What exactly is it that a radioactive atom gives radiates? I beleive that uranium eventually decomposes to an isotope of lead, which would suggest that it is losing protons and that is the radiation it is giving off. However, I fail to see how a proton would be able to cause cancer, as it's really the same thing as an H+ ion that we all used in acid-base experiments in high school. Or are these particular protons more dangerous just because of how fast they're moving? Are they capable of splitting apart smaller atoms in the human body?
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Nuclear Chemistry question.
- Thread starter notfred
- Start date
Chaotic42
Lifer
Ok, here's my understanding of it.
Uranium 238 has an alpha decay which yields Th-234 + He-4
Alpha decay is where the emitted particles are helium nuclei with 2 protons and 2 electrons.
Why would it be poisonous? I've *heard* that it's because it hits parts of your DNA, in effect changing it. I don't know though.
Hope this helps.
Uranium 238 has an alpha decay which yields Th-234 + He-4
Alpha decay is where the emitted particles are helium nuclei with 2 protons and 2 electrons.
Why would it be poisonous? I've *heard* that it's because it hits parts of your DNA, in effect changing it. I don't know though.
Hope this helps.
There are three basic types of radiation released during radioactive decay. These include:
Alpha - During alpha decay, the nucleus of an atom loses two protons and two neutrons. Thus, the atomic number is reduced by 2 and the atomic mass is reduced by 4. Alpha particles have very little penetrating power and aren't particularly harmful.
Beta - During beta decay, a neutron decays into an electron and a proton. The electron is ejected, and the proton is captured. Thus, the atomic number increases by 1 while the atomic mass remains constant. Beta particles have more penetrating power then alpha particles.
Gamma - During gamma decay the nucleus of an atom changes from a high energy state to a low energy state. This state change results in the emmission of a very high energy photon known as a gamma ray. Gamma rays have significant penetrating power and can only be significantly reduced using thick lead shielding.
Ryan
EDIT- What you really need to be concerned with is beta and gamma decay. Especially gamma decay. If a high energy gamma ray passed through your body, it could "hit" the atoms which constitute the protien molecules within your cell's DNA.
Alpha - During alpha decay, the nucleus of an atom loses two protons and two neutrons. Thus, the atomic number is reduced by 2 and the atomic mass is reduced by 4. Alpha particles have very little penetrating power and aren't particularly harmful.
Beta - During beta decay, a neutron decays into an electron and a proton. The electron is ejected, and the proton is captured. Thus, the atomic number increases by 1 while the atomic mass remains constant. Beta particles have more penetrating power then alpha particles.
Gamma - During gamma decay the nucleus of an atom changes from a high energy state to a low energy state. This state change results in the emmission of a very high energy photon known as a gamma ray. Gamma rays have significant penetrating power and can only be significantly reduced using thick lead shielding.
Ryan
EDIT- What you really need to be concerned with is beta and gamma decay. Especially gamma decay. If a high energy gamma ray passed through your body, it could "hit" the atoms which constitute the protien molecules within your cell's DNA.
Actually, the order of dangerousness of radioactive decay is exactly opposite. This is due to the fact that energy of a typical alpha-particle is 4-5 MeV (mega electron volt), beta-particle <1.5 MeV, and most gammas have energies below 1 MeV.
These three forms of radiation fall into two groups: alpha and beta are particle radiation, and gamma is electromagnetic radiation. The interaction of these two with matter is very different. The range of particle radiation is low, and energy high, so the energy of the particle is lost to surrounding matter on a very small area (charged particles feel attraction/repulsion forces in matter, causing collisions). Most of the energy is lost on a single collision causing lots of (often irrepairable) damage on the matter it hits.
Electromagnetic radiation on the other hand is not attracted or repulsed by matter, and loses energy only on direct hits with atoms. Thus the energy of gamma radiation is spread over a large area, and local effects can be quite small (if compared to alpha and beta).
