Quiz #3 Today! Please sit in dark colored chairs!

Topics for Today –Radiation Sickness –Natural sources of radiation –Quiz #3

Readings for Today Hazards Associated with Radioactivity Section 7.8 The DNA double Helix Section12.2

Topics for Monday Clearing the Air… What’s in our atmosphere?

Readings for Monday Section 1.2 What’s in a Breath? Section 1.6 Mixtures, elements, and Compounds How is a mixture different from a solution (page 224)?

Announcements –Practice Questions are online for Exam #1. –Just click the Exam #1 link on the Monthly Calendar

Topics for Today –Radiation Sickness –Natural sources of radiation –Quiz #3

Review - Wednesday H 2 O H 2 O.+ + e – Ionizing radiation H2O.+ + H 2 O. OH + H 3 O + Unpaired electron

Review - Wednesday Another free radical…. OH is the hydroxyl radical. OH will react with just about anything.

Review - Wednesday Another free radical…. OH is the hydroxyl radical. OH will react with just about anything.. OH does not discriminate between molecules

Figure 12.8 Including our DNA

What happens when. OH hits a strand of DNA?

1.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).

What happens when radiation DIRECTLY interacts with the cell?

1.Nothing Remember, γ rays are more likely to interact with water!

1.Nothing 2.Damage the cell

Cell Damage Cell repairs itself Radiation causes genetic mutation Cell Dies Mutation passed on to next generation of cells

Cell Damage Cell repairs itself Radiation causes genetic mutation Cell Dies Mutation passed on to next generation of cells

Untangling the DNA

α Where did the alpha particle come from?

α Double Strand Break! Two β OR 0

α Now what? Two β OR 0

α Now what? Two β OR 0 1.Join the strands 2.Insert the wrong links 3.Join the broken strand to another DNA strand

What kind of cells do mutations most affect?

Rapidly dividing cells.

Some examples of rapidly dividing cells…

Skin cells Sex cells Hair …

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?

Alexander Litvinenko

Poisoned with Po-210 t 1/2 = 140 days

Alexander Litvinenko About 15 days after reporting symptoms Poisoned with Po-210 t 1/2 = 140 days

“…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.''

What makes some radioactive elements more harmful to humans than others?

1. How does your body uptake the element?

Nuclear Fallout These vary in half-life. Cs years Sr years Th days Ba minutes Kr seconds Sr days I days Don’t memorize these!

1. How does your body uptake the element?

Where is calcium used in your bodies?

1. How does your body uptake the element? Chemically speaking, elements in the same columns in the periodic table tend to behave similarly

1. How does your body uptake the element? Chemically speaking, elements in the same columns in the periodic table tend to behave similarly

People living in the 1950’s have more Sr-90 in their bones than people living today t 1/2 = 30 years

Alexander Litvinenko Poisoned with Po-210 t 1/2 = 140 days ''If that [Po-210] enters the body by ingestion, then it will rapidly track through the body and go to most major organs.‘‘ WHY??

1. How does your body uptake the element?

Where do we find sulfur in our bodies?

Pretty much everywhere… Cysteine, an amino acid

What makes some radioactive elements more harmful to humans than others?

2. The half-life These vary in half-life. Cs years Sr years Th days Ba minutes Kr seconds Sr days I days If inhaled or ingested, these will be around for a person’s lifetime.

What makes some radioactive elements more harmful to humans than others?

3. Type of Emission When is alpha radiation dangerous?

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. 3. Type of Emission

Summary What determines if a radioisotope is dangerous?

Summary 1.How does your body uptake the element? 2.What is the half-life? 3.What type of emission? What determines if a radioisotope is dangerous?