Unit 2 Flashcards
Describe Saturation Kinetics
Once the system that processes reached saturation only a fixed amount can be processed and the system reaches zero-order kinetics
Define biomarker and describe the criteria for a useful biomarker
Biomarkers are what we measure in the indicator species. Biomarker is a biochemical, physiological, morphological or histological quality used to imply exposure to. USEFUL: - inexpensice, fast and easy, - applicable to many sentinel species -measurable before higher level damage
What is the role of the P450 monooxygenase?
Explain phase I and Phase II
P450 is the family of enzymes consists of monooxygeneases and dioxygenases. Looking for the activity of the enzymes.
Monooxygenease combines oxygen and xenobiotic (foreign to the body) (Phase I). Either eliminated or goes to Phase II. Conjugates are formed in phase II, they are inactive an elminated
Describe FIAM and how is it related to metallothionein activity ?
Free-ion activity model. Characteristics of metallothions (.6-7 kDa proteins, 25%-30% cysteine, have high heat stability and bioavaibility is correlated with the FIAM
Name some methods for determining genotoxicity
Karyotyping: staining and display of 2nd chromosome at mitosis
Flow cytometry(# of cells), Micronuclei ( looking at chromatid outside cell), Testing DNA adducts,
Explain how build up of substrates can be used to determine how toxins interact with enzymatic pathways
in a sequenced reaction (A->B->C->D) Ideally A and D are in higher concentrations but if C and B are higher the enzyme isnt working
Four types of mutations
Point mutations: substitution
Frame shift: Insert or deleted base pairs
Conditional mutations: altered phenotypes expressed under certain conditions
Suppressor mutations: mutant which has two two mutation, one compensates for the presence of the other
Define mutagen and explain how they relate to cancer development.
mutagen is an agent that causes mutations, such as chemical and radiation mutagens
Define heat shock proteins and discuss their utility as biomarkers
Stress proteins induced by a change in temp. They indicate proteotoxicity (toxic effects due to damage. Hsp70 and Hsp60 are examples of biomarkers.
Explain oxidative stress and how toxins may cause it
damage to biomolecules by oxygen free radicals, Oxidative tress may be produced as a byproduct of aerobic respiration, photosythensis. Organisms counter oxidative stress by production of antioxidants (enzyme). Xenobiotics may cause oxidative damage by interfering with these enzymes.
Define how flow cytometry is used to quantify changes in cellular DNA
Determine the number of significant (less or more) cells by staining DNA with fluorescent dye and comparing to standard .
Define polymorphism and describe hoe it relates to biomarker development
Not everyone will react the same way to toxins and might have same biomarker effects. There is different forms of allelels have are normal )polymorphism
Describe SOS response and what is used for and how it may lead to mutations
Lots of cell damage will cause repair mechanisms to lead to mutations. Many systems can be activated.
Necrosis and how it is different from somatic death
Necrosis is cell death from disease or injury where somatic death is the death of the organism
Ames test and it is use in carcinogen testing
assess chemical carcinogens, initial indicator and observing if they cause mutations in sample bacteria by growing in agar (mutation allowing nutrient synthesis
Metastasis
Development of secondary malignant (cancerous) growths at a distance from a primary site of cancer. enter the bloodstream or lymphatic system. Carry the cancer around the body.
Threshold and linear no threshold
threshold: hockey stick graph, there is safe exposure
No threshold: there is no safe exposure. this is usually radiation exposure
Oncogene
Cancer causing gene, dominant mutation
Proto oncogenes regulate cell death or reproduction. Leaving the gene on for too long can cause mutations.
Describe the utility of FISH approach for characterizing prostate tumors
Fluorescence in situ hybridization. DNA probes can be used that specific for single genes, centromere or chromosomes. Using cameras and dyes.
Teratogen
Physical or chemical agent that causes developmental malformations (Hg)
NOEC, LOEC, EC50, and LD50
No Observed effect concentration –> highest toxicant concentration where no effect is observed
Lowest observed effect concentration –> lowest toxicant concentration where values are significantly different than controls
EC50: effective concentration to observed desired effect on 50% of the population
LD50: lethal dose to kill 50% of the population
