52 Questions
What is the result of the reaction of the ultimate toxicant with the target molecule?
Injury to the target molecule, cell organelles, cells, tissue, and organs
What type of binding occurs between toxicants and receptors, ion channels, or enzymes?
Noncovalent binding
What is a characteristic of target molecules that allows them to react with toxicants?
Appropriate reactivity and/or steric configuration
How can the ultimate toxicant alter the target molecule?
By all of the above mechanisms
What is necessary to identify a target molecule as responsible for toxicity?
All of the above are necessary
What is a possible effect of toxicants on target molecules?
Dysfunction of the target molecule
What is the result of SH groups interfering with the template function of DNA?
Mispairing
What is the consequence of xenobiotics interacting with promoter regions of genes?
Dysregulation of gene expression
What is the result of peroxidative degradation of cellular components?
DNA fragmentation
What is the consequence of dysregulation of transcription factors?
Inappropriate cell division
What is the result of sustained rise in Ca2+ levels?
ATP depletion
What is the consequence of impaired function of integrated systems?
Cellular dysfunction and relative toxicity
What is the function of thioredoxin in protein repair?
To enzymatically reduce sulfhydryl groups in cysteine
What is the result of ATP depletion in a cell?
All of the above
What is the function of DNA photolyase in DNA repair?
Direct reversal of DNA damage
What is the consequence of necrosis on neighboring cells?
Deleterious effects on neighboring cells
What is the effect of cyanide on ATP synthesis?
Inhibition of cytochrome oxidase
What is the function of glutathione in lipid repair?
Reduction of peroxides in lipids
What is the consequence of Ca2+ accumulation in the cytoplasm?
Precipitation of phosphates
What is the function of chaperone proteins in protein repair?
Refolding of proteins
What is the difference between necrosis and apoptosis?
Apoptosis is active, while necrosis is passive
What is the effect of rotenone on ATP synthesis?
Inhibition of complex I
What is the result of the reaction of hydroxylamine with C in DNA?
It converts C to a modified base that pairs only with A
What is the outcome of the reaction of ethyl methanesulfonate with DNA?
It converts NH2 groups to keto groups by oxidative deamination
What is the term for the changes in chromosomal structure, such as breaking off of part of a chromosome or translocation of an arm?
Clastogenesis
What is the term for the uneven separation of chromosomes during cell division?
Aneuploridization
What is the result of sugar-base cleavage by ROS?
C→U
What is the result of a triplet code being misread entirely?
A radical change of the protein structure
What is the mechanism of action of base-analog substitution?
It substitutes a similar base during replication
What is the result of the reaction of a genotoxic substance with DNA that involves base substitution?
Point mutation
What is the most frequently mutated gene in cancer?
p53
What is the term for the type of mutation that involves the addition or deletion of base sequences during DNA replication?
Frameshift mutation
What is the result of alkylation of the OH group in phosphate?
Formation of 3-OH and 5-P
What is the effect of intercalating agents on DNA?
They inhibit the action of Topoisomerase II
What is the result of the reaction of UV radiation with DNA?
All of the above
What is the term for the process of converting an alkyl protein derivative to a hydroxy derivative?
α-amidation pathway
What is the effect of HNO2 on DNA bases?
It causes deamination
What is the characteristic of nucleic acids that makes them reactive?
High pi bond order
What is the result of the reaction of a carcinogen with DNA?
It leads to the formation of a DNA adduct
What is the mechanism of initiation in carcinogenesis?
Reactivity of carcinogen with DNA
What is the effect of endocrine disruptors on wildlife?
They cause both masculinization of females and feminization of males
What is the effect of endocrine disruptors on human health?
They decrease male fertility
What is the concentration gradient of Ca2+ across the plasma membrane?
10,000-fold
Why is Ca2+ excluded from the cytosol?
Due to its larger ionic radius and ability to easily precipitate with phosphates
What is the result of an increase in cytosolic Ca2+?
Increased binding of protein kinase C
What is the primary target for cell damage from ionizing radiation?
DNA
What is the result of mitotic death?
Cell death at mitosis
What is the function of the electron transport system?
To generate ATP through the transport of electrons
What is the result of oxidative phosphorylation?
Generation of ATP
What is the function of uncoupling proteins in brown fat?
To generate heat
What is the result of oxidative stress?
Damage to components of the immune system
What is the result of ROS reacting with proteins?
Oxidative modification
Explore the different types of reactions between toxicants and target molecules, including noncovalent binding, intercalation, and covalent binding. Learn about the attributes of target molecules and how they are affected by toxicants. This quiz is perfect for students of toxicology and pharmacology.
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