The History of the Cell The Cell The basic unit of an organism Discovery made possible by the invention of the microscope

Microscopes A microscope is an optical instrument used for viewing very small objects, such as mineral samples or animal or plant cells, typically magnified several hundred times.

The Eye Piece Also called the ocular The part of the microscope you look through The eye piece magnifies what you are looking at 10x

Arm and Base The arm and the base are used to hold the microscope You should always use two hands when carrying the microscope. One on the arm and one on the base.

Coarse Adjustment The course adjustment knob is used to focus the object Only used under low power.

Fine Adjustment The fine adjustment knob refocuses the object. Only use under high power

Objectives The objectives are used to magnify what you are looking at

Diaphragm Used to adjust the amount of light

Microscopes and Cells 1600’s. Anton van Leeuwenhoek first described living cells as seen through a simple microscope.

Microscopes and Cells 1830’s. Mathias Schleiden identified the first plant cells and concluded that all plants made of cells. Thomas Schwann made the same conclusion about animal cells.

Cell Theory All organisms are made up of one or more cells. The cell is the basic unit of organization of all organisms. All cells come from other cells all ready in existence.

Two Basic Cell Types 1 ) Prokaryote Lacks internal compartments. No true nucleus. Most are single-celled (unicellular) organisms. Examples: bacteria

Two Basic Cell Types 2) Eukaryote Has several internal structures (organelles). True nucleus. Either unicellular or multicellular. unicellular example: yeast multicellular examples: plants and animals

The Parts of The Eukaryotic Cell 1) Boundaries A) Plasma Membrane -- Serves as a boundary between the cell and its external environment. -- Allows materials to pass in and out of the cell.

The Parts of The Eukaryotic Cell B) Cell Wall -- Surrounds the plasma membrane of the cells of plants, bacteria, and fungi. -- Plant cell walls contain cellulose while fungi cell walls contain chitin.

The Parts of The Eukaryotic Cell 2) Controls A ) Nucleus Regulates cell function. Surrounded by a double-layered membrane (nuclear enveloped) with large pores that allow materials to pass in and out of the nucleus. Contains chromatin – long tangles of DNA.

The Parts of The Eukaryotic Cell 2) Controls B) Nucleolus Found in the nucleus and responsible for ribosome production. Ribosomes are the sites of protein production.

The Parts of The Eukaryotic Cell 3) Assembly Cytoplasm The jelly-like material that surrounds the organelles.

The Parts of The Eukaryotic Cell 4) Transport A) Endoplasmic reticulum Folded membrane that acts as the cell’s delivery system. Smooth E.R. contains enzymes for lipid synthesis. Rough E.R. is studded with ribosomes for protein synthesis.

The Parts of The Eukaryotic Cell 4) Transport B) Golgi apparatus (or Golgi body) A series of flattened sacs where newly made lipids and proteins from the E.R. are repackaged and shipped to the plasma membrane.

The Parts of The Eukaryotic Cell 5) Storage A) Vacuoles A sac of fluid surrounded by a membrane used to store food, fluid, or waste products.

The Parts of The Eukaryotic Cell 5) Storage B) Lysosomes Contain a digestive enzyme. Can fuse with vacuoles to digest food, or can digest worn cell parts. Also known as “suicide sacs” because they can also destroy the whole cell.

The Parts of The Eukaryotic Cell 6) Energy Transformers A) Mitochondria Produce the energy for the cell. Also known as the “powerhouse of the cell”. Has a highly folded inner membrane (cristae).

The Parts of The Eukaryotic Cell 6) Energy Transformers B) Chloroplasts -- Found in plant cells and some protists. -- Transforms light energy into chemical energy which is stored in food molecules. -- Contain chlorophyll – a green pigment that traps light energy and gives plants their green color.

The Parts of The Eukaryotic Cell 7) Support Cytoskeleton A network of thin, fibrous materials that act as a scaffold and support the organelles. Microtubules – hollow filaments of protein. Microfilaments – solid filaments of protein.

The Parts of The Eukaryotic Cell 8) Locomotion A) Cilia Short, numerous, hair-like projections from the plasma membrane. Move with a coordinated beating action.

The Parts of The Eukaryotic Cell 8) Locomotion B) Flagella Longer, less numerous projections from the plasma membrane. Move with a whip-like action.

The Parts of The Eukaryotic Cell 9) Cell Division A)Centrioles made of protein. play a role in the splitting of the cell into two cells. found in animal and fungi cells.

Composite Animal Cell

Cellular Organization Cell Tissue – group of cells functioning together. Organ – group of tissues functioning together. Organ System – group of organs functioning together. Organism – group of organ systems functioning together.

Cellular Functions All the different parts of the cell are important to the life of the cell. Cellular activities require energy. All cells are able to release energy from complex molecules. The energy in a sugar molecule is released by the mitochondria in small steps. After a cell has taken in energy-rich molecules, the molecules are used by the mitochondria and energy is released.

Metabolism Metabolism is the sum of all the chemical reactions in a in a cell or organism. Important molecules, like sugar, are processed and energy is transformed to ATP and waste materials. Not all energy is used immediately. Some cells, for example, those in green plants that contain chloroplasts, store energy in complex molecules such as sugars.

Homeostasis and Transport Atoms, molecules and small particles are in constant motion. Molecules tend to move from an area where they are more concentrated to an area where they are less concentrated, until their concentration is the same everywhere. The concentrations of molecules at various points between the high and low areas form what is called the concentration gradient. Molecules are said to move down the concentration gradient.

Homeostasis and Transport Water moves in and out of cells and diffuses down its concentration gradient in the same manner as other substances.

Passive Transport The diffusion of water is called the osmosis. Molecules move across a semipermeable membrane, from an area of high concentration to low concentration. Hypertonic: If concentration of water is higher inside the cell, water diffuses out of the cell and the cell will shrink. Salt solution Plasmolysis is a loss of turgor pressure and the cell will shrink. Hypotonic: If concentration of water is higher outside the cell, water diffuses into the cell and the cell will expand (burst). Provides the plant cell with turgor pressure. In an animal cell, it may result in cytolysis (bursting of the cell) Contractile vacuoles are used to remove excess water in protozoa. Animals use lungs and kidneys. Isotonic: The concentration is the same inside and outside of the cell. Saline solution

Active Transport Movement of molecules up the concentration gradient. Requires energy Carrier proteins can also serve as “pumps” during active transport. Sodium Potassium Pump – works to maintain a higher concentration of sodium (Na) ions inside the cell and a higher concentration of postassium (K) ions outside the cell. Requires energy to do so. Creates and electrical gradient across the cell membrane which is essential for nerve impulses.