Term
|
Definition
Irreversible loss of the ability to multiply under any circumstances
confusing because sometimes the bacteria can appear to be dead, but can come "back to life" |
|
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Term
|
Definition
complete killing or removal of all organisms from a particular
location |
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Term
|
Definition
1) heat
2) UV light
3) gamma radiation
4) filtration |
|
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Term
| types of heat sterilization |
|
Definition
1) incineration
2) dry heat
3) moist heat |
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Term
|
Definition
very efficient... very rapid, very hot! - what we do in lab.
NOTHING survives being incinerated. |
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Term
|
Definition
(160 degrees C, 2hrs) not very efficient. Has very poor
penetrating ability so we use it mainly for metals and glassware (not for linens). |
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Term
|
Definition
has better penetrating ability. Kills germs, but does NOT kill
spores. Today we use moist heat in the form of an Autoclave-chamber
where air is replaced with steam under pressure (115 degrees C, 15 psi,
15 min) can kill spores. Much more efficient (lower temp. and shorter
time)
pressure cooker is a household autoclave |
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Term
|
Definition
causes genetic damage by formation for thymine dimers drawback: the further the light has to travel the less sterilized it is. UV
light has poor penetrating ability (if there is a bacteria in a glass/plastic container and also dust (light bulb) |
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Term
|
Definition
causes breaks in the DNA, and it converts some of the
H2O inside the cell into toxic oxygen radicles. (peroxide, superoxide)anything in the hospital that is prepackaged and is sterilized has been nuked with radiation. |
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Term
|
Definition
for heat sensitive (serum and pharmaceuticals) use pore size
of ~0.2 micrometers. traps bacteria, but won't trap the virus.
disinfection: the use of chemicals to kill harmful microorganisms. Does not necessarily mean it's going to kill ALL microorganisms
Microorganisms differ in their sensitivity to disinfectants. |
|
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Term
| different kinds of disinfectants |
|
Definition
1) alcohol
2) halogens
3) phenol compounds
4) alkylating agents
5) Surfactants |
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Term
|
Definition
most commonly used disinfectant (very often misused)- kills
bacteria by very rapidly denaturing proteins. Does not kill bacterial spores,
and it has no effect on naked viruses.
misused in hospitals and when drawing blood. (touching after disinfecting
and can't penetrate blood soiled instruments.) |
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Term
|
Definition
a disinfection that is mild enough to be used in or on the body. Doesn't
mean it's going to kill ALL microorganisms |
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Term
|
Definition
very potent oxidizing agents...they will react with anything they come
into contact with |
|
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Term
|
Definition
Tincture- 2% I2 in 50% alcohol...kills faster and more efficiently
than just plain alcohol
disadvantage-some people are very sensitive to it (cause burning)
and it will stain whatever it comes into contact with.
Iodophor- I2 combined with organic compounds (detergents)...
causes much less skin irritation than the tincture...what we use to
prep before surgery, and what the Red Cross uses before you
donate blood
ex. Betadine, Wescodyne |
|
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Term
|
Definition
hypochlorous acid in H2O. When in H2O is dissociates to release
free Cl and that is what reacts as the oxidizing agent. This is your
basic chlorine bleach. Lethal within seconds to most bacteria/viruses. Used to clean surfaces in labs (that work with viruses), and
we use it to treat our drinking water (however it is not germ free).
Many protozoan cysts are resistant to chlorine bleach...and many
other microorganisms survive well too (GROSE!!)
