Test4 Flashcards
The process of _____ is: to force a fluid through (an organ or tissue) especially by way of the blood vessels.
perfusion
_______ can be defined as the process in which blood is forced to flow through a network of microscopic vessels within biologic tissue, allowing exchange of oxygen and other molecules across semipermeable microvascular walls.
Perfusion
The ______ are a heterogenous set of vesicles 20-200nm in diameter and formed from the endoplasmic reticulum when cells are disrupted. The vesicles are isolated by differential centrifugation and are composed of three structural features: rough vesicles, smooth vesicles and ribosomes.
microsomes
(liver microsomes used in pre-clinical studies)
https://www.youtube.com/watch?v=6UqtgH_Zy1Y
______ are artificial structures derived from pieces of endoplasmic reticulum (ER) formed during tissue homogenization. They are prepared by differential centrifugation and contain cytochrome P450 enzymes (CYPs), but do not contain soluble enzymes.
Microsomes
(cP450 enzymes are a superfamily of mono-oxygenases)
https: //www.youtube.com/watch?v=YngjrVyzJco
https: //www.youtube.com/watch?v=Y5OQT4iwY8Y
___ ____ ___ are a superfamily of enzymes containing heme as a cofactor that function as monooxygenases.
Cytochrome P450 enzymes
In mammals, these proteins oxidize steroids, fatty acids, and xenobiotics, and are important for the clearance of various compounds, as well as for hormone synthesis and breakdown.
Mono-oxygenases known as ____ ____ enzymes, are found in mammals, these proteins chemically alter steroids, fatty acids, and xenobiotics, and are important for the clearance of various compounds, as well as for hormone synthesis and breakdown.
cytochrome P450
CYP
xenobiotics are:
chemical substances that are foreign to animal life
examples: plant constituents, drugs, pesticides, cosmetics, flavorings, fragrances, food additives, industrial chemicals and environmental pollutants.
____ ____ refers to the material (or tissue) in between a eukaryotic organism’s cells. The structure of connective tissues is an extracellular matrix.
biological matrices
a jelly-like structure that composes connective tissue.
eukaryotic:
any cell or organism that possesses a clearly defined nucleus
__ ___ ______:
modeling, simulation, and visualization of biological and medical processes in computers with the goal of simulating real biological processes in a virtual environment
in silico medicine
_____ is an immortalized cell line of human colorectal adenocarcinoma cells. It is primarily used as a model of the intestinal epithelial barrier.
Caco-2
(In culture, Caco-2 cells spontaneously differentiate into a heterogeneous mixture of intestinal epithelial cells.)
Caco-2 cell permeability assay is the golden standard for in vitro prediction of intestinal drug permeability.
Caco-2 cells can serve as an in vitro model to study the enterocyte transport of lipids, and lipid-soluble drugs.
There are limits to Caco-2: https://www.youtube.com/watch?v=QuJgKGseNDU
An important step in the processes of _____ is: the movement of drug molecules through cellular barriers (e.g. intestinal walls, blood vessel walls, blood-brain barriers, kidney tubule walls)
pharmacokinetics
Examples of cellular barriers:
intestinal walls
blood vessel walls
blood-brain barriers
kidney tubule walls
___ barriers constitute the main restriction to free dissemination of drug molecules throughout the body
Cellular
e.g. intestinal walls, blood vessel walls, blood-brain barriers, kidney tubule walls
To cross most ____ barriers the drug must be able to move through the lipid layer of the cell membrane.
cellular
Non-lipid soluble drugs (e.g., many ____ blocking drugs) cannot easily enter cells. Therefore, it takes longer to absorb them.
neuromuscular
_____ drugs readily enter liver cells (one of the main sites of drug metabolism) and are consequently liable to be rapidly metabolized and inactivated. They can also cross the renal tubule easily and thus tend to be reabsorbed into the bloodstream rather than being excreted in the urine.
Lipid-soluble
In the distal tubule there is passive excretion and re-absorption of lipid soluble drugs. Drugs which are present in the glomerular filtrate can be reabsorbed in the tubules. The membrane is readily permeable to lipids so filtered lipid soluble substances are extensively reabsorbed.
Certain drugs cross cell membranes, particularly in the liver and kidney, with the help of special transport systems, which can be important factors in determining the __ at which drugs are metabolized and excreted.
rate
The liver makes drugs more polar to prevent reabsorption at the kidney tubules, this is especially important for lipid-soluble drugs.
https://www.youtube.com/watch?v=8c3gqI6R-Vw
In any living organism, the smallest unit capable of independent existence is the __.
cell
Each cell has specific functions that it must maintain to sustain life. Instructions for these activities are encoded within genes in the 23 chromosomes in the nucleus. Each cell has access to only a portion of the genes in the chromosomes.
A thread consisting of many genes strung together (large amounts of DNA) is called a ____.
chromosome
every somatic human cell has 23 chromosome pairs - one from each parent
An alteration in any part of DNA structure that results in permanent inheritable changes in cell function is called a mutation, and the agents that cause such mutations are known as genotoxic agents or ___.
genotoxins
There are three major types of genotoxic effects: gene mutations, chromosomal aberrations, and DNA effects.
