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Welcome to Biology 521! Title: Sep 56:48 PM (1 of 65) Introduction to Biology What exactly are we studying? Define Biology Title: Sep 56:46 PM (2 of 65) "Biology is... the study of living things." This sounds simple, but biology is a very broad field. It is closely related to other branches of science. Concepts from chemistry and physics are important to the study of biology. For example, all living things use energy, a topic studied in physics. An understanding of how molecules are formed and how atoms interact is vital to understanding the processes that occur in cells...in other words, chemistry. Title: Sep 56:48 PM (3 of 65) Brainstorm some professions where a knowledge of biology would be helpful. Try to come up with as many as possible. ��������������� Title: Sep 56:51 PM (4 of 65) So biology is the study of living things... ...but what do we mean by "living"? In other words, what separates thing that are "alive" from those that are "not alive"?* *We won't include things like dead bodies of organisms... even though they aren't alive, they once were. Title: Sep 710:02 AM (5 of 65) Take a few minutes and brainstorm...come up with as many characteristics as you can that separate living things from nonliving things. Look at the objects on the following page as you think... which ones are organisms, and which are not? What separates the two categories? Title: Sep 710:06 AM (6 of 65) Are there any exceptions? For example, can any of the nonliving things do some of the same things as living organisms? Title: Sep 710:09 AM (7 of 65) What were the characteristics that define living things? Title: Sep 710:13 AM (8 of 65) How to Effectively Take Notes From the Biology Textbook The ability to take meaning from written text and internalize it is one of the most important skills you should master as you prepare for continuing your education beyond high school. Following the guidelines below will help you develop this ability. We will be practicing it throughout the semester; completion of assigned readings with appropriate notes will form the bulk of your homework check marks View Hints Online Title: Sep 57:00 PM (9 of 65) Chapter 1: The MicroUniverse of the Cell Group practice: beginning with the introduction and the first page of Section 1.1, go through the process described for taking notes. Work first individually, then compare results as a group. Discuss any questions that anyone might have. Title: Sep 57:05 PM (10 of 65) Chapter 1 The MicroUniverse of the Cell SECTION 1.1The Development of Cell Theory State the 4 points of Cell Theory 1) All organisms are made up of one or more cells and the products of those cells. 2) Cells are the basic unit of structure and function in all living things. 3) New cells are from other living cells by cell division. 4) The activity of multicellular organisms is the result of the combined actions of all the cells which make it up. Title: Jun 2011:16 AM (11 of 65) What is spontaneous generation? How is it related to abiogenesis? spontaneous generation *the idea that life comes from nonliving or once living things *this concept was around for close to 2000 years *renamed abiogenesis by Thomas Huxley Title: Sep 66:31 PM (12 of 65) What evidence was there to support abiogenesis? *maggots appear on rotting meat *frogs and salamanders appear suddenly in mud *mixing a dirty shirt and wheat grains produce mice Title: Sep 66:35 PM (13 of 65) What is biogenesis? The idea that life can only come from preexisting living things. Title: Sep 66:38 PM (14 of 65) Four of the scientists whose experiments advanced the argument between abiogenesis and biogenesis: 1) Francesco Redi (1668) 2) John Needham (1748) 3) Lazzaro Spallanzani (1765) 4) Louis Pasteur (1860) Title: Sep 118:54 AM (15 of 65) Francesco Redi Title: Sep 118:50 AM (16 of 65) John Needham & Lazzaro Spallanzani Title: Sep 119:00 AM (17 of 65) Louis Pasteur Title: Sep 119:04 AM (18 of 65) In Class Activity and Homework Assignment To examine the science which lead to the support of biogenesis over abiogenesis, perform the Thinking Lab Activity on page 7. Complete questions1, 2, 3* and 5. *In Question 3, create a timeline, showing scientific developments in green; societal reactions in blue; and technological advancements in red. Title: Jun 2011:28 AM (19 of 65) Sample partial timeline... Aristotle classifies all organisms as plants or animals; writes that living things can form from nonliving matter 334 BC Knowledge of nature passed orally between generations Up to 5,000 years ago Roger Bacon makes first recorded reference to eyeglasses 1268 European scholars regard knowledge as unchangeable; rely on Aristotle 1500 700 1400 Islamic scholars advance knowledge of mathematics, medicine, astronomy, optics 500 BC Ancient Greece supports fulltime scholars. They use observation and thought rather than experimentation Title: Sep 67:00 PM (20 of 65) 1590s Dutch eyeglass makers invent first compound microscope Be prepared to discuss the answers to questions 13 and 5 from page 7 during class. Title: Sep 67:00 PM (21 of 65) Homework Check! (Cell Theory Timeline) Title: Sep 67:21 PM (22 of 65) Answers to Question 5, page 7 (a) When were cells first observed? 1665, by English scientist Robert Hooke When were they next observed? 