Transcript Cells
Cells Cell Theory • All living things are made of cells • Cells are the basic units of structure, function and physiology in living things • Living cells can come only form other preexisting cells • Cells contain and pass on hereditary information during cell division • All cells have the same chemical composition and metabolic activity Robert Hooke – 1635-1703 • • • • Used simple microscopes to observe objects Was the 1st to use the term “Cell” Identified plant cells in a cork Father of Biology Cell Theory Scientists • Anton Van Leeuwenhoek – 1st to describe bacteria and observe prokaryotic cells. • Matthias Schleiden – Discovered that all plants are made of cells • Theodor Schwann – Observed cells in animal tissue – all animals are made of cells • Rudolf Virchow – Determined that every cell comes from another cell Two Classifications of Cells • Prokaryotic Cells – 1st form of life – No nucleus – Only form Unicellular organisms (one celled) – Example: Bacteria • Eukaryotic Cells – Formed from prokaryotes – Have a nucleus – Form unicellular and multi-cellular organisms. – Example: Plants and animals Comparing Prokaryotic and Eukaryotic Cells Prokaryotes Eukaryotes Have Organelles Are mostly bacteria Have cell wall or membrane Have DNA Have cytoplasm Have a nucleus Include all plant and animal cells Have membranes surrounding organelles Plant and Animal Cells • Plant Cells – – – – – Eukaryotic cells Contain a cell wall Contain chloroplasts Have large vacuoles Square or rectangular shaped • Animal Cells – – – – – – Eukaryotic cells No cell wall No chloroplasts Small vacuoles Found in many shapes Humans have about 210 different types of animal cells Animal Cell Plant Cell Cell Wall • Provides plant cells with structure and support Cell/Plasma Membrane • Outer lining of cells that controls what goes in and out of the cell Nucleus • Control center of eukaryotic cells that contains DNA Lysosomes • Stores enzymes and digests food. Ribosomes • Makes and synthesizes proteins for the cell Centrioles and Centrosomes • Used by the cell in cell division during mitosis and meiosis. Chloroplasts • Produces energy during photosynthesis in plant cells Vacuoles • Stores water and other nutrients for the cell Golgi Apparatus (Body) • Stores, modifies and secretes proteins for the cell. Endoplasmic Reticulum • Rough ER – Contains Ribosomes – Packages and transports proteins throughout the cell • Smooth ER – Stores steroids Nuclear Membrane • Outer lining of the nucleus that controls what goes in and out of the nucleus • Surrounds and protects the nucleus Cytoplasm • Liquid inside the cell that allows movement and which organelles float in Mitochondrion • Produces energy for the cell DNA – Deoxyribonucleic Acid • Carries the genetic information that make up chromosomes inside the nucleus of cells Cellular Respiration • Process by which chemical energy from food is released to form ATP that the cell uses for energy. Photosynthesis • Process in which producers (plants) convert energy from light, carbon dioxide and water into glucose (sugar) to provide energy for the cell. Cell Permeability The permitting or activating of the passage of substances into, out of, or through cells. (water, nutrients, oxygen, etc.) Molecular Transport – Active Transport - Materials require energy to move through a cell membrane – Passive Transport - Materials do not requires help (energy) to move through a cell membrane. Movement of molecules Passive Transport • Diffusion - Movement of molecules from an area of great concentration to an area of lesser concentration. • Osmosis - Passive transport of water through a cell membrane by diffusion Mitosis -When cells split • Simple duplication of a cell and all it’s parts. • Duplication of DNA into two new cells. • Phases: – – – – – Prophase - cell gets ready Metaphase - DNA lines up Anaphase - separation begins Telophase - division finishes up Interphase - normal state of cell Meiosis - Two Divisions • For sexual reproduction • Reproduces a new organism • Second division divides the chromosomes in half • Final phase ends with 4 haploid cells called gametes (example - egg and sperm)