Transcript The Cell
Chapter 1 Cells: The Basic Units of Life • Cells • Tissues • Organ (stomach, heart, lungs, skin) • Organ systems (nervous system, digestive system • Organism Organism • Population: same organisms living in same area • Community: two or more different populations. • Ecosystem: a community and all the nonliving things that affect it. – Terrestrial – Aquatic Organisms • Organism-anything that can live on its own. • Unicellular-a single cell living on its own • Multicellular-exists only as a group of cells. • Robert Hooke: Discovery –He was the first to of Cells discover cells in 1665 by looking at a piece of cork • The invention of the microscope led to the discovery of cells because they are too small to see with the naked eye. Anton von Leeuwenhoek • • • • • Dutch merchant 1673 Made his own microscopes Looked at pond scum Named small organisms “animalcules” • Looked at blood • First person to see bacteria • Discovered that yeast is unicellular Matthias Schleiden Found in 1838 that all plant parts are made of cells Theodor Schwann Wrote first two parts of cell theory Rudolf Virchow In 1858 he wrote the third part of the cell theory Cell Theory 1. All organisms are composed of one or more cells 2. The cell is the basic unit of life in all living things 3. All cells come from existing cells Surface to Volume Ratio • Cell needs a larger surface area to exchange materials • The surface to volume ratio is the area of a cell’s outer surface in relation to its volume. •The smaller the cell the larger the surface to volume ratio is. •Cells become less efficient as they grow. Two types of Cell Prokaryotic Cells Eukaryotic Cells No Nucleus Nucleus No membrane-covered organelles Membrane-covered organelles Bacteria All other Cells Circular DNA Linear DNA Eukaryotic Cell Prokaryotic Cell Parts of a Cell The Cell Cell Membrane • • • • Surrounds all cells Protective layer Separates cell from its environment Controls materials going into and out of the cell Cell membrane Structure • Contains proteins, lipids, and phospholipids hydrophobic • ________ - the part of the cell membrane that is water fearing hydrophilic • ________ - the part of the cell membrane that is water loving • The cell membrane controls the movement of materials into and out of the cell. Cytoplasm • Fluid in the cell Organelles • Structures in the cell that perform specific functions within the cell Nucleus • Contains DNA (deoxyribonucleic acid) which is the genetic material that carries information • Surrounded by a membrane (nuclear membrane) that contains pores Cell Wall • Outermost layer of PLANT cells, as well as fungi and some prokaryotes • Gives support to a cell • Contains cellulose Cytoskeleton • Web of proteins in the cytoplasm • Maintains structure of cell Nucleolus • Dark area in the nucleus • Produces ribosomes Ribosomes • Smallest organelles • Most numerous organelles • Some ribosomes float freely in cytoplasm and others are attached to membranes in the cytoskeleton • Function – to make proteins out of amino acids Endoplasmic Reticulum • Rough ER – A system of folded membranes which are covered in ribosomes – protein transport • Smooth ER – A system of folded membrane with no ribosomes –lipid transport Mitochondria • Power House • Breaks down sugar to produce energy • Stores energy in ATP (Adenosine triphosphate) Chloroplasts • In plant cells only • Photosynthesis – process by which plants use sunlight, carbon dioxide,a nd water to make sugar and oxygen • Green • Contain chlorophyll Golgi Complex • Packages and distributes proteins • Looks like smooth ER • Packages lipids and proteins in small bubbles which may be used somewhere else inside or outside of the cell Vesicle • Bubbles that form from the Golgi complex’s membrane • Surrounds material to be moved into or out of a cell Chromosomes • Contain DNA (genes) Vacuoles • Vesicle that stores water • Very large in plants Lysosome • Vesicles that are responsible for digestion • Contain digestive enzymes Cells Alive!