Unit 3 - Translation (Nucleic Acid to Polypeptide)

Question 1

Translation from RNA to proteins

Answer 1

is the assembly of aa into a polypeptide using info encode in the mRNA

Question 2

initation simple

Answer 2

a ribosome binds to mRNA

Question 3

elongation simple

Answer 3

tRNA delivers right aa to the ribosome for + to the growing pp chain

Question 4

Termination simple

Answer 4

transcription ceases, and the polypeptide is released

Question 5

transfer RNA to tRNA

Answer 5

small RNAs - abt 70 to 90 nucleotides long making a cloverleaf pattern

Question 6

function of transfer RNA - tRNA

Answer 6

delivers correct aa to ribosomes (recognition between codon and anticodon is complementarity)

Question 7

if anticodon is 3’-UCA-5’ what is the complimentary codon

Answer 7

5’-AGU-3’

Question 8

Transfer RNA

Answer 8

-amminoacyl-RNA
-enzymes adds AAs to each tRNA
-attached via ESTER BONS
-amino acid to a tRNA is called aminoacylation

Question 9

Ribosomes

Answer 9

• free-floating in cytoplasm or temporary associated w the rough ER
• Eukaryotes recognize the 5’cap of mRNA transcript

Question 10

Eukaryotic ribosome

Answer 10

-made pf two diff sized parts called LARGE (50s) and SMALL (30s) ribosomal subunits

Question 11

subunits made up of

Answer 11

a combination of ribosomal RNA (rRNA) and ribosomal proteins

Question 12

initiation step 1 in debth

Answer 12

AUG start
- assembly of initiation complex
- Met-tRNA forms a complex w the small ribosomal subunit

Question 13

Initiation step 2 in debth

Answer 13

• complex binds mRNA at 5’ cap
• moves along the mRNA (process = scanning) until it finds the first AUG codon

Question 14

Elongation

Answer 14

ribosome moves along the mRNA in the 5’ to 3’ direction
- condons read = amico acids

Question 15

elongation = three sites for tRNA

Answer 15

a (aminoacyl)
p (pepdityl)
e (exit)

Question 16

aminoacyl site

Answer 16

where incoming aminoacyl-tRNA anticodon binds to mRNA codon

Question 17

pepdityl site

Answer 17

tRNA with growing chain is bound

Question 18

exit site

Answer 18

exiting tRNA leaves the ribosome

Question 19

Elongation step 1 in depth

Answer 19

an aminoacyl-tRNA binds the A site

Question 20

Elongation step 2 in depth

Answer 20

peptidyl transferase cleaves the aa from the P site tRNA and bonds it to the aa on the A site tRNA

Question 21

Elongation step 3 in depth

Answer 21

the ribosome moves codon
- tRNA with the growing polypeptide is now in P site
- empyt tRNA is now E site

Question 22

Elongation step 4 in depth

Answer 22

Empty tRNA in E site is now released and the cycle repeats

Question 23

Reading Frame

Answer 23

positioning of ribosome on the mRNA is important and is where mRNA is read and depending on bp from which the ribosome starts translating

Question 24

Termination

Answer 24

tRNA that exit from the P site are recycled by adding more AAs to them
- chain grows until a stop Condon arrives in A site

Question 25

release factor

Answer 25

protein binds in A site
+ protein dismantles the ribosome mRNA complex and the polypeptide chain is released along w the tRNA