Ch 7/8 medical micro

what does the virulence plasmid do?

carry instructions for structures, enzymes or toxins that enable a bacterium to become pathogenic

What is used to automate PCR?

thermocycler

what is the first step of converting DNA into RNA?

transcription

describe negative selection in mutant testing.

selecting for an auxotroph (looking for something that all other wild type cells can do, but others can't).

A daughter DNA molecule is composed of one original strand and one new strand because DNA replication is _________

semiconservative

A DNA microarray consists of

D. single-stranded DNA localized on a substrate.

T/F? Restriction enzymes act at a specific nucleotide sequence within a double stranded DNA molecule

true

T/F? Translation steps require additional protein factors that assist ribosomes.

true

T/F? protoplast fusion is often used in the genetic modification of plants

true

T/F? the Leading strand and Lagging strand are synthesized simultaneously

true

Why are ribosomes important in targeting pathogens?

you can target prokaryotic ribosomes without deleterious affects on eukaryotic ribosomes due to different sizes and subunits.

how does a repressor gene affect the inducible operon?

repressor binds to promoter region and transcription cannot happen.

what can the methylation of DNA do?

can control genetic expression, can initiate DNA replication, can protect against viral infections and can repair DNA

what does the Bacteriocin plasmid do?

carry genes for proteinaceous toxins called bacteriocins that kill bacterial cells of same or similar species that lack this plasmid.

what do Resistance plasmids do?

carry genes for resistance to antimicrobial drugs or heavy metals. These plasmids can be transferred to other cells.

What is the role of mRNA?

carry genetic information from chromosome to ribosome as codons that encode order of amino acid sequences in polypeptide.

What is the function of DNA?

carry information in sequences of nucleotide bases in DNA and RNA.

what do Fertility plasmids do?

carry instructions for conjugation.

What is a wild type?

cells normally found in nature

How do Frameshift mutagens affect genes?

chemicals can insert or delete nucleotide base pairs. Results in nonsense mutations.

what structures house prokaryotic DNA?

chromosomes and plasmids

A triplet of mRNA nucleotides that specifies a particular amino acid is called a _________

codon

What is rRNA?

combine with ribosomal polypeptides to form ribosomes which synthesize polypeptides

What is horizontal gene transfer?

common in prokaryotes, donor cell donates part of its genome to recipient cell

why is reverse transcriptase used in recombinant DNA technology?

complementary DNA can then be inserted into prokaryotic cells (eukaryotic mRNA already processed to remove introns) so they can produce the eukaryotic proteins

What is a DNA microarray?

consists of molecules of single stranded DNA, either genomic DNA or complementary DNA immobilized on glass slides, silicon chips, or nylon membranes

what are complex transposons?

contain one or more genes not connected with transposition. R plasmids often contain transposons. R factors great concern because they spread antibiotic resistance among pathogens

is the leading strand synthesized discontinually or continually?

continually

What gives bacteria protection against viral infection? How does it work?

restriction enzymes. these enzymes will destroy unmethylated DNA. Virus DNA is not methylated so it will destroy virus DNA.

where are eukaryotic chromosomes located? what is their shape? haploid or diploid?

nucleus. they are linear. diploid

Define translation

ribosomes use the genetic information on nucleotide sequences to synthesize polypeptides composed of specific amino acid sequences.

What are transposons?

segments of DNA that move themselves from one location in a DNA molecule to another location in the same or a different molecule. results in frameshift insertion.

summarize what happens in the termination step of translation.

release factor proteins halt elongation. Release factors recognize stop codons and modify larger ribosomal subunit to activate ribozyme to sever polypeptide from final tRNA.Ribosome dissociates into its subunits.

What are the 3 steps of PCR?

1. Denaturation 2. priming 3. Extension

A DNA gene sythesized from an RNA template is

B. complementary DNA

What is the A site?

acceptor site

what is the point of translation?

turn RNA into protein

What are the differences in Eukaryotic replication to prokaryotic replication?

-Euk. has 4 types DNA polymerase -More than one replication origin per chromosome -shorter Okazaki fragments -plant and animal cells will methylate cytosine bases

What are the differences between eukaryotes and prokaryotes in transcription?

-RNA transcription happens in nucleus, or mitochondria/ chloroplast -uses 3 types of RNA polymerases -uses numerous transcription factors -mRNA must be processed before it can be used as message to make protein

what are the differences between eukaryotes and prokaryotes in translation?