The reason radiation causes cancer is when it hits DNA, it can cause serious damage. The double helix of DNA can be totally broken when hit (chemical bonds are broken from both strands), or one of the strands can be broken (chemical bond). Cells have mechanisms to repair minor damage, and are quite often able to repair single strands, but the mechanisms quite often fail when both strands are broken. Cancer is caused when a cell with faulty DNA still has the ability to go through cell division.
what he said, except: Alpha radiation is biologically the most dangerous one but u only need to be concerned with it if the source is like on your skin or u inhale alpha radiating particles (dust), because if its mass the radiation (particles actually) doesnt reach very far. But if an alpha zips through a cell (nucleus) u can be sure it'll cause serious damage to it
*edit* did u know that one reason for lungcancer from cigarettes is alpha radiation. The tabocco enriches with alpha-Polonium from the ground and when u smoke it, alpha-emitting atoms can/will enter your lung and u can imagine what such a heavy projectile is doing to the cell nuclei in your lung cells. ( 9 cigs will give u the radiation dose the u received from the Chernobyl accident in Germany - I know u cant relate but it was an interesting fact to tell all the hysteric idiots after Chernobyl 😀 )
very harmful (biological that is) radiation also includes Neutrons (hence the hate for Neutron bombs - take over the country with intact infrastructure but kill or injure everything living)
It´s a mostly a question of emphasis. Damage caused to any cell by one single particle or gamma quantum diminishes in order alpha>beta>gamma.
However, the order gamma>particle radiation is correct if you consider the fact that most of the external radiation dose caused to people form natural background radiation comes from gamma radiation (except on areas with high Uranium content in groundwater). The number of alpha-active isotopes in nature is very low, but gamma radiating (and beta, as nearly all gamma radiating nuclides also emit beta radiation) nuclides are abundant.
edit:spelling
However, the order gamma>particle radiation is correct if you consider the fact that most of the external radiation dose caused to people form natural background radiation comes from gamma radiation (except on areas with high Uranium content in groundwater). The number of alpha-active isotopes in nature is very low, but gamma radiating (and beta, as nearly all gamma radiating nuclides also emit beta radiation) nuclides are abundant.
edit:spelling
well yeah it depends on how u define dangerous, but in terms of biological danger it it is bascially in accordance with the radiations energy and having a charge makes it even worse, but as it was said, the particle radiation (especially when being charged) is easy to shield...
I would think that cancer caused by radiation cannot be considered to be caused by agitating dormant genes, as the result of erroneous repair process in cells can be a gene that is not part of (natural) human genome (someone with a better understanding of molecular biology or genetics can correct if this is a wrong assumption, this is going quite far from my field of study)
That's my understanding.
Phuz: You must have read that about one certain kind of cancer, or something. There are many, many forms of cancer.
At the basic level, most tumors are composed of "broken" cells that were allowed to live. A cells DNA was damaged, and it no longer knows how to function, except to replicate. There are many things that can cause this to happen.
Radiation causes cancer, as do carcinogenic substances.. amongst other things.
Even leather and wood dust can cause cancer if you're exposed to it everyday.
well, gamma rays can have varying amounts of energy - its electromagnatic radiation, the Energy just depends on the frequency E=h*v
If your physics teacher said that he doesnt really know alot of physics, I dont want to say that it is wrong but generally such radiation can penetrate indefinately, the questions is just the intensity that reaches the other side.... which is a fct. of the mass of the atoms involved, the frequency of the radiation and... (i am not to familiar with this anymore either) well basically its funky quantum mechanics to calculate
If your physics teacher said that he doesnt really know alot of physics, I dont want to say that it is wrong but generally such radiation can penetrate indefinately, the questions is just the intensity that reaches the other side.... which is a fct. of the mass of the atoms involved, the frequency of the radiation and... (i am not to familiar with this anymore either) well basically its funky quantum mechanics to calculate
dullard
Elite Member
Cancer lesson:
A cell needs two things to become cancerous.
Event 1) Most cells have a timed death. That is, they self destruct when they are no longer needed. You probably won't be happy if you still had your stem cells growing new limbs all the time - or maybe you would 😉. But those cells did their purpose and then self destructed. Cells also self destruct when they sense danger. There are a few different self destruct triggers - for example they notice a virus is trying to multiply inside them. The self destruct mechanism has several steps - if just one step is prevented the cell cannot die on its own (you could kill it externally, but lets hope you are doing that to your cells inside your body). The cells without the ability to self destruct are called 'immortal cells'. Immortal cells have been shown to live decades in tissue cultures and are still living - often far longer than the host it came from could ever live.
