Kinesin-5 is a motor protein that binds to overlapping interpolar microtubules near the midzone of the mitotic spindle. each of these kinesin proteins has two motor domains that walk toward the plus ends of the microtubules to which the kinesin is bound. when is this kinesin active and how does it affect the spindle? choose one: o a. during anaphase a, kinesin-5 slides the microtubules past one another toward the spindle poles, pulling the poles together and shortening the spindle. o b. during anaphase b, kinesin-5 slides the microtubules over one another toward the spindle equator, pulling the poles together and shortening the spindle. o c. during anaphase b, kinesin-5 slides the microtubules past one another toward the spindle poles, pushing the poles apart and lengthening the spindle. d. during anaphase a, kinesin-5 slides the microtubules past one another toward the spindle poles, pushing the poles apart and lengthening the spindle. © e. during anaphase b. kinesin-5 slides the microtubules past one another toward the spindle poles, pulling the poles together and shortening the spindle.

Proteins are the workhorses of the cell, controlling virtually every reaction within as well as providing structure and serving as signals to other cells. proteins are long chains of  amino acids  , and the exact sequence of the amino acids determines the final structure and function of the protein. instructions for that sequence are encoded in  genes  . to make a particular protein, a messenger ribonucleic acid (mrna) copy is made from the gene (in the process called  transcription  ), and the mrna is transported to the  ribosome  . protein synthesis, also called  translation  , begins when the two ribosomal subunits link onto the mrna. this step, called initiation, is followed by elongation, in which successive amino acids are added to the growing chain, brought in by transfer rnas (trnas). in this step, the ribosome reads the  nucleotides  of mrna three by three, in units called  codons  , and matches each to three nucleotides on the trna, called the anticodon. finally, during termination, the ribosome unbinds from the mrna, and the  amino acid  chain goes on to be processed and folded to make the final, functional protein