-initiation occurs when small ribosomal subunit binds to 5' guanine cap -one gene and one mRNA transcript -no formal methionine, only regular methionine. -ribosomes of rough ER can synthesize polypeptides into cavity of rough ER.

What are some of the uses of real time PCR?

-used in healthcare to monitor progression of disease and effectiveness of treatment. -used for finding out the number of new molecules of double stranded DNA by using a dye -used to determine the number of copies of a specific mRNA in a cell which can determine the expression level of the corresponding gene.

what are the 3 uses of DNA microarrays?

1. Monitoring gene expression 2. Diagnosing infection 3. Identifying organisms in environmental sample

what are the 3 main goals of recombinant biotechnology?

1. To eliminate undesirable phenotypic traits in humans, animals, plants, and microbes. 2. to combine beneficial traits of two or more organism s to create valuable new organisms. 3. to create organisms that synthesize products that humans need.

85 year old woman admitted to a hospital after breaking her hip. While in the hospital, she acquired a life threatening infection of multi- drug resistant Enterococcus faecium. While this bacteria is a commensal organism and a normal part of the human gut microbiota, it's not normally antibiotic resistant. 1. why did this bacteria become resistant to antibiotics in the patient? 2. list three ways in which this bacterial might have acquired the genes for drug resistance? 3. how could hospital personnel prevent the spread of the resistant bacteria throughout the hospital?

1. Well, basically it has gained that antibiotic resistance gene. That means it has acquired this gene somehow. 2. Well, our three ways we know of, we've got our transformation. It could have gotten it from the environment. It could have gotten it from transduction where maybe there's some virus involved, or conjugation. Conjugation, that's your bacteria sex. 3. So if you want to make sure this bacteria doesn't go anywhere else, you need to make sure that this patient is completely isolated away from other people so then that way this bacteria can't go to another patient.

what are the 5 reasons Synthetic nucleic acids are used in recombinant DNA technology?

1. allowed scientist to elucidate genetic code. 2. creating genes for specific proteins 3. synthesizing DNA and RNA probes to locate specific sequences of nucleotides 4. synthesizing antisense nucleic acid molecules- Can be used to control genetic diseases. 5. synthesizing PCR primers

How can a lab tech prove that a patient is infected with HTLV-1 even though there is no sign of cancer?

1. can get patient DNA, order primers against virus and run PCR. If you get a band, means you have amplified viral DNA and there is virus DNA inside patient sample. OR 2. can do southern blot because you can run out DNA from the patient. Can have probe against viral DNA and if it finds itself in that sample, you know you have virus in patient sample.

what are the 5 agriculture applications in recombinant technology?

1. herbicide tolerance 2. pest resistance 3. salt tolerance 4. freeze resistance 5. improvements in nutritional value and yield

what are the 7 medical applications of recombinant biotechnology?

1. protein synthesis 2.vaccine production 3. genetic screening 4. gene therapy 5. medical diagnosis 6. xenotransplantation 7. biomedical animal models

How does replication stop in prokaryotes?

2 replication forks meet each other

summarize what happens in initiation of translation.

2 ribosomal subunits, mRNA, protein factors and tRNAfMet form initiation complex. In bacteria an occur while cell transcribes mRNA from DNA.

a 100 base pair piece of the Mycobacterium tuberculosis genome is 20% adenine. So, what percentage of guanine nucleotides are present in the piece?

20% adenine= 20% thymine = 40 % A/T 60% is made up of G/C 60/2= 30% Guanine

in which direction does DNA polymerase replicate?

5' to 3'

Which of the following is most likely the number of base pairs in a bacterial chromosome? a. 4,000,000 b. 4000 c. 400 d. 40

A (4,000,000)

Which recombinant DNA technique is used to replicate copies of a DNA molecule?

A. PCR

Which application of recombinant DNA technology involves replacing a nonfunctional, mutated gene with a functional gene?

A. gene therapy

what are some of the methods used to find mutants?

Ames test, positive selection, negative (indirect) selection.

Restriction enzyme Hha1

B. cuts DNA at a specific nucleotide sequence.

Which of the following would be most useful in following gene expression in a yeast cell?

C. DNA microarray

Which of the following techniques is used regularly in the study of genomics?

C. Fluorescent nucleotide bases are sequenced.

After scientists exposed cultures of Penicillium to agents X, Y, and Z, they examined the type and amount of penicillin produced by the altered fungi to find the one that is most effective. Agents X, Y, and Z were probably

C. mutagens

how do nucleotide analogs affect genes?

