Chapter 7Cell Structure & Function I. Life is Cellular A-The Discovery of the Cell • • It was not until the _________ that scientists began to use microscopes to observe organisms. In 1665 ____________used an early compound microscope to see tiny chambers in cork.He called these chambers cells after the tiny rooms in monasteries….we know these not to be empty now. Mid-1600’s Robert Hooke • About the same time in Holland________________used a singlelens microscope to look @ pond water, Anton van Leeuwenhoek • In 1838 Matthew Schleiden concluded plants were made of cells • 1839 Theodore Schwann said all animals were made of cells • 1855-Virchow said cells could only come from existing ones. These 3 things compile_________________ – All living things composed of ___________ – Cells are the basic units of ___________________of living things – New cells are produced from ______________________. Existing cells cells Structure and function B-Exploring the Cell • • • Florescent labels and light microscopy have been used to follow molecules through the cell. _________________,which scans cells w/a laser beam can make 3-d images of cells Video technology make it possible to watch cell growth , division and development Confocal light microscopy • Light makes it difficult to visualize tiny structures because it scatters/______________________allow things like proteins to be visualized (things as much as 1000 x smaller can be visualized….TEMS allow you to see specimens cut into ultra thin slices Electron microscopes • W/ a ______________specimens do not have to be cut to see 3-D images….both must be placed into a vacuum so air molecules do not scatter electrons • 1990’s____________________________have revolutionalized visualization of surfaces and atoms have been observed…can be used in ordinary air and can show DNA structure SEM Scanning probe microscopes pollen C .Prokaryotes and Eukaryotes • Cells typically range from _________micrometers,but some bacteria are .2 and some amoeba are 1000 micrometers • All cells have 2 things in common: » cell membrane-a barrier » @ some point they contain_______ 5-50 micrometers DNA 2 broad categories: – _____________________________genetic material is NOT contained in a nucleus/generally less complicated than other cells/carry out all cell activities…present day members are ________________. Prokaryotes bacteria • _____________________________contain a nucleus w/ genetic material,generally larger,much diversity Eukaryotes Division of Labor Section 7-2 •A cell is made up of many parts with different functions that work together. Similarly, the parts of a computer work together to carry out different functions. •Working with a partner, answer the following questions. •1. What are some of the different parts of a computer? What are the functions of these computer parts? •2. How do the functions of these computer parts correspond to the functions of certain cell parts? Go to Section: Venn Diagrams Section 7-2 Prokaryotes Cell membrane Ribosomes Cell wall Animal Cells Lysosomes Go to Section: Plant Cells Cell membrane Ribosomes Nucleus Endoplasmic reticulum Golgi apparatus Vacuoles Mitochondria Cytoskeleton Cell Wall Chloroplasts Eukaryotes Nucleus Endoplasmic reticulum Golgi apparatus Lysosomes Vacuoles Mitochondria Cytoskeleton II. EUKARYOTIC CELL STRUCTURE • Organelles • 2 major parts of eukaryotic cells nucleus cytoplasm Specialized structure that performs important functions within an eukaryotic cell. Cytoplasm is material inside membrane and outside nucleus Figure 7-5 Plant and Animal Cells Section 7-2 Smooth ER Ribosome (free) Vacuole Chloroplast Ribosome (attached) Cell Membrane Nuclear envelope Cell wall Nucleolus Golgi apparat Mitochondrian us Nucleus Rough ER Plant Cell Go to Section: Figure 7-5 Plant and Animal Cells Section 7-2 Nucleolus Nucleus Nuclear envelope Ribosome (attached) Ribosome (freeCell ) Membrane Mitochondrian Smooth endoplasmic reticulum Rough endoplasmic reticulum Centrioles Golgi apparatus Animal Cell Go to Section: The Nucleus • Contains nearly all the cell’s DNA • Codes for instructions to make proteins and other molecules • Surrounded by nuclear envelope---has many pores to allow material in and out • Contains chromatin—has DNA bound to protein,usually spread throughout nucleus,but condenses during cell division to make CHROMOSOMES,containing genetic info • Usually contain Nucleolus—assembly of ribosomes begin here. Ribosomes • Proteins are assembled here • Made out of small particles of RNA and protein • Found throughout cytoplasm • Coded instructions from nucleus tell how to make proteins • Cells active in protein synthesis have a lot of ribosomes Endoplasmic Reticulum • Site where lipid components of cell membrane are assembled,along w/ proteins and other materials exported from cell(those proteins are made there) • Rough ER is involved in protein synthesis,because ribosomes are on it • Newly made proteins leave ribosomes and insert on rough ER ,where they may be modified • If cell makes a lot of protein ,there is much ER • Smooth ER may contain many specialized enzymes Lysosomes • Small organelles filled w/enzymes • May digest or break down lipids,carbs,and proteins into small molecules that can be used by the rest of the cell • Lysosomes remove “junk”,or used up organelles….very important that this aspect function occurs Vacuoles • Sac like structures that store water ,salts ,proteins, and carbs • Plants may have a single large water filled vacuole • Contractile vacuoles control water in paramecium Mitochondria and Chloroplasts • Most all eukaryotic cells contain mitochondria that convert chemical energy stored in food into compounds convenient for cell to use • Mitochondria have an outer and inner membranes • In humans,nearly all mitochondria comes from ovum(egg cell) Chloroplasts • Capture energy from sunlight and convert into chemical energy in photosynthesis • Contain 2 membranes and chlorophyll Organelle DNA • • • • In chloroplasts and mitochondria Small DNA molecules Maybe descendants of early prokaryotes ----Endosymbiotic theory says these prokaryoic ancestors developed a symbiotic relationship w/ early eukaryotes and resided within---evolving into mitochondria Cytoskeleton • Network of protein filaments that help cell maintain shape • Also involved in movement • MICROFILAMENTS are threadlike structures made of a protein-actin….make a major network and a tough framework///allows amoebas and such to move • MICROTUBULES-hallow structures made of proteins called tubulins—important in holding a cell’s shape---form a mitotic spindle in cell division/which helps separate chromosomes • CENTRIOLES are microtubules near nucleus in animals and help organize cell division • Microtubules also help make projections like cilia or flagella Figure 7-7 Cytoskeleton Section 7-2 Cell membrane Endoplasmic reticulum Microtubule Microfilament Ribosomes Go to Section: Michondrion