Central Dogma Tutorial
-
Upload
mohd-hasrul-ramlee -
Category
Documents
-
view
229 -
download
0
Transcript of Central Dogma Tutorial
-
8/12/2019 Central Dogma Tutorial
1/17
Genes structure
Chromosomes become visible during ___________ and meiosis.
Chromosomes come in pairs (_______________); one from ______________ and one from
__________
Chromosomes contain genes; each gene is made of two _______________.
1
-
8/12/2019 Central Dogma Tutorial
2/17
Structure of nucleic acids
Two types: 1. !" # ______________________ $. %!" # ______________________
!ucleotide is the monomer& polynucleotide is the polymer.
'ach monomer consists of : 1. ____________________________ $. ____________________________
. ____________________________
1. hosphate group*ive negative charge to !". hosphates carry negative charges at cellular p+ and give the
nucleotides their acidic character.
$. entose sugar unit
, C sugar
%!" is ribose!" is deo-yribose ( atom at C$ is removed)
. !itrogenous base$ types: 1. urine ("&*) $ rings$. yrimidine (/& T& C) 1 ring
$
%ibose
%ibose
-
8/12/2019 Central Dogma Tutorial
3/17
Base Nucleoside Nucleotide Abbreviation in
RNA / DNA
adenine adenosine adenylic acid "0 d"0guanine guanosine guanylic acid *0 d*0
cytosine cytidine cytidylic acid C0 dC0thymine tymidine thymidylic acid 222222 dT0
uracil uridine uridylic acid /0 222222
"denosine (nucleoside) "denylic acid (nucleotide)
RNA and DNA
-
8/12/2019 Central Dogma Tutorial
4/17
ifferences between %!" and !"
3
-
8/12/2019 Central Dogma Tutorial
5/17
DNA replication
!" twist into double heli- (4atson and Cric5 model& 16,)The polynucleotides are anti2parallel to each other.
Complementary base pairingouble heli-.
7emiconservative replication
The Meselson-Stahl experimentwas an e-periment by 0atthew 0eselsonand 8ran5lin 7tahlto prove
that !" replication was semiconservative.7emiconservative replication means that when the doublestranded !" heli- was replicated& each of the two double stranded !" helices consisted of onestrand coming from the original heli- and one newly synthesi9ed.
,
http://wiki/Matthew_Meselsonhttp://wiki/Franklin_Stahlhttp://wiki/DNA_replicationhttp://wiki/Semiconservative_replicationhttp://wiki/DNAhttp://wiki/Matthew_Meselsonhttp://wiki/Franklin_Stahlhttp://wiki/DNA_replicationhttp://wiki/Semiconservative_replicationhttp://wiki/DNA -
8/12/2019 Central Dogma Tutorial
6/17
%eplication of !" is semiconservative: each daughter heli- contains one strand of the parental heli-.(Conservative replication would be where the entire parental double heli- was used as a template for
the formation of an entirely new daughter double heli-).
7emi2conservative replication:
arental _____________________ separate
'ach ________________________ acts as a template "fter replication& each new !" double heli- has one ________ !" strand and one _________
!" strand.
Gene expression / protein synthesis
The central dogma of biology
1. Transcription $. translation . *ene e-pression
1. Transcription: messenger %!" (m%!") is made on a ________ template in the_______________.
$. Translation: m%!" moves into the ____________________& m%!" combines with ribosomes to
direct protein synthesis.
. *ene e-pression: the information in a cistron (genes on !") is used to ma5e a functionalpolypeptide chain by transcription and translation.
he !enetic code
- /sing triplet codon on m%!".
- Three2base (triplet) code on the m%!" codes for ____________________ of polypeptides.
- 1 amino acid is coded by bases& e.g. /// for phenylalanine.
-
8/12/2019 Central Dogma Tutorial
7/17
- ossible combinations: __________ combinations& more than enough for $ amino acids re
-
8/12/2019 Central Dogma Tutorial
8/17
$. rocessing
- rocessed to ribosomal %!" (r%!") ?@& m%!" ,@& and transfer %!" (t%!") 1,@.
m%!"- 8or eu5aryotic m%!"& it consists of __________ and e-ons.
- Antrons will be removed and ____________ are spliced together.
- 8inal m%!"
- The #$ capis a specially altered nucleotideend to the ,B end ofprecursor messenger %!" as foundin eu5aryotes. The process of ,B capping is vital to creating maturemessenger %!"which is then
able to undergo translation. Capping ensures the messenger %!"Bs stability while it undergoestranslation in the process ofprotein synthesis& and is a highly regulated process which occurs in the
nucleus.
%olyadenylationis the covalent lin5age of a poly(") tail to a messenger %!"(m%!")molecule. At ispart of the route to producing mature messenger %!"for translation& in the larger process ofprotein
synthesisto produceproteins.Aneu5aryotic organisms& most messenger %!" molecules end with a
poly2" stretch at theirB ends.The polyadenosine (poly2") tail protects the m%!" molecule frome-onucleasesand is important for transcription termination& for e-port of the m%!" from the nucleus&
and for translation.
