Cells and microscopes

All living things are made of one or more cells, the smallest units of life. Most cells are too small to see without a microscope. A light microscope uses lenses to magnify a specimen on a glass slide; you start with the lowest-power lens, focus with the coarse knob, then switch up and use the fine focus.

Most cells have a nucleus, which contains genetic material and controls the cell. The cell membrane is a thin layer that controls what goes in and out. Cytoplasm is the jelly where most chemical reactions happen. Mitochondria release energy from food in respiration. Magnification tells you how many times bigger the image is than the real object.