ex. Cryptosporidium, Giardia, and Acanthamoeba (reason you
don't wash your contact lenses in tap water. |
|
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Term
|
Definition
cause a damage to bacterial membranes. They are toxic to us, and can burn the skin. Have been replaced by milder derivatives Alkyl Phenols (Cresols)-still have their germ killing ability...just aren't as toxic. They aren't very soluble in water, so they are mixed with emulsifying agents (detergents)
ex. Lysol, Pinesol) |
|
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Term
|
Definition
modify the structure of cell components (proteins,
nucleic acid...) by adding an alkyl group thereby damaging the function |
|
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Term
| Glutaraldehyde- 2% solution in H2O - |
|
Definition
an alkylating agent. very effective disinfectant that kills a
wide variety of microorganisms (bacteria, viruses, TB in 10-90 min &
bacterial spores in 10 hours...impressive b/c very few disinfectants kill bacterial spores)
uses to protect against hepatitis viruses against lab surfaces, and on
places that can't be sterilized but see alot of microorganisms
does cause irritation to the skin, eyes, and mucus membranes, so you
can't use it as an antiseptic on a person
ex. of products- Cidex, Sporicidin |
|
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Term
|
Definition
| an alkylating agent. - Hibiclens- is active against gram + and gram -... non irritating to the skin, and will persist on the skin wheras iodophors will not. can be used for skin wounds and to clean minor cuts and scrapes. |
|
|
Term
| Surfactants (Surface- Active Compounds) |
|
Definition
have both hydrophobic and
hydrophilic groups/regions. enable the compounds to attach to and solubolize a variety of "stuff" (your basic detergents) |
|
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Term
|
Definition
surfactants (soaps)- very good cleaners and have very little direct
germ killing ability (they will wash the germs off but not necessarily kill
them) |
|
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Term
|
Definition
surfactants-(quaternary ammonium compounds) - they will KILL
germs (sort of)- they damage the bacterial membranes- they have very low toxicicty to the skin and mucus membranes
ex. Zephiran, Cepacol
Drawbacks- more active against gram+ bacteria than gram - (some gram -
are even resistant to them), they will readily attach to dirt, cloth, anything they come into contact with which takes away from the germ killing ability...so wash your hands 2 times 1) get rid of the dirt and 2) to get rid of the germs. |
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Term
|
Definition
| 1st experiment on genetic exchange- he had virulant and avirulant strains of the same bacteria. He injected the live virulent into mice and they died (as suspected). So he killed the bacteria by boiling them then injected them into the mice and the mice lived (as suspected). then he injeced the avirulent bacteria into the mice and the mice lived (as suspected) then he mixed the two (killed virulent and avirulent) and the mice died and he recovered virulent bacteria from the corpses of the mice. he reasoned that the avirulent picked up the virulent trait from the dead bacteria (but didn't know what b/c then we didn't know what trait carried the virulance) transformation |
|
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Term
|
Definition
| repeated Griffeth's experiment but with a twist. He wanted to see what was transferred. He mixed a dead virulent and live avirulent with protease and injected this mixture into mice and they died (told him what was being transferred was NOT proteins). did the same thing with RNase and they died (told him what was being transferred was NOT RNA). did the same thing with DNase and they LIVED (told him that what was being transferred was DNA). this is the 1st experiment to prove that DNA carried genetic info. |
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Term
|
Definition
determined the structure of DNA- double helix. A-T & G-C, antiparallel, only one strand carries genetic information (sense strand) the complimentary strand (antisense strand), nucleotides are held together by phosphodiester bonds and A-T and G-C are connected with
Hydrogen bonding. |
|
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Term
|
Definition
makes a copy of the DNA using the parents as the
template |
|
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Term
| DNA synthesis (replication) |
|
Definition
1) Helicase- separates the 2 DAN strands; single-stranded binding proteins
(SSBP) keeps them from rejoining together
2) DNA has a leading and a lagging strand
3) on the leading strand, DNA polymerase synthesized a complementary
strand continuously as the strand opens
4) can't do the same on the lagging strand DNA polymerase synthesizes a
complementary strand in fragments (okazaki) because DNA polymerase can
only work in the 5'-3' direction
5) on the lagging strand primase adds RNA primers at interval along the
strand which provide starting points for DNA polymerase
6) DNA polymerase synthesized DNA between the primers
7) the primers are then removed and replaced by DNA
8) DNA ligase links the DNA fragments together |
|
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Term
