino acid residue
answer
an amino acid that is part of a peptide, polypeptide or protein chain
question
N-teminal residue
answer
an amino acid on the end of a chain that has an unreacted or free amino acid
question
C-terminal residue
answer
an amino acid on the end of a chain that has an unreacted or free carboxylate group
question
which side is the N-terminal on?
answer
the left
question
disulfide bridge
answer
a bond produced by the oxidation of -SH groups on two cysteine residues. The bond loops or holds two peptide chains together.
question
what is the difference in the structure of vasopressin and oxytocin?
answer
two amino acids
question
are proteins relatively large or small molecules?
answer
large
question
what is one of the most important properties of proteins that is based on its R group?
answer
acid base behavior
question
what determines at what pH a protein will clump together?
answer
the charge on the R group
question
name eight functions of proteins in the body:
answer
catalysts, structural, storage, protective, regulatory, nerve impulse transmission, movement, and transport
question
what are two types of proteins that are based on their structural shape?
answer
fibrous and globular
question
fibrous proteins
answer
made up of long rod shaped molecules that can intertwine with one another and form strong fibers.
question
are fibrous proteins water soluble?
answer
no
question
where are fibrous proteins usually found?
answer
tissue, hair and skin
question
globular proteins
answer
more spherical
question
are globular proteins soluble in water?
answer
yes, they either dissolve or form colloidal dispersions in water
question
what are the two types of proteins based on composition?
answer
simple and conjugated
question
simple proteins
answer
contain only amino acid residues
question
conjugated proteins
answer
contain amino acid residues and other organic or inorganic compounds
question
prosthetic group
answer
the non amino acid parts of conjugated proteins
question
what do all proteins have in common?
answer
carbon nitrogen backbone
question
what does the primary structure of a protein tell you?
answer
the order in which amino acid residues are linked together
question
what causes a protein chain to fold and curl into distinctive shapes that in turn enables the protein to function properly.
answer
the sequence of amino acids
question
when a primary structure folds and becomes aligned in a certain orderly pattern, this is called...
answer
secondary structure
question
what kind of bonding makes secondary structures?
answer
hydrogen
question
what are the two forms secondary structures can take?
answer
alpha helix and beta sheets
question
in an alpha helix, what compounds are hydrogen bonded?
answer
the carbonyl oxygens and amide hydrogens
question
are all amide groups or all carbonyl oxygens involved in hydrogen bonding?
answer
all amide groups
question
what is the less common structure: alpha helix or beta sheets
answer
beta sheets
question
where is the only place beta sheets are found extesively?
answer
silk proteins
question
what are hydrogen bonded in beta sheets?
answer
the amide carbonyl oxygens and amide hydrogens
question
what is tertiary structure?
answer
the bending and folding of the protein into specific three dimensional shape.
question
the tertiary structure results from the interactions between
answer
the R side chains and the amino acid residues
question
what are the four types of R group interactions
answer
disulfide bridges, salt bridges, hydrogen bonds, and hydrophobic interactions
question
what two residues can a disulfide linkage occur between
answer
cysteine
question
are disulfide linkages present in secondary structures?
answer
no
question
what are salt bridges?
answer
a result of ionic bonds that form between the ionized side chain of an acidic amino acid and the side chain of a basic amino acid
question
what is the difference between the hydrogen bonds of the tertiary structure and the hydrogen bonds of the secondary structure?
answer
in the secondary structure the bonding is between backbone carbonyl and amide groups, in the tertiary structure, it is between the R groups
question
hydrophobic interactions
answer
result when nonpolar groups are either attracted to one another or forced together by their mutual repulsion of an aqueous solution
question
what is the weakest of the four types of bonds?
answer
the hydrophobic interactions
question
quaternary structure
answer
arrangement of subunits
question
what is a subunit
answer
a polypeptide chain
question
if proteins are exposed to physical or chemical conditions such as extreme temperatures or pH values, what happens?
answer
denaturation
question
what happens during denaturation?
answer
folded structure breaks down and the protein takes on a random disorganized conformation
question
what else, besides heat and pH cause denaturation?
answer
heavy metal ions
Get an explanation on any task
Get unstuck with the help of our AI assistant in seconds
New