BIO Exam 3

Primary protein structure

amino acid sequence

Secondary protein structure

shapes caused by hydrogen bonds between backbones, e.g. beta sheet or alpha helix

Tertiary protein structure

shapes caused by strong bonds between positively and negatively charged amino acids. Caused by interactions between the R groups.

Quaternary protein structure

shapes caused by bonds that form between separate polypeptide strands. Not all proteins have a quaternary structure. Hemoglobin is one that you are familiar with - it consists of four separate strands bound together.

Special amino acids: Glycine

small, allows flexible backbone

Special amino acids: Cysteine

strong bonds form between S atoms of 3 cysteine amino acids

Special amino acids: Proline

creates link in chain; restricts folding

Hydrophilic amino acids: 

Polar: 

• One end of R group, slightly more negative than other

• Form H-bonds with each other and with water

Hydrophilic amino acids: 

____: 

• One end of ____, slightly more _____ than other

• Form _____ with each other and with ____

Hydrophilic amino acids: 

Basic/Acidic: 

• strongly polar (either + or -)

• Usually on the outside of protein 

• Form bonds with each other (+ or -)

Hydrophilic amino acids: 

_____: 

• strongly ____ (either + or -)

• Usually on the ____ of the protein 

• Form ____ with each other (+ or -)

Hemoglobin consists of…

• 4 globular protein subunits (2 α + 2 β)

• 4 heme groups (with iron) → 4 green parts on graph

  • bind O2

Hemoglobin consists of…

• 4 globular ____ subunits (2__ + 2__)

• 4 ___ groups (with ___) → the 4 green parts on graph

  • bind O2