Scientists have successfully engineered the bacterium Escherichia coli (E. coli) to produce human insulin, an important endocrine peptide in mammals. When the human gene that encodes insulin, flanked by certain regulatory sequences, is integrated into the genetic material of E. coli cells, the resulting E. coli cells can produce insulin that is active in humans. Such E. coli strains are called recombinant E. coli. The insulin-producing trait of recombinant E. coli can be passed down to new generations when cells are grown in a proper selective medium. Why can the recombinant E. coli strain produce biologically active human insulin?

Gene transfer has changed the genetic code of E. coli.
Gene transfer has changed the way E. coli regulates gene expression.
E. coli cells and human cells have similar compositions of nucleotides and amino acids.
E. coli cells and human cells have similar enzymes and processes for synthesizing mRNA and protein.

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.

Explain why the plants cortex would serve as the best food source for animals

What is one way intensive agriculture can contribute to climate change? a. tree loss to agriculture increases earth's albedo b. livestock manure absorbs greenhouse gases c. large herds of livestock release greenhouse gases d. fewer trees are available to replenish petroleum stores appex