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Vitamin A is a fat-soluble vitamin essential for many physiological functions in the body.  Chemical name - Retinol Retinol or All-Trans-Retinol and Beta-carotene Retinol and beta-carotene are both related to vitamin A but differ in several significant ways: Retinol: Retinol is a form of preformed vitamin A. It is found in animal-based foods such as liver, fish oils, milk, eggs, and some fortified foods. Retinol is directly usable by the body. It plays a crucial role in vision, immune function, and skin health. It does not require conversion to be utilized by the body. Retinol is more potent than beta-carotene, meaning it is more effective in smaller amounts. Molecular formula - C₂₀H₃₀O Molecular weight - 286.46 g/mol Beta-Carotene: Beta-carotene is a provitamin A carotenoid. It is found in plant-based foods such as carrots, sweet potatoes, spinach, and other leafy green vegetables. Beta-carotene is an antioxidant and a precursor to vitamin A. The body converts beta-carotene into reti

01. What is the foundation stone principle of biology that states all living organisms are composed of cells? A. Germ Theory B. Evolution Theory C. Cell Theory D. Gene Theory Answer: C. Cell Theory Explanation: The Cell Theory is fundamental to biology, positing that all living organisms are composed of cells, the cell is the basic unit of life, and all cells arise from pre-existing cells. This principle is essential for understanding the structure and function of all living things. 02. What advancements have cell imaging and molecular assays brought to medical diagnostics? A. Improved surgical techniques B. Early detection of diseases C. Development of new vitamins D. Creation of synthetic organs Answer: B. Early detection of diseases Explanation: Advances in cell biology, such as cell imaging and molecular assays, have significantly improved the ability to detect diseases at the cellular level, allowing for early diagnosis and better treatment outcomes. 03. How has understanding cell

Understanding cell structure and function is fundamental to the field of biology and has significant implications for various scientific and medical disciplines. Here are some key reasons why studying cell structure and function is crucial: 01. Foundation of Life Understanding the Basics of Cell Theory The cell theory is a cornerstone of biology, stating that all living organisms are composed of cells, the cell is the basic unit of life, and all cells arise from pre-existing cells. This fundamental principle underscores the importance of studying cells to understand life itself. Historical Milestones in Cell Discovery From Robert Hooke's coining of the term "cell" to Anton Van Leeuwenhoek's observations of live cells, the history of cell biology is rich with discoveries that have shaped our understanding of life. Each milestone has provided deeper insights into the intricate world within each cell. The Role of Cells in Organismal Structure and Function Cells are not

01. What significant cellular component did Robert Brown discover in 1831? A) Mitochondria B) Nucleus C) Endoplasmic reticulum D) Golgi apparatus Answer: B) Nucleus Explanation: Robert Brown discovered the nucleus in 1831, identifying it as a key organelle within cells. The nucleus houses genetic material (DNA) and regulates various cellular activities, including gene expression, DNA replication, and interaction with other organelles. This discovery was crucial for understanding cell structure and function. 02. Who first coined the term "cell" while examining cork tissue under a microscope? A) Anton Van Leeuwenhoek B) Robert Hooke C) Matthias Schleiden D) Theodor Schwann Answer: B) Robert Hooke Explanation: Robert Hooke coined the term "cell" in 1665 when he observed cork tissue under a simple microscope. He noticed small, box-like compartments that reminded him of the cells in a monastery, leading to the use of the term "cell" in biological contexts. His

Cell biology, also known as cellular biology or cytology, is the branch of biology that studies cells—the fundamental units of life. This field explores the structure, function, and behavior of cells, encompassing a wide range of topics that are essential for understanding life at its most basic level. Cell biology encompasses both prokaryotic and eukaryotic cells and has many subtopics which may include the study of cell metabolism, cell communication, cell cycle, biochemistry, and cell composition. The study of cells is performed using several microscopy techniques, cell culture, and cell fractionation. These have allowed for and are currently being used for discoveries and research pertaining to how cells function, ultimately giving insight into understanding larger organisms. Historical Perspective The study of cells dates back to the 17th century when the invention of the microscope enabled scientists to observe structures that were previously invisible to the naked eye. In 1665,

01. According to Bohr's model of an atom, electrons move in specific orbits called: a) Energy orbits b) Quantum orbits c) Stationary states d) Angular orbits Answer: c) Stationary states Explanation: Bohr proposed that electrons revolve around the nucleus only in certain selected circular paths called stationary states or orbits. These orbits are associated with definite energies and are also known as energy levels or quantum levels. 02. Which principle of Bohr's model states that only certain orbits are permitted in which angular momentum of the electron is a whole number multiple of h/2π? a) Stationary principle b) Quantized energy levels c) Angular momentum quantization d) Radiation emission principle Answer: c) Angular momentum quantization Explanation: Bohr's model introduced the principle of angular momentum quantization, stating that only specific orbits are allowed where the angular momentum of the electron is a whole number multiple of h/2π, where 'h' is Pl

Bohr's Model of an Atom, proposed by Niels Bohr in 1913, revolutionized the understanding of atomic structure and addressed the limitations of Rutherford's model. It was based on the principles of quantized energy levels and angular momentum. The important postulates are: 01. Electrons Move in Specific Orbits: The electrons revolve round the nucleus only in certain selected circular paths called orbits. These orbits are associated with definite energies and are called energy shells or energy levels or quantum levels. These are numbered as 1, 2, 3, 4 etc. (starting from the nucleus) or designated as K, L, M, N..., etc. 02. Radiation Emission and Absorption: As long as an electron remains in a particular orbit, it does not lose or gain energy. This means that energy of an electron in a particular path remains constant. Therefore, these orbits are also called stationary states. Electrons can move between different orbits by either absorbing or emitting photons of electromagneti

The structure of an atom refers to its fundamental composition and organization, which consists of a nucleus surrounded by one or more electrons. Atoms are the basic building blocks of matter and are composed of three primary subatomic particles: Electron, Proton and Neutron. Subatomic Particle: Subatomic particles are particles that are smaller than an atom, constituting the building blocks of atoms and forming the basis of all matter. These particles include electrons, protons and neutrons, which are the three primary subatomic particles found within atoms. These subatomic particles play crucial roles in determining the properties of atoms and molecules. Protons and neutrons contribute to the mass of the atom and are involved in nuclear reactions, while electrons are responsible for chemical bonding and the formation of chemical compounds through interactions with other atoms. Understanding the characteristics and behavior of subatomic particles is essential for comprehending the str