Karteikarten
Meiosis and Variarions
Karten in diesem Stapel (25)
- 1why is it important to keep a common ancestorgene bank;
source of alleles;
for future (selective) breeding;
to counteract, genetic erosion/loss of genetic variation;
to counteract, inbreeding/homozygosity;
to counteract extinction;
for changed conditions;
example of changed conditions; e.g. climate/environment/disease/fashion
to preserve as yet unidentified, alleles/traits; - 2why is selective breeding carried outfor benefit of humans;
to improve, trait(s)/named trait;
to produce desirable, phenotype/genotype;
to increase number of desirable alleles;
to increase homozygosity;
AVP; - 3why does a plant that self poolinates have narrow g.ddue to inbreeding & having a limited gene pool
- 4define crossing overreciprocal exchange of portions of, chromatids / DNA; A swapping alleles
between (paternal and maternal) homologous chromosomes; A bivalent
in prophase I (of meiosis); - 5WHY IS DNA IN SISTER CHROMATIDS IDENTICALdna molecule unzips, free dna comp base pairs to reference strand, sugar phosphate back bone form, dna polymerase
- 6predicted phenotype of dominant epistasis12:3:1
- 7predicted phenotype of recessive epistatsis12:3:4
- 8what is dominant epsistatisdominant allele on the first allele masks the expression of other genes
- 9What is recessive epistatsisneither a dominant or recessive allele is expressed due the lack of a dominant allele on the previous gene
- 10Contiouse varitiation is effect by how many genes?2 + and is polygenic
- 11Discountinouse variation is caused by how many genetwo or less so is monogenic
- 12What effect does different alleles have on continous variationmakes little difference
- 13What effect do different alleles at differnt gene loci have on discontinouse variationhas a large effect
- 14define stabilizing selectionstabilizing selection is when no environmental change occurs all organisms are under the same selection pressure so no new alleles become advantagouse, each generation keeps getting the same alleles
no need for variation - 15define directional selectionwhen the environment changes/change is selection pressure new alleles become advantageous which previously were not and are passed on to the next generation, changing the gene pool
- 16Ecological isolating mechanisms arewhen they are in the same area/habitiat but never actually meet e.g. both in pond but one on surface and one on the top
- 17Phylogenetic species conceptif can see a difference they must have evolved from common ancestors
- 18Genetic Drift in a populationsmall population with very small election pressures
- 19How does selection pressure occurby chance, one or two populations have breeding success and over time their alleles become more apparent in the population and other allele in a population become less apparent
- 20What do selection pressure causeChanges in the gene pool, a change in the variation/characterisitics in a population
- 21Definition of CodominanceAlleles in a hetrozygote are both expressed in the genotype neither is dominant or recessive
- 22An example of co domiancethe ABO blood group - red blood cells contain a glycoprotein in their plasma membrane that determines the abo blood group. Two forms of the protein antigen A and antigen B - the gene has 3 allels coding for A/B or no antigen at all
- 23How do you right co dominancewith a super script
- 24Define Homozygoushomozygous is when two copies of the same allele are at a particular gene locus
- 25How does independent assortment occur during metaphase 2different combinations of sister chromotids go into each cell
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- F215 Karteikarten am Meiosis and Variarions, erstellt von lauratyley am 01/06/2013.
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