Consequences Of Ionizing Radiation In Human Cells

Question 1

Identify sources of unstable atoms and free electrons

Answer 1

1. An atom can be unstable when a high energy particle knocks an electron free from the inner most shell of an atom creating unstable atom. And the knocked out electron is a free electron.

Principles of attenuation

Question 2

What interactions can bring about free electrons.

Answer 2

• photoelectric effect
• Compton scattering
• Pair production

Question 3

Behavior of free electrons

Answer 3

Electrons like to be in pairs therefore they scavenge the body to seek out other electrons so they can become a pair, thereby causing damage to cells, proteins and DNA

Question 4

What determines the energy of x-ray photons

Answer 4

Kvp

Question 5

Biological effects of low energy x-ray photons.

Answer 5

• Blood disorders
• Intestinal disorder
• Depressed sperm count
• Sterility
• Erythema
• DNA damage

Question 6

Define radiolysis

Answer 6

Dissociation of water into molecular products as a result of interaction with ionizing radiation.

Question 7

formation of free radicals.

Answer 7

• when ionizing radiation interacts with water, it knocks out an electron to form
  A positive ion
  HOH+ ,
  And when this reacts with another electron, no damage will occur.
  HOH+ + e=H2O no damage

But when the electron reacts with a water molecule to form a negative water ion.
H2O + e = HOH- unstable and may result in harmful effects.

HOH+ and HOH- are unstable hence they will break apart into smaller molecules.

HOH+ = H+ and OH*
HOH- = H* and OH-

The interaction of radiation with water therefore results in the formation of an ion pair and 2 free radicals .

Question 8

Explain the damage or injury to cells caused by free radicals.

Answer 8

Once free radicals form, a chained reaction occurs.
* The first free radicals pull an electron from a molecule which in turn destabilizes the molecule and turns it into a free radical as well. This can damage the whole cell

• The radical chain reaction can also lead to broken cell membranes which can alter what enters and leaves the cells.
• Hand OH contain unpaired electrons which are unstable and very reactive.

Question 9

Consequences caused by free radicals when they transfer their excess energy to other molecules in biological cells.

Answer 9

• breaking the molecules chemical bonds causing point lesions
• Reduction or absence of normal function in rare case the gain of a new function.
• Have excess energy making it capable of travelling through the cell
• Can donate an electron or accept electron from other molecules therefore behaving as oxidants or reactants

Question 10

New biological molecules formed from free radicals.

Answer 10

1. Two OH* can combine to form H2O2
2. When H* combine with O2 they form HO2* hydroperoxyl radical

These 2 are believed to produce biological damage directly after the interaction of radiation with water