Translation and protein turnover

Cell Bio

( ) is the “output” of genetic code 

gene expression

the “flow of genetic information” in biology/life is called the?

The central dogma of molecular and cellular biology

RNA synthesis aka

transcription

protein synthesis aka

translation 

( ) and ( ) are processes driven by direct base pairing

RNA synthesis (transcription)

protein synthesis (translation))

The ( ) is a triplet code of nucleotides= ( )

“genetic code”

codon

( ) these are specifically recognized by tRNAs

codons

What are the three stop codon?

UAA

UAG

UGA

multiple codons code for most ( )

amino acids

look

kk

an mRNA sequence could be “read” by the translation machinery in ( ), actual ( ) reading frame for a given polypeptide is set by the start codon ( ) , but one correct reading frame is “set” by ( )

three different reading frames 

ONE

ATG

start codon

Th process of translation of the genetic code- a “sub-outline”

1) ( )

2) ( )

3) ( )

4) ( )

1) charging the tRNA- done by tRNA synthetases- one for each codon for each a.a.- and codon-anticodon pairing 

2) initiation 

3) elongation

a.transfer of growing polypeptide to next amino acid on the tRNA in position A

b.reset-move the tRNA with the growing polypeptide to the P position

c.Bring in nect charged tRNA

d.repeat 4a.-4c. over and over…

4)… until ribosome reaches a stop codon- then translation stops= termination

Cells “( )“ RNA information into proteins (nucleotides translated into amino acids)

translate

( ) molecules bring the amino acids to the site of protein synthesis (translation) on mRNA/ribosome complexes

Transfer RNA (tRNA)

amino acids attach to the ( ) end of tRNA

3’

Transfer RNAs (tRNAs) match ( ) to mRNA ( ), anticodons of tRNAs ( ) with ( ) of the mRNA and bring in correct amino acid

amino acids

codons

base pair

codons 

Aminoacyl-tRNA “charging” is done by ( )

tRNA synthetase

Specific binding between tRNA synthetase and anticodon of tRNA ensures that ( ) is attached to ( ) , so just as critical as codon to ( )

correct amino acid

correct tRNA

anticodon pairing

tRNAs are “charged” with ( )- done by tRNA synthetases, one for each ( ) for each ( ) 

amino acids

codon 

amino acid

tRNA “charging” requires ( )- amino acids first linked to ( ) initially, so charged molecule

energy input

AMP

tRNAs get amino acids ( ) attached (aka “charged”)- by ( ) called tRNA synthetases

covalently attached

enzymes

tRNA synthetase recognizes this ( ) in the tRNA

specific anticodon 

look at slide 19

ikay

Incorrect charging is corrected by ( )

tRNA synthetase proofreading

UGG codon in mRNA codes for

Trp

The ribosome has ( ) tRNA binding sites- called ( )

three

E P A

look at slide 27 now

okay

initiation is regulated by the ( ) 

G-protein elF2

elongation is driven by ( ) that are also ( ), namely ( ) and ( )

GTPases

elongation factors (EF)

EF-Tu

and EF-G

GTPases ( ) the elongation phase of translation and they provide some ( )- only if proper codon-anticodon base pairing is GTP hydrolyzed

regulate

fidelity/proofreading

Termination:

1)binding of ( ) to an ( ) site bearing a ( )

2) ( )

3) ( )

4) ( )

release factor (that does NOT have an amino acid attached)

A

stop codon 

GTP hydrolysis by GTPase

ribosome conformation change 

dissociation

To initiate translation, it really important to recognize two concepts what are they?

1) that translation NEVER starts at the very end of the mRNA but at the internal start codon

2) the orientation of the START CODON: 5’-AUG-3’

the ribosome:

-very complex ( )

-site of:

( )

ribozyme (enzyme that uses RNA for catalysis)

1)tRNA anticodon- codon pairing

2) catalyzes the transfer (covalent bonding) of growing polypeptide to the next amino acid (so peptide bond formation)

Ribosomes are ( )- have RNA ( ) in them, catalyze peptide bond formation using rRNA (so are ( ))

ribonucleoproteins (RNPs)

rRNA

ribozymes

ribosomes are made of ( ) 

large subunit, small subunit and rRNA

Ribosomes are the same among prokaryotes and eukaryotes

false l

look at slide 39

okay

The ribosome is a ribozyme- bound rRNA participates in ( )

enzyme activity 

( ) are the target of several antibiotics, because they are necessary and differ from the eukaryotic host’s ribosomes

bacterial ribosomes

Ribosomes may be ( ) or ( ) to the rough ER

free

bound

look at slide 43

okay 

Ribosomes may be ( ) to rough ER or free

membrane-bound

Potential steps in post-translation modifications to create a functional protein,:

nascent (newly formed) polypeptides can begin ( ) as they emerge from a ribosome, assisted by 

folding

chaperone proteins 

look at slide 48

mkat