|
Definition
| when a gene is expressed, that gene makes __. |
|
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Term
|
Definition
| DNA controls __ synthesis and RNA controls __ synthesis |
|
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Term
| two regions in the gene you need to know about |
|
Definition
|
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Term
|
Definition
| point where RNA polymerase binds (start site) |
|
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Term
|
Definition
|
|
Term
| two types of RNA that are being made by this process that we need to know |
|
Definition
Messenger RNA (mRNA)
Transfer RNA (tRNA) |
|
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Term
|
Definition
directs protein synthesis
base sequence of mRNA determines the amino acid sequence of protein
codon-sequence of 3 base pairs that code for a specific amino acid
remember RNA has Uracil (U) instead of Thyamine |
|
|
Term
|
Definition
carries amino acid to mRNA during protein synthesis
two specificities:
1) attaches to a specific amino acid
2) recognized a specific codon on a mRNA |
|
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Term
|
Definition
| sequence of 3 base pairs that code for a specific amino acid. |
|
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Term
|
Definition
|
|
Term
|
Definition
Start codon & MET - where protein synthesis starts
1) ribosome binds mRNA at start codon (AUG) |
|
|
Term
| ribosome has 2 sites on it |
|
Definition
A site and P site
tRNA-aa1(attached amino acid) binds at A site of ribosome, then shifts to P
site
tRNA-aa2 binds to A site
tRNA-aa1 at P site transfers its amino acid to tRNA -aa2 at A site, resulting
in tRNA-aa2-aa1 |
|
|
Term
| when tRNA loses its aa, it detaches from |
|
Definition
P site, tRNA-aa2-aa1 shifts to P
site opening up A site for another tRNA-aa3
another tRNA-aa3 binds to the A site
the process continues until we reach a stop codon |
|
|
Term
| Protein synthesis (translation) process |
|
Definition
1) initiation START (AUG) A-site
2) elongation A-site to P-site to detachment repeated over and over
3) termination stop codon (UAG, UGA, UAA) |
|
|
Term
Regulation of gene expression: bacteria (and us) only express the genes they need (turn on and off certain
genes). What regulates this process? |
|
Definition
lac operon: operon- group of closely related genes whose expression is
controlled by a single promotor. Remember a promoter is the starting point of
RNA synthesis. lac operon genes are involved in lactose metabolism. |
|
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Term
|
Definition
| codes for repressor which binds the operator in certain circumstances |
|
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Term
|
Definition
| for promotor which RNA synthase must bind to |
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Term
|
Definition
|
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Term
|
Definition
| produced enzymes needed for lactose metabolism |
|
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Term
|
Definition
occurs in the absence of lactose: R gene coded for
repressor which binds to operator, preventing RNA polymerase from
expressing genes genes |
|
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Term
|
Definition
occurs in the presence of lactose: lactose binds to
repressor, preventing it from binding to operator. RNA polymerase can now
express structural genes, but only at a LOW level. |
|
|
Term
|
Definition
| High Level of AMP are needed for full expression of structural genes. (in the presence of Lactose no glucose can be present). |
|
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Term
| Three mechanisms of control |
|
Definition
| Repression control, Induction control, Catabolite Activation |
|
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Term
|
Definition
a change in the base sequence of DNA that is passed to the next
generation. Can occur as a result as the addition or deletion of one or more
bases, or the substitution of one base for another |
|
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Term
|
Definition
| point mutation, frameshift mutation, |
|
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Term
|
Definition
most common type of mutation-change in one base in the
DNA molecule. Ex. DNA=GAC-> mRNA=CUG -> a.a. luecine / DNA=
GCC -> mRNA= CGG -> a.a. = arginine. (results in a missense or
nonsense) |
|
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Term
|
Definition
| addition or deletion a base. almost always results in a non-functioning protein because it alters the reading frame of the mRNA |
|
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Term
|
Definition
| nonsense mutation, missense mutation |
|
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Term
|
Definition
changing the codon that results in the wrong amino
acid being added |
|
|
Term
|
Definition
resulting the the codon being changed to a stop codon
where it was not at first. you end up with only part of a protein that is
usually non functioning. |
|
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Term
|
Definition
| spontaneous mutation, induced mutation |
|
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Term
|
Definition
mutation that occurs naturally. Nothing caused it.
