A marine biologist is someone who studies plants, animals, and other organisms of the oceans, ranging from large marine mammals to microscopic plankton. Marine biologists study such subjects as animal behavior and ecology, biomedical uses of the sea, the commercial importance of the ocean's natural resources, and methods for preservation of species and habitats.
Marsupials, also known as metatherian mammals, are an ancient and diverse mammal group. They are distinguished from other mammals by a number of cranial and skeletal characteristics, including larger numbers of teeth.
Mating systems are descriptions of who mates with whom in the animal world. In simplest terms, definitions of mating systems are based on how many mates an individual acquires during the breeding season.
In the words of James Watson, codiscoverer of the structure of deoxyribonucleic acid (DNA), Barbara McClintock was one of the most important geneticists of the twentieth century. McClintock made major discoveries about chromosome structure and showed for the first time that movable elements within the chromosome (transposons) could control gene expression.
A medical assistant is a health care professional who provides administrative or clinical assistance to a doctor. Duties of the administrative medical assistant include general office responsibilities, such as answering the phone and making appointments, as well as more specialized skills, such as keeping medical records and processing insurance reimbursements.
Science and medical illustrators provide art for books, newspapers, magazines, advertisements, articles in scientific journals, online Web sites and other electronic references, and museum, zoo, and legal exhibits. Illustrators may draw an illustration of an arrowhead dug from an archaeological site, a diagram showing how neurons in the brain transmit signals, or an animation of a chemical reaction.
Meiosis is the two-step series of specialized cell divisions that makes sexual reproduction possible. Meiosis produces haploid cells, which contain just one member of every chromosome pair characteristic of an organism.
Cells and their organelles are aqueous compartments bounded by thin membranes. The core of these membranes is a film of specialized lipids, two molecules thick.
A membrane separates a cell from its environment or subdivides a cell into specialized regions or compartments. The structure of a membrane is best understood in light of its component parts and in the context of the specialized functions performed by the cell or by its various, membrane-bound compartments.
Biological membranes are the structures that divide biological space into functional aqueous compartments: cells and their organelles. To allocate hundreds of different solutes to their proper locations, cells equip their various membranes with multiple transport mechanisms, some simple and some complex.
Gregor Johann Mendel was born on July 22, 1822, in what is now Hyncice, Czech Republic. He entered a monastery in what is now Brno, Czech Republic, and performed a famous and important series of breeding experiments while at the monastery.
Plants have the impressive abilities to reproduce asexually and regenerate damaged parts. The secret to these abilities lies within a tissue type called meristem.
Cellular metabolism is the sum total of all the biochemical reactions taking place within a cell. It includes all the reactions involved in degrading food molecules, in synthesizing macromolecules needed by the cell, and in generating small precursor molecules, such as some amino acids, for cellular needs.
Metabolism means the sum of all chemical changes in a cell or the body of an organism. It has two subdivisions: catabolism and anabolism.
Microbiologists are scientists who investigate the world of microscopic organisms including all bacteria, protozoa, and viruses, along with some algae and fungi. The microbes studied can be found everywhere from thermal hot springs (more than 100 degrees Celsius) to Antarctic ice shelves (less than 0 degrees Celsius).
A microscopist is any scientist or technician who routinely uses a microscope in his or her work. While beginning students usually have some experience with simple light microscopes, there are many types of more sophisticated microscopes for special purposes, such as phase contrast and fluorescence light microscopes, scanning and transmission electron microscopes, and tunneling electron microscopes that can see even down to the level of individual molecules.
Many animals move from one place to another at certain times of the year or during a particular period of their life cycle. These movements are often referred to as migration.
Many predators search for their prey with their eyes. As a result, many prey species have evolved special body coloration to reduce their chance of being eaten.
Mitochondria (singular mitochondrion) are abundant organelles present in nearly all eukaryotic cells. The main function of mitochondria is to produce adenosine triphosphate (ATP), the cellular energy source.
Mitosis is the process of dividing chromosomes during cell division in eukaryotic cells. Mitosis is followed by cytokinesis, the splitting of the cytoplasm.
Model organisms are used to study basic mechanisms common to many forms of life and to experiment with biological processes that may be difficult or unethical to study in humans. Model organisms are usually chosen for some combination of ease of study (for example, the transparent bodies of the nematode Caenorhabditis elegans or the zebrafish Brachydanio rerio), ability to grow and reproduce quickly in a small space (Arabidopsis thaliana, a four-inch plant with a life cycle of four to six weeks), prominent cell structure of interest (the giant chromosomes of the fruit fly Drosophila melanogaster), or ability to closely model some aspect of human biology (the mammalian genome and complex brain of the mouse).
A model organism is a member of an easy-to-study species that is used in experiments to learn how a more complex organism functions. Biomedical research relies heavily on model organisms as stand-ins for humans, but other types of research use these organisms too.