Cells Review List Cell Theory The three parts of the cell theory are: 1. All living things are composed of cells. 2. Cells are the basic units of structure and function for living things. 3. All cells come from pre-existing cells Also, organisms grow by “adding on more cells” NOT by increasing the size of their cells. These scientists are credited with the following contributions towards the development of the cell theory: Robert Hooke 1665 Examined cork cells. He is responsible for naming the spaces in the cork “cells.” Anton Van Leeuwenhoeke 1673 Examined pond scum and saw “little animals” (bacteria and other single celled organisms) swimming around. He named the creatures “animalcules.” Matthias Schleiden 1838 Examined plant cells and concluded that all parts of plants are composed of cells. Theodore Schwann 1839 Examined animal tissue and concluded that all parts of animals are composed of cells. Rudolf Virchow 1858 Observed that cells could not develop from anything but existing cells. Cell Structure The structures within a cell are called organelles. Organelle structures are designed to help them complete their functions. Be able to differentiate between structure and function of each organelle. Be able to identify if a cell is plant or animal based on the structures it contains. Cell Membrane – found in both plant and animal cells Function: controls the passing of materials in and out of the cell; gets rid of waste Structure: surrounds the cytoplasm Nucleus – found in both plant and animal cells Function: acts as the control center of the cell Structure: holds the DNA/chromosomes Mitochondria – found in both plant and animal cells Function: release ATP energy Structure: double membrane organelle with inner folds Vacuole – found in both plant and animal cells Function: Storage site for water, nutrients, and waste Structure: much larger in plant cells Cilia – found in unicellular organisms and some animal cells Function: used for motion Structure: tiny hair-like projections on the outside of certain cells Flagellum – found in unicellular organisms and some animal cells Function: used for motion Structure: a long whip-like structure on the outside of certain cells Cell Wall – found in ONLY plant cells Function: supports and protects Structure: rigid; surrounds cytoplasm in plant cell s Chloroplasts – found in ONLY plant cells Function: site of photosynthesis (how a plant makes food) Structure: Green; contains chlorophyll; stacks of disc inside The shape of a cell is designed for its function. Examples of this include: Plant cells are elongated for stacking up; the cells are more box-like and rigid, with larger vacuoles for storing water. Blood cells are round so they can travel through blood vessels and deliver oxygen and nutrients to the other cells of the body. Muscle cells are elongated for contracting and pulling on bones Single-celled pond organisms have cilia or flagella for movement. ALL cells can…. Obtain energy (organelles responsible: chloroplast and mitochondrion) Get rid of waste (organelles responsible: lysosome and cell membrane) Grow and reproduce (organelles responsible: centriole and nucleus) .