Spindle fibers play a significant role during nuclear division. They are responsible for the separation of sister chromatids during mitotic and meiotic cell division. When Do They First Become Visible Structure Its Formations Types of Mitotic Spindle Functions They are spindle-shaped fibers composed of 97% motor protein (tubulin) and 3% RNA. The microtubules are a polymer of 𝜶 and 𝞫-tubulin dimers. Spindle fibers, associated proteins, condensed chromosomes, and centrosomes or asters together form the spindle apparatus....

History and Discovery of the Strong Nuclear Force The first theory of the strong nuclear force was discovered in 1935 by Japanese physicist Hideki Yukawa, who discovered the force-carrying particles known as mesons. He suggested that nucleons exchanging particles create a force field. Strength and Range of Strong Nuclear Force How does the Strong Nuclear Force Work Properties of Strong Nuclear Force Examples of Strong Nuclear Force Relative Strength and Range of Fundamental Forces The particles responsible for carrying the strong nuclear force are known as gluons....

The first DNA topoisomerase was discovered by James Wang in 1971. It was initially named omega protein and is now called Escherichia coli topoisomerase I. Structurally, topoisomerases have a catalytic core involved in the cleavage and rejoining DNA strands, a DNA-binding domain, and an optional ATP binding site found in some enzymes. How Does Topoisomerase Work Types of Topoisomerases Functions of Topoisomerase Topoisomerase vs. Helicase Topoisomerase Inhibitors In such situations, topoisomerase acts like a molecular scissor and untangler....

Transcription is almost similar in prokaryotes and eukaryotes. Here, we will discuss transcription by describing the process in the bacterium Escherichia coli. Where does Transcription Occur in Prokaryotes Since E. coli is single-celled and does not have membrane-enclosed nuclei, transcription occurs in the cell’s cytoplasm. Structure of RNA Polymerase Stages of Transcription What Happens to the RNA Transcript after Transcription The polymerase with all five subunits is called a holoenzyme....

They were discovered in the 1940s by geneticist Barbara McClintock in maize (Zea mays). Types of Transposons Autonomous and Non-Autonomous Transposons Transposons in Maize Transposons in Drosophila Transposons in Bacteria Transposons Used in Laboratory Applications of Transposons Class I Transposons: Retrotransposons Class I transposons are also known as retrotransposons because the DNA segment is first copied into an RNA, then reverse transcribed back to DNA by the enzyme reverse transcriptase....

Location: Where does it Take Place Types with Equations Process: What Happens during Cellular Respiration Why is Cellular Respiration Important Summary 1) Aerobic Respiration It is so named, as here the glucose gets broken down in the presence of oxygen, producing ATP. Being autotrophs, plants produce their food by photosynthesis, whereas animals get their glucose by consuming food. The whole process initiates in the cell cytoplasm and is further carried out in the mitochondria....

In reality, the electromotive force is not a force but a measure of energy. The source converts one form of energy into electrical energy. For example, a battery converts chemical energy, and a generator converts mechanical energy. The term electromotive force was coined by Italian physicist and chemist Alessandro Volta, who invented the electric battery in 1800. Electromotive Force (EMF) Equation Electromotive Force (EMF) vs. Voltage ε = IR + Ir Where, I: Current passing through the circuit R: Resistance of the resistor r: Internal resistance of the battery Symbol: ε, Greek letter epsilon Using Ohm’s law, V = IR Therefore, ε = V + Ir A voltmeter is used to measure the EMF....

What is a Eukaryotic Cell Where are they Found How did Eukaryotic Cells Evolve Characteristics of Eukaryotic Cells Components Eukaryotic Cell Structure How Do Eukaryotic Cells Reproduce: Cell Cycle Examples of Eukaryotic Cells Some of the small cells were able to break down the large cell’s wastes and, in return, generate energy for them and the large cell. Those cells became the mitochondria. Other small cells were able to utilize sunlight for making food....

What is a Food Chain Trophic Levels Types of Food Chain Many herbivores eat grass, and deer can eat other plants besides grass. Even a tiger can eat many types of animals and plants. Thus, each animal is part of multiple food chains. All interconnected to make a food web. The different trophic levels in a typical food chain are: Primary Producers They are the first biotic factor occupying the first tropic level or the bottom of the food chain....

Sunlight is more direct at the equator but is further away as we move toward the poles. The reason is the Earth’s tilt. Earth’s axis has a tilt of 23.4° from the vertical. The north and south poles have sunlight during their summer months. The equator has sunlight all year around. The two regions are heated unevenly, resulting in a temperature difference. How does Temperature Difference Affect Atmospheric Pressure How does Pressure Difference Form Wind Effect of Earth’s Rotation Daily Wind Cycle At the poles, air masses sink as they become dense....

