Guyzz in bio. I hve nt …

Guyzz in bio. I hve nt gt most of d topics in molecular inheritance......toh kya kruuu after reading d txt book also & plzz yaar anyone help me ...bcz till now only lil hve came frwrd to help.....so plzz if u r perfect in any topic then its good & it will also be a revision fr u all...u to all know better than me !!!

Posted by Ayaan Ali ?? 6 years, 1 month ago

CBSE > Class 12 > Biology

11 answers

Muskaan Vig 6 years ago

You are welcome ?

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Muskaan Vig 6 years, 1 month ago

Y gene codes for protein named permease because it increases permeability(permission for entry) of cell to beta galactosides and even of lactose.....Z gene codes for beta galactosidase that hydrolyse/convert lactose to glucose and galactose.......a gene codes for transacteylase......as soon as glucose level increases in cytosol and lactose reduces ,i gene starts it's working....Lactose is also called inducer because it is responsible for inducing means initiating the transcriptional process....and i gene is also called inhibitor because it inhibits or prevents RNA polymerase from transcription...... Hope it helps

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Muskaan Vig 6 years, 1 month ago

i gene works only when there is sufficient glucose in cytosol and lactose is absent.........................lactose is absent-->i gene codes for repressor that binds to operator.. Repressor protein is so called because it represses RNA polymerase from transcribing structural genes..so no proyein synthesis takes place .............lactose is present (means there is deficiency of glucose in cytosol)-lactose will bind to Repressor protein and protect operator site.....Now operator is not blocked by repressor protein..RNA polymerase starts transcribing z,y,a gene and protein synthesis will occur...

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Muskaan Vig 6 years, 1 month ago

Lac operon--Lactose operon( a polycistronic structural gene)that contain genes that will code for those proteins which bring lactose inside cytosol and convert it into glucose and galactose.......Components--promoter->i gene also called regulatory gene->operator gene->structural genes i.e. z,y and a......................Functions--i gene-codes for reprresor protein that binds to operator and suppresses its activity and (see diagram) it blocks RNA polymerase from transcribing z,y,a genes.......operator gene-where repressor protein binds..........structural genes-transcription occurs.....

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Muskaan Vig 6 years, 1 month ago

In prokaryotes some of structural genes of related functions are grouped together in operons and an operon is trancribed as a single unit producing a polycistronic mRNA.........

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Muskaan Vig 6 years, 1 month ago

Lac operon-- all about a polycistronic gene...in eukaryotes like us a single transcriptional unit contain single structural gene that will code for single protein but in prokaryotes a single trancriptional unit contains a no. Of structural gene coding for a no. Of proteins but are a part of single metabolic pathway........

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Muskaan Vig 6 years, 1 month ago

About Locations--->>location of promoter and terminator in transcriptional unit are with reference to coding strand because it's polarity is similar to transcriptional RNA i.e. 5'-3'...............Promoter-located at 5' end (upstream) of coding strand......terminator-located at 3' end (downstream) of coding strand...... Which strand will act as non coding strand depend on position of these two parts.......if they interchange their position then coding strand will become non coding strand and vice versa.......

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Muskaan Vig 6 years, 1 month ago

''About Strands in transcriptional unit->Non-Coding strand--Strand with polarity 3' to 5' acts as template strand or strand that will get transcribed...though it codes for transcriptional RNA but still called Non-Coding strand only because of its polarity 3'to 5' which is opposite to tanscriptional RNA 5' to 3'..................Coding strand--Strand of transcriptional unit that will not take part into transcription(5' to 3'), though does not take part in transcription but called coding strand is also only because of polarity(5'-3') which is same as that of transcritional RNA(5'-3')..............

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Muskaan Vig 6 years, 1 month ago

Transcription unit of eukaryotes--segment of DNA that takes part in transcription......it consists of three parts-...........1.promoter-dna sequence that binds with RNA polymerase and initiates trancription process........2.Structural gene-part of transcriptional unit that will be transcribed into RNA (hnRNA)....3.terminator-dna sequence of transcritional unit that is responsible for terminating(means ending) of transcription process..................

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Muskaan Vig 6 years, 1 month ago

I m good in topics from page 106 to page 117 of ncert..if u say i can send notes of topics u don't understand in these pages via this app they are really helpful...tell name of topic..

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▪▪Amrit▪▪ ❤ 6 years, 1 month ago

Same bro..mera bho yhi hai..hmare teacher hi leave kr gye the ..nov. me 3 chapter rehte the..baki ho gya ..molecular biology end se rehta gai...vipin sharma ki videos dekho..maiene vha se kia hai...

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