describe - gene alteration
DESCRIPTION
miscoded mRNA, mRNA mutations, frameshift mutation, base-pair substitutions, missense mutation, nonsense mutation, silent mutation, mutagens, uv light mutagen, nitrous acid mutagen, base analog mutagensTRANSCRIPT
Describe: gene alteration
b.stev
chromosomes may alter abnormally - this is said to be a: mutation> It causes miscoded mRNAmRNA codes for proteins that gives
functions to the bacteria’s processes,
thus alteration to this changes how the
bacteria can operate correctlysome have little effect/ others, contained within codons that would aid survival of the bacteria: - defence toxin production against competition - digestion enzyme change to the environmentOR various purposes that effects their abilities
(Campbell N. A, Reece J. B, 2005)
A U G A A G U U U G G U U A A
Met Lys Phe Gly STOP
U instead of a CGlyGly CODONS CODONS:
GGU GGC GGA GGG
MISSENSE MUTATION:
makes an amino acid,though the specific amino acid that was wanted within the sequence of the mRNAhas changed
A U G A A G U U U A G U U A A
Met Lys Phe Ser STOP
A instead of a G change in
the amino acidamino acid
NONSENSE MUTATION:
codon changeschanges to the codes for a STOP codon
Results: a shorter protein is made that is usually non-functional to the bacteria
A U G U A G U U U G G U U A A
Met STOP
U instead of A
(Campbell N. A, Reece J. B, 2005)
HAS a disastrous effect as it causes the sequence to become,’out of lineout of line,’ & as such results in extensive missense mutationsRESULTS:
proteins that are probably non-functional and/ or prematurely terminate in sequence
INSERTION/ DELETION OF PAIRS
A U G A A G U U U G G U U A A
Met Lys Phe Gly STOP
A G
INTENDED SEQUENCE
insertion
mutagens
UV light- causes thymine dimers in chemical bonding:
DNA
RESULTS: inability to insert correct bases
when
transcribed in process to the
mRNANOTE: this is how UV lightcan be used to kill bacteria
Chemical OR Physical agent that causes a mutation
(Pommerville J.C, 2004)
A C A A C C
T G T T G G normal DNA
A C A A C CT G T T G G
abnormal DNA
UV light: chemical bonding change
Nitrous acidTHE [A]:adenine base; in
DNA
converts into a
hypoxanthinehypoxanthine molecule(s)RESULTS:no existance of an, [A-T] pairinstead; [hypoxantine&hypoxantine& C] pair entire purpose is thereafter
altered
o CHEMICAL structure is similar
o resembles the bases of DNA
Replaces the, [ T ]: thymine base; DNA
AGAIN – entire purpose is then
altered
Base analog
ie: chemical, 5-bromouracil
other chemicals effect DNA in some way
ie: benzopyrene (in soot) aflatoxin heavy smoke
Different effects
(Pommerville J.C, 2004)
Bibliography
Campbell N. A, Reece J. B. (2005). Biology (7th ed.). San Francisco: Benjamin Cummings
Pommerville J.C. (2004). Alcamo’s – Fundamentals of Microbiology (7th ed.). Massachusetts: Jones and Bartlett.