Event 2) A few cells living forever inside you doesn't cause any harm. There is a second step that must occur to cause cancer. This second step is called 'transformation'. A transformed cell is stuck in its reproductive mode. There are signals that tell a cell to stop reproducting and several chemical reactions occur moving the cell to its next stage in its life cycle. If these cell cycle steps are blocked, the cell will repeatedly replicate. A normal cell that is transformed will sense the problem and self distruct, causing no harm. But if you have an immortal cell that is transformed you have cancer - a cell cannot kill itself and can only replicate.
Many cells have oncogenes (misspelled in a post above, but good effort) which can cause one of the two events. Many viruses also have these ongogenes (thus viruses can and do cause cancer). I've never had a class on the exact mechanism that radiation causes cancer, but radiation must cause one or both of the events listed above. When radiation hits you it is usually a one time event - the radiation hits the cell and either stops there or passes through. Thus it might be possible that one radiation will stop one chemical reaction and temporarily prevent the self destruct mechanism or temporarily prevent the cell cycle progression from replication to the next stage. But that wouldn't cause cancer since those would be temporary events. Instead to cause cancer the radiation must alter the genes in a way that (a) doesn't kill the cell, and (b) permanently causes BOTH of the events listed above. To permanently cause the damage either new DNA must enter the cell or the current cell DNA must be altered (radiation would cause the latter).
Notice I clearly listed BOTH must occur in the same cell. It is highly unlikely that one event can cause two changes. That is the reason that not everyone gets cancer, only one third of smokers gets cancer, etc. It is likely that any one source of damage will cause one event to occur not both. But then you have to consider the fact that some people are hit by more than one damage causing event. Maybe you smoke AND you are hit by a second source of radiation. Maybe you had a virus that immortialized some cells and then those cells are hit by radiation. I could go on and on, but I'm already rambling. My point is that normally healthy people probably won't get cancer from radiation - but how many of us are 100% healthy (by chance or by choice)?
A cell needs two things to become cancerous.
Event 1) Most cells have a timed death. That is, they self destruct when they are no longer needed. You probably won't be happy if you still had your stem cells growing new limbs all the time - or maybe you would 😉. But those cells did their purpose and then self destructed. Cells also self destruct when they sense danger. There are a few different self destruct triggers - for example they notice a virus is trying to multiply inside them. The self destruct mechanism has several steps - if just one step is prevented the cell cannot die on its own (you could kill it externally, but lets hope you are doing that to your cells inside your body). The cells without the ability to self destruct are called 'immortal cells'. Immortal cells have been shown to live decades in tissue cultures and are still living - often far longer than the host it came from could ever live.
Event 2) A few cells living forever inside you doesn't cause any harm. There is a second step that must occur to cause cancer. This second step is called 'transformation'. A transformed cell is stuck in its reproductive mode. There are signals that tell a cell to stop reproducting and several chemical reactions occur moving the cell to its next stage in its life cycle. If these cell cycle steps are blocked, the cell will repeatedly replicate. A normal cell that is transformed will sense the problem and self distruct, causing no harm. But if you have an immortal cell that is transformed you have cancer - a cell cannot kill itself and can only replicate.
Many cells have oncogenes (misspelled in a post above, but good effort) which can cause one of the two events. Many viruses also have these ongogenes (thus viruses can and do cause cancer). I've never had a class on the exact mechanism that radiation causes cancer, but radiation must cause one or both of the events listed above. When radiation hits you it is usually a one time event - the radiation hits the cell and either stops there or passes through. Thus it might be possible that one radiation will stop one chemical reaction and temporarily prevent the self destruct mechanism or temporarily prevent the cell cycle progression from replication to the next stage. But that wouldn't cause cancer since those would be temporary events. Instead to cause cancer the radiation must alter the genes in a way that (a) doesn't kill the cell, and (b) permanently causes BOTH of the events listed above. To permanently cause the damage either new DNA must enter the cell or the current cell DNA must be altered (radiation would cause the latter).
Notice I clearly listed BOTH must occur in the same cell. It is highly unlikely that one event can cause two changes. That is the reason that not everyone gets cancer, only one third of smokers gets cancer, etc. It is likely that any one source of damage will cause one event to occur not both. But then you have to consider the fact that some people are hit by more than one damage causing event. Maybe you smoke AND you are hit by a second source of radiation. Maybe you had a virus that immortialized some cells and then those cells are hit by radiation. I could go on and on, but I'm already rambling. My point is that normally healthy people probably won't get cancer from radiation - but how many of us are 100% healthy (by chance or by choice)?
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