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Unformatted text preview: In some disorders, the repeat is in coding sequence (glutamine
repeats); in others, it’s in 5’ or 3’ untranslated sequence
• Thus, it may not be the change in protein sequence that is responsible,
but rather something regulatory Radiation Exposure in Humans:
The light (but nontrivial)
• UV light is mutagenic...which is why sunburns are bad
• UV light is weakly energetic - doesn’t penetrate beyond the
outer layers of skin...but that’s enough • High levels of UV exposure on your skin leads to the
formation of pyrimidine dimers • Pyrimidine dimer repair during replication leads to new
mutations Radiation Exposure in Humans:
The light (but nontrivial) • New mutations in cells that can already divide rapidly? A
shortcut to cancer. • If you learn ONE thing in this course, let it be this: always
wear sunscreen Radiation Exposure in Humans:
• On August 6, 1945, the United States dropped an atomic bomb on
the city of Hiroshima, Japan, soon to be followed by one on
Nagasaki. • The explosion killed 90,000-140,000 people and injured almost as
many. • Those in close proximity were simply killed by the explosion.
• Those farther away, who survived the initial blast, suffered
from acute radiation syndromes within hours to days. Radiation Exposure in Humans:
The Heavy • Certain tissues were affected and died...skin died and fell off,
hair fell out, the lining of the gut died and people died of
peritonitis...why these tissues and not others?
rapidly dividing tissues most affected, Radiation Exposure in Humans:
• Exposed individuals who survived t...
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