Charge Carriers in Intrinsic Semiconductors Electrical Conduction in Intrinsic Semiconductors Uses and Applications Movement of Charge Carriers The movement of charge carriers, specifically electrons, is crucial in determining the current flow within a semiconductor. In an intrinsic semiconductor, some electrons gain enough energy to break free from their atomic bonds through various mechanisms such as applied electric field, thermal excitation, and exposure to light. These free electrons become mobile and contribute to the conductivity of the material....

Magnetic Flux Equation Significance of Magnetic Flux Difference Between Electric Flux and Magnetic Flux If the angle between the magnetic field vector and the area vector is θ, then the magnetic flux is given by Symbol: Greek letter phi, φ SI Unit: Weber or Wb CGS Unit: Maxwell Dimensions: [M1 L2 T-2 I-1] When θ = 0o , φ = BA. Therefore, the flux is maximum when the area under consideration is perpendicular to the magnetic field....

Malus’ law has been named after Étienne-Louis Malus, who was a French engineer, physicist, and mathematician. Malus published his work on the polarization of light in 1809. E = Eo cos Ø Where Eo is the amplitude of the electric field vector. This equation gives the displacement of the electric field vector after passing through the analyzer. Since the intensity, I, of the polarized beam is proportional to the square of the electric field, therefore, I ∝ E2 I = Io cos2 Ø This equation is Malus’ law....

Examples of semiconductors include silicon (Si), germanium (Ge), gallium arsenide (GaAs), gallium nitride (GaN), indium phosphide (InP), and silicon carbide (SiC). Properties of Semiconductors Carrier Mobility in Semiconductor Band Theory of Semiconductors Band theory in semiconductors explains how electrons are arranged in energy bands. The valence band contains electrons tightly bound to atoms, while the conduction band holds electrons that can move freely. The energy gap between these bands is called the band gap, which is denoted in the unit of electron volts (eV)....

Cathode Ray Tube History Cathode Ray Tube Description Cathode Ray Tube Mechanism Video Cathode Ray Tube Experiment by J.J.Thomson Cathode Ray Tube Applications Health Risks The earliest version of the cathode ray tube, Braun Tube, was invented in 1897 by the German physicist Ferdinand Braun. It employed a cold cathode for working. He used a phosphor-coated mica screen and a diaphragm to produce a visible dot. The cathode beam was deflected by a magnetic field only, in contrast to the discharge tube used earlier in the same year by J....

What is Chemosynthesis Why is Chemosynthesis Important How does Chemosynthesis Work Chemosynthesis vs Photosynthesis Such microbes called chemoautotrophs can survive extremely harsh conditions like high temperature and osmotic pressures. Sulfur-oxidizing gamma proteobacteria, neutrophilic iron-oxidizing bacteria, epsilon proteobacteria, and methanogenicarchaea are typical chemoautotrophs. Besides hydrothermal vents, chemosynthesis also happens in hot springs and cold seeps. When was it Discovered Chemosynthesis was discovered in 1977 when a group of scientists on an ocean research expedition near the Galápagos Islands found hot hydrothermal vents emitting a hot chemical fluid on the ocean floor....

According to Huygens’ principle, the aperture or slit diffracting the waves becomes the secondary source of waves. The diffracted waves fall a screen and form a pattern known as a diffraction pattern. It consists of alternating dark and bright fringes spread across the screen. A bright central fringe is observed at the center, surrounded by several maxima and minima. Diffraction experiments have shown that light has wavelike properties. Diffraction experiments can be performed with one slit (single-slit diffraction), two slits (double-slit diffraction), or multiple slits (diffraction grating)....

It receives molecules, changes them, and then categorizes and addresses them for transport to different cell parts. Golgi is thus analogous to the post office. Due to its relatively large size, the Golgi apparatus was one of the first organelles discovered. In 1897, Italian scientist Camillo Golgi first identified the Golgi apparatus. Later, in 1898 it was named after him. Where is the Golgi Apparatus Located Structure of Golgi Apparatus Functions of Golgi Apparatus What is the Golgi Apparatus Made of They are made of the following parts:...

In most cells, microtubules extend outward from the microtubule-organizing centers (MTOCs). In animal cells, the major microtubule-organizing center is the centrosome, located adjacent to the nucleus. Microtubules are also located in cilia and flagella of prokaryotes and human sperm cells. Structure of Microtubules Assembly and Disassembly of Microtubules Functions of Microtubules Composition Each microtubule subunit comprises two closely related polypeptides: α-tubulin, and β-tubulin, forming heterodimers. Multiple units of these dimers polymerize to form a chain called the protofilament....

How to Use a Prism? The best way to use a prism is to keep it in front of a light source, like sunlight and incandescent white light bulb and a screen behind it. The prism will disperse white light into its constituent colors, which gives the appearance of a rainbow when observed on the screen. Rectangular prism A rectangular prism is a solid 3-dimensional object which has six faces (sides) that are rectangles....