DNA polymerase just added the wrong base when making the copy of
DNA |
|
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Term
|
Definition
mutation that has been caused by chemical or physical
agents |
|
|
Term
|
Definition
UV light-formation of thymine dymers (unless it can be
repaired a wrong base is inserted), radiation-causes breaks in the DNA (put in the wrong bases to fill in the gaps)- oxygen radicles inside the cell
(change the structure of DNA). |
|
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Term
|
Definition
Intercalating agent- inserts between bases in DNA then
mistaken for a base in DNA synthesis resulting in addition of a base
(cause frameshift mutation). ex. acridine, base modifiers- modify the
structure of the base so that it is mistaken for another base so that it is
mistaken for another base during DNA synthesis. ex. Nitross acid
(modifies C to pair with A instead of G). Base analog- replaces a base in
DNA pairs with a different base. ex. 5-bromouracil replaces T and pairs
with G vs. A. (alot of anit-tumor med. are these guys and target tumorsinducing
lethal mutations on cancer cells). |
|
|
Term
| Photoreactivation (light repair) |
|
Definition
where light (sunlight-visible) is used to repair
DNA (specifically repairs thymine dimers caused by UV light). DNA
photolyase is energized by visible light to do the repair.
Excision Repair-you have a damaged portion of DNA, damaged region is going
to be removed. Gap is filled in by DNA polymerase using complementary
strand of DNA as a template |
|
|
Term
|
Definition
occurs when there is overlapping damage on the strand of DNA.
Starts out like excision repair and repairs one strand at a time using the
complimentary strand as a template until it reaches the damage on the
complimentary strand (it can't read the damage). It inserts random bases and
hopes for the best. Then it will start on the second strand by the same
mechanism. SOS repair almost always result in a mutation (how radiation
causes mutaion). |
|
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Term
|
Definition
|
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Term
|
Definition
transfer o DNA from 1 bacteria to another by means of a
virus |
|
|
Term
|
Definition
| direct exchange of DNA from bacteria to bacteria |
|
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Term
|
Definition
uptake of DNA that has been released into the environment
(experiment of Fred Griffith-virulent and avirulent bacteria). Not all bacteria are
capable of this. |
|
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Term
|
Definition
means they have the ability
to take in exogenous DNA and incorporate it into their own DNA. Catch: DNA that is taken in and incorporated must be from the same, or closely related,
species. |
|
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Term
|
Definition
| E.coli does not normally is not normally competent, but we can make it competent by a process called __ (induced competence). |
|
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Term
|
Definition
| virus that infects bacteria (species specific) |
|
|
Term
| two types of transductions based on the two types of bacteriophages |
|
Definition
| Generalized transduction, specialized transduction |
|
|
Term
| Generalized transduction --full definition |
|
Definition
| Lytic infection (fatal to the cell) bacteriophage has a gene that encodes DNA to take over the cell by degrading bacterial DNA. Viral segmented DNA is then recopied to a full length and a protein coat is assembled around each copy. Occasionally a protein coat will be assembled around a piece of bacterial DNA, so when the cell lyses, instead of transferring a virus it transfers a piece of bacterial DNA (random piece of DNA)that will be incorporated into the other DNA. |
|
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Term
| Specialized transduction--full definition |
|
Definition
lysogenic infection (non fatal, but can switch to lytic cycle and become fatal.)
Viral DNA inserts itself into the Bacterial DNA (a specific region). Converts to lytic-> viral DNA will remove itself from the Bacterial DNA, but it has a tendency to take a piece of the bacterial genome with it. it chews up the bacterial DNA, makes multiple copies of the viral DNA (with small segment of Bacterial DNA attached to it), assembles a protein coat around it. Cell lyses, bursts, releasing all the copies, and they infect other cells inserting the viral DNA with the bacterial DNA also. Simplified it's the transfer of a specific region of the bacterial DNA).
