Lec 18 Translation & Protein Transport

Question 1

Where does translation take place

Answer 1

in cytosol

Question 2

what is a codon

Answer 2

3 nucleotide sequence in mRNA that is translated into an amino acid

Question 3

What is redundant genetic code

Answer 3

more than one codon encodes most amino acid

Question 4

what is the start codon

Answer 4

AUG

Question 5

what are the three stop codons

Answer 5

UAA
UAG
UGA

Question 6

How many reading frames does mRNA have

Answer 6

has 3 reading frames

Question 7

what are ribosomes made of

Answer 7

proteins and rRNA

Question 8

what do ribosomes consist of (two subunits)

Answer 8

large subunit: 49 proteins + 3 rRNA
small subunit: 33 proteins + 1 rRNA

Question 9

what is anticodon in tRNA

Answer 9

3 nucleotide sequence on tRNA complementary to codon in mRNA

Question 10

what do tRNA carry?

Answer 10

amino acid

Question 11

in tRNA what are amino acids attached to?

Answer 11

amino acids are attached to the OH group of the 3’ end of tRNA which responds to anticodon

Question 12

what is aminoacyl-tRNA synthetase

Answer 12

enzymes attach specific amino acid to corresponding tRNA

Question 13

What are the three translations process

Answer 13

1) initiation
2) elongation
3) termination

Question 14

explain initiation in translation

Answer 14

small subunit of ribosome loaded with met-tRNA and initiation factors which is initiation complex
initiation complex binds to the 5’ cap of mRNA
initiation complex searching for the first AUG codon
large subunit binds

Question 15

explain elongation in translation

Answer 15

new aminoacyl-tRNA binds to A site
peptide bond forms by peptidyl transferase enzyme
large subunit translocate
small subunit translocate
empty tRNA leaves the ribosome

Question 16

explain termination in translation

Answer 16

the A site meet a stop codon
release factor binds to A site
dissociation of the translation machinery

Question 17

Antibiotics that inhibit protein synthesis
explain how tetracycline works

Answer 17

blocks binding of aminoacyl-tRNA to A site

Question 18

Antibiotics that inhibit protein synthesis
explain how cycloheximide works

Answer 18

blocks translocation of ribosome

Question 19

what is protein transport

Answer 19

the synthesis of virtually all proteins in the cell begins on ribosomes in the cytosol

Question 20

what is signal sequence in protein transport

Answer 20

the fate of any protein synthesized in the cytosol depends on the signal sequence within its amino acid sequence

Question 21

Transport by Vesicles
explain exocytosis

Answer 21

ER-> Golgi-> transport vesicle-> cell surface

Question 22

Transport by vesicles
explain lysosome pathway

Answer 22

ER-> Golgi->endosome-> lysosome

Question 23

transport by vesicles
explain endocytosis

Answer 23

cell surface-> endosome-> lysosome

Question 24

Which transport by vesicles use COP-coated and clathrin-coated vesicles

Answer 24

Exocytosis and Lysosome pathway

Question 25

which transport by vesicles uses clathrin-coated vesicles

Answer 25

endocytosis

Question 26

explain translation couple with ER transport

Answer 26

translation happens on RER Protein transported into ER ER signal sequence- 8 or more hydrophobic amino acids Aid by two components (signal recognition particle (SRP) in cytosol) and then (SRP receptor embedded in ER membrane)

Question 27

What are clathrin coated vesicles

Answer 27

Cargo molecules bind to cargo receptor at the transport signals adaptins select cargo molecules for transport by trapping the cargo receptors clathrin-coated pit dynamins assemble as a ring around the neck of each coated pit dynamin ring constricts and pinches off the vesicle vesicles shed the coat

Question 28

what is phagocytosis

Answer 28

phagosome to engulf an entire cell

Question 29

what is Autophagy

Answer 29

from autophagosome to engulf organelles

Question 30

what is 5' cap and 3' poly adenylation for mature mRNA

Answer 30

Question 31

explain how mature mRNA turns into reading frame and amino acid sequence

Answer 31

Then codons of the mature mRNA will turn into the right amino acid

Question 32

what are the amino acid ends

Answer 32

H3N+-----COO-

Question 33

what do eukaryotic ribosome look like

Answer 33

Question 34

what do eukaryotic tRNA look like and what is important on it

Answer 34

Question 35

explain Aminoacyl-tRNA Synthetases

Answer 35

Dont memorize Lewis structure of amino acid

Question 36

What is step 1 of translation initiation

Answer 36

Question 37

explain step 2 of translation initiation

Answer 37

Question 38

explain step 3 of translation initiation

Answer 38

Question 39

explain step 4 of translation initiation

Answer 39

Question 40

explain step 1 of translation elongation

Answer 40

Question 41

explain step 2 of translation elongation

Answer 41

Question 42

explain step 3 of translation elongation

Answer 42

Question 43

explain step 4 and 5 of translation elongation

Answer 43

Question 44

explain step 1 of translation termination

Answer 44

Question 45

explain step 2 of translation termination

Answer 45

Question 46

explain step 3 of translation termination

Answer 46

Question 47

explain protein transport and the types

Answer 47

Question 48

explain translation couple with ER transport

Answer 48

Question 49

explain the three types of transport of vesicles

Answer 49

Question 50

explain clathrin coated vesicles

Answer 50

Question 51

explain phagocytosis and autophagy and endocytosis

Answer 51