g2. Tertiary structure (proteins)

yes

How is a tertiary structure formed?

When the secondary protein structure is folded and twisted to give a more complex and compact 3D structure

Where do bonds happen in the tertiary structure?

Between parts of the R-groups. Every polypeptide has a different order of R-groups so there are bonds in different places. Results in different shapes

What are the four types of bonds involved?

Hydrogen bond, ionic bond, disulphide bridge and hydrophobic interactions

What is the hydrogen bond?

The most common and weakest bond.

How is a hydrogen bond formed?

When electropositive hydrogen atom on OH group or a NH group on 1 R-group attracts electronegative oxygen atom on another R-group

What is the ionic bond?

Stronger than hydrogen bonds and can be broken by pH changes

How is an ionic bond formed?

between an amino group and carboxyl group of R-group, if present

What is the disulphide bridge?

The strongest bond

How is a disulphide bridge formed?

Covalent bonds between R-groups with cysteine i.e. SH group

Where does a hydrophobic interaction occur?

Occurs between R-groups that are non-polar.

How is a hydrophobic reaction formed?

R-groups stay together as they are repelled by the watery environment around them