Can lead to inhibiting DNA replication or or result in mismatch base pairing. can also kill cancer and viral cells because presence of nucleotide or nucleoside is deleterious to cell

if you think a patient has a viral infection, what kind of test can you run on patient sample?

Can use southern blot. Can find viral piece of DNA in chromosome.

Which of the following statements is true concerning recombinant DNA technology?

D. It involves modification of an organism's genome.

Which of the following is false concerning vectors in recombinant DNA technology?

D. Vectors must contain genes for self-replication.

Why is the accuracy DNA transcription more important than the accuracy of RNA transcription?

DNA has only 1 copy (if haploid) so its important to be perfect. RNA polymerase can keep making RNA transcripts and produces many copies. If one RNA is messed up, it's okay another one that was made will be better.

Why can't DNA have covalent bonds between the 2 strands?

DNA needs to be able to come apart easily. Would take lots of energy to break those bonds. Hydrogen bonds are easy to separate and don't require too much energy.

what type of DNA polymerase in prokaryotes adds nucleotides in DNA replication?

DNA polymerase 3

what enzyme is responsible for adding nucleotides to the chain of DNA?what type of DNA polymerase is used in bacterial DNA replication?

DNA polymerase. DNA polymerase 3 used.

How does gel electrophoresis work?

DNA samples loaded into wells, drawn through semisolid gel by electric currents toward positive electrode. Gel acts a sieve and separate segments by size. Small segments move faster and farther than larger ones. Size of fragment determined by comparing distance traveled to distance traveled of standard DNA fragments of known sizes.

What is the central dogma of molecular biology?

DNA transcribed into RNA, RNA translated to form proteins/ polypeptides.leads to phenotype (if applicable)

Why is DNA antiparallel?

Each chain has a 5' end and a 3' end & they run in opposite directions.

what are the 3 artificial methods of introducing DNA into cells?

Electroporation, Protoplast fusion, Injection

what are the 2 different types of cuts restriction enzymes can make?

First type is staggered cuts of 2 strands of DNA producing fragments with sticky ends. Second type of cut is cutting both strands of DNA at the same point resulting in blunt ends

how can radiation affect genes?

Gamma and X rays are ionizing radiation causing free electrons to escape from atoms, free electrons strike other atoms to produce mutations. Electrons and ions can also break bonds in DNA backbone. UV light is nonionizing and causes adjacent pyrimidine bases to covalently bond together

what is injection in artificial DNA introduction?

Gene gun used and powered by blank .22 caliber cartridge or compressed gas to fire tiny tungsten or gold beads coated with DNA into a target cell. Microinjection uses DNA inserted into target cell with glass micropipette with very small nucleus.

explain self termination in the termination of RNA polymerase in transcription.

Hairpin loop forms inside RNA molecule, puts tension on union of RNA polymerase and DNA. When the RNA polymerase reach adenosine rich portions cannot withstand tension so the RNA transcript breaks away from DNA which releases RNA polymerase.

why do eukaryotic cells have to process mRNA before translation? What can mRNA do after it has been processed?

Has to remove the noncoding (intron) regions to make the strand shorter. after processing, can exit nucleus and meet with ribosome

what are synthetic nucleic acids?

Molecules of DNA and RNA produced in cell free solutions.

what type of blot is used for RNA?

Northern blot

The lagging strand is synthesized using what kind of fragments? How are the fragments joined?

Okazaki fragments. Fragments joined with ligase.

What is PCR?

Polymerase Chain Reaction; used to amplify DNA without a cell.

summarize what happens in termination of transcription.

RNA polymerase and transcribed RNA released from DNA. RNA not easily removed from DNA. Termination can be self-terminating or Rho dependent termination.

summarize what happens in initiation of transcription.

RNA polymerase binds to DNA nucleotide promoter sequence near beginning of gene and initiates transcription. In bacteria, sigma factor needed for recognition of promoter. RNA polymerase unzips/unwinds DNA molecule in promoter region and travels along DNA unzipping double helix. Sigma factor drops off as transcription proceeds.

summarize what happens in elongation stage of transcription.

RNA polymerase links ribonucleotides (ATP, UTP, GTP, CTP) to complementary DNA in the open DNA strand using energy from phosphate bond. Enzyme moves down DNA strand elongating RNA strand. Only 1 strand of separated DNA is transcribed.

