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EIN-O’s INTRO

Almost all living things are composed of one or many more cells. Scientists group cells into two types: eukaryote and prokaryote cells.

•Animals and plants are made of eukaryote cells.

•Bacteria are prokaryote cells. Eukaryote cells have internal compartments and are more complex than prokaryote cells. Prokaryote cells are usually much smaller than eukaryote cells and their internal components are not so well organized. However, no matter which type of cell we look at, cells have certain features in common: They have an outer layer (called a cell membrane), they contain a fluid material (called cytoplasm), and they possess genetic material.

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ANIMAL & PLANT CELLSBACTERIA CELLS

100um 10um 1um 100 nm 10 nm

0.1mm 0.01mm 0.001mm 0.0001mm 0.00001mm

VIRUSES

ANIMAL & PLANT CELLS

Getting things in to scaleAnimal and plant cells are about ten to a hundred times smaller than a millimeter or 100 - 10 um (scientists call this 100 or 10 microns). This is 0.1 – 0.01 mm.

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Bacteria cells are about a hundred to a thousand times smaller than a millimeter of 10 – 1 um (10 or 1 micron). This is 0.01 – 0.001 mm.

Viruses are about ten thousand to a hundred thousand times smaller than a millimeter (scientists call this 100 – 10 nanometers). This is 0.0001 – 0.00001 mm.

The Bio Signs Cell and Microbiology series is an assortment of 6 cell and microbiology models. The detailed models are the: Animal Cell, Plant Cell, White Blood Cell, Red Blood Cell, Bacteria, and Virus.

This I Know Guide provides an introduction to: an Animal Cell

3 4ANIMAL CELLAll animals are made up of billions or trillions of cells. Most cells have a similar basic structure. They have an outer layer (cell membrane) and contain a fluid material (cytoplasm). Moving around in the cytoplasm are specialized structures (organelles).

This generalized animal cell model shows the various features found in a cell. They are the: Cell Membrane, Nucleus,Cytoplasm,EndoplasmicReticulum,GolgiComplex,Lysosomes,Mitochondria.

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Cell Membrane

All cells have a cell membrane that is like a barrier, rather like skin. It allows a few molecules to pass through it but mainly serves to keep in cell contents, like chemicals, proteins and organelles.

The contents (chemicals, proteins and organelles) of the cell are termed protoplasm, and are further subdivided into cytoplasm (all of the protoplasm except the contents of the nucleus) and nucleoplasm (all of the material, plasma and DNA and proteins within the nucleus).

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Nucleus

The nucleus is found only in eukaryote cells; that is, animal and plant cells. It is the control center and determines the shape and features of the cell. Deoxyribonucleic acid, DNA, is the genetic material that contains the cell’s instructions. Most DNA stays within the nucleus. Ribonucleic acid, RNA, is formed in the nucleus from DNA and then moves out into the cytoplasm. The nucleolus is an area of the nucleus where small organelles called ribosomes are made.

CytoplasmThe cytoplasm is the material between the cell membrane and the nucleus. Fibrous proteins that occur in the cytoplasm, referred to as the cytoskeleton, help to maintain the shape of the cell as well as anchoring organelles, moving the cell and controlling internal movement of structures.

Endoplasmic ReticulumThe endoplasmic reticulum is a folded sheet of interconnected membranes that helps make proteins and transports them. There are two forms of endoplasmic reticulum: rough and smooth.

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Rough endoplasmic reticulum (Rough ER) is named because its rough appearance is due to the numerous ribosomes that occur along the ER. Rough ER connects to the nucleus and enables the messenger RNA (mRNA), which has instructions for making proteins, to travel to the ribosomes.

Smooth ER lack ribosomes and are believed to be involved in transport and lipid production.

Golgi ComplexThe Golgi Complex is a flattened stack of membrane-bound sacs. It helps to put sugars on newly-made cell components like proteins and enzymes.

LysosomesLysosomes are relatively large vesicles formed by the Golgi Complex. They contain strong enzymes that could destroy the cell. They are essentially small spheres that contain digestive enzymes to break down large particles.

9Mitochondria

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Mitochondria contain their own DNA (termed mDNA) and are thought to have been bacteria-like organisms that joined with eukaryote cells over 700 million years ago. They function as the sites of energy release and ATP production during the process of respiration. The mitochondrion has been called the “powerhouse” of the cell; they are the cell’s power packs. Mitochondria has two membranes. The inner membrane folds into a series of cristae, which are the surfaces on which ATP is generated.