nicked circle (Science: molecular biology) During extraction of plasmid dNA from the bacterial cell, onestrand of the DNA becomes nicked. This relaxes the torsional strain needed to maintain supercoiling, producing the familiar form of plasmid...
Meet the colorful takahē, an extremely rare flightless bird. Find out more about its unique features and why they matte..
The body is comprised of different elements with hydrogen, oxygen, carbon, and nitrogen as the major four. This tutorial..
This tutorial digs into the past to investigate the origins of life. The section is split into geological periods in the..
In plants, growth occurs in meristems, which are the site of repeated cell division of unspecialized cells. These cells ..
Hormones are produced in the endocrine glands of animals. The pituitary gland and hypothalamus are the most impor..
Dinosaurs represented a major turn in the evolutionary development of organisms on Earth. The first dinosaurs were presu..
