T2: Mechanisms

12 important questions on T2: Mechanisms

Indicate what is true about mechanisms of toxicity


-inhibition of oxygen binding to hemoglobin by CO is an example of non covalent binding causing toxicity
-Lipid peroxidation is can be caused by reactive oxygen species (ROS)
-Methemoglobinemia is caused by chemicals that cause electron transfer that oxidizes the Fe in hemoglobin from Fe2+ to Fe3+

Which chemicals act by non-covalent interactions?

Tetrodoxin and saxitoxin

What is true about reactive oxygen species (ROS)


n the Haber Weiss reaction superoxide anions and hydrogen peroxide are converted to hydroxyl radicals


Reactive oxygen species are toxic because they are able to modify biomolecules
  • Higher grades + faster learning
  • Never study anything twice
  • 100% sure, 100% understanding
Discover Study Smart

The formations of reactive oxygen species (ROS)

They form during biotransformation, there is no toxicant needed to form ROS, they also form in normal environment. There is a redox reaction caused by oxidative stress. This cuases dagame, it could be returnable but also adverse.

What is lipid peroxidation

The lipid can be bend through the reaction and therefore the structure of de membrane can be disturbed.

What interaction does Carbon monoxide (CO) has?

CO has a way higher affinity to Fe of hemoglobin than O2. This will block the space for O2 and therefore anemia can occure. Also hemoglobin is transformed a bit.
Example of non covalent binding

How does tetrodotoxin interact

comes from the puffer fish
This toxicant blocks the Na channels in the neurons. Therefore you will get paralysed or die.
Example of non covalent blocking

How does saxitoxin interact

This is produced by algy, the shellfish will eat this and are contaminated. They have paralytic shellfish poison PSP. This blocks Na channels.
Example of non covalent blocking.

How does aflatoxine B1 interact?

This is present in nuts, beer and wheat.
it will be activated through metabolism and is the most common cause of liver cancer. It causes a mutation on the P53 tumor suppressor gene and therefore a tumor can develop easier.

How does acetylcholinesterase (AchE) interact?

Acetylcholine is present in the synapses of the neurons. AChE will split this in choline and acetate and therefore the postsynaptic recepters will not bind.
Example of covalent binding, covalent irreversible AChE inhibition

What is the difference between apoptosis and necrosis?

apoptosis is controlled cell death. This results in slowly breaking down the cell without releasing any harmfull molecules.
Necrosis is cell death which is no longer in control. This results in breaking down the membrane and the inside of the cell will come out.
Apoptosis is sort of repair
Necrosis is sort of disrepair

What are the variations in toxic response

- Intra (within) species or between individuals of one species     - Genetic polymorphisms
- age
- nutrition and life style diseases
- gender
- combined exposures

The question on the page originate from the summary of the following study material:

  • A unique study and practice tool
  • Never study anything twice again
  • Get the grades you hope for
  • 100% sure, 100% understanding
Remember faster, study better. Scientifically proven.
Trustpilot Logo