Unit 1- Protiens

Question 1

What is the proteome?

Answer 1

The entire set of proteins expressed by a genome.

Question 2

What structures increase the surface area in cells?

Answer 2

Endoplasmic reticulum, Golgi apparatus, lysosomes, vesicles.

Question 3

What are the 2 types of ER?

Answer 3

Rough ER, Smooth ER.

Question 4

Describe the functions of the different ERs.

Answer 4

RER- to synthesise proteins.
SER- to synthesise lipids.

Question 5

Describe the Golgi apparatus.

Answer 5

A series of flattened membrane discs involved in the transport and modification of proteins.

Question 6

Describe lysosomes.

Answer 6

Membrane bound organelles containing a variety of hydrolyses that digest proteins, lipids and carbs.

Question 7

Describe vesicles.

Answer 7

Vesicles transport materials between membrane components.

Question 8

Describe the synthesis of proteins.

Answer 8

RER has ribosomes on its cytosolic face. Lipids are synthesised on the SER and inserted into its membrane. The synthesis of all proteins begins in the cytosolic ribosome.

Question 9

Describe the movement of proteins after the ER.

Answer 9

Ribosome on ER - Lumen - vesicle - Golgi apparatus (post translational modifications) - vesicle - other membrane.

Question 10

Describe the secretory pathway.

Answer 10

Ribosome on ER - RER lumen - vesicle - Golgi apparatus - secretly vesicles - plasma membrane.

Question 11

Describe an acidic R group.

Answer 11

Hydrophilic, -ve, CH2CO2

Question 12

Describe a basic R group.

Answer 12

Hydrophilic, +ve, NH3

Question 13

Describe a polar R group.

Answer 13

Hydrophilic, 0, OH

Question 14

Describe a hydrophobic R group.

Answer 14

Hydrophobic, 0, long carbon chain.

Question 15

Describe the primary structure.

Answer 15

Amino acids joined by peptide bonds to form polypeptides.

Question 16

Describe secondary structure.

Answer 16

Aplha helix, B sheet, Turns.

Question 17

Describe an alpha helix.

Answer 17

A spiral with the R groups sticking outwards, stabilised by hydrogen bonds.

Question 18

Describe a Beta sheet.

Answer 18

Polypeptide is arranged in rows. Rows are parallel or anti parallel. Stabilised by hydrogen bonds.

Question 19

Describe Turns.

Answer 19

They reverse the direction of the polypeptide chain and the chain folds back on itself.

Question 20

Describe tertiary structure.

Answer 20

The final folded shape of the polypeptide.

Stabilised by hydrophobic interactions, Ionic bond, LDFs, Hydrogen bonds, disulphide bridges.

Question 21

Describe quartanery structure.

Answer 21

Exists in proteins with two or more connected polypeptide subunits.

Question 22

Describe a prosthetic group.

Answer 22

Non protein unit bound to the protein and necessary for its function.

Question 23

What is a ligand?

Answer 23

A substance that can bind to a protein.

Question 24

What is an allosteric enzyme?

Answer 24

An enzyme whose activity is regulated by altering its conformation. It has an allosteric site elsewhere on the enzyme..

Question 25

Describe a modulator?

Answer 25

Modulators regulate the activity of an enzyme when they bind to the allosteric site. The conformation changes after binding altering the affinity of the active site for the substrate.

Question 26

Describe a positive modulator.

Answer 26

Positive modulators bind to allosteric site changing conformation shape increasing affinity and enzyme activity.

Question 27

Describe a negative modulator.

Answer 27

Negative modulators bind to allosteric site changing conformation shape decreasing affinity and enzyme activity.

Question 28

Describe cooperativity.

Answer 28

Allosteric proteins with multiple subunits show cooperativity in binding, in which changes in binding at one subunit alter the affinity of the remaining subunits.

Question 29

Describe the cooperativity in haemoglobin.

Answer 29

Changing in binding of oxygen at one subunit, increases the affinity of the remaining subunits for oxygen.

Question 30

Describe protein kinases.

Answer 30

They catalyse the transfer of a phosphate group from ATP to other proteins. Phosphorylation causes conformation changes.

Question 31

Describe protein phosphatases.

Answer 31

They catalyse the transfer of a phosphate from proteins onto to ADP to create ATP