What are the 4 types of RNA transcribed from DNA?

RNA primer, mRNA, rRNA, tRNA

what are 2 techniques in genetic mapping used to locate genes?

Restriction fragmentation, Fluorescent in situ hybridization (FISH)

explain Rho protein termination in RNA polymerase termination in transcription.

Rho protein binds to specific RNA sequence near end of RNA transcript. Rho moves toward RNA polymerase at 3' end on growing RNA molecule which pushes between RNA polymerase and DNA strand and forces them apart.

why can prokaryotes transcribe and translate at the same time?

Transcription and translation occurs in cytosol, lead to ribosomes being able to begin translation before transcription is finished.

Why can't eukaryotes transcribe and translate at the same time?

Transcription occurs in nucleus and translation occurs in ribosomes in cytoplasm.

what are southern blots used for?

Used for diagnosis of infectious disease. Good for organisms that cant be cultured.

In prokaryotes, where does DNA methylation occur? why is this important?

Usually only adenine bases, sometimes cytosine too. This is important because it is how the organisms can control genetic expression, can initiate DNA replication, can protect against viral infections and can repair DNA

Ligase plays a major role in a. lagging strand replication b. mRNA processing in eukaryotese c. polypeptide synthesis by ribosomes d. RNA transcription

a

The Ames test a. uses auxotrophs and liver extract to reveal mutagens b. is time intensive and costly c. involves the isolation of a mutant by eliminating wild-type phenotypes with specific media d. proves that suspected chemicals are carcinogenic

a

The addition of ---CH₃ to a cytosine nucleotide after DNA replication is called a. methylation b. restriction c. transcription d. transversion

a

Which of the following molecules functions as a "proofreader" for a newly replicated strand of DNA? a. DNA polymerase III b. primase c. helicase d. ligase

a

Which of the following statements is true? a. conjugation requires a sex pilus extending from the surface of a cell b. conjugation involves a C factor c. conjugation is an artificial genetic engineering technique d. conjugation involves DNA that has been released into the environment

a

What is a silent mutation?

a base pair substitution that does not change amino acid sequence due to redundancy in genetic code

the tryptophan operon is repressible. this means it is usually _____________ and is directly controlled by ______________.

active, a repressor

how are vectors/plasmids used in recombination DNA technology?

after restriction enzyme cuts DNA molecule with gene of interest into fragments with sticky ends, ligase anneals fragments to produce recombinant plasmid. Recombinant plasmid inserted into bacterial cell. Bacteria grown on medium containing antibiotic. Only cells that contain recombinant plasmid can grow on medium.

during translation what do polyribosomes in prokaryotes allow for?

allows for multiple ribosomes to make proteins at the same time

is DNA replication anabolic or catabolic?

anabolic

where are restriction sites usually located?

at palindromes (same sequence forward or backward).

A sequence of nucleotides formed during replication of the lagging DNA strand is a. a palindrome b. an Okazaki fragment c. a template strand d. an operon

b

Repressible operons are important in regulating prokaryotic a. DNA replication b. RNA transcription c. rRNA processing d. sugar catabolism

b

The trp operon is repressible. This means it is usually _______________ and is directly controlled by ______________ a. active / an inducer b. active / a repressor c. inactive / an inducer d. inactive / a repressor

b

Transcription produces a. DNA molecules b. RNA molecules c. polypeptides d. palindromes

b

Which of the following is part of each molecule of mRNA? a. palindrome b. codon c. anticodon d. base pair

b

briefly summarize bacterial conjugation gene transfer. why is this a concern?

bacteria sex with pilus. Requires physical contact between donor and recipient cells. transfers F plasmid from donor to recipient cell. is concern due to spread of resistance plasmids

What is a nonsense mutation?

base pair substitution changes amino acid codon into STOP codon. Results in nonfunctional proteins.

How do DNA microarrays work?

by measuring the amount of mRNA for every gene that is present in a cell sample so that scientists can determine which genes are turned on and which are turned off. Single strand of fluorescent labeled DNA washed over array and adhere only to locations on the array where there are complementary DNA sequences.

