Forwarded from SoMA
ملاحظات د. عبد الله بشين - المحاضرة الثانية * Regulation of Gene Ex. *
- Genes responsible for the synthesis of histones will be upregulated in the S phase.
- Microenvironment: the envir. that cells live in.
- 3 Types of Temporal Responses: *Gene Expression*
1- Type-A as long as the signal is present genes will be expressed.
2- Type-B signal causes expression, but expression will eventually stop even if the signal persists.
3-Type-C expression continues even if the signal is terminated.
- Most important site of regulation: Transcription.
- A cistron is a nucleotide seq. that produces 1 polypeptide chain.
- cAMP-CAP (Active) complex increases rate of transcription 1000 times. *in the presence of allolactose*
- Operons are a group of genes that are coordinately expressed and regulated.
- Lactose is an Indirect inducer.
Allolactose is a direct inducer of the Lac Operon.
- IPTG is used in genetic cloning. It replaces lactose in inducing the Lac Operon.
- A mutation in the CAP-site that prevents the binding of the cAMP-CAP results in basal rates of gene expression *
- Genes responsible for the synthesis of histones will be upregulated in the S phase.
- Microenvironment: the envir. that cells live in.
- 3 Types of Temporal Responses: *Gene Expression*
1- Type-A as long as the signal is present genes will be expressed.
2- Type-B signal causes expression, but expression will eventually stop even if the signal persists.
3-Type-C expression continues even if the signal is terminated.
- Most important site of regulation: Transcription.
- A cistron is a nucleotide seq. that produces 1 polypeptide chain.
- cAMP-CAP (Active) complex increases rate of transcription 1000 times. *in the presence of allolactose*
- Operons are a group of genes that are coordinately expressed and regulated.
- Lactose is an Indirect inducer.
Allolactose is a direct inducer of the Lac Operon.
- IPTG is used in genetic cloning. It replaces lactose in inducing the Lac Operon.
- A mutation in the CAP-site that prevents the binding of the cAMP-CAP results in basal rates of gene expression *
Forwarded from SoMA
lecture4
DNA repair:
-if there's mispair (one or more than one nucleotide(either base ,or the whole nucleotide), and this happened each day in one cell about a million mismatch escape the proofreading property of DNA polymerase.
_agents which cause mutations or alteration could be
endogenous(mainly by replication system mispair)
exogenous(by radiation,chemicals,UV light,free radicals....etc)
_ newly synthesized strands aren't methylated,so this is use to identify ,and diffrentiate b\w them and parental strand(v.imp).
-excinuclease v.imp identify and excise the dimers by UV specific endonuclease.
-xeroderma pigmentosum v.imp
_correction of base alteration :
cytosine is deaminated to uracil by nitrous oxide,there will removal of base(uracil)by uracil N glycosylase(can recognize ) and Apyrimidinic site is formed,then apyrimidinic endonuclease will cut the strand ,so the lyase will cut in order for DNA poly can work and ligase will seal both parts of the strand.
_repair of ds. breaks :
those breaks caused by radiation and free radicals or gene rearragements.
-house keeping genes breaks is lethal
-high eupkaryotes(plants and animals)
-lower euokaryotes(monocellualar ,fungi ,viruces,algae)
-there's no repair in transcription
RNA is single strand of ribonucleac acid
functions of different RNA are imp
DNA mutation is replicated b\c genetic material of DNA is preserved as it is.
and,this will result may may be in producing supraactive enzyme or non functioning one.
in 5 prime of mRNA there's a cap(protect from exonucleases)and it's consists of methyl guanosine triposhpate,and recognition
in 3 prime ther's poly A tail also protect from exonuclease actitvity.
rRNA is part of ribosomes(rRNA+proteins)
tRNA transfer of A.As and contain anticodon that recognize the seqense of nucleotide in order to put the right A.As on
DNA repair:
-if there's mispair (one or more than one nucleotide(either base ,or the whole nucleotide), and this happened each day in one cell about a million mismatch escape the proofreading property of DNA polymerase.
