Mutagens
What is a mutagen?
Any agent that causes a genetic mutation.
Mutation of DNA can occur spontaneously. True or False?
True.
Mutations occur at a rate of one per every ten million cell replications.
Point mutations occur when two or more nitrogenous bases are changed. True or False?
False. Only one base is changed.
Term for a section of the chromosome that is lost.
Deletion
Term used to describe a cell that has one copy of each chromosome.
Haploid
Radiation that can split off electrons which cause damage in cells.
Ionising radiation
What are the two categories of naturally occurring mutagens?
Biological and non-biological.
Term used for a mutation that does not result in a different protein.
Silent.
Term for a segment of a chromosome that is flipped.
Inversion
General term to describe a cell that has more than 1 or 2 copies of each chromosome.
Polyploidy
Name two types of non-ionising radiation.
Radiowaves, infrared radiation.
Name a virus that has been linked to an increase in specific cancers.
Human Papilloma virus (HPV) - throat and cervix
Helicobacter pylori - stomach
Term used to describe a change in the amino acid sequence as a result of point mutation.
Missense.
Term for mutation where a piece from one chromosome breaks off and joins onto a different chromosome.
Translocation.
General term to describe a cell that has an abnormal number of chromosomes.
Anueploidy
The term used to describe the effect of UV radiation's energy on DNA strands in skin cells.
Thymine dimers. (can also be termed pyrimidine dimers)
Name two naturally occurring heavy metal mutagens.
cadmium, mercury
Term used when a polypeptide product is truncated (shortened) by a mutation changing a codon to a stop codon as a result of point mutation.
Nonsense.
Term for a segment lost from one chromosome and the fragment is added to its homologue. One chromosome is missing a section, while its homologue chromosome now has a 2 copies of a section.
Duplication
Term for the when chromatids fail to separate during Meiosis 1 resulting in one gamete with an extra chromosome and another that is missing the chromosome.
Non-disjunction. Example is Trisomy 21 (Down's Syndrome).
Name two examples of chemical mutagens.
benzene, tobacco, PFAS (and others)
What abiotic factor filters UV radiation before it reaches ground level?
Ozone layer.
The most severe type of point mutation where a base is inserted or deleted from the coding strand.
Frameshift.
Explain why chromosome mutations result in more widespread and severe dysfunction than point mutations.
Point mutation - affects one gene.
Chromosome - many genes that can code for a wide range of characteristics.
What are consequences of polyploidy in crop plants such as wheat?
More chromosomes = more copies of each gene = greater expression of genes associated with growth and yield.