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CAPE BIOLOGY Grade A Project! Done by: Crystal Sutherland Olicia Sylvester Janet Noyan Toni-anne Murray

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The Cell The cell is the simpliest unit of life. All living organism are composed of cells

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Each and every cell is composed of many different organelles. All of these organelles play an important part or role in the healthy function of the cell. Today we are looking at two specific forms of cells, the plant and animal cell!

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A plant cell Plant cells are quite different from the cells of the other eukaryotic organisms. Their distinctive features are: A large central vacuole (enclosed by a membrane, the tonoplast), which maintains the cell's rigidity and controls movement of molecules between the cytosol and sap. A primary cell wall containing cellulose, hemicellulose and pectin, deposited by the protoplast on the outside of the cell membrane; this contrasts with the cell walls of fungi, which contain chitin, and the cell envelopes of prokaryotes, in which peptidoglycans are the main structural molecules

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Plant cell contd The plasmodesmata, linking pores in the cell wall that allow each plant cell to communicate with other adjacent cells; this is different from the functionally analogous system of gap junctions between animal cells. Plastids, especially chloroplasts that contain chlorophyll, the pigment that gives plants their green color and allows them to perform photosynthesis. Higher plants, including conifers and flowering plants (Angiospermae) lack the flagellae and centrioles that are present in animal cells.

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The structure of a plant cell!

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An animal cell An animal cell is a form of eukaryotic cell that makes up many tissues in animals. The animal cell is distinct from other eukaryotes, most notably plant cells, as they lack cell walls and chloroplasts, and they have smaller vacuoles. Due to the lack of a rigid cell wall, animal cells can adopt a variety of shapes, and a phagocytic cell can even engulf other structures. There are many different cell types. For instance, there are approximately 210 distinct cell types in the adult human body

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The structure of an animal cell!

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Cell Structures! In each cell there are many and different unique types of organelles. They are like miniature structures. These structures all have different jobs to do and helps to keep the cell in perfect form.

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The Cell Wall This structure is found only in plant cells and is made from the polysaccharide Cellulose. Cellulose forms fibres in a criss-cross pattern with spaces which allow the cell wall to be permeable. Even very large molecules are allowed to pass though. The cell wall promotes support and protection of the cell. It encloses the cell membrane and protoplasm of the cell.

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The Cell Membrane The cell membrane or plasma membrane is very thin and is made up mainly of protein and fat. It is found in both plant and animal cells. It controls substances that enter and leave the cell.

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Cytoplasm This is a clean or transparent, jelly-like liquid consisting of the cells organelles suspended in it. 80% water and 20% dissolved substances. It supports organelles and inclusions.

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Mitochondrion This organelle is often referred to as the power house of the cell. The more energy a cell needs and use the more mitochondrion it will have. It is rod-shape with smooth outer membrane and dark, folded inner membrane. Contains respiratory enzymes. Releases energy from food, during the process of respiration.

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Mitochondrion Contd It has two membranes: a smooth outer membrane and a highly folded inner membrane. Thus it contains two compartments, the intermembrane space and the internal matrix space. The enzymes that catalyze the reactions of respiration are components of either the gellike matix or the inner mitochondrial membrane. These enzymes couple the energy producing oxidation of nutrients to the energy-requiring synthesis of ATP

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Mitochondrion

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Vacuoles These organelles are referred to as bubbles in cells. It is a spaced surrounded by a membrane, called the vacuolar membrane. It contains water, ingested materials, proteins, sugars and minerals. The vacuole serves purpose to gather sugar and minerals or waste products, this solution is called cell sap.

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Chloroplast These are plastids which contain the green pigment chlorophyll. This pigment is needed by plants and plant-like protists to make their food. Chloroplasts are found only in plant cell.

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Nucleus This is a small, oval body which is enclosed by a porous membrane called the nuclear membrane. It contains matter called nucleoplasm. Within The nucleus there are long, thin structures called chromosomes which store the information on the features the an organism will inherit from its parent.

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Nucleus Contd Contains information which helps the ribosomes to make proteins of the right kind. the nucleus is important in the role of cell division in order for it to grow and reproduce. Therefore without a nucleus the cell will not grow or reproduce and will have a greatly reduced life span.

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Nucleus Contd The eukaryotic cells most conspicuous organelle, is the repository of its genetic information. Within the nucleus, the genetic information encoded by the DNA is transcribed/copied into molecules of RNA Which, after extensive processing, are transported to the cytoplasm where they direct the ribosomal synthesis of proteins. Contains a dark-staining body known as the nucleolus.

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Ribosomes These organelles are made of proteins and other macromolecules. They are found either floating freely throughout the cytoplasm or attached to the membranes of the endoplasmic reticulum. Ribosomes attached to the ER sythesize proteins for secretions, or release, from the cell for use by other cells. Protein synthesis (putting substances together to make protein) occurs on ribosomes. Unattached ribosomes in the cytoplasm sythesize proteins that would be used in the cell.

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Endoplasmic Reticulum Is a network of membranes within the cytoplasm (abbreviated as ER). The ER provide a place for the attachment of enzymes. The spaces between the ER membranes seem to serve as canals in the cytoplasm, through which materials are transported. So materials are able to move all the way from the nucleus to the outside of the cell through this canal system. There is a Rough ER and a Smoothe ER

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Endoplasmic Reticulum Contd A large portion is called the rough ER which is studded that are engaged in the sythesis of proteins. The other is the smooth ER, which is devoided of ribosomes, is the site of lipid synthsis. Many synthesized products are eventually tranported to the Golgi apparatus.

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Centrioles Centrioles function during mitosis. Centrioles are present in animal cells and in the body of some single celled organisms.

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Microtubules Microtubules form a type of cellular skeleton. They are very small tube-like structures that lie in parallel bundles, often just outside the cell membrane. They are like a cell skeleton that makes the cell more rigid.

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Lysosome The lysosome is a bag of digestive enzymes. It attaches to and encloses materials brought into the cell. The digestion then takes place inside the membranes of the lysosome. The digested materials then pass through the lysosome membrane. The enzymes remain inside, so they cannot digest the rest of the cell.

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Golgi apparatus It is a specialized part of the ER. Its function is the manufacture and export of materials from the cell. From time to time one of the sacs will break off from the others and migrate to the outside of the cell. This is one means by which some of the manufactured products reach the outside of the cell.

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Differences between a plant cell and an animal cell. Plant Animal Usually round, square or rectangular Have a cell wall made of cellulose Have chloroplast containing chlorophyll Have a large permanent vacuole containing cell sap Stores food as starch grains Have a great variety of shapes Have no cell wall No chloroplast or chlorophyll Have many small temporary vacuoles whose contents vary Stores food as glycogen granules

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Questions 1. What is the network of canals called that runs through the cytoplasm? 2 What is the function of the lysosome? 3. What is the function of the cell membrane? 4. How are microtubules beneficial to certain cells?