Bio Lecture 1 - Cells and Microscopy PDF

Biol 120.03 The Nature of Life Dr. Yangdou Wei Department of Biology University of Saskatchewan Office: CSRB 220.04 Phone: 306-966-4447 E-mail: [email protected] Biology 120 – where to direct questions Make sure you check the course syllabus before contacting anyone. Most course questions...

Biol 120.03 The Nature of Life Dr. Yangdou Wei Department of Biology University of Saskatchewan Office: CSRB 220.04 Phone: 306-966-4447 E-mail: [email protected] Biology 120 – where to direct questions Make sure you check the course syllabus before contacting anyone. Most course questions can be answered there. Who to contact regarding lecture material:  The Instructor: Yangdou Wei ([email protected]) Who to contact for questions on everything lab-related:  Lab Coordinator: Paul Dick ([email protected]) Who to contact for questions related to the online component (MindTap):  MindTap Coordinator: Jordyn Stalwick ([email protected]) Course Resources Learning Objectives in Canvas Course Syllabus Lecture notes (provided as a courtesy of the instructors) Textbook – Chapters Textbook – the “purple pages” Lab manual MindTap Wikipedia and search for images, videos, definitions, featured news… Textbook information Biology - Exploring the Diversity of Life (5th Canadian Edition) by Fenton et al. Available from the U of S Bookstore in various formats, which all contain a copy of the e-text. There is a special code required in order to access MindTap and the e-text Previous editions of this book can also be used Chapters covered are listed in the syllabus and learning objectives If something is not covered in lecture, but is found in the textbook, you are not responsible for that information. On the other hand, if we cover something in lecture that is not in the textbook, you are still required to know it. Thus, the textbook supplements lectures, but cannot replace them Course objectives and terms (i.e. what you need to know for the exams) It’s all in the Learning Objectives Summary file on Canvas. Here is the info for part 1 (book chapter 2) of the course as a reference: KEY CONCEPTS 1. All organisms are made up of cells. 2. All cells share some common structures/characteristics (unity), but there are some differences between cells within and between different organisms (diversity). DEFINITIONS  cell, nucleic acids, DNA, RNA, microscopy, illumination, magnification, resolution, plasma membrane, bilayer, hydrophobic, gene, cytosol, cytoplasm, organelle, cytoskeleton, prokaryote, eukaryote, nucleus, nucleoid, messenger RNA (mRNA), ribosomal RNA (rRNA), ribosome, ATP, flagellum, pilus. LEARNING OBJECTIVES  Describe the cell theory.  Identify how cell theory underlies topics in biology.  What basic features of cell structure and function are shared by all living cells?  Compare and contrast light microscopy and electron microscopy.  Explain why most cells are very small.  Describe the basic structure and function of the plasma membrane.  What structures and activities typically occur in a cell’s cytoplasm.  Describe what is meant by the term “organelle,” and the purpose and significance of such structures in eukaryotic cells.  Describe the basic structure of a ribosome.  Describe the structure and functions of organelles discussed in this chapter (including the nucleus; rough endoplasmic reticulum, smooth endoplasmic reticulum; Golgi complex; lysosomes; mitochondria; chloroplasts).  Explain the relationship (and connections) between the plasma membrane, endoplasmic reticulum, and Golgi complex in eukaryotic cells. The endomembrane system  List and describe the major eukaryotic cytoskeletal elements, where they are typically found, and their roles in the cell.  Explain why cytoskeletal elements associate with motor proteins for certain cellular processes, providing examples of two different processes.  Compare and contrast cells of prokaryotes and those of eukaryotes, identifying similarities and key differences between prokaryotic and eukaryotic cells. Course evaluation (assignments, tests, grading) Lecture Midterm Exam 15% Lecture Final Exam 35% Lab Quizzes and Assignments 25% Lab Practical Exam 5% Lab Exam 20% Total 100% Course evaluation specifics – lecture portion Midterm Exam:  Friday, Oct 11th from 6:30 - 7:30 pm  There is only one midterm  It will be held in-person and outside of class time  An on-campus location to be announced  40 multiple-choice questions to be answered within 1 hour (60 minutes) Final Exam:  December 6 - 23, 2024  Date TBD. It will be scheduled by the Examinations Office  In-person  100 multiple-choice questions to be completed in 2.5 hours (150 minutes) Tips for success Attend Attend every lecture and lab Notes Take careful notes