How does genotype determine phenotype?

by specifying the types of RNA and the structural, enzymatic, and regulatory protein molecules are produced. The phenotypic traits result from the actions of RNA and protein molecules that are encoded by DNA

Although two cells are totally unrelated, one cell receives DNA from the other cell and incorporates this new DNA into its chromosome. This process is a. crossing over of DNA from the two cells b. vertical gene transfer c. horizontal gene transfer d. transposition

c

In DNA, adenine forms __________________hydrogen bonds with _________________. a. three / uracil b. two / uracil c. two / thymine d. three / thymine

c

Which of the following forms ionic bonds with eukaryotic DNA and stabilizes it? a. chromatin b. bacteriocin c. histone d. nucleoid

c

Which of the following is a true statement concerning prokaryotic chromosomes? a. They typically have two or three origins of replication b. They contain single-stranded DNA c. They are located in the cytosol d. They are associated in linear pairs

c

Which of the following is not a mechanism of natural genetic transfer and recombination? a. transduction b. transformation c. transcription d. conjugation

c

Which of the following is not part of an operon? a. operator b. promoter c. origin d. gene

c

Which of the following methods of DNA repair involves enzymes that recognize and correct nucleotide errors in unmethylated strands of DNA? a. light repair of T dimers b. dark repair of P dimers c. mismatch repair d. SOS response

c

How do nucleotide altering chemicals affect genes?

can alter structure of nucleotides by base pair substitutions and missense mutations

What are the 2 ways RNA polymerase stops in transcription?

can be self-terminating or Rho dependent termination.

_______________ _______________ is a recombination event that occurs during gamete formation in eukaryotes.

crossing over

A nucleotide is composed of a. a five-carbon sugar b. phosphate c. a nitrogenous base d. all of the above

d

A plasmid is a. a molecule of RNA found in bacterial cells b. distinguished from a chromosome by being circular c. a structure in bacterial cells formed from plasma membrane d. extrachromosomal DNA

d

Before mutations can affect a population permanently, they must be, a. lasting b. inheritable c. beneficial d. all of the above

d

Cells that have the ability to take up DNA from their environment are said to be a. Hfr cells b. transposing c. genomic d. competent

d

In translation, the site through which tRNA molecules leave a ribosome is called the a. A site b. X site c. P site d. E site

d

Nucleotides used in the replication of DNA a. carry energy b. are found in four forms, each with a deoxyribose sugar, a phosphate, and a base c. are present in cells as triphosphate nucleotides d. all of the above

d

Which of the following are called "jumping genes"? a. Hfr cells b. transducing phages c. palindromic sequences d. transposons

d

What is the role of tRNA?

deliver the correct amino acids to ribosomes based on sequence of nucleotides in mRNA

what is a mutant?

descendant of a cell that does not repair a mutation

what is functional genomics? what are 2 methods used?

determining what genes products do. gene knockout and over expression method used.

is the lagging strand synthesized discontinually or continually?

discontinually

Summarize the lac operon

lactose binds and inactivates repressor. RNA polymerase can then bind to the now free promoter region and will make mRNA

why is DNA replication semiconservative?

each daughter DNA molecule is made up of one original stand and one new strand of DNA.

what is electroporation?

electric current used to puncture microscopic holes through a cells membrane so DNA can enter cell from environment

What is reverse transcriptase?

enzyme that usually comes from retroviruses, creates a complementary DNA strand from RNA template.

What do gyrase and topoisomerase do?

enzymes that unwind any excessive supercoiling by cutting DNA and rotating cut ends to undo supercoiling, and then rejoin ends

what is genetic recombination?

exchange of nucleotide sequences between 2 DNA molecules and involves segments that are composed of identical or nearly identical nucleotide sequences called homologous sequences

what happens in denaturation of PCR?

exposure to heat 94*C separates DNA strands by breaking hydrogen bonds between base pairs.

T/F? Gel electrophoresis is used in DNA microarrays

false, Southern blot is used

T/F? A thermocycler separates molecules based on their size, shape, and electrical charge

false, electrophoresis

T/F? restriction enzymes inhibit the movement of DNA at specific sites

false, it cuts DNA at specific sites

describe the Ames test.

fast inexpensive way to screen for mutants of salmonella. tests for potential mutagens if the beginning mutant salmonella reverts back to wild type.

describe positive selection in mutant testing.

fast, easy, cheaper method. Selecting a mutant by eliminating wild type phenotypes (looking for cell to do what majority of others can't).

what are the different types of plasmids in prokaryotes?

fertility plasmids, resistance plasmids, bacteriocin, virulence plasmids.

in a triplet of codons, which letters have the most effect on the type of amino acid coded?

first 2 nucleotides determine amino acid and third nucleotide has no effect

What is RNA primer?

for DNA polymerase to use during replication

insertions and deletions in the genetic code are also called __________ mutations.

frameshift

are prokaryotic cells haploid or diploid?

haploid

bacterial DNA replication is bidirectional. what does this mean?

happens in both left and right directions from origin

what enzyme unwinds DNA? how does it do it?

helicase. breaks hydrogen bonds between bases and exposes the replication fork site

why is the regulation of proteins synthesis important?

helps the cell conserve energy by not making proteins that are already available

What is a mutation?

heritable change in nucleotide base sequence of genome. Mostly deleterious, or can rarely improve ability of organisms and offspring to survive and reproduce.

