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Draw a diagram of a human cell, include; the Nucleus, the Golgi Apparatus, Lysosomes, Ribosomes and Mitochondria, annotating your diagram with the general functions of each component and of the cell membrane.

                                     Annotated Diagram of a Human Cell

As the human cell is a eukaryotic, animal cell, it has no cell wall, chloroplast, or a large vacuole. Instead, the animal cell has a cytoplasm enclosed in a cell membrane. The cytoplasm has certain organelles that specialise in different functions of the body. These organelles are described below:

·      Cell membrane: It is a phospholipid bilayer that restricts the entry of some materials like hydrophilic and water-soluble molecules, while allowing movement of hydrophobic materials. It has transport proteins embedded that help in transport of such polar molecules. Also, they have receptors in the form of glycolipids that help in cell communication.

·     Cytoplasm: Cytoplasm is present in each cell, mainly composed of water, mineral salts, and proteins. All of the organelles are located in the cytoplasm.

·     Nucleus: The nucleus is a double membrane organelle with nuclear pores through which mRNA can pass through. It also has nucleolus which is the site of ribosome production. It has DNA, the genetic material that controls most of the activities in a cell. It manages the cell activities like cell division.

·       Endoplasmic Reticulum: ER is made up of elongated sacs called cisternae, and there are two types of ER: rough and smooth. The rough ER has ribosomes embedded onto it, where protein is produced and then the ER transports the proteins in the cell. The smooth ER has no ribosomes attached; hence it has a smooth surface. Also, it produces lipids and steroids, and metabolises carbohydrates.

·       Golgi body/ apparatus: The proteins made in ER can be transported to the Golgi body where proteins are modified and packaged. Then, these proteins are released in the form of vesicles.

·    Mitochondria: It is a double membrane organelle that carries the process of respiration that uses oxidation of glucose to produce energy in the form of ATP.

·       Vacuole: They are small, temporary that can store water, ions and waste.

·    Ribosome: Ribosomes are sites for translation of mRNA into a polypeptide chain, which leads to the synthesis of proteins. The animal cells have 80S ribosomes. The mRNA has codons that are read and anticodons of tRNA bind to them, bringing the correct tRNA with the respective amino acid. Hence, a peptide bond forms between two adjacent amino acids.

·    Centrioles: These are microtubule organizing centres, which are involved in cell division. 

·  Lysosome: A lysosome is a pouch of enzymes, which break down large macromolecules, and also degrade toxic and old cell components. 

·     Microfilaments: These protein molecules are part of the extracellular matrix that keeps the organelles in a specific place in the cytoplasm. Also, they provide cell rigidity and shape. 

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