because it inserts itself in the same spot everytime |
|
|
Term
| Generalized transduction simplified |
|
Definition
| can take any type of bacterial DNA with it because it is it starting with cut up strands of bacterial DNA. (random piece of bacterial DNA) |
|
|
Term
| Specialized transduction simplified |
|
Definition
| begins with lysogenic infection because it inserts itself at a specific point region of the bacterial genome everytime. changes to lytic (death cycle) and transfers a specific piece of bacterial DNA everytime. REASON: because it inserts itself first then removes itself. inserting itself at the same point of the bacterial genome everytime ensures removal of the same genes everytime! |
|
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Term
|
Definition
| transfer of plasmids between bacteria by sex pilus. Genes are carried on the F plasmid. goes from F+ to F- and F+ to F+, but never from F- to F- (they don't have the plasmid). Results in 2F+ cells. Usually take place between same or closely related species. |
|
|
Term
|
Definition
| bacteria that contain the F plasmid |
|
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Term
|
Definition
| bacteria that lack the F plasmid |
|
|
Term
| F+ to Hfr (high frequency recombination) |
|
Definition
when the plasmid is inserted into
the bacterial genome. Act just like plasmid, but when they undergo conjugation they have the ability to transfer their bacterial genes along with the plasmid |
|
|
Term
|
Definition
contains structural genes and part of the plasmid. Are considered
the same as F- because the only way to get the sex pilus gene is to transfer the entire genome...which usually doesn't happen. |
|
|
Term
| Plasmids are important because |
|
Definition
| they usually carry genes for antibiotic resistant as well as for bacterial toxins. |
|
|
Term
| F+, F-, Hfr, F' (summary) |
|
Definition
| contains at least one plasmid with sex pilus gene, contains no plasmid or sex pilus gene, contains plasmid inserted into bacterial genome with sex pilus gene, contains structural genes and a partial plasmid with no sex pilus gene |
|
|
Term
| why is the sex pilus gene important? |
|
Definition
| must have it to undergo conjugation. Without the sex pilus gene there is no way to undergo conjugation and the cell acts as if it was F- |
|
|
Term
| Ways genetic recombination can occur |
|
Definition
| transformation, plasmid inserting itself into the bacterial genome (Hfr), bacteriophage injecting DNA into the bacterial cell |
|
|
Term
| DNA taken in by the bacteria is either |
|
Definition
broken down (degraded)- what happens when it is from foreign DNA (ex.
from a different species or non-closely related species, or undergoes recombination into bacterial DNA (must be closely related
species or better yet same species...or plasmid |
|
|
Term
| Enzymes involved in recombination |
|
Definition
| Restriction Endonuclease and DNA methylase |
|
|
Term
|
Definition
cleaves (cuts) DNA at a specific base
sequence and involved in degrading foreign DNA. makes "Sticky ends" |
|
|
Term
|
Definition
protects the bacterias own DNA from being cut by
its own Endonuclease |
|
|
Term
|
Definition
| are very important in recombination because its where the new strand of DNA will be inserted |
|
|
Term
| Polymerase chain reaction (PCR) |
|
Definition
| makes many many many copies of DNA |
|
|
Term
|
Definition
| Separates fragments, (smallest fragments move the farthest down the gel) |
|
|
Term
|
Definition
Use of a specific probe to locate a
specific gene in DNA. |
|
|
Term
|
Definition
| Make a small portion of gene using a __ __, add a fluorescent dye to the __ __, put sheet in dish of buffer containing DNA probe. What happens is the base sequence of the DNA probe pairs up with the base sequence of the DNA. when we look at it under florescent light it glows, and we just located the potential altizhemers treatment!! |
|
|
Term
| Use of Recombinant Technology in medicine |
|
Definition
PCR to diagnose infections-used to diagnose diseases that are too
dangerous or too hard to grow in a lab
Recombinant vaccines (ex. Hepatitis B)
Transgenic animals (recombinant mice/rats/rabbits-used to develop diseases
that they don't normally have but humans might get so we can learn better
ways to treat like diabetes, morbid obesity, Alzheimer's). |
|
|
Term
| Use of Recombinant technology in agriculture |
|
Definition
Recombinant bacteria to protect crops from frost (ex. strawberries)
Recombinant crops to produce medicines
Super bacteria to kill crop-damaging insects |
|
|
Term
| Use of recombinant technology in industry |
|
Definition
Recombinant bacteria to degrade pollutants.
Recombinant bacteria to clean up oil spills
Recombinant bacteria to replace chemicals in manufacturing |
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