How would you test a population of bacteria for antibiotic resistance?
Grow a bacteria colony, and expose it to a form of antibiotic such as penicillin. If the colony dies off in the antibiotic agar then it is non-resistant.
How is the Ames test used to determine if a compound is mutagenic?
Using the Ames test, a nutrient agar with antibiotics, bacteria should not be able to colonize. Add the compound in question and try culturing bacteria again. If the compound causes successful antibiotic resistant mutagens, bacteria will begin to colonize in the antibiotic NA.
How is it that a test using bacteria can be predictive of the mutagenicity of a compound for humans?
If a compound causes mutagens in bacteria, it means it is able to damage or mutate DNA during replication. All living organisms DNA is exposed during DNA replication, which means the compound might also damage human DNA. After DNA is mutated, it replicates the mutated DNA.
Use finches to present Darwin?s explanation as to why each island was populated by finches with a particular beak structure.
Each island had different beak structures because the birds that were able to reproduce and pass on their genes were the ones who were able to find a food source to survive. Each island had different sources of nutrients, such as nuts and insects? The birds that were able to crack open nuts on an island with a primary nutritional source of hard shelled nuts were the finches that survived. Each island was isolated, and over time without migration to vary the genetic traits in the population, the birds would pass on the traits necessary to survive.
Eventually, all the Orcas in the park leaped out of the water at every mealtime to eat the birds that ate the fish the keepers provided. Does this scenario describe the process of evolution? Explain your answer.
This does not describe evolution, evolution is the genetic inheritance passed on from the parents generation to offspring. This scenario describes classical conditioning. If this hunting intelligence trait was passed on from previous generations to enhance survival and reproduction, then yes, it was evolution. Evolution occurs in a population, and the means is by natural selection.
Why is it that we can observe the process of evolution in bacteria for the trait of antibiotic resistance?
Bacteria reproduce very quickly, as they reproduce asexually. The multiple generations allows more mutations to occur over a shorter amount of time than other organisms. When we use antibiotics, it kills all non-resistant bacteria leaving only the resistant to reproduce and form a colony of resistant bacteria.
What is meant by the terms ?natural selection? and ?artificial selection?? Compare and contrast these two processes.
Natural selection occurs when only the reproductively fittest organism survives to reproduce due to limitation and the competition of nutrition, and space. This could include predator vs. prey, mutual relationships, antagonist, and parasitic all competing over food and area. Artificial selection occurs when humans use intelligence to select organisms with desired traits, and breed one organism with another to produce the desired traits, such as breeding animals and crops.
Use the principles of evolution to explain the rationale for planting conventional corn in the same field as genetically modified Bt corn.
If there are any Bt resistant pests in the field, and GM corn is the only crop, the resistant pests will be the only ones to survive and reproduce leaving no non-resistant insects to reproduce. When parts of the field are left conventional, it allows non-resistant pest to survive. Their dominant traits when breed with recessive resistant traits will produce offspring of non-resistant pests. That way the GM corn will still be effective the following year and years to come.
What is a land race of plants?
Plants that humans selected the ?best? seed from, based on the traits that would be advantageous to their needs. These crops have genetic diversity due the differing preference of other seed gatherers. Over time, these plants became very distinct and more uniform.
Compare the traits of a land race with their wild relatives and a cultivar that can be purchased from a store.
Wild-lots of diversity, reproduce- seed spread by wind, animals? Land race- diversity due to the gathers preferences, reproduces by artificial selection. Cultivar- Genetically uniform crops, very low variance in the U.S. narrowed down to ~24 species that feed the world. As plants go from wild to land races to cultivars traits become more uniform which means less diverse and more suitable for human use than for reproductive fittness of the plant.
Why is the process of plant breeding time consuming?
You must first identify a trait of interest. Locate the plant population varying the trait of interest. Control the mating Select the progeny of interest The time needed to for plants to produce seed and reproduce can take months; it may take several generations to achieve the desired phenotype.
What is a hybrid?
A hybrid is an organism that contains the genes of two unrelated inbred parents. Which causes the less vigorous inbred genes to produce a vigorous offspring when bred with another inbred parent. One that is homozygous and another heterozygous and breed them to produce their hybrid offspring.
Give examples of some of the traits breeders might consider when developing a new soybean hybrid.
Grain yield Stalk strength Root strength Stay green Drought tolerance Plant height Seed size Resistance to several diseases herbicide and pesticide resistance
What is meant by the sentence: ?There is a lot of genetic variation in the plant species Solanacearum tuberosum (potato) for skin color.? Use the terms ?phenotype? and ?genotype? in your answer.
The large variance of genotypes are expressed in many different phenotypes of potato plants, such as different skin coloring
If you cross two plants with the same phenotype and see that 100% of their offspring show the same phenotype what can you say about their genotype?
At least one parent plant is homozygous dominant plant, the other plant can be heterozygous dominant or homozygous dominant. If they were both heterozygous, there is a 25% possibility that one plant would produce offspring with the recessive phenotype. They could also both have homogeneous recessive genotypes expressing only recessive phenotypes.
What is the Central Dogma?
Central dogma is the process of DNA transcription to translation; genes are expressed to produce proteins that form the various traits
What is ?base complementarity?s?? Use this term to explain the structure of DNA, and the semi conservative nature of DNA replication.
DNA is a double stranded helix when uncoiled resembles a ladder. It has a sugar phosphorous skeleton and nitrogenous bases that make the rungs of the ladder. Adenine has a weak hydrogen bond with Thymine, Guanine with Cytosine. DNA that makes up chromosomes starts uncoiling when the enzyme helicase initiates it. DNA?s complimentary bases split and expose the DNA template. RNA polymerase an enzyme starts building RNA off the DNA template. The promoter is attached, which signals the gene to start. mRNA, which contains the codons necessary for translation, leaves the nucleus. The mRNA goes to the ribosome, which is translated when the codons and anticodons attach to form amino acids. The amino acid chains produced are folded up to form protein. DNA replication is semi-conservative. Each new DNA molecule is composed of one strand from the parent molecule that serves as the template for one newly- constructed strand.
What is a mutation?
Molecular process that gives rise of variation when there is an error in DNA replication, or when a cell is exposed to a mutagen.
What is a SNP?
Single nucleotide polymorphism
How is it that the human genome project revealed SNPs?
Correlations between harmful predispositions and genes
Why is the process of plant breeding time consuming?
Identify desired trait(s), locate trait in a population, control-mating processes, select progeny that shows trait. Greenhouse trials, field trials, multiple locations and years, collecting all that data
Why might you be interested in using a wild relative in a plant-breeding program?
Because wild relatives have large variance in the gene pool, not as susceptible to pathogens, pests, wild relatives express the most common dominate traits so you could pick from the group to start breeding the plants.
What are three drawbacks to using wild relatives (eg. non-domesticated species) to breed for a cultivar likely to be popular with farmers?
Time consuming, not uniform for harvesting. The crop is not as appealing to consumers or distributors.
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