Cell Structure & Function. Did You Know? The average human is composed of over 100 Trillion...
Transcript of Cell Structure & Function. Did You Know? The average human is composed of over 100 Trillion...
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 Tissues Organs Organ Systems Organism
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
Plant Animal
“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