Cells and Cell Theory

Organisms – living things  All organisms are made up of cells.  Multicellular: made of many cells  Examples: Insects, snails, fish, people  Unicellular: made of one cell  Examples: bacteria, protists Exception: Viruses - Not alive - Made of proteins, not cells

Organ system  organ  tissues  cells  organelles  Organ - Group of different tissues that work together to do a certain job  Organ system – a group of organs  Tissue - Group of cells that look alike and work together to do a certain job

Cell Theory (a scientific theory, not a law!)  All living things or organisms are made of cells  New cells are created by old cells dividing into two cells  Cells are the basic building units of life

Cells  Basic unit of life  The smallest living things  First observed by Robert Hooke ( )  A cell is like a factory with each “worker” having its own job.  There are many types of cells, doing many different jobs in plants and animals.

Types of Cells  Eukaryotic  Single cell  Has a nucleus  All organisms EXCEPT bacteria and archaea  Prokaryotic  Simplest type of cell  No nucleus  DNA and other materials float freely within the cytoplasm  Bacteria and archaea

Other Vocab  Diffusion – Material moves from crowded area to less crowded area

 Homeostasis - Ability of organisms to maintain a state of balance  Example: We maintain our body temperature by shivering to get warm and sweating to cool off.

Organelle - Small structure inside a cell that performs a certain job

 Endoplasmic Reticulum (ER) - system of tubes that move proteins within a cell A & P

 Golgi Bodies - package and distribute (move) proteins outside the cell A & P

Lysosome: digests waste, breaks down substances A only

Mitochondria: use oxygen to release energy, power supply A & P

 Ribosome - Small round structure that makes proteins A & P

 Meiosis  Process of cell division  Results in reproductive cells  Mitosis  Process of cell division  Results in two cells  Cells are identical to the parent cells

Animal vs. Plant Cells

Three Main Parts of Cells 1. Cell Membrane 2. Nucleus 3. Cytoplasm

Cell Membrane  Thin layer  Encloses (surrounds) the cell  Controls movement of materials into and out of the cell  Provides shape to the cell  Provides protection for the cell

Nucleus  Controls all cell activity  Round or egg-shaped  Found near the center of the cell  Dark in color  Contains DNA  Deoxyribonucleic Acid: chemical in chromosomes that stores information about the organism

Cytoplasm  Gel-like  Contains a ll the living material except the nucleus  Examples:  Proteins  Nutrients  Organelles

Plant cell parts Plant cells may contain some extra parts.

Chloroplasts (plant cells) Chloroplasts which are disc shaped and contain chlorophyll for photosynthesis.

Cell wall (plant cells) A cell wall which is a strong outer layer to support the cell and give it shape.

Vacuole (plant cells) A vacuole where the plant cell stores sap (the food that it has made; a mixture of sugars, salts and water).

To summarize: (draw and label this!)