DNA Test Part Three: Gene Mutation And Regulation Flashcards
Gene Mutation
Heritable changes in genetic information
Substitution
The change of one base to another in a DNA sequence
Point mutation
A change in one or a few nucleotides that occur at a single point in the DNA sequence
Frameshift mutation
A kind of mutation that can change every amino acid that follows the point of mutation
Insertion
The addition of a base to the DNA sequence
Translocation
Part of one chromosome breaks off and attaches to another
Inversion
A chromosomal mutation that reverses the direction of parts of a chromosome
Duplication
A mutation that produces an extra copy of all or part of a chromosome
Difference between deletion as a gene mutation or chromosomal mutation
As a gene mutation one base is removed from the DNA sequence while in a chromosomal mutation the deletion would involve the loss of one or more chromosomes
Effect of Substitution
Only affects the amino acid if anything
Effect of Insertion
Affects every amino acid that comes after the mutation
Effect of deletion
Affects every amino acid that comes after the mutation
Mutagen
An agent such as radiation or a chemical substance that causes genetic mutation
Gene regulation
Gene regulation is the process of controlling which genes in a cell’s DNA are expressed (used to make a functional product such as a protein)
P How do prokaryotes conserve energy
Prokaryotes regulate their activities producing only those genes necessary for the cell to function
P How do DNA binding proteins in prokaryotes regulate genes
They control transcription. Some of these regulatory proteins help switch genes on,
while others turn genes off
P What is an operon
It is a group of genes that are regulated together
P What is the lac operon is E. coli
three genes
P What is the function of the genes in the lac operon of E. coli
They allow E. coli to use lactose for food when it is present.
P What turns the lac operon off
A repressor protein turns the operon off.
P How does a repressor protein turn off the lac operon
It binds to the operating region, blocking RNA polymerase from transcribing the lac
genes
P How does lactose turn on the lac operon
It binds to the operating region, blocking RNA polymerase from transcribing the lac
genes
Repressor protein
Binds to the operator, preventing transcription of the lac genes
Operator
Binding site for the repressor protein
RNA polymerase
When the repressor is not present this enzyme carries out the transcription of lac genes
Lactose
Causes the repressor to drop off the operator so transcription of the lac genes can begin
Lac genes
The lac operon (lactose operon) is an operon required for the transport and metabolism of lactose in Escherichia coli and many other enteric bacteria
E Difference between gene regulation in prokaryotes and eukaryotes
a. Most eukaryotic genes are controlled individually.
b. Eukaryotic cells have more complex regulatory sequences than those of the lac
repressor system.
E TATA box
It is a short region of DNA that contains a sequence of T and A base pairs. The protein
that binds to this site helps position RNA polymerase.
E Transcription factors
They are DNA-binding proteins that bind to DNA sequences in the regulatory regions
of genes and help control gene expression.
How gene regulation makes cell specialization possible
It allows particular genes to be expressed in some kinds of cells but not others.
E. coli with a limited nutrient supply response
The lac operon is switched on when lactose is the only food source
Tadpole with a lack of water response
The tadpole may speed up it’s metamorphosis