What are restriction enzymes?

in bacterial cells, cut double stranded DNA molecules only at locations called restriction sites (unmethylated sequences)

In general, ___________ operons are inactive until the substrate of their genes polypeptides is present.

inducible

what 2 steps of translation require energy?

initiation and elongation

The tree steps in transcription are__________, ____________, __________

initiation of transcription, elongation of the RNA transcript, termination of transcription

What are the 3 steps of translation?

initiation, elongation, termination

what are the simplest transposons?

insertion sequences- no more than 2 inverted repeats and gene that encodes enzyme transposase.

What is a frameshift mutation? what are the types of frameshift mutations?

insertions or deletions in DNA code, new sequence of codons produced so new polypeptide produced. Affects all codons. very deleterious. consists of inversions or duplications.

what is recombinant biotechnology?

intentionally modifying the genomes of organisms by natural processes for practical purposes. Creates GMO.

describe the structure and location prokaryotic chromosomes (genome).

it is circular and is located in nucleic region.

what is genetic mapping? what information can it provide?

locating genes on a nucleic acid molecule. provides info on organism's metabolism and growth characteristics and potential relatedness to other microbes.

what 3 types of RNA are needed for translation to occur?

mRNA, tRNA, ribosomes and rRNA.

What is the point of transcription?

make mRNA from DNA strand

what are the 3 different types of RNA interference?

microRNA (miRNA) small interfering RNA (siRNA) Riboswitch

In eukaryotes, in what structures can you find extranuclear chromosomes?

mitochondria or chloroplast

what happens in priming of PCR?

mixture of DNA primers, DNA polymerase, and the 4 deoxyribose triphosphates added to target DNA. Temp is 65*C

what are the Tools of recombinant DNA technology?

mutagens, reverse transcriptase, synthetic nucleic acids, restriction enzymes, vectors

what is DNA overall charge?

negative

If you want to find a mutant of methacin resistant staph. aureus that was no longer resistant to methacin, what type of test would you do?

negative selection because you want to look for the few cells that cannot o what the majority wild type of cells can do.

in general, do eukaryotes have plasmids? who are the few exceptions?

no they usually do not. exceptions are Some fungi, algae, protozoa.

why is tax polymerase used in PCR?

not denatured at 94*C so it doesn't need to be replenished after each cycle.

what is a vector?

nucleic acid molecules like viral genomes, transposons, plasmids that deliver a gene into a cell.

Where does transcription occur in prokaryotes?

nucleoid region

Where does DNA replication begin?

origin

where does DNA replication begin?

origin

What is a phenotype?

physical features and functional traits of an organism including characteristics such as structures, morphology, metabolism.

what is a mutagen?

physical or chemical agents that alter DNA and induce mutations. Increase mutation rate.

What are the different types of mutations?

point mutations, frameshift mutation,

an operon consists of _______,_________, and _________ and is associated with a regulatory gene.

promoter, operator, series of genes

what is Protoplast fusion?

protoplast encounter another cytoplasmic membranes fuse and form single cell that has both genomes.

what are some mutagens of genes?

radiation, chemical mutagens (Nucleotide analogs, Nucleotide altering chemicals, Frameshift mutagens).

what happens in extension of PCR?

raising temp to 72*C increases DNA polymerase replication rate and produces more DNA.

briefly summarize transformation gene transfer. give an example

recipient cells that can take up DNA from environment. Ex: encapsulated pneumonia changing unencapsulated pneumonia into having a capsule and making it deadly

What is gel electrophoresis?

separates molecules based on their charge, size and shape and isolates fragments of DNA molecules that can be inserted into vectors, multiplied by PCR or preserved in a gene library

what is genomics?

sequencing and analysis of the nucleotide bases of genomes of organisms, viruses, and eukaryotic mitochondria/ chloroplasts

Three effects of point mutations are _______, _________ and ____________.

silence, missense, nonsense

what are the types of point mutations? briefly summarize point mutations.

silent, missense and nonsense. a single nucleotide pair is affected, most common type of mutation. involves substitutions of nucleotides.

what are plasmids?

small circular molecules of DNA that replicate independently of the chromosome

________________ RNA and _____________ RNA are antisense, that is, they are complementary to another nucleic acid molecule.

small interfering, micro

What are plasmids? are they crucial to cell survival? Can they confer advantages?

small molecules of DNA that replicate independently. No they are not crucial. yes they can confer advantages.

