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Control And Coordination

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🧠 1. What is a nerve impulse? A nerve impulse is a tiny electrical signal that travels through a nerve cell. Think of it like electricity travelling through a wire: Stimulus → Nerve cell → Electrical impulse → Next nerve cell → Brain/muscle/gland For example: 👉 You touch something hot 👉 Your sensory nerve detects it 👉 A nerve impulse travels rapidly 👉 Your brain receives the information 👉 Your muscles respond 👉 You pull your hand away. 🔗 2. What is a synapse? A synapse is the tiny junction between two nerve cells. There is a very small gap between them called the synaptic cleft. The important parts are: Presynaptic neuron → first nerve cell Synaptic cleft → tiny gap Postsynaptic neuron → next nerve cell The first neuron sends the message, and the second neuron receives it. Important point: The electrical impulse usually cannot directly jump across the gap. Instead, the first neuron releases a chemical messenger called a neurotransmitter. ⚡ 3. Types of synapses The textbook des...
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Human Reproductive System

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  Human Reproductive System 1. Male Reproductive System: The male reproductive system is basically a system for producing sperm, allowing sperm to mature, adding fluids to them, and finally carrying them outside the body . The main parts are: Testes A male normally has two testes . They are present inside a pouch called the scrotum . The testes have two major jobs: They produce sperm . They produce the male sex hormone testosterone . The testes are outside the main abdominal cavity because sperm production requires a temperature slightly lower than normal body temperature. 2. What is inside the testis? Inside each testis there are many tiny, highly coiled tubes called seminiferous tubules . You can imagine them as tiny factories where sperm are made . Special cells present in these tubules undergo meiosis and eventually form sperm. What is meiosis? Meiosis is a special type of cell division. A normal human body cell has: 46 chromosomes But a sperm needs only...
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Biotechnology Explanation

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  What is a Cloning Vector? Imagine you want to put a specific piece of DNA into a living cell so that the cell can make many copies of it. You need a carrier or vehicle to carry that DNA into the cell. This carrier is called a cloning vector . Simple definition: A cloning vector is a DNA molecule that carries a foreign DNA fragment into a host cell and helps it make many copies of that DNA. 🧬 Example: A plasmid such as pBR322 can be used as a cloning vector. Think of it like this: Foreign DNA = A passenger Vector (plasmid) = A vehicle Host cell (usually a bacterium) = The factory Replication = Making many copies Essential Features of an Ideal Plasmid Vector A good cloning vector should have several important characteristics. Two major features are explained below. 1. Marker Genes and Unique Restriction Sites What are marker genes? Marker genes help scientists identify the cells that have received the vector . For example, some marker genes provide a...
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