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Cellular respiration is a complex process by which cells convert nutrients, primarily glucose, into energy in the form of adenosine triphosphate (ATP). This process occurs in both the cytoplasm and mitochondria of cells and involves three main stages: glycolysis, the Krebs cycle (citric acid cycle), and the electron transport chain (ETC).  Note : Cellular respiration is typically described as a three-stage process, although some explanations break it down into four stages for clarity. Four stages: glycolysis, Pyruvate Oxidation, the Krebs cycle (citric acid cycle), and the electron transport chain (ETC).  01. Glycolysis Location: Cytoplasm Process:  Glycolysis is the first step in cellular respiration and occurs in the cytoplasm. It involves the breakdown of one molecule of glucose (a six-carbon sugar) into two molecules of pyruvate (each containing three carbons). This process consists of ten enzymatic steps that convert glucose into pyruvate, producing a net gain of energy-rich mol

Mitochondria are double membrane-bound organelles found in the cytoplasm of nearly all eukaryotic cells. They are often described as the "powerhouses" of the cell due to their primary role in generating adenosine triphosphate (ATP), the main energy currency of the cell. Mitochondria (singular = mitochondrion) were first discovered by Albert vonkollicker in 1850 from striated muscle tissue of insects and the term "mitochondrion" (In Greek, Mito = "thread" + chondrion = "granule") was coined by Carl Benda because of the thread like appearance of these granules when examined under light microscope. Structure of Mitochondria Mitochondria occupy up to 25% volume of the cytoplasm. A mitochondrion is enclosed by a double membrane. Outer Membrane: Permeable barrier with porins for metabolite exchange. Outer membrane is constituted by 50% lipids and 50% proteins along with porin protein (conferring permeability to molecules with molecular weight as hig

The primary organelles involved in photosynthesis are the chloroplasts. Chloroplasts Except for vacuoles, chloroplast, the double-mebraned organelle, are the largest and the most characteristic organelles in plant cell. These are specialized organelles found in the cells of plants and algae. Chloroplasts contain the pigment chlorophyll, which captures light energy for photosynthesis. Like mitochondria, chloroplasts have their own genome and contain 70s ribosomes, DNA and enzymes involve in protein synthesis. The chloroplast belongs to a group of related organelles in plants called plastids. Plastids differ in structure, carry out diverse functions, and are classified according to the kinds of pigments they contain.  Chloroplasts contain chlorophyll while chromoplasts are lycopene-containing plastids and are responsible for yellow, orange and red colors of some flowers and fruits. Leucoplasts are non-pigmented plastids, and amyloplasts are starch-storing plastids of potato tubers. All

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

The fluid mosaic model of plasma membrane was proposed by the S.J. Singer and Garth L. Nicolson in 1972. The fluid mosaic model of plasma membrane describes the structure of the plasma membrane. Plasma membrane (also called cell membrane or plasmalemma) is a thin, elastic, semifluid, living protective membrane which separate the internal contents (cytoplasm and cytoplasmic organelles) from the external surroundings. The plasma membrane control the passage of materials, such as organic molecules, ions and water between the cells and its surrounding. It also prevents the passage of some substances to cell exterior to maintain the ionic concentration gradient between the cytoplasm and the surroundings.   The plasma membrane is made up of proteins and lipids. Several models were proposed to explain the arrangement of proteins and lipids is the membrane; however, the fluid-mosaic model proposed by the S.J. Singer and Garth L. Nicolson in 1972 is the most widely accepted model.  Accordi

A cell is the smallest structural and functional unit of an organism, often referred to as the "building block of life". It possessing all the characteristics necessary to maintain life, including structure, function, energy production, genetic continuity, and the ability to respond to their environment. Cells can exist as independent entities (unicellular organisms like bacteria and protozoa) or as part of multicellular organisms (plants, animals, and fungi). The study of cells is fundamental to understanding the biology and physiology of all living organisms. Robert Hook in 1665 is credited with giving the concept of cell from the microscopic observation of a dead piece of cork tissue. The small compartments which constituted it was called "cells" (In Latin, cell = small room) and thereby the term "cell" was coined. Antonie van Leeuwenhoek was the pioneer in observing bacteria, sperms and red blood corpuscles under the microscope. Essential Character

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