Learning goal 1 (case3)

Question 1

where translation occures in eukaryotic cell

Answer 1

cytoplasma

Question 2

which organel do the translation

Answer 2

ribosomes

Question 3

codons

Answer 3

sets of thre nucleotides, on the MRna strand, codes for protein amino acids synthesizing

Question 4

how many amino acids are in the human body

Answer 4

20

Question 5

how many codons can code for a specific amino acids

Answer 5

one or more codons can code for one amino acid

Question 6

imagine the General tRNA structure, descripe it, descripe its function briefly

Answer 6

base pairing on the same streng, with loops, a 3’ ACC 5’ end here the amino acid attaches, anticodon 5’ GAA 3’ where MRna binds its start codon 5’-AUG-3’

Question 7

which molecule binds amino acids to tRNA’s

Answer 7

aminoacyl-tRNA synthase

Question 8

how many sorts are out there for this Molecule that bind tRNA’s to Amino acids

Answer 8

20

Question 9

what is the process of binding tRNA to amino acid, and its energy source

Answer 9

Aminoacylation, ATP

Question 10

CCA, and Amino acid

Answer 10

carboxyl group from amino, attached to the 3’-OH or 2’-OH of ribose of the Adenine nucleotide, ester bond (Adenine-O-C=O (carboxyl group))

Question 11

initiation translation pro

Answer 11

tRNA-fMet (formylated methinone) + (if-2) attached to the 30S body + initiation factors (If-3 IF-1) = pre-initiation complex

pre initiation complex binds to the mRNA the ribosome Aligned with mRNA base by recognizing Shine-dalgarno sequence

3’ UAC 5’ tRNA
5’ AUG 3’ mRNA

forming the full ribosomal complex: 50S+30S=70S
now it has A P E sites

P site here peptide chain grows
A (acceptor) tRNA binds
E (end) dittached tRNA

full initiation complex is completed, the initition factors dissociate and the GTP is hydrolzed to GDP

Question 12

initation facors prokaryotes

Answer 12

IF1, IF2, IF3

Question 13

translation elongation prokaryotation and eukaryote

Answer 13

(Aminocyl-tRNA) Alanine binds on A with help of EF-Tu(or IF1)-Ts (pro) (eEF1a1, eEF1a) (euk) complex binding Ts requires GTP> GDP+P

At A site Ala forms and is linked to fMet with a peptide bond (o=c-n-h) with help of Peptidyl transferase, with fMET on p site

eFE2(euk) (EF-G pro) helps with the translocation of ribosomal bodies towards 3 end the peptide chain that was on A is on P site now, this requires a GTP and H2O is formed

E site is emptied of its empty tRNA
the cycle occurs again

Question 14

peptidyl transferase

Answer 14

binds aminoacids formed from translation in euk and pro

Question 15

elongation factors pro

Answer 15

eEF1A, eEF1B, eEF2

Question 16

translation termination prokaryotation

Answer 16

stopation (5’ UAA, UGA, UAG 3’)
releasing factors (3D structure similar to tRNA)

Question 17

releasing factors pro

Answer 17

RF1 UAA UAG
RF2 UAA UGA
RF3 releases the RF1 and RF2 from stop codon

Question 18

releasing factors euk

Answer 18

eRF1 recognises all stop codons
eRF3 stimulate termination events

Question 19

termenation

Answer 19

eleasing factors then cleave the polypeptide chain from the last tRNA via a GTP requiring mechanism (active research area not fully understood yet)

1-stop codon Lys
2-RF-1 binds to stop codon on A site
3- the peptide chain is released
4- RF3-GDP binds causing RF-1 releases
5- GTP replaces the GDP and hydrolisis causing the releases of RF3
6-recycling factor binds to A site (RRF)
7- EF-G-GTP binds ribosome> hydrolysis> EF-G-GDP in A relocation of ribosome is (RRF) in the P and the tRNA in E
8-RRF releases tRNA> EF-G> RRF it self and the ribosomal bodies disbond at the same time
from the MRNA.

RRF only in eukaryotes

Question 20

Transcription Factor

Answer 20

regulate gene expression, which regulates protein synthesis
binds to promotor DNA
Can work alone to regulate or together with a rotein complexes, activators, repressors influences transcription factors

Question 21

Micro-RNA’s (miRNA)

Answer 21

non-coding, post- transcriptional regulation of gene expression

can degrade mRNA, speeding up the breakdown of the poly-A tail (deadenylation)
prevent mRNA from being translated

Question 22

protein secondery, with mos common ones

Answer 22

Secondary structure: the folding pattern of the protein, mostly caused by hydrogen bonds between N-H and C = O groups in the polypeptide backbone.

Two different, most common ones alpha-helix: right handed helix form. The H-bonds are between N-H group and a C = O group of four amino acids away.
beta-sheet: the strands are parallel or antiparallel bonded with H-bonds (this one is a antiparallel one).

Question 23

teritary structure protein

Answer 23

the folding of the protein altogether.(Hydrophobic interactions between non-polar side chains.(Van der Waals interactions.
electronatic attractions.
ion-bonds (salt bridges).
Di-sulphide bridges between cysteines, these are covalent.
Metal-bridges between two side chains with similar charge
H-bridges between polar groups of backbone and side chains
more than one polypeptide chain folded into each other and forming bonds between those chains.

Question 24

determine protein destination

Answer 24

After the proteins got their total structure, they are scanned just outside the endoplasmic reticulum (ER) and then modified inside of the ER. Here a short amino acid sequence is added to show where the protein should go in the body.
The proteins are sorted out in the Golgi apparatus and then sent oû to the correct part of the human body.

Question 25

protein lifetime

Answer 25

After a protein is released from the ribosome, a cell can control its activity and longevity in various ways. Proteins vary enormously in their life-span.!For example:!-Structural proteins (bone and muscle tissue) lasts for months/years.!-Metabolic enzymes/regulation proteins for cell growth and division lasts for days/hours/secondsÉ

Question 26

protein degrade, proteolysis

Answer 26

There are diûerent pathways to ezymatically break proteins down into amino acids, this is called proteolysis. The enzymes who do this are generally known as proteases. They cut the peptide bonds between amino acids (hydrolyzing).!

Functions of proteases:!-Rapidly degrade proteins whose lifetimes must be kept short.!-Recognize and remove proteins that are damaged/misfolded.
Long lasting proteins are eventually being damaged, so they have to be degraded by proteolysis.!

Question 27

poteasomes

Answer 27

The proteolysis in eukaryotes is done by large protein machines called proteasomes, which are present in the nucleus and cytosol.!1. First a small protein called ubiquitin is attached by ubiquitin-ligase with a covalent bond to proteins that have to be degraded.!2. Specialized enzymes recognize these proteins which have a short polyubiquitin chain.!3. This complex goes to the proteasomes, where the protein is unfolded in the stopper.!4. When itÕs unfolded, the chain goes to the central cylinder (made out of proteases). Here the proteases chop the protein into amino acids.

Question 28

How does ubiquitin know where to bond?

Answer 28

Short-lived proteins contain a short amino acid sequence that identifies the protein as on to be ubiquitylated and then degraded

Healthy proteins contain an amino acid sequence or conformational motifs that are buried deep in the 3D structure.!When a protein is damaged or misfolded, this amino acid sequence or conformational motif is no longer buried and then sends out a signal.!Special enzymes recognize this signal and adds a polyubiquitin chain to the protein. The protein is now ready to be degraded