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BC_243Dr_Ahmed_zaid_lecture_notes.pdf
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ملاحظات د. عبد الله بشين في المحاضرة الأولى * Regulation of Gene Ex. *
- Each cell expresses particular genes; therefore, each cell has its own morphological and functional characteristics.
- Insulin gene: found in all cells but only expressed in Beta cells of pancreas.
- Constitutive genes are expressed in all types of cells.
e.g. enzymes for glycolysis
- DNA is not converted to RNA, it is only photocopied. *used as a template to synthesize RNA*
- Proteins, RNA, carbs can't act as a template.
Except in reverse transcriptase of retroviruses which uses an RNA as a template to transcribe a DNA segment in a process called reverse transcription.
Telomerases can use RNAs to synthesize nucleotide sequences in the DNA as well.
- Types of DNA:
cDNA "Complementary DNA"
Genomic DNA (found in nucleus)
Mitochondrial DNA
- Unicellular organisms are affected faster by the external environment than multicellular organisms.
- At temperatures: 25-37 degrees Celsius, yeast will produce heat-shock proteins to adapt to the new environment.
- Operons are found in prokaryotes.
Polycistronic mRNA is found in prokaryotes.
- Monocistronic mRNA found in both.
- LacI is a constitutive gene which is continuously expressed at low* rates. (Has a weak promoter: sequence for attachment of factors is far from the consensus seq.)
- The area between the start and stop codons in the mRNA *the translated area* is known as: Open-reading frame.
- Prokaryotes don't have a nucleus, so both transcription and translation happen in the cytosol. Translation can start before transcription ends.
- In eukaryotes transcription and translation are separated both in time and location. So gene expression is a lot slower in eukaryotes.
- Post-transcriptional modification *adding CAP and Poly-A tail* happens only in eykaryotes and is another reason why Gene Ex. is slower in eukaryotes.
- Haematopoietic stem cells divide rapidly, so they express genes responsible for the cell cycle at very high rates. "Proto-oncogenes"
- Proto-oncogenes: genes expressed in haem. cells to speed up cellular proliferation.
- The mature** cell will not express these genes.
- Tumor suppressor genes: stop cellular proliferation.
- Leukemia: cells don't achieve maturity *they replicate non-stop*.
- Each cell expresses particular genes; therefore, each cell has its own morphological and functional characteristics.
- Insulin gene: found in all cells but only expressed in Beta cells of pancreas.
- Constitutive genes are expressed in all types of cells.
e.g. enzymes for glycolysis
- DNA is not converted to RNA, it is only photocopied. *used as a template to synthesize RNA*
- Proteins, RNA, carbs can't act as a template.
Except in reverse transcriptase of retroviruses which uses an RNA as a template to transcribe a DNA segment in a process called reverse transcription.
Telomerases can use RNAs to synthesize nucleotide sequences in the DNA as well.
- Types of DNA:
cDNA "Complementary DNA"
Genomic DNA (found in nucleus)
Mitochondrial DNA
- Unicellular organisms are affected faster by the external environment than multicellular organisms.
- At temperatures: 25-37 degrees Celsius, yeast will produce heat-shock proteins to adapt to the new environment.
- Operons are found in prokaryotes.
Polycistronic mRNA is found in prokaryotes.
- Monocistronic mRNA found in both.
- LacI is a constitutive gene which is continuously expressed at low* rates. (Has a weak promoter: sequence for attachment of factors is far from the consensus seq.)
- The area between the start and stop codons in the mRNA *the translated area* is known as: Open-reading frame.
- Prokaryotes don't have a nucleus, so both transcription and translation happen in the cytosol. Translation can start before transcription ends.
- In eukaryotes transcription and translation are separated both in time and location. So gene expression is a lot slower in eukaryotes.
- Post-transcriptional modification *adding CAP and Poly-A tail* happens only in eykaryotes and is another reason why Gene Ex. is slower in eukaryotes.
- Haematopoietic stem cells divide rapidly, so they express genes responsible for the cell cycle at very high rates. "Proto-oncogenes"
- Proto-oncogenes: genes expressed in haem. cells to speed up cellular proliferation.
- The mature** cell will not express these genes.
- Tumor suppressor genes: stop cellular proliferation.
- Leukemia: cells don't achieve maturity *they replicate non-stop*.
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 *
SoMA
المحاضرة الرابعة من الجين
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
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.
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…
المحاضرة الخامسة من الجين ركزوا ع الرسمات!
SoMA
BC_243Dr_Ahmed_zaid_lecture_notes.pdf
تعديل
صفحة 6
DNA poly. I read the lagging strand from 3to 5 prime direction and synthesize it from 5 to 3.
صفحة 6
DNA poly. I read the lagging strand from 3to 5 prime direction and synthesize it from 5 to 3.