What is nucleus in biology

Your ability to perceive your surroundings – to see, hear, and smell what’s around you – depends on your nervous system. So does your ability to recognize where you are and to remember if you’ve been there before. In fact, your very capacity to wonder how you know where you are depends on your nervous system! If your perceptions indicate danger (“Oh no, the house is on fire!”), your ability to act on that information also depends on your nervous system. In addition to letting you consciously process the threat, your nervous system triggers involuntary responses, like an increase in heart rate and blood flow to your muscles, intended to help you cope with danger. All of these processes depend on the interconnected cells that make up your nervous system. Like the heart, lungs, and stomach, the nervous system is made up of specialized cells. These include nerve cells (or neurons) and glial cells (or glia). Neurons are the basic functional units of the nervous system, and they generate electrical signals called action potentials, which allow them to quickly transmit information over long distances. Glia are also essential to nervous system function, but they work mostly by supporting the neurons. The cell bodies of some PNS neurons, such as the motor neurons that control skeletal muscle (the type of muscle found in your arm or leg), are located in the CNS. These motor neurons have long extensions (axons) that run from the CNS all the way to the muscles they connect with (inner...

Take a moment and look at yourself. How many organisms do you see? Your first thought might be that there's just one: yourself. However, if you were to look closer, at the surface of your skin or inside your digestive tract, you would see that there are actually many organisms living there. That’s right - you are home to around 100 trillion bacterial cells! All cells fall into one of these two broad categories. Only the single-celled organisms of the domains Bacteria and Archaea are classified as prokaryotes— pro means before and kary means nucleus. Animals, plants, fungi, and protists are all eukaryotes— eu means true—and are made up of eukaryotic cells. Often, though—as in the case of we humans—there are some prokaryotic friends hanging around. Despite these similarities, prokaryotes and eukaryotes differ in a number of important ways. A prokaryote is a simple, single-celled organism that lacks a nucleus and membrane-bound organelles. We’ll talk more about the nucleus and organelles in the next article on eukaryotic cells, but the main thing to keep in mind for now is that prokaryotic cells are not divided up on the inside by membrane walls, but consist instead of a single open space. The majority of prokaryotic DNA \text DNA start text, D, N, A, end text is found in a central region of the cell called the nucleoid, and it typically consists of a single large loop called a circular chromosome. The nucleoid and some other frequently seen features of prokaryotes are shown ...

Your ability to perceive your surroundings – to see, hear, and smell what’s around you – depends on your nervous system. So does your ability to recognize where you are and to remember if you’ve been there before. In fact, your very capacity to wonder how you know where you are depends on your nervous system! If your perceptions indicate danger (“Oh no, the house is on fire!”), your ability to act on that information also depends on your nervous system. In addition to letting you consciously process the threat, your nervous system triggers involuntary responses, like an increase in heart rate and blood flow to your muscles, intended to help you cope with danger. All of these processes depend on the interconnected cells that make up your nervous system. Like the heart, lungs, and stomach, the nervous system is made up of specialized cells. These include nerve cells (or neurons) and glial cells (or glia). Neurons are the basic functional units of the nervous system, and they generate electrical signals called action potentials, which allow them to quickly transmit information over long distances. Glia are also essential to nervous system function, but they work mostly by supporting the neurons. The cell bodies of some PNS neurons, such as the motor neurons that control skeletal muscle (the type of muscle found in your arm or leg), are located in the CNS. These motor neurons have long extensions (axons) that run from the CNS all the way to the muscles they connect with (inner...