Secretion of Proteins

Question 1

What do protein coding genes in higher eukaryotes contain?

Answer 1

Introns

Question 2

What do the the Introns that are transcribed form?

Answer 2

pre-mRNA

Question 3

What is RNP?

Answer 3

Ribonucleoprotein

Question 4

What are RNP complexes?

Answer 4

Spliceosomes

Question 5

What do Spliceosomes do?

Answer 5

Remove the introns and ligate the exons together

Question 6

What does the Spliceosomes form?

Answer 6

Mature mRNA

Question 7

What happens with Splicing in PTM of mRNA?

Answer 7

Become mRNP

Question 8

What addition is added at the 5’end to mRNP?

Answer 8

7-MeG

Question 9

Where is the PolyA tail end? and what does it include?

Answer 9

3’ end and 100/300 adenosine ribonucleotides

Question 10

What can selected mRNA also have, by editing?

Answer 10

Additional bases

Question 11

What part of the mRNA sequence does the ribosome read?

Answer 11

The codons

Question 12

How many codons in mRNA?

Answer 12

64 possible, 4 nucleotide bases

Question 13

if mRNA have more than 1 codon what is this reffered to as?

Answer 13

Redundancy

Question 14

What is the ORF?

Answer 14

Open reading frame - region between start and stop codons

Question 15

What are the 2 types of secretion?

Answer 15

Constitutive and Regulated

Question 16

What is constitutive secretion?

Answer 16

includes all cells and continual export substances e.g. ecm proteins

Question 17

What is regulated secretion?

Answer 17

Specialised secretary cells e.g. pancreatic acinar cells

Question 18

In regulated secretion where are substances stored for release to a response signal?

Answer 18

Secretory vesicles

Question 19

What are the 2 pathways of localisation of proteins to organelles?

Answer 19

Direct pathway

secretory pathway

Question 20

What is the direct pathway?

Answer 20

Proteins are moved from cytosol to mitochondria, nuclei and peroxisomes

Question 21

What is the secretory pathway?

Answer 21

Proteins are moved from ER

Question 22

What happens to proteins when moved to ER?

Answer 22

Moved to golgi then final destination

Question 23

What happens in the ER?

Answer 23

Proteins are folded into correct 3D structures and assembled with other proteins into complexes

Question 24

In the secretory pathway where does new mRNA go to?

Answer 24

Cytoplasm

Question 25

what does mRNA on ribosomes translate to?

Answer 25

String of AA directed to lumen of ER for PTM

Question 26

Where to transport vesicles take proteins to?

Answer 26

Golgi Apparatus

Question 27

What happens to proteins that leave the cell?

Answer 27

Packaged in secretory vesicles

Question 28

What happens to proteins that remain in the cell?

Answer 28

Packed in lysosomes or storage vesicles

Question 29

What is the Exocrine component of Pancreatic cells?

Answer 29

Secretory acini and associated ducts

Question 30

What is the endocrine component of pancreatic cells and where are they located?

Answer 30

Islets of langerhans in tail of pancreas

Question 31

What do Islet of Langerhan cells secrete?

Answer 31

B-cell secrete insulin A cells secrete glucagon D cells secrete somatostatin

Question 32

Is there secretion in pancreatic acinar cells?

Answer 32

Unusual - mainly digestive enzymes synthesised

Question 33

What digestive enzymes secreted by pancreatic acinar cells?

Answer 33

Trypisinogen and chymotrypsinogen

Question 34

What are digestive enzymes secreted for?

Answer 34

Produced as inactive precursors e.g. trypsinogen to trypsin

Question 35

What are pancreatic inactive digestive enzymes referred to as?

Answer 35

Zymogen

Question 36

What do pancreatic acinar cells contain?

Answer 36

Large amounts of RER, Secretory granules and ordered cytoplasmic structures

Question 37

What is the 6 step process of secretion?

Answer 37

``` Initiation of protein synthesis sysnthesis segregate from cytosolic proteins process proteins package and condense store in vesicles release exocytosis ```

Question 38

What happens during initiation of protein synthesis?

Answer 38

Secretory proteins synthesised by ribosomes attached to E.R

Question 39

What happens in synthesis segregated from cytosolic proteins?

Answer 39

mRNA determines whether protein synthesis in RER or cytosol

Question 40

What do proteins code?

Answer 40

Secretion plasma membrane lysosomes

Question 41

What does recognition system contain?

Answer 41

A signal sequence in their mRNA

Question 42

what does signal recognition protein in cytoplasm bind to?

Answer 42

Ribosome when signal sequence made

Question 43

Why does protein synthesis stop?

Answer 43

So ribosome can attach to RER

Question 44

Where do secreted proteins cross into?

Answer 44

ER membrane into lumen

Question 45

What is removed in the lumen?

Answer 45

Signal peptide

Question 46

What are secretory process in P acinar cell localised by?

Answer 46

Radiolabelled AA

Question 47

What is the ER?

Answer 47

Highly convoluted single membrane with a lumen inside that is entry regulated

Question 48

What does the ER play a central role in biosynthesis of?

Answer 48

Transmembrane proteins e.g PM Lipids e.g. mitochondria Lumen proteins e.g lysosomes Secreted proteins e.g. ecm

Question 49

What does protein processing involve?

Answer 49

Extensively process in ER and Golgi

Question 50

What does the addition of oligosaccharide molecules create?

Answer 50

Glycosylation forms glycoproteins

Question 51

what common protein is in the ER lumen?

Answer 51

Glycoproteins

Question 52

What type of proteins are not clygosylated?

Answer 52

Cytosolic

Question 53

What does the golgi consist of?

Answer 53

Series of flattened, membrane bound cisternae called golgi stacks

Question 54

Where is the golgi situated?

Answer 54

Near nucleus

Question 55

What does the GA show for a cell?

Answer 55

Polarity

Question 56

Where is the cis face of GA?

Answer 56

near er where transport vesicles bring the proteins

Question 57

What does the trans face face?

Answer 57

Cell membrane

Question 58

at GA where do transport vesicles from ER fuse to?

Answer 58

Protein to membranes of ga and contents to lumen of ga

Question 59

What process does ga complete?

Answer 59

Glycosylation

Question 60

What happens to secretory zymogen vesicles?

Answer 60

Budded from GA, stored in cytoplasm when needed then released by exocytosis

Question 61

What is exocytosis?

Answer 61

Fusion of membrane bound vesicles with PM releasing contents outside cell

Question 62

What is exocytosis triggered by?

Answer 62

External signals such as hormones and neurotransmitters