An hfr strain of genotype: arg- lac- leu+ strs is mated with a recipient strain of genotype: arg+ lac+ leu- strr. the strs marker is known to be transferred very late. among the other three markers, leu+ is the last one to enter the f- cell. (note: all bacteria have the ability to utilize glucose as a sugar source. the alleles arg+and leu+ are necessary for synthesis of arginine and leucine respectively. the lac+ is necessary for utilization of lactose.)exconjugants are plated on a medium containing glucose, streptomycin, and arginine. the following results are obtained for 500 colonies isolated from these plates and tested for growth on various media: minimal medium (with glucose): 135 coloniesminimal medium (without glucose) + lactose: 85 coloniesminimal medium (without glucose) + lactose + arginine: 90 coloniesa) write a list of possible genotypes from those 500 colonies, and indicate the number in each genotype. show your work and circle your answer. provide a detailed explanation for each answer. b) calculate the recombination frequencies. show your work and circle your answer. provide a detailed explanation as to why those certain genotypes and numbers are used to calculate the recombination frequencies. i do not understand how the rf are calculated. c. ) what is the gene order? include the position of the origin of transfer.

Use the drop down menus to match each example to the fossil topic discussed then to show how the fossil record gives evidence of evolution

Rease is an enzyme used by plants to break down urea (a nitrogen-containing compound) into carbon dioxide and ammonia. urease urea > > > carbon dioxide and ammonia ammonia is broken down by plants into a nitrogen source plants need to grow. thus, plants could not use urea as a nitrogen source unless it was first converted to ammonia. in soybean plants there are two different kinds of urease, one produced in the seeds and the other produced in the leaves of the plant. three types of soybean plants were used in a set of experiments: normal soybeans and two mutant strains, one lacking the urease in the seeds only (strain 1) and one lacking urease in the leaves only (strain 2). experiment 1 separate areas in a field were planted with normal, strain 1, and strain 2 soybeans. all types of soybeans appeared to grow, flower, and produce seeds equally well. there were no externally detectable differences among the strains. experiment 2 small pieces of plant leaves of equal weight were obtained from each type of soybean plant and separately placed on media in culture dishes. tissue growing in this way will become an unorganized clump of cells referred to as callus. to provide a controlled nitrogen source, half the tissue samples of each type were placed on media containing urea, and the other half of the samples were placed on media containing ammonia. after 30 days, the weight gain for each of the callus samples was determined. results are shown in the table below.

All organisms contribute some water to the water cycle by conducting