Cell Storybook
A Report on the Organelles of Plant Cells
Zachary Delle 6/28/06 ID 808 Bio 100
Table of Contents
Introduction ..3
Nucleus 4
Ribosomes 6
Endoplasmic Reticulum ...7
Golgi Apparatus ...9
Lysosomes ..10
Vacuoles .11
Mitochondria .. 12
Chloroplasts ...13
Cytoskeleton ..14
Cell Membrane ..15
Cell Wall 16
Bibliography ..17
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Introduction
Hello, I am a plant cell. Over the next 20+ pages I will be telling you about all the organelles I contain. I will be going over Nucleus, Ribosomes, Endoplasmic Reticulum, Golgi Apparatus, Lysosomes, Vacuoles, Mitochondria, Chloroplasts, Cytoskeleton, Cell Membrane, and the Cell Wall.
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Nucleus
Many books describe the nucleus as being the brain of all cells, including me. That is because the nucleus controls pretty much all the activities in the cell. It also contains most of the genetic and hereditary information.
The nucleus is usually located near to the center of the cell, and there is usually only one nucleus per cell. It is usually shaped like a sphere, and takes up about 10% of the total body of the cell, making it very noticeable.
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The nucleus is made up of three major parts; the Nuclear Envelope, Chromatin, and the Nucleolus. The Nuclear Envelope is basically just two membranes which control the flow of materials into and from the nucleus. Chromatin is used in mitosis, or cell reproduction, to create chromosomes that pass genetic information. The Nucleolus is where ribosomes are created.
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Ribosomes
Ribosomes are tiny little floating things that make protein. Thats about all they do and they arent particularly interesting otherwise. They are made in the nucleus and are controlled completely by the nucleus. They synthesize protein.
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Endoplasmic Reticulum
The textbook definition of the Endoplasmic Reticulum is The site where lipid components of the cell membrane are assembled, along with the proteins and other materials that are exported from the cell.
Basically, what this means is the endoplasmic reticulum is a little network of tubules that basically help produce proteins and lipids.
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There are two kinds of endoplasmic reticulum: smooth and rough. Smooth endoplasmic reticulum are more concerned with lipid synthesis, while rough endoplasmic reticulum are attached to ribosomes that help produce/assemble proteins for the cell. The endoplasmic reticulum basically produces all the protein in the cell and the rest of the body.
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Golgi Apparatus
The Golgi Apparatus basically sets up the protein for delivery around the cell. It takes whatever the Endoplasmic Reticulum produces and sends it off to where it needs to go.
Golgie Apparati are shaped like deflated balloons, and are relatively large. It was discovered and named after an Italian scientist named Camillo Golgi. It plays a critical function in spreading the protein cells produce around. Moving on
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Lysosomes
Lysosomes are tiny organelles full of little enzymes that destroy useless organelles and other cell parts. They basically go around and clean me up, eating away at everything thats dead or useless within me, the cell. This is critical in preventing disease and/or cell mutation.
Also, they play a key part in digesting lipids and proteins and other energy sources into usable form for the rest of the cell. Lysosomes are generally very important.
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Vacuoles
In plant cells such as myself, vacuoles are very important. In essence, vacuoles store things for us cells. They are rather large facilities that store carbohydrates, proteins, water, etc.
Vacuoles look like big jelly bubbles, and are in almost all kinds of cells. They provide valuable services and help maintain a level of homeostasis by pumping out water when necessary (to cool me down).
The large size of vacuoles, as illustrated, means that they also play a key role in maintaining the actual physical structure of a cell.
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Mitochondria
Mitochondria process the food and turn it into energy for the cell to use. Their function is very similar to that of a human stomach. Mitochondria are basically the main source of energy for most cells, except plant cells like myself. Though we do have a Mitochondria, we are far more dependant on the Chloroplast for our energy.
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Chloroplast
The chloroplast is the organelle only contained in plant cells that has the unique ability to convert sunlight into usable energy, the way the mitochondria does with food. They also are responsible for making plants green, as they are filled with green pigment.
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Cytoskeleton
By textbook definition, the cytoskeleton is a network of protein filaments that helps the cell to maintain its shape. The cytoskeleton is also involved in movement. Basically, the cytoskeleton is the skeleton of the cell. It is the bone structure that makes up and holds together the structure of the cell.
The cytoskeleton is made up of two main filaments, microfilaments and microtubules. Both of those are made out of protein, but that is about where the similarities end. Microfilaments are thread-like structures made of a protein called Actin. The movement of a cell is caused by the actions of the microfilaments.
Microtubules on the other hand, are hollow tube-like structures (obviously) made of a protein called Tubulin.
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Cell Membrane
The cell membrane acts as a gatekeeper. It is a thing layer that surrounds the cell. It regulates what objects and chemicals can or cannot enter or exit the cell. It is under the direct control of the nucleus. Cell membranes are made entirely out of proteins, carbohydrates, and lipids. Confusingly enough, there are actually two layers of lipids for some reason that remains unclear to me. Something to do with flexible structure.
Here is a picture of the cell membrane.
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Cell Wall
The last organelle I intend to discuss is the Cell Wall. It is rather unique to plant cells, and very valuable. Cell walls basically go on the outside of the cell membrane and allow all gaseous and liquid substances through, like a filter with big holes, but they can still be used to help the cell maintain its shape. That is basically their purpose in existence in five words: Help the cell maintain shape.
The cell wall is formed from cellulose (which, in turn, is formed by fibers that are extracted from carbohydrates).
Picture:
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Bibliography: