Quiz

1
Quiz 3 Today!

• Please sit in dark colored chairs!

2
Topics for Today

• Radiation Sickness
• Natural sources of radiation
• Quiz 3

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Readings for Today

• Hazards Associated with Radioactivity Section
  7.8
• The DNA double Helix Section12.2

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Topics for Monday
Clearing the Air Whats in our atmosphere?
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Readings for Monday
Section 1.2 Whats in a Breath? Section
1.6 Mixtures, elements, and Compounds
How is a mixture different from a solution (page
224)?
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Announcements

• Practice Questions are online for Exam 1.
• Just click the Exam 1 link on the Monthly
  Calendar

7
Topics for Today

• Radiation Sickness
• Natural sources of radiation
• Quiz 3

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Review - Wednesday

• H2O H2O. e

Ionizing radiation
H2O. H2O .OH H3O
Unpaired electron
Unpaired electron
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Review - Wednesday

• Another free radical
• .OH is the hydroxyl radical
• .OH will react with just about anything.

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Review - Wednesday

• Another free radical
• .OH is the hydroxyl radical
• .OH will react with just about anything.

.OH does not discriminate between molecules
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Including our DNA
Figure 12.8
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What happens when .OH hits a strand of DNA?
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• Usually, the .OH damages the cell, but the cell
  repairs itself.

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• Usually, the .OH damages the cell, but the cell
  repairs itself.

But cells may not be able to keep up with high
doses of radiation (and .OH radicals).
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What happens when radiation DIRECTLY interacts
with the cell?
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• Nothing

Remember, ? rays are more likely to interact with
water!
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• Nothing
• Damage the cell

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Cell Damage
Radiation causes genetic mutation
Cell Dies
Cell repairs itself
Mutation passed on to next generation of cells
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Cell Damage
Radiation causes genetic mutation
Cell Dies
Cell repairs itself
Mutation passed on to next generation of cells
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Untangling the DNA
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a
Where did the alpha particle come from?
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a
OR
0 -1
Two ß
Double Strand Break!
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a
OR
0 -1
Two ß
Now what?
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• Join the strands
• Insert the wrong links
• Join the broken strand to another DNA strand

a
OR
0 -1
Two ß
Now what?
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What kind of cells do mutations most affect?
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What kind of cells do mutations most affect?
Rapidly dividing cells.
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• Some examples of rapidly dividing cells

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• Some examples of rapidly dividing cells
• Skin cells
• Sex cells
• Hair

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• Some examples of rapidly dividing cells
• Skin cells
• Sex cells
• Hair

In Hiroshima, why did people not notice the
effects until 7 or so days AFTER the bomb?
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Alexander Litvinenko
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Alexander Litvinenko
Poisoned with Po-210 t1/2 140 days
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Alexander Litvinenko
About 15 days after reporting symptoms
Poisoned with Po-210 t1/2 140 days
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polonium 210 was a byproduct of the nuclear
industry and is used in the production of
antistatic materials. a large quantity of
alpha radiation had been found in Mr.
Litvinenko's urine. Referring to the effects of
polonium 210, he said ''If that enters the body
by ingestion, then it will rapidly track through
the body and go to most major organs,'' causing
''tissue damage characteristic of radiation.''
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What makes some radioactive elements more harmful
to humans than others?
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1. How does your body uptake the element?
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Nuclear Fallout

• These vary in half-life.
• Cs-137 30.2 years
• Sr-90 29.1 years
• Th-234 24.1 days
• Ba-137 2.5 minutes
• Kr-90 32 seconds
• Sr-89 50 days
• I-131 8 days

Dont memorize these!
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1. How does your body uptake the element?
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Where is calcium used in your bodies?
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Where is calcium used in your bodies?
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1. How does your body uptake the element?

• Chemically speaking, elements in the same columns
  in the periodic table tend to behave similarly

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1. How does your body uptake the element?

• Chemically speaking, elements in the same columns
  in the periodic table tend to behave similarly

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People living in the 1950s have more Sr-90 in
their bones than people living today t1/2 30
years
43
''If that Po-210 enters the body by ingestion,
then it will rapidly track through the body and
go to most major organs. WHY??
Alexander Litvinenko
Poisoned with Po-210 t1/2 140 days
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1. How does your body uptake the element?
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1. How does your body uptake the element?
Where do we find sulfur in our bodies?
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Pretty much everywhere
Cysteine, an amino acid
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What makes some radioactive elements more harmful
to humans than others?
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2. The half-life

• These vary in half-life.
• Cs-137 30.2 years
• Sr-90 29.1 years
• Th-234 24.1 days
• Ba-137 2.5 minutes
• Kr-90 32 seconds
• Sr-89 50 days
• I-131 8 days

If inhaled or ingested, these will be around for
a persons lifetime.
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What makes some radioactive elements more harmful
to humans than others?
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3. Type of Emission
When is alpha radiation dangerous?
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3. Type of Emission

• If the source is outside your body, then alpha
  particles are almost harmless.
• However, beta and gamma emission can still travel
  far enough to damage cells.

52
Summary
What determines if a radioisotope is dangerous?
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Summary

• How does your body uptake the element?
• What is the half-life?
• What type of emission?

What determines if a radioisotope is dangerous?