What are operons? what do they consist of?

special arrangements of prokaryotic genes that play roles in gene regulation. Consists of a promoter, series of genes that code for enzymes and structures and an operator

what stabilizes separated strands of DNA?

stabilizing proteins

what type oF cut is easy to ligase? what type of cut is had to ligase?

staggered cut easy to ligase. blunt cut hard to ligase.

What is a missense mutation?

substitution that changes the code for another amino acid. If amino acid in critical location of protein is changed, protein becomes nonfunctional. If amino acid in less important region is changed, it might have no effect.

What is the E site?

tRNA is ejected

what is a genotype?

the actual set of genes in an organisms genome. . Consists of all series of DNA nucleotides that carry instructions for organisms life.

where does energy come from in DNA replication?

the bonds in the nucleotide phosphate groups ex- GTP, ATP, CTP, TTP

why are mutagen used in recombinant DNA technology?

to change a microbes genome which in turn changes the microbes phenotype. Cells can then be selected for beneficial characteristics and isolated.

summarize what happens in elongation step of translation.

the sequential addition of amino acids to polypeptide chain growing at P site.

describe a repressible operon. what type of pathway are they usually involved in? give an example

they are continually active until repressors deactivate them. involved in anabolic pathways. ex- tryptophan operon

What are the 3 ways prokaryotes can transfer genetic information?

transduction, transformation, conjugation

___________ RNA carries amino acids

transfer

What is a southern blot?

transfer DNA from gels onto nitrocellulose membranes that are less delicate. Fluorescent labeled probes then added and probes detected using digital camera which reveals presence of DNA of interest

briefly summarize transduction gene transfer.

transfer of DNA from one cell to another via replicating virus. Bacteriophage can infect bacterial cell, it attaches to bacterial host cell and injects its genome. The virus will transfer host DNA to a new host.

A gene for antibiotic resistance can move horizontally among bacterial cells by ________, ____________, and ___________.

transformation, transduction, bacterial conjugation

What step converts the RNA into the amino acid or polypeptide?

translation

_____________ are nucleotide sequences containing palindromes and genes for proteins that cut DNA strands

transposons

what are the building building blocks and energy sources in DNA replication?

triphosphate deoxyribonucleotides (GTP, ATP, CTP, TTP)

What is a codon?

triplets of mRNA nucleotides that code for specific amino acids.

What is biotechnology?

use of microorganisms to make products

what do bacteria use restriction enzymes for?

use them for protection from phages by cutting phage DNA into nonfunctional pieces.

what is restriction fragmentation?

used for mapping relative locations of genes in plasmids and viruses. Compare DNA fragments resulting from cleavages by several restriction enzymes to determine each fragments location relative to others.

describe an inducible operon. what type of pathway are they usually involved in? give an example

usually inactive and must be induced by inducers. involved in catabolic pathways. ex- Lac operon

what is the most common way of gene transfer?

vertical gene transfer- progeny that inherit genes.

what is Fluorescent in situ hybridization (FISH)?

when scientist want to know where in the environment, clinical sample or biofilm a particular microbial species is located. Fluorescent DNA probes used and hybridize with complementary target. Using different color fluorescent probes, scientist then use microscope to view where gene and organism are located

How do drugs that are analogs of nucleotide bases of DNA work?

when the analogs are incorporated into a new strand of DNA the drugs prevent the replication of new DNA strands because the lack an OH group on the 3' carbon of the sugar which is needed for continuous elongation.

summarize the tryptophan operon

when tryptophan is available, it binds to the repressor to activate it, repressor sits on operator and stops the synthesis of tryptophan since its available.

when should you use probes?

when you want to find a particular cell that has DNA of interest. Probes used to find specific pieces of DNA.

What is the P site?

where polypeptide bond being formed between 2 different amino acids brought by tRNA