Cells Cell Study Guide What is a cell? A cell is the basic unit of all living organisms. They are too small to be seen without the use of magnification. How do you use magnifiers to observe cells and their structures? Magnifiers consist of a lens or a combination of lenses that make an object appear larger. Examples of magnifiers that may be used to observe cells and their structures include magnifying glasses, hand lenses, and microscopes. What structures do you find in a plant cell, but not in an animal cell? 1. Plant cells have a cell wall, but animal cells do not. 2. Plant cells have chloroplasts, and chlorophyll, but animal cells do not. 3. Plant cells generally have a more rectangular shape because the cell wall is more rigid. Animal cells have a round or irregular shape because they do not have a cell wall. What are the functions of the cell membrane, cytoplasm, chloroplast, nucleus, and cell wall? 1. The cell membrane acts as a barrier and controls what goes in or out of a cell. 2. Cytoplasm is a jelly-like fluid that maintains the shape, the consistency of the cell, and provides suspension to the organelles. 3. Chloroplasts store material to help plants make food. 4. The nucleus regulates all activity within the cell. It acts as the brain of the cell and contains the DNA (genetics) 5. The cell wall surrounds the plant cell. It does not exist in an animal cell. It gives structure to the cell. 6. The Vacuole is the part of the cell that stores the food, water, and waste How do single-celled and multi-celled organisms compare and contrast? Single-celled or uni-celled organisms are made up of one cell. Their size varies greatly. They acquire nourishment in two ways. First, they are able to produce their food by the use of chloroplasts during the process of photosynthesis. Second, they seek out prey and engulf it with their bodies. Many uni-celled organisms reproduce by dividing in two; others rely on a host. Some cells can double their population in 20 minutes due to a rapid rate of cell division. Multi-celled organisms contain more than one cell. They are most often much larger than single-celled organisms and can be seen with the naked eye. Plants and animal cells that are multi-cellular and are made up of specialized cells called differentiated cells. Differentiated cells are a group of cells that work together and form tissue. Tissue makes up organs and organs make up systems. Multi-celled organisms rely on these systems to digest food, breathe, and reproduce.