during lectures Study your lecture notes every day. Have learning objectives Study document open as you study and read Read the lab manual and textbook, use Wikipedia if these Read don’t explain it well enough Lab Hand in all lab assignments in time assignments Biol 120.3 Lecture Modules: 1) Introduction – Cells & Microscopy 2) Cell Structure & Function 3) Cell Membrane 4) Cell Cycle (Mitosis & Meiosis) 5) Origins of Life 6) Energy, Enzymes & Metabolism 7) Genetics - Mendelian & Chromosomal Genetics 8) Molecular Biology (DNA Structure, Replication & Gene Expression) 9) Bioenergetics (Cellular Respiration & Photosynthesis) What is Biology? - Biology is the study of life: The word biology is formed by combining the Greek “bios,” meaning life, and the suffix “logy”, meaning science of, knowledge of, or study of Various forms of life exist in the form of organisms: Plants, animals and communities of macroscopic and microscopic forms of life in the soil: Earth-worms, bacteria, and other microorganisms What is an Organism? Latin for: Organum Term directly related "organization”. - broadly defined as “an assembly of molecules functioning as a stable whole that exhibits life” Unicellular organisms Multicellular organisms The Cell Theory By the mid-19th century, microscopic observations had yielded three generalizations, which constitute the Cell Theory: 1. All organisms are composed of one or more cells 2. The cell is the basic structural and functional unit of all living organisms 3. Cells arise only from the division of preexisting cells Discovery of cells Antonie van Leeuwenhoek (a Dutch microbiologist Robert Hooke (an English scientist, 1635-1703) and microscopist, 1632-1723) was one of the first was the first to use a microscope to observe living people to observe microorganisms, using a things. The “cell” was first discovered by him in microscope of his own design, and made one of the 1665, which can be found to be described in his most important contributions to biology. book Micrographia. Drawing of the structure of cork by Robert Hooke that appeared in Micrographia Basic Features of Cell Structure and Function Cells are visualized using a microscope As the basic structural and functional units of all living organisms, cells carry out the essential processes of life All cells have the plasma membranes, DNA, and ribosomes Cells have a DNA-containing central region that is surrounded by cytoplasm Cells contain DNA and RNA, which carry hereditary information and direct the manufacture of cellular molecules Cells use energy, respond to changes in their environment, reproduce, and pass on hereditary information Cells occur in prokaryotic and eukaryotic forms, each with distinctive structures and organization Prokaryotic and Eukaryotic Cells Cells can be classified as prokaryotic or eukaryotic: Prokaryotic cells lack a nucleus and have no internal compartmentalization. Eukaryotic cells have a nucleus and internal membrane-bound organelles. Many Kinds of Cells Unicellular organisms carry out all activities necessary for life In multicellular organisms, the activities of life are divided among numbers of specialized cells Cells assume a wide variety of forms in different prokaryotes and eukaryotes Examples of Cells Sizes and Visualization of Cells Most cells are too small to be seen by the unaided eye - ranging from about 0.5 μm (bacteria) to a few hundred micrometres (plant cells) Scientists use microscopes to visualize cells too small A sense of scale between living cells and atoms to see with the naked eye Units of Measure: 1 mm = 1000 μm (micron) 1 μm = 1000 nm (nanometer) 1 nm = 10 Å (ångström) Molecular Biology of the Cell Magnification and Resolution Two important parameters in microscopy are magnification and resolution (resolving power). Magnification is the ratio of the object’s image size to its real size (e.g., 1200X) Resolution is a measure of the clarity of the images; it is the minimum distance that two points in the specimen can be separated and still be seen as two points Depends primarily on the wavelength of light or electrons used to illuminate the specimen Microscopy To see cells and the structures within them we use two types of microscopes: Light microscopes use light to illuminate the specimen  reflected light  transmitted light  fluorescence Electron microscopes use electrons to illuminate the specimen  transmission  scanning Characteristics of Light and Electron Microscope Microscopy: Light and Electron Microscopy Light Microscopy: Electron Microscopy: - Bright field microscopy - Transmission electron microscopy (TEM) - Differential interference contrast microscopy (DIC) - Scanning electron microscopy (SEM) - Fluorescence microscopy - Confocal microscopy