MCBG 11

Question 1

Protein sorting. Which organelles use the ER to get their proteins?

Answer 1

Lysosomes

ER

Question 2

Which organelles get their proteins from free cytosolic ribosomes?

Answer 2

Nucleus
Mitochondria
Peroxisomes

Question 3

What is required for protein sorting?

Answer 3

Signal
Receptor
Translocational machinery
Energy

Question 4

How do protein get to the ER?

Answer 4

mRNA (specific translocational sequence) and a ribosome in the cytoplasm get bound by a SRP (signal recognition particle) where it is transported to the ER

Question 5

How is PDI (an ER resident protein) retained

in the ER and not secreted?

Answer 5

The golgi body has retrograde secretions back to the ER

Question 6

What is the signal used to get golgi vesicles back to the ER (WHERE IS IS FOUND SPECIFICALLY)

Answer 6

KDEL on the C-terminus

Question 7

What does the signal for retrograde transportation back to the ER bind to?

Answer 7

KDEL receptor which forms a vesicle with a COPI coat

Question 8

Whats the signal in lysosome import?

Answer 8

Mannose-6-phosphate

Question 9

Lysosome import. What happens for to the signal so it know where its going?

Answer 9

In Golgi M6P binds to

Question 10

Whats the mitochondrial signal called? WHERE IS IS FOUND SPECIFICALLY

Answer 10

MTS Mitochondrial targeting signal

N-terminus

Question 11

Whats MTS?

Answer 11

Mitochondrial targeting signal

Question 12

What are the additional proteins needed in MITO import?

Answer 12

Chaperone proteins

Question 13

MITO. Energy?

Answer 13

Yes. Transporters

Question 14

Nuclear transport. What is the signal?

Answer 14

NLS. Nuclear localising signal

Question 15

What are the additional proteins needed in Nuclear import?

Answer 15

Importin

Question 16

Describe how the nuclear protein in imported?

Answer 16

PP chain binds to importin (alpha and beta) this transports it into the cell via a nuclear pore. RanGTP binds to Importin, displaces the protein and is transported out of the cell. GTP->GDP causes ran to be recycled back to the nucleas

Question 17

What are the two ways of Short term regulation of enzyme activity

Answer 17

1. Substrate and product concentration
2. Change in enzyme conformation
   (A)llosteric. Allosteric regulation
   (B)onds. Covalent modification
   (C)leavage. Proteolytic cleavage

Question 18

What are the two ways of LONG TERM REGULATION of enzyme activity

Answer 18

1. Change in rate of protein synthesis

2. Change in rate of protein degradation

Question 19

What is Phosphofructokinase?

Answer 19

allosterically regulated and sets the pace of glycolysis.

Question 20

What activates Phosphofructokinase? What regulation is this?

Answer 20

AMP, fructose-2,6-
bisphosphate
Allosteric

Question 21

What deactivates Phosphofructokinase?

What regulation is this?

Answer 21

ATP, citrate, H+

Allosteric

Question 22

What is haemophilia?

Answer 22

mostly inherited genetic disorder that impairs the body’s ability to make blood clots. X-linked recessive disorders

Question 23

What are the two types of haemophilia?

Answer 23

There are two main types of haemophilia: haemophilia A, which occurs due to not enough clotting factor VIII, and haemophilia B, which occurs due to not enough clotting factor IX.

Question 24

Why is protein phosphorylation so effective? 3/5

Answer 24

• Adds 2 negative charges
• A phosphoryl group can make H-bonds
• Allow for amplification effects
• Rate of phosphorylation/dephosphorylation can be adjusted
• Links energy status of the cell to metabolism through ATP

Question 25

define the term zymogen

Answer 25

inactive substance which is converted into an enzyme when activated by another enzyme

Question 26

Coagulation cascade. Whats the intrinsic pathway?

Answer 26

``` XII XI IX +VIII X + V II THROMBIN I FIBRIN ```

Question 27

Coagulation cascade. Whats the extrinsic pathway?

Answer 27

``` III (Tissue factor) VII X II I ```

Question 28

How does the Coagulation cascade get activated?

Answer 28

By the extrinsic pathway (SPARK) At a epithelial break, platelets and Tissue factors form at the blood clot. This activates the extrinisic cascade forming thrombin which activates the intrinsic pathway (WORK HORSE)

Question 29

Whats a thrombosis

Answer 29

The formation of a solid mass of blood within the circulatory system of a living body

Question 30

What factors get activated by thrombin?

Answer 30

All odd numbers (kinda) | (2) 5 7 (X9X)8 11 13

Question 31

What does XIII do?

Answer 31

Connects the fibrin strands with cross strands

Question 32

What inactivates the coagulation cascade? 2

Answer 32

``` Thrombin forms plasmin (breaks down crosslinks) Stimulates antithrombrin ( inhibits thrombin and Factor X ```