NaimExplain

Describe the various contributions of PCR to microbiology. PCR has made it possible to track transmission of disease between individuals, communities, and countries. PCR enables researches to study environments and organisms that no longer exist in their natural form.

Describe the use of plasmid and viral vectors. Plasmids: chromosome like element. can be inserted into a cell by transformation. They are the vehicle in which carries the desired gene to be expressed in a new host. Viral Vectors: containing a new gene can be inserted into a cell by transduction

Define restriction enzymes, and outline how they are used to make recombinant DNA. Restriction Enzymes: DNA cutting enzymes that exist in many bacteria. Very specific in their fxn and action. Some produce "sticky" ends, which are short stretches of single-stranded DNA at the ends of the DNA fragements. -Fragments of DNA production by the same restriction enzyme will spontaneously join by hydrogen bonding(thus "sticky") -DNA ligase is an enzyme that can covalently link the DNA backbones. -Restriction enzymes take apart the DNA in a certain area and allow for a plasmid to be inserted within the gap that is created

Discuss the value of the Human Genome Project. The Human Genome Project sequenced the entire genome, approx 3 billion nucleotide pairs, which comprises of 20,000 to 25,000 genes.

List at least five applications of rDNA technology. -subunit vaccines -gene therapy: treating a disease by replacing abnormal genes. -gene silencing: inhibits gene expression Which of the following pairings of recombinant DNA techniques and applications does NOT match? a. genetic modification of yeast: production of purified insulin b. gene therapy: replacing a defective gene c. PCR: making many copies of a segment of DNA d. gene silencing: production of subunit vaccines

Compare and contrast biotechnology, genetic modification, and recombinant DNA technology. --Biotechnology - the purposeful application of biology principles to industrial and agricultural production - commercial production of: foods (e.g. cheese, yogurt), antibiotics,vitamins and fermentation products --Genetic engineering:- the isolation and propagation of DNA molecules in suitable hosts, molecular modification of genes and regulatory elements for special purposes, transfer of genes among diverse organisms by by-passing constraints of sexual reproduction - in order to manipulate them for medical, industrial and agricultural use. --Recombinant DNA Technology (rDNA) Precise manipulation of genes by artificial techniques - almost no limit to gene construction

Discuss how genetic mutation and recombination provide material for natural selection to act upon. mutations and recombination provide diversity; fittest organisms for an environment are selected by natural selection. continually changed by alterations in their genetic properties and acquisition of adaptations to many different habitats

Describe the functions of plasmids and transposons. Plasmids: Conjugative plasmid: carries the genes for sex pili and transfer of the plasmid Dissimilation plasmid: encode enzymes for catabolism of unusual compounds R factors: encode antibiotic resistance Transposons: segments of DNA that can move fro one region of DNA to another; contain insertion sequences for cutting and resealing DNA (transposase); complex transposons carry other genes

Compare the mechanisms of genetic recombination in bacteria. VERTICAL GENE TRANSFER-occurs during reproduction between generations of cells HORIZONTAL GENE TRANSFER-the transfer of genes between cells of the same generation TRANSFORMATION- genes are transferred from one bacterium to another as "naked" DNA in solution CONJUGATION- genetic material is transferred fro one bacterium to another; requires direct cell-to-cell contact; cells must be of the opposite mating type (F- and F+, Sex pili) TRANSDUCTION-bacterial DNA is transferred from a door cell to a recipient cell inside a virus that infects bacteria called a bacteriophage.

Differentiate horizontal and vertical gene transfer. vertical gene transfer- occurs during reproduction between generations of cells; genes are passed from an organism to its offspring. horizontal gene transfer- occurs between cells of the same generation; donor cell gives a portion of its DNA to a recipient cell.

Identify the purpose of and outline the procedure for the Ames test. purpose: access chemicals for their ability to cause mutations 1. two cultures are prepared of salmonella bacteria that have lost the ability to synthesize histidine (histidine-dependent) 2. the suspected mutagen is added to the experimental sample only; rate liver extract (an activator) is added to both samples 3. each sample is poured onto a plate of medium lacking histidine. the plates are then incubated at 37 degrees Celcius for two days. only bacteria whose histidine-dependent phenotype has mutated back (reverted) to histidine-synthesizing will grow into colonies 4. the number of colonies on the experimental and control plates are compared. the control plate may show a few spontaneous histidine-synthesizing revertants. the test plates will show an increase in the number of histidine-synthesizing revertants if the test chemical is indeed a mutagen and potential carcinogen. the higher the concentration

Describe two ways mutations can be repaired. -enzymes that cut out and replace the damaged portion of DNA ex: in UV radiation damage -base repair by enzymes ex: photoreactivation enzymes that repair thymine dimers in the presence of visible light

Define mutagen. Describe the effect of mutagens on the mutation rate. Mutagen is an agent in the environment that brings about mutation. If a mutagen is present, it will usually increase the spontaneous rate of mutation, which is approximately 1 in 106 replicated genes, by a factor of 10-1000 times. This is a 1 to 3 order of magnitude increase, meaning a mutation rate of 10-6 becomes 10-5 or possibly 10-3.

Explain the regulation of gene expression in bacteria by induction, repression, and catabolite repression. -Constitutive genes are expressed at a fixed rate -Other genes are expressed only as needed Repression controls the synthesis of one or several (repressible) enzymes. It is the regulatory mechanism that inhibits gene expression and decreases the synthesis of enzymes. When cells are exposed to a particular end product, the synthesis of enzymes related to that product decreases. Repression is mediated by regulatory proteins called repressors, which block the ability of RNA polymerase to initiate transcription from the repressed genes. The process that turns on the transcription of a gene or genes is called induction. In the presence of certain chemicals (inducers), cells will synthesize more enzymes (induction). Transcription of structural genes for catabolic enzymes (such as B-galactosidase) is induced by the absence of glucose. It is important to note that the presence

Describe protein synthesis, including transcription, RNA processing, and translation. In the process of transcription, genetic info in DNA is copied, or transcribed, into a complementary base sequence of RNA. The cell then uses the info encoded in this RNA to synthesize specific proteins thru the process of translation.

Describe the process of DNA replication. 1. the double helix of the parental DNA separates as weak hydrogen bonds between the nucleotides on opposite strands break in response to the action of replication enzymes 2. hydrogen bonds form between new complementary nucleotides and each strand of the parental template to form new base pairs 3. enzymes catalyze the formation of sugar-phosphate bonds between sequential nucleotides on each resulting daughter strand

Describe how DNA serves as genetic information. the structure of DNA helps explain two primary features of biological info storage. -first, the linear sequence of bases provides the actual info -genetic info is encoded by the sequence of bases along the strand of DNA, in much the same way as our written language uses linear sequence of letters to form words and sequences

Define genetics, genome, chromosome, gene ,genetic code, genotype, phenotype, and genomics. Answer: genetics-the study of what genes are, how they carry info, how info is expressed, and how genes are replicated genome-the entire genetic makeup of an organism including both its genes and noncoding sequences that link these chromosome-naked, circular piece of DNA containing approx. 3000-4000 genes gene-a segment of DNA that encodes a functional product, usually a protein genetic code-the set of rules that determines how a nucleotide sequence is converted into the amino acid sequence of a protein genotype-an organism's genetic makeup, the info that codes for all particular characteristics of that organism; represents potential properties, but not the properties themselves phenotype-actual, expressed properties, such as the organism's ability to perform a particular chemical reaction; manifestation of genotype genomics-the sequencing and molecular characteriz