Transcript CELL
It’s All About Cells! In 1665, Robert Hook, an English scientist, experimented with a simple microscope. Can you see cells? He observed tiny, orderly, but empty spaces in a thin slice of cork, a type of dead plant material. He called these spaces cells. CELLS Cells are the BASIC units of ALL LIVING organisms. The Cell Theory ALL living things are made up of CELLS. The CELL is the BASIC unit of ALL living things. Only LIVING cells can produce LIVING CELLS. The structure of cells Cells come in many SHAPES and SIZES. Some cells are very SIMPLE in their STRUCTURE. Other cells, however, do contain many SPECIALIZED structures that perform the various functions of cell activity. TYPES OF CELLS: PLANT, ANIMAL, BLOOD, SKIN, ETC. BASIC PARTS OF ALL CELLS PLANT & ANIMAL CELL MEMBRANE SURROUNDING each cell is a COVERING called the cell membrane. This is the part of the cell that determines what ENTERS and LEAVES the cell. CYTOPOLASM All cells have a JELLY-LIKE substance called cytoplasm. Many of the ACTIVITIES of a CELL are CARRIED out here. NUCLEUS Near the CENTER of most cells is a structure called the nucleus. It is the “CONTROL CENTER” of the CELL that directs all of the CELL’S activities. It is surrounded by a MEMBRANE called the NUCLEAR MEMBRANE. Contained in the nucleus are the genetic materials DNA and RNA. DNA RNA DNA stands for DEOXYRIBONUCLEIC ACID. These complex organic molecules contain, TRANSPORT, and INTERPRET the instructions for the REPRODUCTION, growth, and DEVELOPMENT of all LIVING organisms. Throughout the nucleus are structures called CHROMOSOMES. They are ROD- shaped structures that are made of coiled DNA. All human cells have 46 chromosomes. OGANELLES TINY specialized structures within a CELL that PERFORM cell functions. Organelles means “LITTLE ORGANS” VACUOLES STORAGE areas located in the CYTOPLASM Some of these vacuoles store FOOD for future use. Some store CHEMICALS. Others store WASTES until they can be removed from the cell. In animal cells they resemble TINY AIR BUBBLES. In plants they are much larger. MITOCHONDRIA Structures in the CYTOPLASM that release ENERGY and FOOD. These are also called the POWER GENERATORS or the “power house” of the cell. They produce energy for cell activities by CELLULAR RESPIRATION, a process that is similar to burning. RIBOSOMES Structures in the CYTOPLASM where PROTEINS are made. They are TINY, round structures that are attached to a LONG, WINDING NETWORK in the cytoplasm called the endoplasmic reticulum. UNIQUENESS OF PLANT CELLS Plant cells contain all the structures that are found in animal cells. But there are several (mainly 3) differences that are unique to plant cells. Size of Vacuole Vacuoles in plant cells are very large. Like the vacuoles in animal cells, the plant cell vacuole also acts as a storage area. It’s also filled with a clear fluid that is mostly water, but also contains some sugar, starch, and protein molecules. CELL WALL Plant cells also have a THICK, FIRM, outer boundary called a cell wall. It is a rigid, protective structure that SURROUNDS the plant cell. The cell wall SUPPORTS and PROTECTS the cell. Animal cells DO NOT have a cell wall, just a CELL MEMBRANE. Ability to Make Its Own Food In the CYTOPLASM of some plant cells, there are many SMALL, GREEN structures called CHLOROPLASTS. These OVAL-shaped structures in plant cells contain CHLOROPHYLL. Chlorophyll is organic MATERIAL in green plants that ABSORBS sunlight for MAKING FOOD. Chlorophyll enables a plant cell to make its own food by a process called PHOTOSYNTHESIS.