Description of a Cell
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What is a cell exactly? A cell is the structural and functional units of all living organisms which means every living thing on planet earth is made up of cells. It is the basic unit of life. Without it there would be no life because nothing would function. That is where the cell theory comes into place. The theory is that all living things are made up of cells.
Not every cell contains everything that makes up a cell, however they do all have a skin called the plasma membrane which is the cells outer membrane. It serves to separate and protect a cell from its surrounding environment and is made mostly from a double layer of proteins and lipids, fat-like molecules. It regulates what enters and exits the cell. The cell membrane controls the movement of water, nutrients, and wastes that go into and out of the cell by a process known as osmosis. In osmosis, particles move easily from an area of high concentration to an area of low concentration by molecular motion only. Cells can push particles in the opposite direction, but it will take energy from the cell to do this. Inside the membrane are the working parts of a cell. In the center is the nucleus. It is a spherical shape that has pores that allows the flow of cell traffic. The nucleus acts as the brain of the cell. It helps control eating, movement, and reproduction. It also contains the cells DNA which is what coordinates protein synthesis.
Protein synthesis has three steps to it, transcription, transferal, translation. The first step is the transcription of mRNA from a DNA gene in the nucleus. The other many types of RNA are synthesized by the right DNA. This makes the RNA migrate into the cytoplasm from the nucleus. During transferal the amino acid will connect to one of the ends of the RNA. The last step, translation, is where an amino acid will attach itself to an adapter, and from that point on each ribosome will connect to an amino acid.
Back to the nucleus, there are many organelles inside of the cell. Organelles are small structures that help carry out the day-to-day operations of the cell. One important cellular organelle is the ribosome. Ribosomes participate in protein synthesis. The transcription phase of protein synthesis takes places in the cell nucleus. After this step is complete, the mRNA leaves the nucleus and travels to the cells ribosomes, where translation occurs. Another important cellular organelle is the mitochondria. Mitochondria are often referred to as the power plants of the cell because many of the reactions that produce energy take place in mitochondria. Also important in the life of a cell are the lysosomes. Lysosomes are organelles that contain enzymes that aid in the digestion of nutrient molecules and other materials. There are many interesting parts that make up a cell. Below is a diagram of all cell parts and their function:
Cell Membrane ( Plasma)
Controls entry in and out of the cell
Cell Wall
Shapes and supports a plant cell
Chlorophyll
Traps light and is used to produce food for plants
Chloroplasts
Food for plant cell is made here
Chromosomes
Contains code which guides all cell activities
Cytoplasm
Jellylike substance in a cell
Endoplasmic reticulum
Surface for chemical activity
Golgi Bodies
Stores and releases chemicals
Lysosome
Digestion Center
Microtubule
Hollow cylinder