Celluar Control Flashcards
(18 cards)
What effect does Insertion and Deletion mutation have on DNA sequence
Causes FRAMESHIFT effect
Distinguish between the terms “Regulatory genes” and “Structural Genes”
Regulatory -> Makes TRANSCRIPTION FACTOR -> switches gene on + off + contains expression of structural gene
Structural -> codes for protein
What are the possible effects that occur because of mutation to the structure and function of a gene
Protein may be unchanged due to silent mutation
Different primary structure
Function may be worse
What is a homeobox gene
regulatory gene which initiates transcription and controls gene expression/body plan
why is there little change by mutation in homeobox genes
As these genes are important and a mutation is likely to be lethal
why are there different functions between RNA and DNA polymerase
RNA P.
-makes mRNA
Transcription
DNA P.
-Involved in semi conservative replication
-DNA rep.
What is aptosis
Programmed cell death and when old cells which have undergone large n. of miotic cell divisions are led to cell death
These processes include:
-DNA becoming tightly packed + denser
-Nuclear envelope breaking down and chromatin condensing
-Vesicles form containing hydrolytic enzymes
Which groups is mitosis controlled by
-proto -oncogenes stimulate cell division
- Tumour - suppressor genes reduce cell division
Why do non coding regions of DNA show more variation
Do not affect survival
Why are some regions of DNA described as non coding
Not present in mature mRNA
Introns removed
Not translated
How can gene expression be regulated after transcription
Pre mRNA is modified
Introns removed to form mature mRNA
Alternative splicing produces different version of mature mRNA
How can a mutation alter a protein so that it no longer performs correct funvtion in cell
Insertion/Deletion causes frameshift effect -> Sequence of triplets downstream is different, tertiary structure of protein is altered
How can gene expression be regulated after transcription
Pre mRNA is modified
Removal of introns to produce mature mRNA
Exons join together to form mature mRNA
What is transcription factors
Proteins which bind to specific DNA Sequeences to initiate transcription of genes into mRNA
What is the action of RNA Polymerase
-RNA forms phosphodiester bonds between nucleotides
-Adds RNA Nucleotides
Outline action of Lac Operon
Lac I produced repressor protein and if lactose is absent repressor protein binds to operator regions blocking RNA Polymerase from binding to promotor region
If lactose is present Lactose binds to repressor protein and changes the shape of it hence repressor protein is unable to bind to operator region allowing RNA polymerase to bind to operator region
What is the name of the 3 structural genes
Lac Z
Lac Y
Lac A
Why is sequence of nucleotides greater than normal
-Introns removed from primary mRNA
- Only exons code for proteins
