Biology Questions and Answers
- How are mutagenic agents
related to cancer incidence in
a population? Is cancer a
disease transmitted to the
individual offspring?
The exposition of mutagenic agents (for exampla population toe, the (^)
people living in the surrounds of the
Chernobyl nuclear exposed to the radiation fpower plant anrom thed
nuclear accident in 1986) increases the
cancer occurs bincidence in that pecause the mutagenic agopulation. Thisents
increase the rate of mutation and the
probabilityin pathological of mutant cells to proliferate manner (cancer).
Cancer itself is ntransmissible disot a hereditarilyease. Genetic
predispositionscancer, however, can be inherited. for the development of
- How do the repairing
enzymes of the genetic
system act?
There are enzymes within thdetect errors or alterations in DNAe cells that
molecules and begin a repair of those
errors. First,restriction endonucleases, enzymes known as specialize (^) d in
cutting DNA molecules (also used in
genetic engineering), cut the affectedpiece of DNA. Then polymerase
enzymes build correct sequences of
nucleotidaffected piece takines correspondent to theg as template (^) the
DNA chaiaffected chain. n complFinally the new correctementary to the (^)
sequence is bound in the DNA under
repair by specific enzymes.
- What are some diseases or
genetic abnormalities caused
by recessive genes?
Examples oare: cystic fibrosis,f recessive ge albinism,netic d iseases
phenylketoSachs disease.nuria, galactosemia, Tay- - What are some diseases or
genetic abnormalities caused
by dominant genes? Why are
severe dominant genetic
diseases rarer than recessive
ones?
Examples of dominant genetic diseases
are: Huntington's disease (Huntington’s chorea), or
neurofibromatosis,
hypercholesteroldisease. emia, polycystic kidney
Severe and early autosomal dodiseases are rarer than recessiveminant
autosomal diseases because in this last
group the affected allele in the heterozygous individuals andmay be hidden
transmitted to the offspring until
undergoing homozygmanifestation of the disease). osity (actualIn severe (^)
dominant diseases thmanifests the condition e heterozygousand often dies (^)
without having offspring. (Some genetic
diseasesHuntington disease; i are of later manifn these cases theestation, like
incidence is higher because many
individuals hthat they are carriers oave children before knowingf the dominant
gene).
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