There are three major types of ___ effects: gene mutations, chromosomal aberrations, and DNA effects.
genotoxic
Because no single in vitro assay is capable of detecting all three types, a battery of tests is recommended.
All 23 somatic human cell ____ have two chromatids that come together at a junction known as the centromere.
chromosomes
are large amounts of DNA, genes strung together. Each cell - except for gametes - has 46 chromosomes, 23 pairs
An alteration in any part of ___ structure that results in permanent inheritable changes in cell function is called a mutation, and the agents that cause such mutations are known as genotoxic agents or genotoxins.
DNA
Each cell has specific functions that it must maintain to sustain life. Instructions for these activities are encoded within genes in a _____.
chromosome
large amounts of DNA, genes strung together, can be divided into two chromatids that come together at a centromere
All human cells are diploid (the chromosomes are in pairs, one from each parent) except for ____ cells.
gamete
gamete cells are haploid (only 23 chromosomes, not in pairs)
The ____ of any organism contains its complete genetic information.
genome
bacteria (prokaryotes) only have one chromosome, unprotected by a membrane
eukaryotes (animals and plants + fungi and protists) have a set of chromosomes housed in a protected sheath (usually the nucleus and the mitochondria)
https://www.youtube.com/watch?v=tsVHWbXqum8
Bacteria (prokaryotes) only have one _______, unprotected by a membrane
chromosome
Gene mutation and chromosomal aberration tests detect actual ____ in the DNA molecule, while DNA effects tests detect events that may lead to cell damage.
lesions
Mutations affecting a small portion of the DNA molecule, including frameshifts and base-pair substitutions, are referred to as ___ mutations.
point
https://www.youtube.com/watch?v=xYOK-yzUWSI
Many carcinogens are mutagens but some work by increasing the rate of cell division; and not all ____ are carcinogens.
mutagens
https://www.youtube.com/watch?v=xYOK-yzUWSI
The Ames bacterial reverse mutation assay is often used to detect ___.
mutagens
specifically: point mutations
Point mutations include:
frameshifts and base-pair substitutions
Ames:
https://www.youtube.com/watch?v=9sCHHD5dqy0
Point mutations include: ____ and ____ ______.
frameshifts, base-pair substitutions
Cells spend most of their life-cycle in _____, except for cancerous cells.
interphase
https://www.youtube.com/watch?v=U5vAO_f2LDQ
the other phase is mitosis
https://www.youtube.com/watch?v=VXLSTd_dlKg
DNA becomes tightly coiled into its ____ form at the end of mitosis when the cell undergoes cytokinesis (divides).
chromatin
Mitosis is the phase where cell divides into __ identical cells.
2
https://www.youtube.com/watch?v=TKGcfbyFXsw
___ is a process where one eukaryotic cell divides into two genetically identical daughter cells. The 4n cell distributes the chromosomes equally between the two new nuclei of the daughter cells.
Mitosis
Before mitosis begins, during interphase, the cell copies its genetic material (the 23 chromosome pairs) and goes from 2n to 4n.
Cytochrome p450 enzymes are proteins that have ____ as a cofactor.
heme
The cofactor combines with CO and shows max absorption at 450nm.
https://www.youtube.com/watch?v=Y5OQT4iwY8Y
Cytochrome p450 enzymes are proteins that have heme as a cofactor and are primarily found in the liver, functioning primarily in ___ .
detox
Metabolism of drugs: oxidize steroids, fatty acids, and xenobiotics, and are important for the clearance of various compounds, as well as for hormone synthesis and breakdown.
https://www.youtube.com/watch?v=ztsBn8gsfHw
Oxidation is an ____ movement reaction.
In cP450 enzymes, the heme (iron) cofactor reacts with oxygen and the iron loses some electrons; and the oxygen is reduced bc the oxygen has gained some electrons.
electron
Oxidation is the __ of electrons during a reaction by a molecule, atom or ion.
loss
the opposite (gaining electrons) is reduction
What is the difference between a molecule, atom, and ion?
Atom: smallest particle of an element, each element is classified by the # of protons in its nucleus (atomic #)
Element: a substance consisting of atoms that all have the same number of protons in its nucleus (atomic #)
Ion: an atom or molecule with a net electric charge (determined by the # of electrons)
An ____: the smallest unit of an element, each element is classified by the # of protons in its nucleus (atomic #)
Atom
Made of: electrons, neutrons, and protons.
An _____: a substance consisting of atoms that all have the same number of protons in its nucleus (atomic #)
Element
An ___: a particle, atom or molecule with a net electric charge (determined by the # of electrons)
Ion
____ are made of electrons, neutrons, and protons.
Atoms
neutral charge
___: a single bit of something; often used when referring to the smallest unit of something.
Particle
Often used to denote the parts of an atom:
Electrons, protons, and neutrons.
An atom has a net charge of ___.
zero
_____: an independent structure consisting of atoms chemically bonded together (with a covalent bond), electrically neutral.
Molecule
neutral charge
______ are electrically neutral.
Molecules (and atoms).
