Proteins Flashcards
(24 cards)
what can you remember?
-amino acids joined by peptide bonds
-code for different amino acids coded for by dna nucleotides in the nucleus
-primary structure of proteins= amino acid chain
-folded into secondary structure and forms
alpha helices and beta pleats due to hydrogen bonding between amino acids?
-amino acids have r groups which are the variable groups, make amino acids different
whatre the 3 functional groups in amino acids
-amine group H
l
H-N
-R group/side chain
-carboxyl group O
ll
C-OH
what reaction joins 2 amino acids and whats formed
condensation (with loss of water)
peptide bond between them
dipeptide formed
hydrolysis reaction splits dipeptide by adding water back in
why is there less water content in the mucus of people with CF
-faulty or absent CFTR protein
-causes abnormal salt and H2O transport across cell surface membrane
hows the amino acid chain turned into secondary structure
hydrogen bonds between amino acids cause it to coil into alpha helices or fold into beta pleated sheets then further coiled or folded due to hydrogen and ionic bonding in diff sections of the chain
secondary structure only relates to hydrogen bonds forming between the amine and carboxyl group
polypeptide definition
multiple amino acids joined by peptide bonds
what does a peptide bond look like
O
ll
C - N
l
H
how do dipeptides become polypeptides
repeated condensation reactions forming many peptide bonds
what makes a protein soluble or insoluble
whether its R group is hydrophobic or hydrophillic
what bonding forms alpha helices
hydrogen bonds form between H-N - C=O of every 4th amino acid/peptide bond between oxygen of the carboxyl group and hydrogen of the amine group
hydrogen bonding in beta pleated sheets
protein folds so 2 parts of the polypeptide chain are facing each other and hydrogen bonds form between parallel peptide bonds
what breaks H bonds between amino acids
high temperatures and Ph changes
what forms a proteins teriary structure
changes in 2ndary structure lead to bonds forming between R groups
which bonds form between R groups
disulphide (only between cytesine amino acids) , ionic, hydrogen, weakhydrophobic interactions can happen between non polar R groups
when does quaternary structure occur?
a functional macromolecule formed by more than one polypeptide chain e.g. haemoglobin
which types of bonding only occur in tertiary structure
disulphide bridges
hydrophobic interactions
ionic
what types of bonding can occur in secondary structure and between which groups
peptide
hydrogen
only between amino and carboxyl groups, not R groups
what types of bonding can occur in primary structure
only peptide
which is stronger H bonds or disulphide bridges
disulphide bridges
what does haemoglobin consist of
4 tertiary structures bonded together with iron in the middle
whatre modified proteins?
also called conjugated proteins
proteins with a non-protein unit
characteristics of fibrous proteins
-often insoluble with hydrophobic R groups on the outside
-long
-rope like
-often structural proteins
-primarily made up of secondary structure
-cross linked for strength
-high tensile strength
globular proteins characteristics
-often shaped for specific functions e,g active site for specific substrate
-spherical
-often soluble in water,hydrophillic R groups on outside
-hydrophobic R groups on inside
examples of globular proteins
-transport proteins
-enzymes
-hormones
