proteins : amino acids Flashcards
what is an amino acid ?
monomers of all proteins,and all amino acids have the same basic structure
what is an peptide bond ?
a bond formed when 2 amino acids are joined by a condensation reaction
what are proteins ?
large polymers comprised of long chains of amino acids
what are the function of proteins for animals ?
-form structural components of animals in particular e.g. muscles are made up of protein
what are the properties of proteins that provide a function in terms of enzymes ?
tendency to adopt specific shapes makes proteins important as enzymes (antibodies and some hormones)
what are properties of proteins that provide a function in terms of membranes ?
membranes have protein constituents that act as carriers and pores for active transport across the membrane and facilitated diffusion
why do animals and plants need amino acids ?
as amino acids are needed to make up proteins
what is meant by essential amino acids ?
essential amino acids are those that animals cannot synthesise themselves and must therefore obtain from their diet
why must animals obtain essential amino acids from their diet ?
animals can make some amino acids but others are essential and must be ingested because their bodies cannot produce them
how many naturally occurring (proteinogenic) amino acids are there in proteins and enzymes ?
20
how many amino acids are essential and must be taken in diet ?
8-10
how do plants make all the amino acids ?
if they have access to fixed nitrogen (such as nitrate )
what elements does each amino acid contain ?
carbon,hydrogen,oxyegn and nitrogen
what element does amino acid sometimes contain ?
sulphur
what does proteinogenic mean ?
they are only found in proteins
what does each protein chain of amino acids have (structure) ?
-has an amino acid group (-NH2) at one end
-a carboxyl (-COOH) group at the other end
draw the molecular structure of amino acids
find elsewhere :)
what does the R group stand for ?
not for a particular element but different in each amino acid
how can the R-group be complaicated ?
as in alanine = CH3
cysteine = CH3S
what does almost all of amino acids end in ?
-ine
what is the exception in terms of R-groups ? (ine)
those that have acidic R-groups e.g. aspartic acid and glutamic acid
what can R-groups vary in ?
charge , size , polarity and whether is hydrophobic or hydrophilic
why does R-group vary in properties ?
allows proteins to have a wide variety of shapes and functions in the body
what shape does individual amino acids display and why ?
a tetrahedral shape due to the angles of the bonds between the atoms
