Introductory Toxicology Quiz

A highly reactive molecule with an unpaired electron, capable of initiating a chain reaction by abstracting an electron from another molecule, like a lipid.

A type of free radical formed when an oxygen molecule gains an electron, which can further react with lipids in the cell.

A complex series of reactions initiated by the formation of free radicals, involving repeated electron transfer and the creation of reactive oxygen species (ROS).

A chemical species that can react with biological molecules, causing damage and contributing to various cellular impairments.

Molecules, often produced during normal cellular processes, that can readily damage biomolecules, leading to oxidative stress.

A condition where the production of ROS overwhelms the cellular antioxidant defenses, resulting in damage to lipids, proteins, and DNA.

A critical process in cells, where energy is produced from glucose in the presence of oxygen via a series of reactions.

The main mechanism of toxicant action that involves disruption of the normal function of various cellular processes by binding to and altering the function of target molecules.

A toxicant that interferes with any step in aerobic metabolism can lead to a decrease in cellular ATP levels.

Cells lacking sufficient ATP cannot perform essential functions like active transport, ultimately leading to disruptions in homeostasis.

A rise in cytosolic Ca2+ can signal cellular distress. It can cause increased Ca2+ pumping into the mitochondria, leading to ATP depletion and decreased ATP synthesis.

Increased cytosolic Ca2+ disrupts the cytoskeleton, leading to membrane instability. The cytoskeleton needs low Ca2+ levels for stability.

High cytosolic Ca2+ activates hydrolytic enzymes, which can break down integral membrane proteins and lipids, damaging the cell membrane.

High Ca2+ inside the mitochondria increases electron flow through the electron transport chain, potentially leading to the formation of ROS and RNS if ATP synthase is inhibited.

The depletion of ATP hinders Ca2+ pumps, leading to a vicious cycle where increased cytosolic Ca2+ further inhibits ATP production.

The cell tries to compensate for ATP depletion by pumping Ca2+ into the mitochondria, which further reduces ATP synthesis by hindering the H+ gradient across the mitochondrial membrane.

Toxicants need to be present at a sufficient concentration at the cellular target to cause an adverse effect. This means the toxicant must reach the target and interact with it in a way that causes disruption.

The process by which a toxicant is delivered to its target. This involves factors like absorption, distribution, and metabolism.

Biotransformation processes that increase the toxicity of a substance, often by converting it into a more reactive or harmful form.

Biotransformation processes that decrease the toxicity of a substance, either by preventing the formation of a toxic metabolite or eliminating it once formed.

This happens when toxicants interact directly with their target molecules. This interaction can either activate or inhibit the target molecule, leading to a disruption in its function.

Toxicants can damage or destroy target molecules, often by breaking their chemical bonds.

This happens when toxicants alter the cell membrane, which controls what enters and leaves the cell. This disruption can lead to a loss of vital nutrients or the influx of unwanted substances.

Toxicants can interfere with the processes that control gene expression, which determines which proteins are produced in a cell. This can lead to the production of harmful proteins or the lack of essential proteins, both contributing to cellular dysfunction.

Genes that normally signal a cell to progress through the cell cycle. If their regulation is altered, they can cause cancer.

Genes that normally signal a cell to stop progressing through the cell cycle, repair DNA, or trigger apoptosis if DNA damage is irreparable. Mutations in these genes can contribute to cancer.

A cell that has acquired one or more mutations that could contribute to the development of cancer but is not yet cancerous.

A group of abnormal cells that form in a localized area. It represents an early stage in the development of cancer.

The process of transforming a normal cell into a cancerous cell through multiple stages.

A substance capable of causing cancer by damaging DNA or altering cell processes.

A substance that binds directly to DNA, forming a complex called an adduct. This interference can lead to DNA mutations and potentially cancer.

Substances that damage DNA directly, often by causing oxidative stress or radiation exposure.

Reactive oxygen species (ROS) and reactive nitrogen species (RNS) are molecules that damage cellular components, including proteins, lipids, and DNA. They can arise from normal metabolic processes or from environmental stressors like pollutants and radiation.

Calcium ions (Ca2+) are crucial for many cell functions, but excessive intracellular calcium can disrupt cell signaling and trigger cell death pathways.

Mitochondria are the powerhouses of the cell, producing ATP (energy currency). Damage to mitochondria disrupts energy production, leading to cell dysfunction and potentially death.

Necrosis is an uncontrolled cell death that occurs when a cell is severely damaged. It involves the swelling and bursting of the cell, releasing its contents into the surrounding environment.

Apoptosis is a programmed cell death process that eliminates cells in a controlled manner. It doesn't damage surrounding cells and involves the orderly breakdown of the cell into small packets that are engulfed by other cells.

Cytochrome C is a protein involved in the electron transport chain within the mitochondria. Its leakage from the mitochondria into the cytoplasm signals the activation of caspase enzymes, which trigger apoptosis.

The process by which cells are repaired after being damaged. It can involve repairing individual molecules, removing damaged organelles, regenerating tissues, or even deleting damaged cells to make way for new ones.

The process by which cells adapt to a toxic insult. This involves changing the way the cell functions to reduce the impact of the toxin.

When the body's repair mechanisms are overwhelmed or impaired, the body may not be able to fully recover from the damage. This can lead to tissue necrosis or even fibrosis.

When adaptive responses are prolonged or excessive, they can become harmful to the body. This can lead to chronic health issues or even cancer.

The process by which cells are removed from the body, typically because they are damaged or unwanted. This can be done through various methods like apoptosis or autophagy.

The process by which a tissue regenerates after injury. This typically involves the division and growth of new cells to replace the damaged ones.

A type of tissue repair that involves the formation of scar tissue. This can occur after injury or inflammation.

An uncontrolled growth of cells that can lead to the formation of tumors. This can result from a failure of cell cycle regulation, leading to cells dividing uncontrollably.