Unit 1 Cells and Proteins: Key Area 2 Proteins (Structure) Flashcards
what is a distinguishing feature of proteins?
there folded nature and ability to bind specifically to other molecules.
what are proteins polymers of?
amino acids.
what are 2 functional groups of amino acids?
the amine and acid group
what does wide range of functions carried out by proteins result from?
the wide range of functions carried out by proteins results from the diversity of R groups.
what determines the structure of the protein?
the sequence of amino acids.
what makes each amino acid different?
the R group.
what are 5 components of amino acids?
the amine group, acid group, R-group, hydrogen atom and central carbon.
what are amino acids linked together by and what does this produce?
peptide bonds which produces a polypeptide.
what are the 4 main R-groups of amino acids?
polar, hydrophobic, acidic (negatively charged), basic (positively charged).
what can R-group of amino acids vary in?
size shape charge hydrogen bonding capacity chemical reactivity
what are the key features of an acidic R-group?
- ends with a negatively charged group
- hydrophilic
- key component is a carboxylic acid group
- COOH
what are the key features of a basic R-group?
- ends with a positively charged group
- hydrophilic
- key component of their R-groups is an amine group
what are the key features of a polar R-group?
- slightly charged
- hydrophilic
- key component: carbonyl (CO), (OH), or amine (NH)
what are the key features of a hydrophobic R-group?
- hydrophobic
- do not have charge
- non-polar
- key component is a hydrocarbon - CH3, long chain of CH and rings
what are the other level of proteins structure other than the sequence and binding of amino acids?
- Primary structure
- Secondary structure
- Tertiary structure
- Quaternary structure
what is the primary structure?
the primary structure is the sequence in which the amino acids are synthesised into the polypeptide
what happens in the primary structure?
amino acids link by peptide bonds to form a polypeptide
what results in regions of a secondary structure?
hydrogen bonding along the backbone of the protein strand results in regions of secondary structure
what are the 3 types of secondary structure?
- alpha helix
- beta sheets
- turns
how are alpha helix formed?
by twisting the polypeptide into a spiral/ helix then establishing with hydrogen bonds. where the R-groups stick out
what are the 2 types of beta sheet?
- parallel: the chains run in the same direction
- anti-parallel: the chains run in opposite directions
what’s stabilises the alpha helix?
hydrogen bonding
what is the tertiary structure?
further folding of secondary shapes into an overall three- dimensional shape
how is the tertiary structure established?
by many different interactions between the R-groups of the amino acids
