Download Cell Theory Review - CHS Science Department Mrs. Davis

Cell Theory Review
The cell is the basic unit of structure and function in every living thing.
The development of microscopes aided in the understanding of this theory.
Robert Hooke used the word cell, which means small room, to describe what he saw
when he looked at thin slices of cork under a microscope.
Anton van Leeuwenhoek was the first scientist to use a microscope to see tiny living
organisms in a drop of water.
The cell theory is one of the fundamental concepts of biology. The three tenets of the cell
theory are…
1. All living things are composed of cells.
2. Cells are the basic unit of structure and function in living things.
3. New cells are produced from existing cells.
Basic Cell Structures
Cells differ in size, structure, and function, but every cell has a cell membrane,
cytoplasm, DNA, and ribosomes.
Biologists divide cells into two categories, eukaryotes and prokaryotes. The cells of
eukaryotes have a nucleus, but the cells of prokaryotes do not. Prokaryotes are generally
small single-celled organisms. Eukaryotes are generally larger and more complex single
or multi-celled organisms that contain a nucleus and specialized structures called
organelles. A nucleus is a large structure that contains the cell’s genetic material and
controls the cell’s activities.
Multi-cellular organisms contain many different kinds of cells that work together. The
levels of organization in these organisms are cell → tissue → organ → organ system
Cell specialization means cells are specialized for the type of work they do.
Plant and Animal cells are both eukaryotic, however they differ in several ways. Plant
cells have chloroplasts, cell walls, and a large central vacuole. Animal cells do not have
chloroplasts or cell walls, but they may contain small vacuoles. Animal cells have
cytoskeleton structures called centrioles that plant cells do not.
Microscopes
Place your slide on the stage in the spring clip with the specimen facing up. Always start
with the lowest power objective lens (4x). Move the stage to the highest position. While
looking through the ocular lenses, use the coarse focus knob to slowly move the stage
down until the image comes into view. Adjust the light source to achieve the best
contrast. Center your specimen and switch to the medium power objective lens (10x).
Adjust the fine focus knob until the specimen is in focus. Repeat for high power.
To calculate total magnification, multiply the objective lens magnification by the ocular
lens magnification (e.g. low power lens [4x] times ocular lens [10x] equals 40x).
Cell Structure and Function
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cell
cell membrane
cell wall
nucleus
cytoplasm
prokaryote
eukaryote
organelle
chromatin
lysosome
The basic unit of all forms of life.
Thin, flexible barrier around the cell.
Strong layer around the cell membrane that protects the cell.
Large structure that contains the cell’s genetic information.
Material inside the cell membrane, not including the nucleus.
Organism whose cells do not contain a nucleus
Organism whose cell contains a nucleus.
Specialized structures within a cell that performs cell functions.
Granular material visible within the nucleus.
Structure that breaks down worn-out structures.