MODULE 6:GENETIC CHANGE Flashcards
Define a mutagen
an agent such as electromagnetic radiation or chemicals that can cause genetic mutation
Define mutation
a permanent change in the nucleotide sequence of an organism’s genome
Give the Effect of electromagnetic radiation, how they operate
Cause:X-Rays and Gamma Rays
Effect: classed as ionising radiation because when they strike an atom/mlcle they, ‘bump off’ an eletron leaving an ion
What is the outcome of ionising radiation
It can break DNA molecules
Damage bases and cause chromosomal deletion
It also causes cross-linking of DNA to itself and proteins
Give the Effect of electromagnetic radiation, how they operate
Cause:UV light
Effect: short wavelength and high energy ways are absorbed by DNA
Which excite adjacent prymidine (C and T) to form covalent bonds
Outcome of UV light exposure
pyrimidine dimers to form possible translation and transcription errors
Give the Effect of chemicals and how they operate
Cause: Nitrogen mustard
Effect: alkylating agents produce mutations by adding small hydrocarbon groups to either bases or backbone of DNA
Outcome of : Nitrogen mustard
Possible source
Bone marrow suppression === anemia
Side effects of chemotherapy
Give the Effect of chemicals and how they operate
Cause: dimethyl nitrosamine
removes amine groups from bases such as converting C bases to U and producing mutations
Outcome of dimethyl nitrosamine
Possible source
Lung Cancer
Source: produced in the stomach of animals after eating foods containing nitrous acid
Give the Effect of chemicals and how they operate
Cause: proflavin
Insert themselves into DNA stretching it and causing frameshift mutations
Outcome of Proflavin
Possible source
Tumors
used labs as dyes
Define frameshift mutations
mutations that result the way we read codons in mRNA
Give the Effect of naturally occuring mutagens and how they operate
Cause: VIRUS HPV
HPV hits the genome, disrupting and rearranging nearby host-cell genes “This can lead to overexpression of cancer-causing genes in some cases, or it can disrupt protective tumor-suppressor genes in others. Both kinds of damage likely promote the development of cancer.”
Outcome of HPV
This can lead to overexpression of cancer-causing genes in some cases eg brca gene which can result in Cancer
Give the Effect of naturally occuring mutagens and how they operate
Cause: metals such as mercury
can induce chromosomal variation or abnormal cell divisions in animals or plant cells
Outcome of mercury
Cancer
Give the Effect of naturally occuring mutagens and how they operate
Cause: Reactive Oxygen Species (ROS)
result in mutagens attached to nitrogenous bases as well as DNA strand breaks and crosslinks
What are the different types of point mutations
Silent, nonsense and missense, frameshift insertion and deletion
Normal DNA LEVEL: TTC
mRNA LEVEL: AAG
Protein: Lys
Example DNA LEVEL: TTT mRNA: AAA protein: Lys what type of mutation is that ?
point mutation, silent mutation
Normal DNA LEVEL: TTC
mRNA LEVEL: AAG
Protein: Lys
Example DNA LEVEL: ATC mRNA: UAG protein: STOP what type of mutation is that ?
Nonsense point mutation
Normal DNA LEVEL: TTC
mRNA LEVEL: AAG
Protein: Lys
Example DNA LEVEL: TCC mRNA: AGG protein: Arg what type of mutation is that ?
Missense, point mutation
missense is equal to
changed amino acid in polypeprtide chain
When does chromosomal mutation occur
when a cell in undergoing cell division