An ____ is formed when an atom or a molecule gains or loses electrons (with a resulting net charge greater or less than zero).
ion
ions can be monoatomic or polyatomic (consisting of only one type of atom or more than one type)
Most ______ are made of nonmetal atoms.
molecules
e.g. C(12)H(22)O(11) = table sugar
What is the difference between cytosol and cytoplasm?
Cytosol is the cell’s fluid outside the nucleus and the cytoplasm is all the fluid and all it contains.
Connective tissue is composed of living cells and protein fibers suspended in a gel-like material called ___.
matrix
The main functions of the different types of _______ tissue include providing support, filling in spaces between organs, protecting organs, and aiding in the transport of materials around the body.
connective
Connective tissue is composed of living cells and protein fibers suspended in a gel-like material.
The extracellular matrix of connective tissue is composed of ground substance and fibers. In ordinary connective tissue, the ground substance consists mainly of water. The principal fiber type is ____ (the most abundant protein in the body), with elastic fibers as a minor element.
collagen
____ is the most abundant protein in the body.
Collagen
is found in connective tissue, the extracellular matrix.
The Ames test uses a number of different strains of the bacterium Salmonella to reveal the presence of mutations. The mutant strains are unable to synthesize ______. When added potential mutagens and liver enzymes, a reverse mutation will occur and they will be able to grow.
histidine
The United States Pharmacopoeia (USP) has established standard preparation methods for materials testing that can be used for genotoxicity testing. ________ test systems are frequently exposed to 0.9% sodium chloride solution and either ethanol or dimethyl sulfoxide extracts.
Bacterial
Since in vitro mammalian test systems require media that can support cell growth, the nutrient medium used for culture is often employed as the extraction vehicle.
In vivo test models frequently employ the standard aqueous and nonaqueous USP extraction fluids that are capable of extracting both water- soluble (polar) and lipid-soluble (nonpolar) chemicals.
The test most commonly used to detect such point mutations is the Ames bacterial reverse mutation assay, which utilizes histidine-dependent _____ typhimurium strains as the test organisms.
Salmonella
active rat liver microsomes are incorporated into a portion of the test organisms to simulate whole-animal exposure.
In the ____ test, following exposure to the fluid extract from the test article, the organisms are plated in triplicate onto histidine-free growth nutrient agar and incubated for a specified period. The colonies are then enumerated and these data are compared to counts obtained for negative and positive control conditions. Since the unreverted test strains will not grow without histidine, any further growth indicates that exposure to a genotoxic agent has caused point mutations that have produced bacterial strains that no longer require histidine.
Ames
If the histidine-free agar plates have growth, then a mutation has occurred.
The ___ ___ ___ is another (besides Ames test) in vitro method for detecting gene mutations in a mammalian system.
mouse lymphoma assay
L5178Y mouse lymphoma cells are exposed to test extracts in the presence and absence of exogenous metabolic activation. Following incubation, the cultures are cloned in restrictive media for the mutant phenotype. Mutations are measured at the thymidine kinase locus to detect base-pair mutations, frameshift mutations, and small deletions. Since mutant colonies exhibit a characteristic size distribution frequency, colony measurements can be used to distinguish the type of genetic effect.
What methods can be used for chromosomal aberration testing?
Either in vitro or in vivo methods can be used.
These tests detect chromosomal damage induced after one
cellular division; structural changes in the chromosomes are evaluated while cells are in the metaphase stage of division. The in vitro model employs Chinese hamster ovary cells. As with other in vitro methods, the test system is evaluated in the presence and absence of exogenous metabolic activation. Most aberrations can be identified as either chromosomal or chromatid type. Gaps, breaks, and exchanges are other examples of observable aberrations.
Lipid-soluble drugs diffuse most ___ through the cell membrane.
rapidly
Small molecules tend to penetrate membranes more rapidly than larger ones.
Most drugs are weak ____ acids or bases, existing in un-ionized and ionized forms in an aqueous environment.
organic
Drug ____ occurs in the proximal tubule and is mediated by several factors including:
lipid solubility, polarity of the drug, and proportion carried inside red cells.
secretion
A _____ is the erratic (third) nucleus that is formed during the anaphase of mitosis or meiosis.
micronucleus
Micronuclei (the name means ‘small nucleus’) are cytoplasmic bodies having a portion of acentric chromosome or whole chromosome which was not carried to the opposite poles during the anaphase. Their formation results in the daughter cell lacking a part or all of a chromosome. These chromosome fragments or whole chromosomes normally develop nuclear membranes and form as micronuclei as a third nucleus. After cytokinesis, one daughter cell ends up with one nucleus and the other ends up with one large and one small nucleus, i.e., micronuclei. There is a chance of more than one micronucleus forming when more genetic damage has happened. The micronucleus test is used as a tool for genotoxicity assessment of various chemicals. It is easier to conduct than the chromosomal aberration test in terms of procedures and evaluation. Using fluorescent in situ hybridization (FISH) with probes targeted to the centromere region, it can be determined if a whole chromosome, or only a fragment is lost.
