Cell Structure & Function
Did You Know? The average human is composed of over 100 Trillion individual cells!!! It would take up to 50 cells to cover the dot in the letter i
Definition of Cell A cell is the smallest unit that is capable of performing life functions. Recall from your studies in characteristics of life the organization of living organisms Cells TissuesOrgansOrgan SystemsOrganism
Cell Theory All living things are made up of cells. Cells are the smallest working units of all living things. All cells come from preexisting cells through cell division.
Cell Specialization and Organization Cells are the basic unit of structure and function in living things Serve a specific function within the organism Examples: blood cells, nerve cells, bone cells, skin cells, etc…
Examples of Cells Amoeba Proteus Plant Stem Red Blood Cell Nerve Cell Bacteria
Level 2—Tissues Made up of cells that are similar in structure and function that work together to perform a specific activity Examples: blood, nervous, bone, etc. In humans, we have 4 types of tissue: connective, epithelial, muscle, and nerve
Level 3--Organs Made up of tissues that work together to perform a specific function Examples: heart, brain, kidney, skin
Level 4—Organ Systems Groups of two or more organs that work together to perform a specific function for the organism Examples—Circulatory System, Nervous System, Digestive System
Level 5--Organism Entire living things that can carry out all basic life processes. They can take in materials, release energy from food, release waste, grow, respond to the environment, etc…remember the 6 characteristics of living organisms??? Organisms are usually made up of organ systems, but an organism may only be made up of one cell as is the case with bacteria Examples—human, bacterium, amoeba, euglena, mushroom, sunflower
Discovery of Cells Scientists who were instrumental in the discovery of cells and the development of the Cell Theory: Robert Hooke Anton van Leuwenhoek Matthias Schleiden & Theodore Schwann Louis Pasteur & Francisco Redi
Robert Hooke Discovered Cells while viewing a cork under a microscope
Anton van Leuwenhoek Observed single-celled organisms in pond water Observed blood cells
Matthias Schleiden & Theodore Schwann Said that plant parts and animal tissues were made of cells
Louis Pasteur & Francisco Redi Disproved the Theory of Spontaneous Generation
Two Types of Cells Prokaryotic Eukaryotic
Prokaryotic Do not have structures surrounded by membranes Few internal structures One-celled organisms, Bacteria
Eukaryotic Contain organelles surrounded by membranes Most living organisms PlantAnimal
“Typical” Animal Cell
“Typical” Plant Cell
Cell Parts Organelles
Surrounding the Cell
Cell Membrane Outer membrane of cell that controls movement in and out of the cell Double layer
Cell Wall Most commonly found in plant cells & bacteria Supports & protects cells
Inside the Cell
Nucleus Directs cell activities Separated from cytoplasm by nuclear membrane Contains genetic material - DNA
Cytoplasm Gel-like mixture Surrounded by cell membrane Contains hereditary material
Chloroplast Usually found in plant cells Contains green chlorophyll Where photosynthesis takes place