IBHL BIO protein structure

To be used with Bioninja

What is Primary Structure in proteins and its importance?

1: The sequence of amino acids that make up a polypeptide chain formed by covalent peptide bonds between the amine and carboxyl groups of adjacent amino acids

2: The primary structure determines the final shape of the protein and by proxy its functional properties

What is Secondary Structure in proteins and its importance

1: The repeating local 3D folds in a polypeptide chain to form alpha helix or beta-pleated sheets, which is a result of hydrogen bonds between the amine and carboxyl groups of non-adjacent amino acids

2: This provides the polypeptide chain with stability from the hydrogen bonds

What is Tertiary Structure in proteins and its importance

1: The turns and coils of a polypeptide to form a complex 3D shape that is caused by interactions between R groups; including hydrogen bonds, disulfide bridges, ionic bonds, and hydrophobic interactions

2: This is important for the function of the protein (e.g. specificity of active site in enzymes)

What is Quadernary Structure

1: A mature protein that consists of more than one polypeptide chain (subunits)

2: A protein can also have a quaternary structure if they include a non-protein component called a prosthetic group (e.g. Hemoglobin's subunits associate with iron-heme groups

What are Globular Proteins and their characteristics? Provide an example

1: Typically round and have an irregular amino acid sequence

2: Carry out specific biological activities

3: Soluble in water and sensitive to changes in temperature and pH

4: Insulin, a protein responsible for blood sugar regulation

What are Fibrous Proteins and their characteristics? Provide an example

1: Typically long and narrow due to repetitive amino acid sequence

2: Carry out structural roles within cell

3: Insoluble and are less sensitive to changes in temperature and ph

4: Collagen, a protein found in connective tissues

Free floating ribosomes synthesize what kind of proteins?

Proteins for intracellular use

Ribosomes attached to the ER synthesize what kind of proteins?

Proteins for secretion from the cell or membrane fixation

What is the function of the Golgi apparatus during protein modification?

1: Proteins from the rough ER arrive in vesicles at the Golgi and are modified into functional molecules

2: The different sacs of the Golgi are responsible for specific chemical modifications like phosphorylation

Some proteins require post-translational modifications to become functional, name some modifications and give an example protein

1: Conjugation with non-protein components, chemical modifications like glycosylation or phosphorylation

2: Human insulin

What are proteasomes and their role within cells?

1: Proteasomes are protein complexes that degrade unneeded or misfolded proteins through proteolysis (breaking of peptide bonds)

2: They are used by the cell to help regulate protein expression levels and recycle amino acids

What small protein tags proteins for proteolysis?

Ubiquitin