_agents which cause mutations or alteration could be
endogenous(mainly by replication system mispair)
exogenous(by radiation,chemicals,UV light,free radicals....etc)
_ newly synthesized strands aren't methylated,so this is use to identify ,and diffrentiate b\w them and parental strand(v.imp).
-excinuclease v.imp identify and excise the dimers by UV specific endonuclease.
-xeroderma pigmentosum v.imp
_correction of base alteration :
cytosine is deaminated to uracil by nitrous oxide,there will removal of base(uracil)by uracil N glycosylase(can recognize ) and Apyrimidinic site is formed,then apyrimidinic endonuclease will cut the strand ,so the lyase will cut in order for DNA poly can work and ligase will seal both parts of the strand.
_repair of ds. breaks :
those breaks caused by radiation and free radicals or gene rearragements.
-house keeping genes breaks is lethal
-high eupkaryotes(plants and animals)
-lower euokaryotes(monocellualar ,fungi ,viruces,algae)
-there's no repair in transcription
RNA is single strand of ribonucleac acid
functions of different RNA are imp
DNA mutation is replicated b\c genetic material of DNA is preserved as it is.
and,this will result may may be in producing supraactive enzyme or non functioning one.
in 5 prime of mRNA there's a cap(protect from exonucleases)and it's consists of methyl guanosine triposhpate,and recognition
in 3 prime ther's poly A tail also protect from exonuclease actitvity.
rRNA is part of ribosomes(rRNA+proteins)
tRNA transfer of A.As and contain anticodon that recognize the seqense of nucleotide in order to put the right A.As on
Forwarded from SoMA
lecture 5
mRNA production occur in nucleus,but it's function in ribosomes and it's giuded by special eupkaryotic str. that exist in the 5 prime end a chemical str. called cap and it exist for two purposes:
(protection\recognetion).
Genome : all DNA that is present in organism
the number of nucleotides(bp): it's not proportional to number of genes ,it doesn't mean that the more chr. the more the number of genes .
there's no different in gens b\w human (healthy individuals)
-gene expression=transcription+translation(in case of protein only)
because for example tRNA ,rRNA,and snRNA are only transcribed.
-RNA polymerase synthesize the RNA strand in direction of 5prime to 3 prime
-promotor is never transcribed(receive receptor hormone complex ,and regulate the process)
-the genes and promoters are the same in each cell for the same gene ,but what make the promoter start a transcription of same genes differntly is the transcription factors and acticvators
-holoenzyme:is very imp. recognize promoter region.
-difference b\w replication &transcription is very imp.
mRNA production occur in nucleus,but it's function in ribosomes and it's giuded by special eupkaryotic str. that exist in the 5 prime end a chemical str. called cap and it exist for two purposes:
(protection\recognetion).
Genome : all DNA that is present in organism
the number of nucleotides(bp): it's not proportional to number of genes ,it doesn't mean that the more chr. the more the number of genes .
there's no different in gens b\w human (healthy individuals)
-gene expression=transcription+translation(in case of protein only)
because for example tRNA ,rRNA,and snRNA are only transcribed.
-RNA polymerase synthesize the RNA strand in direction of 5prime to 3 prime
-promotor is never transcribed(receive receptor hormone complex ,and regulate the process)
-the genes and promoters are the same in each cell for the same gene ,but what make the promoter start a transcription of same genes differntly is the transcription factors and acticvators
-holoenzyme:is very imp. recognize promoter region.
-difference b\w replication &transcription is very imp.
Forwarded from SoMA
BC_243Dr_Ahmed_zaid_lecture_notes.pdf
1.6 MB
Forwarded from قروب البشري للتسجيلات
تفريغ أول ثلاث محاضرات د.أحمد زايد Gene Expression.
Forwarded from قروب البشري للتسجيلات
تفريغ محاضرات Regulation of gene expression in eukaryotes.
Forwarded from SoMA
BC243 Recombinant_20190127210831.pdf
3.5 MB
Forwarded from قروب البشري للتسجيلات
تفريغ محاضرات Recombinant د.بشين