Chapter 19 Keywords Flashcards
Mutation
Change in the sequence of bases in DNA. Istrupting proten synthesis
Mutagen
A chemical physical or biological agent that causes mutation
Physical mutagen
Ionising radiation eg X ray
Breaks one or more DNA strands. Some breaks can be replaced but mutations can happen in the process
Chemical mutagen
Deaminating agents
Chemically alters bases I DNA such as converting c to U in DNA. Changing the DNA base sequence
Biological agents
Can be lkylating agents
Base analogs
Virus
Alkylating agent
Methyl or ethyl groups are attached to bases so incorrect pairing of bases during replication
Base analogs
Added to DNA instead of the usual base during replication, changing bases sequence
Viruses
May insert itself into genome changing the base sequence
Depurination
Loss of a purine base
Often Happens spontaneously
The absence of a base can lead to insertion of an incorrect base through complementary base pairing during DNA replication
Depyrimidination
Loss of a pyrimidine
Often Happens spontaneously
The absence of a base can lead to insertion of an incorrect base through complementary base pairing during DNA replication
Anticarcinogens
Vit ACE in fruit and veg
Negate the effects of free radicals that are oxidising agents and can affect the structures of nucleotides and also distrupt base pairing during DNA replication
Silent mutation
Don’t change any proteins or the activity of any proteins made
Have no effect on the phenotype
Can happen in introns or code for the same a.a
May change the primary structure but don’t change the overall structure or function
Nonsense mutation
Codon becomes a stop codon
So shorted protein made that is normally non functional
Normally have negative or harmful effect on phenotype
Missence
Incorrect amino Acid/s added to primary structure when protein made. Two types. Conservative and non conservative
Result depend on role the a.a plays in the structure
Could be beneficial silent or harmful.
Conservative mutation
Type Of missense mutation
A.a change leads to a.a coded for with similar properties to the O.g so effects are less servere
Non conservative mutation
New a.a coded for have different properties to the o.g
More likely to have an effect on protein structure and may cause disease
Gene mutation
Happens in single genes or whole sections of DNA
Chromosome mutation
Affect the whole chromosome or number of chromosomes within a cell. Can be cause by mutagens and normally happen during meiosis. Can be silent but often lead to developmental difficulties Deletion Duplication Translocation Inversion
Inversion chromosome mutation
A section of chromosome breaks off and is reversed the joins back onto the chromosome
Translocation chromosome mutation
A section of one chromosome breaks off and joins another non homologous chromosome
Duplication chromosome mutation
Section is duplicated on a chromosome
Deletion chromosome mutation
A section of a chromosome breaks off and is lost within the cell
Gene regulation
Fundamentally the same in pro and eukary 4 types. Transcriptional Post Transcriptional Translational Post translational