What is an open reading frame? 

what is the start codon? 3' to 5'

once translated what direction does the strand read?

a stretch of DNA with a start and a stop codon going from 3' to 5' 

the start codon is 3'TAC5'

reads 5' to 3' AUG

If AUG is attached to the first block where is the N-terminus located?

If AUG is not attached to the first block where is the N-terminus located?[image]

if attached the N-terminus is located in the Lumen/outside the cell.

if not attached the N-terminus is located in the cytoplasm/inside the cell  

List from largest to smallest 

4,3,1,2,5 

changes in the manose-6-phosphate receptor would cause a failure of any degradative enzymes to reach the cytoplasm.

Change in the mannose-6-phosphate receptor so that it cannot recognize its ligand.

 what would cause a Failure of a single receptor protein, such as the LDL receptor, to be internalized by endocytosis

Deletion of this protein’s C-terminal 4-6 amino acid “hook” motif would cause a Failure of a single receptor protein, such as the LDL receptor, to be internalized by endocytosis

What would cause a Failure of signal peptidase to be inserted into the ER?

Deletion of the LDL receptor would cause a Failure of signal peptidase to be inserted into the ER

 A Change in a single amino acid critical for the addition to this protein of a sugar chain ending in mannose-6-phosphate would cause a Failure of one protease, cathepsin B, to reach the lysosome

what cargo does the Golgi receive in the recycling endosome?

what cargo does the early endosome receive in the recycling endosome 

newly synthesized LDL receptors or newly synthesized membrane proteins are received in the Golgi of the recycling endosome 

the early endomes receives LDL receptors that have been taken up by endocytosis

the Golgi receives newly synthesized lysosomal enzymes 

the early endosome receives LDL taken up by endocytosis 

[image]

1 and 2 

[image]

2

[image] 

C

[image]

1

[image]

A

[image]

3

[image]

B

EXAM 2006 

Under what conditions can a protein be phosphorilated by a cytoplasmic enzyme?

where must it be facing?

1) The cell is converting glucose into the complex carbohydrate, glycogen

2)Adenylyl cyclase activity is balanced by phosphodiesterase activity, maintaining low [cAMP]

3) The 6-adrenergic receptor is in the plasma membrane with no bound epinephrine

4)G-protein is bound to GDP

5)Lower concentrations of glucose in the cytoplasm.

1)G-protein is bound to GTP 

2) Increased phosphorylation of glycogen synthase

3) High probability that cAMP will be bound to the regulatory subunit of protein kinase A

4) Higher concentrations of glucose in the cytoplasm

In what organelle is the LDL receptor sorted in order to reach different destinations?

Arrange the following in order from largest to smallest 5 being the smallest 

1)a microtubule

2) phosphotidyl inositol

3) a tubulin dimer

4 )á-tubulin

5) IP3, a signaling molecule

has an ATP binding site, can hydrolyze ATP and exchange ADP for AT

forms filaments that are major components of muscle cells, and of active protrusions of locomoting cells.

forms relatively rigid filaments that are major components of the mitotic spindle and the ciliary axoneme

has a GTP binding site, can hydrolyze and exchange GTP

tubulin dimers

forms filaments that serve as tracks for directional molecular motors

 forms asymmetric filaments with distinct structural polarity (ends that are different)

asymmetric, globular protein

True of actin monomers and tubulin dimers, but NOT of IF protein

 elongated, mainly alpha-helical protein

forms symmetric filaments with identical ends

protein

can self-assemble into filaments without any accessory proteins needed

actin monomers, tubulin dimers, and IF protein: