MCBG 11 Flashcards
Protein sorting. Which organelles use the ER to get their proteins?
Lysosomes
ER
Which organelles get their proteins from free cytosolic ribosomes?
Nucleus
Mitochondria
Peroxisomes
What is required for protein sorting?
Signal
Receptor
Translocational machinery
Energy
How do protein get to the ER?
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
How is PDI (an ER resident protein) retained
in the ER and not secreted?
The golgi body has retrograde secretions back to the ER
What is the signal used to get golgi vesicles back to the ER (WHERE IS IS FOUND SPECIFICALLY)
KDEL on the C-terminus
What does the signal for retrograde transportation back to the ER bind to?
KDEL receptor which forms a vesicle with a COPI coat
Whats the signal in lysosome import?
Mannose-6-phosphate
Lysosome import. What happens for to the signal so it know where its going?
In Golgi M6P binds to
Whats the mitochondrial signal called? WHERE IS IS FOUND SPECIFICALLY
MTS Mitochondrial targeting signal
N-terminus
Whats MTS?
Mitochondrial targeting signal
What are the additional proteins needed in MITO import?
Chaperone proteins
MITO. Energy?
Yes. Transporters
Nuclear transport. What is the signal?
NLS. Nuclear localising signal
What are the additional proteins needed in Nuclear import?
Importin
Describe how the nuclear protein in imported?
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
What are the two ways of Short term regulation of enzyme activity
- Substrate and product concentration
- Change in enzyme conformation
(A)llosteric. Allosteric regulation
(B)onds. Covalent modification
(C)leavage. Proteolytic cleavage
What are the two ways of LONG TERM REGULATION of enzyme activity
- Change in rate of protein synthesis
2. Change in rate of protein degradation
What is Phosphofructokinase?
allosterically regulated and sets the pace of glycolysis.
What activates Phosphofructokinase? What regulation is this?
AMP, fructose-2,6-
bisphosphate
Allosteric
What deactivates Phosphofructokinase?
What regulation is this?
ATP, citrate, H+
Allosteric
What is haemophilia?
mostly inherited genetic disorder that impairs the body’s ability to make blood clots. X-linked recessive disorders
What are the two types of haemophilia?
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.
Why is protein phosphorylation so effective? 3/5
- 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
define the term zymogen
inactive substance which is converted into an enzyme when activated by another enzyme
Coagulation cascade. Whats the intrinsic pathway?
XII XI IX +VIII X + V II THROMBIN I FIBRIN
Coagulation cascade. Whats the extrinsic pathway?
III (Tissue factor) VII X II I
How does the Coagulation cascade get activated?
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)
Whats a thrombosis
The formation of a solid mass of blood within the circulatory system of a living body
What factors get activated by thrombin?
All odd numbers (kinda)
(2) 5 7 (X9X)8 11 13
What does XIII do?
Connects the fibrin strands with cross strands
What inactivates the coagulation cascade? 2
Thrombin forms plasmin (breaks down crosslinks) Stimulates antithrombrin ( inhibits thrombin and Factor X
