Mitosis and The Cell Cycle dur The cell cycle consists of three major parts: 1) characterized by cell growth and of the chromosomes; 2) phase characterized by the division of the ; and 3) cell itself actually divides into two cells. during Before mitosis can begin, the chromosomes in the nucleus forms (a chromosome and its identical copy). During step is the sister chromatids condense and the nuclear membrane breaks d when the chromosomes line up down the middle of the cell. They which reach from the at opposite poles of the of each pair of sister chromatids. by the to the the chromosomes are pulled toward opposite ends of the In Finally, in new nuclear membranes begin to form around the chromoso of the cell. This is the end of mitosis. The next 2 phases of the cell cycle and

Describe two recent or ongoing space missions.

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.

Which scientific design has both practical limitations and limitations due to scale? studying the effect of bleach on the growth of mold spores exposing cultures of duckweed to different intensities of light observing the replication of dna molecules with a hand lens using colored marbles to model a cross between two colors of rabbits