?
http://wiki/Nucleotidehttp://wiki/5'_endhttp://wiki/Precursor_messenger_RNAhttp://wiki/Eukaryoteshttp://wiki/Mature_messenger_RNAhttp://wiki/Messenger_RNAhttp://wiki/Translation_(genetics)http://wiki/Protein_synthesishttp://wiki/Cell_nucleushttp://wiki/Messenger_RNAhttp://wiki/Moleculehttp://wiki/Mature_messenger_RNAhttp://wiki/Translation_(genetics)http://wiki/Protein_synthesishttp://wiki/Protein_synthesishttp://wiki/Proteinhttp://wiki/Eukaryoteshttp://wiki/3'_endhttp://wiki/Exonucleasehttp://wiki/Nucleotidehttp://wiki/5'_endhttp://wiki/Precursor_messenger_RNAhttp://wiki/Eukaryoteshttp://wiki/Mature_messenger_RNAhttp://wiki/Messenger_RNAhttp://wiki/Translation_(genetics)http://wiki/Protein_synthesishttp://wiki/Cell_nucleushttp://wiki/Messenger_RNAhttp://wiki/Moleculehttp://wiki/Mature_messenger_RNAhttp://wiki/Translation_(genetics)http://wiki/Protein_synthesishttp://wiki/Protein_synthesishttp://wiki/Proteinhttp://wiki/Eukaryoteshttp://wiki/3'_endhttp://wiki/Exonuclease -
8/12/2019 Central Dogma Tutorial
9/17
t%!"
- t%!" and r%!" are transcript by special genes (cistrons on !")
- "mino acids are carried by t%!" (anticodon) using information in m%!" (codon)
- $ types of t%!"& e.g. t%!"cys& t%!"his& t%!"ala& etc.
- 7ingle strand& folded& clover leaf arrangement
- ne end attached to amino acid
- "nticodon complementary to codon on m%!"
r%!"
6
-
8/12/2019 Central Dogma Tutorial
10/17
- r%!" maor component of ribosomes
- most abundent ?@
- synthesised in nucleolus: nucleolar organiser.
- '-ported to cytoplasm oin with proteins to form ribosomes
. Transport
r%!"& m%!" and t%!" are transported through __________________ pore to the cytoplasm.
%rotein synthesis
1. $. .
1. t%!" activation
- "n en9yme _________________________ ma5es sure t%!" is carrying the correct amino acid
by its anticodon before it moves to a ribosome.
- Dinding in ,= to = direction
- "T is re
-
8/12/2019 Central Dogma Tutorial
11/17
- "n en9yme peptidyl transferase forms a peptide bond between methionine and the second a.a.
proline.
- The t%!" that was holding methionine is now released from the ribosome& and is free to carryanother methionine molecule.
- %ibosome moves one more triplet codon in ,= to = direction
- 7econd a.a proline occupies 2site and the third t%!" ( ) is entering the "2site
-The process continues until ribosome reaches a Fstop= codon: /""& /*" or /"*.
- The m%!"& ribosome& and t%!" molecules separate& and the polypeptide chain is released.
- Complementary base pairing between anticodons and codons ensure correct se
-
8/12/2019 Central Dogma Tutorial
12/17
1$
-
8/12/2019 Central Dogma Tutorial
13/17
1
-
8/12/2019 Central Dogma Tutorial
14/17
%8 # release factor
. rocessing
- "ccording to the final destination
- Ancludes folding& and adding chains.
- rotein in cell& e.g. haemoglobin& directly from ribosome to cytoplasm.
- 'n9ymes& are made on %'%& transported to *olgi apparatus& modified and pac5aged. Transported
by *olgi vesicles and secreted by e-ocytosis.- 0embranes proteins are made on %'% and remainfused in the membrane.
13
-
8/12/2019 Central Dogma Tutorial
15/17
8(h) olysomes: speeding up translation
- 7ingle ribosome: a single polypeptide chain 1, amino acids per second
- "ccelerated by polysomes
- , to , ribosomes on the same m%!"
- "t end of m%!"& ribosomes detached and returns to the beginning on the samem%!"
-Garge number of the samepolypeptide chains produced
The figure below shows an electron micrograph and its interpretation. DNAand strings of individual
ribosomes attached to a single mRNA (polyribosome) are visible. The mRNA and RNAPolmolecules are barely visible& and the protein polypeptidesare too small to be seen.
7elf test:
1. Dased on figure below& name the process"________________________
D________________________C________________________
1,
-
8/12/2019 Central Dogma Tutorial
16/17
7tructure ____________________
' ____________________0olecule
8 _____________________
$. Dased on the figure below&
a. (i) !ame the amino acid (ii) 7tate the base se
-
8/12/2019 Central Dogma Tutorial
17/17
. istinguish between a nucleoside and a nucleotide.3. Dy what type of chemical reaction does a phosphodiester bond formH
,. Af one strand of !" has the three base se