chapter 3- proteins Flashcards
what are the 5 most common chemical elements that make up proteins
carbon, hydrogen, oxygen, nitrogen, sulphur
what is the monomer from which proteins are made
amino acids
what is the general structure of an amino acid
a central carbon atom bonded to a hydrogen atom, an r group, carboxyl group and a amine group (hydroxyl group??)
how many amino acids are commonly found in cells
20
how many non essential AAs are there and what does this mean
5, our bodies are able to make them from other AAs
how many essential AAs are there and what does this mean
9, means that they can only be obtained from what we eat
a further … AAs are said to be….. meaning
6, conditionally essential meaning they are only needed by infants and growing children
what is a peptide bond
a covalent bond between two amino acids resulting from a condensation reaction
what is a dipeptide
a molecule formed by the condensation of two AAs
what is a polypeptide
a polymer formed by the condensation of many AAs (3+)
what is a proteins primary structure
the sequence of amino acids that makes up the polypeptide of a protein
what is a proteins secondary structure
the particular folding/conformation/shape of a chain of AAs in the polypeptide(s) of a protein
what is a proteins tertiary structure
the particular folding of a whole polypeptide chain as determined by the AAs that make up the polypeptide
what is a proteins quaternary structure
a number of polypeptide chains linked together and sometimes associated with non protein groups to form a protein
what is a conjugated protein
a protein that contains non protein prosthetic groups attached by covalent, ionic or hydrogen bonds
what is haemoglobin and its structure
a protein enabling transport of oxygen in the blood, it has a quaternary structure and 4 prosthetic ahem groups which are able to bind to oxygen
what do peptide bonds form between
individual amino acid molecules between the carbon and hydrogen
what is the reaction called which forms a peptide bond and a water molecule
condensation reaction
peptide bond and adds to water back into the amino acids
hydrolysis
what is a dipeptide
2 amino acids joined together by a peptide bond
what is a polypeptide chain
3 or more amino acids joined together
how many peptides are in a protein
a protein consists of 1 or more polypeptide chains folded into a specific 3d shape
why is the structure of a protein important
because it plays an important role in the overall structure and function of the protein
what is the primary structure of proteins
refers to simple long chains with NO intramolecular BONDS or interactions, specific order of AAs
what is the secondary structure of proteins
what is the secondary structure of proteins
what is the tertiary structure of proteins
hydrophilic or phobic interactions, hydrogen, ionic and disulphide bonds (or bridges) that hold the molecules together in shape
what is the quaternary structure of proteins
same as tertiary but have 2 or more separate polypeptide chains interlinked
what are the 2 structures in a secondary level structure of proteins
alpha helix or beta pleated sheet
alpha helix structures always make……proteins
globular
beta pleated sheet structures always make…..proteins
fibrous
name 3 fibrous proteins
keratin
elastin
collagen
what is a peptide bond
it is the bond that forms between the amine group of 1 amino acid and the carboxyl of another amino acid to form a dipeptide
Scientists call the non-amino acid part in a globular protein the
prothetic group
A globular protein is known as conjugated if it contains a/an…
prosthetic group
are fiberous proteins soluble or insoluble in water
insoluble
what type of proteins contain lots of hydrophobic side groups and what does this allow them to do
fibrous, have lots of structural functions
a scientist analysed and recorded all of the chemical elements in one particular amino acid which elements did the scientist record
C, H, O, N
which is correct:
a) a glucose molecules contains 5 OH groups and has a C:O ratio of 1:1
b) glucose molecules contain 6 OH groups and has a a C:H ratio of 1:2
A
if 2 amino acids on a tlc had different r groups and their spots have travelled different distances what can be suggested about the chemical properties of their r groups
they different in terms of polarity, charges and functional groups
the one that travelled the least is more polar
chromatography: why a pencil and not a pen
