Cellular Controll 6.1 Flashcards
two main types of mutation …
2
- point mutations
- indel (insertion , deletion )
whats the lac operon ? 1
-used in respiration if glucose is unavailable , then lactose is broken down
outline the structure of the lac operon …
4
From left to right :
- Regulatory gene (i) =codes fro repressor protein (laci)
- Promotor region= RNA polymerase binds here to begin the transcription of the lacZ and lacY.
- Operator region=repressor protein (laci) binds here
- lacZ and LacY = structural genes =codes fro enzymes such as B galactosidase and lactose permease .
what does a regulatory gene do in the lac operon ? -name -function -explanation , when expressed 4
- name is i
- codes for repressor protein = laci
- when expressed repressor protein is made - (Laci) protein binds to the operator
- this means that the lacZ and LacY genes aren’t transcribed.
- enzymes for lactose metabolism aren’t made so genes are OFF
what does the promotor region do in lac operon ?
1
-RNA polymerase binds here to begin transcription
What does the Operator region do in lac operon ?
operator+promoter are know as …
- REPRESSOR protein binds here and stops RNA polymerase binding to Promoter region .
= operator + promotor===>controll sites
what do the structural genes do in lac operon ?
4
explain what the enzymes do …
lacZ and lacY :
- lacZ = B galactosidase=> turns lactose –>glucose + galactose
- lacY = Lactose Permease —> allows lactose to enter the bacterial cell.
what molecule is the inducer in the lac operon ?1
lactose
what happens when lactose is present ?
4
- Lactose binds to repressor protein (lacI)
- This causes a conformational change meaning that it can no longer bind to the operator region
- RNA polymerase now can transcribe the lacZ and lacY
- enzymes produced for lactose metabolism …
what’s a transcription factor ? 3
- proteins or short non coding parts of RNA
- act in the nucleus
- controll what’s turned on or off
why is mRNA shorter than the gene is was transcribed from ? 3
- whole gene= introns and exons
- primary RNA = introns and exons
- mRNA = only EXONS hence it is shorter
whats a homeobox gene ? 2
sequence of 180 base pairs ( without introns), found in genes that regulate ANATOMICAL DEVELOPMENT = animals , plant and fungi
whats a HOX gene ? 3
subset of homeobox genes ,
- found only in animals ,
- involved in formation of anatomical features in correct location of body plan .
why is it important that homeobox sequence is high;y conserved ?
2
- means we all had common ancestor (plant and animals and fungi )
- still present today so it must be important !
How is Hox gene different form Homeobox genes ?
2
- Hox is only in animals and it controls cell differentiation mitosis, apoptosis , regulates cell cycle,cell migration
Whats colinearity ? 2
-genes that control anterior and posterior axis , develop in same order as organs ( head , shoulders , knees and toes )
why doesn’t apoptosis damage surrounding cell tissue ?
- no hydrolytic enzymes involved
why should the rate of apoptosis = the rate of mitosis ?
2
- tumour will occur if rate of apoptosis is too slow
- Degeneration will occur if the rate of apoptosis is too fast
why should pregnant mothers not eat liver?
3
- liver has a lot of RENTINOL
- body converts this to RETANOIC ACID
- this interfere with HOX genes
- leads to abnormalities in child
whats the difference between RNA polymerase and DNA polymerase …
4
RNA POLYMERASE : used to make mRNA and tRNA , used in transcription ,and only small part of one strand of DNA used …
DNA POLYMERASE : used in DNA replication, whole length used ,2 strands formed
why do stop codons stop the translation ? 1
- no matching Amino Acid present …
whats the sequence of apoptosis ?
1- enzymes break down cell cytoskeleton
2-cytoplasm = dense with tightly packed organelles
3-small protusions called BLEBS form
4-Chromatin condenses , nucleur envelope breaks and DNA breaks into fragments
5-Cells = vesicles that are ingested by phagocytic cells
(no hydrolytic enzymes involved )
