Introduction to the Cell

Characteristics of Life Made of one or more cells The ability to develop and grow The ability to respond to the environment The ability to reproduce The ability to obtain and use energy

The Needs of Life Energy: All organisms require a steady supply of energy to stay alive. The energy used by almost all life on earth comes from THE SUN Materials: Substances such as carbon dioxide, nitrogen, oxygen and water. Living Space: Space to live and grow.

Definition of Cell A cell is the smallest unit of life that is capable of performing life functions. Unicellular: Organisms made of a single cell. Usually too small to see directly. Multicellular: Organisms made of many cells, like you!

Early Cell Scientists Anton van Leeuwenhoek Robert Hooke Developed the first compound microscope First to view living things Robert Hooke Coined the term cell Looked at cork cells

Early Cell Scientists Matthias Schlieden Theodor Schwann All plants are made from cells Theodor Schwann All animals are made from cells Rudolf Virchow Cell can only arise from pre-existing cells

Cell Theory Every living thing is made of one or more cells. Cells carry out the functions needed to support life. Cells come only from other living cells.

Spontaneous Generation Theory of the 1600s Idea that living things can arise from non-living material Based on observation of real life Fish from the mud of previously dry lakes Maggots from rotting meat Mice from corn Replaced with theory of Biogenesis after experimental evidence presented

Pasteur’s Experiment

Germ Theory of Disease Louis Pasteur Coined the term “germ” Microscopic organisms cause disease Disproves spontaneous generation Developed pasteurization Leads to first human vaccinations

Two Types of Cells Prokaryotic Eukaryotic

Prokaryotic Few internal structures No nucleus Unicellular Bacteria No organelles No nucleus Unicellular Bacteria

Eukaryotic Contain organelles surrounded by membranes Nucleus to contain DNA Most living organisms are eukaryotic Plant Animal

DO NOW One person from each table group get textbooks from the back shelf for everyone at your table. Write your name in the textbook and get ready to tell me the number. Take out your Amoeba Sisters video worksheet from yesterday. Title notes “Cell Organelles” Turn to page 20

Lipid bilayer membrane structure Surrounding the Cell Cell wall Cellulose molecules Rigid, around membrane Only plant cells Cell membrane Lipid bilayer (2 layers of fat molecules) Plant and animal cells Boundary of the cell Controls movement into and out of the cell Lipid bilayer membrane structure

Cytoplasm Gel-like mixture Surrounded by cell membrane Water and proteins Surrounded by cell membrane Provides cell structure Holds organelles All cells

Structures that Process Information Nucleus Directs cell activities Has nuclear membrane Contains the genetic material (DNA) Only in eukaryotic cells Ribosome Translate information from DNA Gather materials to build proteins No outer membrane, just a protein itself (enzyme) Both pro- and eukaryotic

Organelles that Process and Transport Endoplasmic Reticulum (ER) Moves materials around the cell Linked to ribosomes Vesicles Transport proteins from ER to Golgi Apparatus Golgi Apparatus Finishes processing proteins Can move material out of the cell

Organelles that Provide Energy Mitochondria In plant and animal cells Produces energy through chemical reactions Breaks down fats and carbohydrates using oxygen: Respiration Chloroplasts In plant cells only Contain chlorophyll Capture Sun energy directly to make sugar: Photosynthesis

Organelles for Storage and Waste Vacuoles Membrane bound sac Removal of waste from the cell Stores water In plant cells: large central vacuole Structure – why plants wilt Lysosomes Cellular stomach Digests fats, proteins, and carbohydrates Removes waste from the cell