1666 or 1667, by Dutch scientist Antony van Leeuwenhoek When were they recognized as the basic unit of life? 1845 by German botanist Alexander Carl Henrich Title: Sep 910:21 AM (23 of 65) (b) Reexamine the four hypotheses that make up the cell theory. Are any of these based on an event that is not shown in your organizer? Title: Sep 910:27 AM (24 of 65) (c) What technological tools helped scientists develop the cell theory? (d) What techniques and methods helped scientists develop the cell theory? Title: Sep 910:30 AM (25 of 65) (e) Which public and scientific reactions hindered development of the cell theory? Which reactions helped? Title: Sep 910:31 AM (26 of 65) (f) The Internet was originally designed to enable scientists all over the world to communicate quickly and easily. What earlier inventions or processes had a similar effect? Title: Sep 910:34 AM (27 of 65) (g) In 1953, water, methane, hydrogen, and ammonia were mixed and exposed to electrical discharges. This resulted in the production of chemicals that are found in components of all living cells. How do these results affect the abiogenesis/biogenesis debate? Title: Sep 910:35 AM (28 of 65) (h) So far, no scientists have been able to produce living cells from nonliving matter. If this did happen, what might three possible responses from the public and scientific community be? Title: Sep 910:37 AM (29 of 65) Read the following definition of "paradigm": One that serves as a pattern or model. A set of assumptions, concepts, values, and practices that constitutes a way of viewing reality for the community that shares them, especially in an intellectual discipline. What do you think would be meant by a "paradigm shift"? Title: Sep 67:24 PM (30 of 65) Do you agree or disagree with the following statement: "The cell theory represented a paradigm shift in our understanding of nature and life." Title: Sep 128:44 AM (31 of 65) Section 1.3: Structures in the Cell Title: Sep 1011:33 AM (32 of 65) Read pages 2326 Skip the diagram on page 25 for now (stop at the top of page 26 when you reach the subsection heading "Cell Organelles") Use the guidelines given in class to take your own notes on these subsections. View Guidelines Title: Sep 119:06 AM (33 of 65) What are the seven tasks that living cells have to perform to maintain life? (see Section 1.3, page 2333) 1) 2) 3) 4) 5) 6) 7) Title: Sep 119:10 AM (34 of 65) Compare prokaryotic and eukaryotic cells Prokaryotic Cells Title: Sep 119:21 AM (35 of 65) Eukaryotic Cells Compare prokaryotic and eukaryotic cells Prokaryotic Cells • do not have a nucleus • are the smallest of cell types • lack internal membranebound organelles e.g. bacteria Eukaryotic Cells • have a nucleus • are 10 to 1000 times larger than prokaryotic cells • have many kinds of organelles, many of which are membrane bound e.g. all other cells, which make up animals, plants, fungi, protists Types of Bacteria Title: Jun 2011:48 AM (36 of 65) Cell Size Read the rest of Section 1.3, pages 2633 Take your own notes on the various organelles found in typical cells. Be sure you include: • The structure and function of each organelle • The differences between animal and plant cells • The specialized regions within prokaryotic cells You may find it helpful to organize these notes in a table. Title: Sep 119:13 AM (37 of 65) Eukaryotic Organelles: Structure and Function Title: Sep 127:38 PM (38 of 65) Cell Membrane The cell membrane separates the contents of the cell from the surrounding environment. It is composed of a double layer of phospholipid, forming a flexible barrier. The structure of the cell membrane will be studied in detail during Chapter 2. Title: Sep 127:39 PM (39 of 65) Nucleus nucleolus nucleoplasm/crhomatin nuclear envelope nuclear pore Largest organelle, and the control center of cell. Surrounded by a double membrane (the nuclear envelope) with nuclear pores allowing transport of materials into and out of the nucleus. Contains fluid nucleoplasm, and chromatin (strands of DNA). The nucleolus is responsible for producing ribosomes. Title: Sep 127:39 PM (40 of 65) Ribosomes Every cell contains thousands of ribosomes, either floating in the cytoplasm or attached to the rough endoplasmic reticulum. Each ribosome is composed protein and RNA, and consists of a large and a small subunit. They are the site of protein synthesis. Title: Sep 127:39 PM (41 of 65) Endoplasmic Reticulum ribosomes smooth ER rough ER A network of folded membranes throughout the cytoplasm. The ER provides a large surface area for cell reactions to occur on, and a transport system for materials to be moved throughout the cell while being kept isolated. The ER can be rough (with attached ribosomes) or smooth (no ribosomes). Smooth ER can pinch off bubbles, or vesicles, to transport molecules to the cell membrane or the Golgi. Title: Sep 127:39 PM (42 of 65) Golgi Apparatus The Golgi apparatus appears as a stack of membrane sacs. It completes the processing of molecules synthesized on the ER, and packages them into membrane bubbles called vesicles for transport, either throughout the cell or to the cell membrane where they are secreted. Title: Sep 127:39 PM (43 of 65) Mitochondria cristae inner membrane outer membrane matrix Mitochondria are the powerplants of the cell. Glucose breakdown begins in the cytoplasm, and is completed in the mitochondria. The energy released is used to form ATP (adenosine triphosphate), which the cell can use to run its chemical reactions. Each mitochondria has an outer membrane, and an inner membrane with many folds called cristae. The fluid inside the mitochondria is called the matrix. Mitochondria are more numerous in cells which use a great deal of energy, such as muscle or liver cells. They contain their own ribosomes and DNA, and can divide on their own. *mitochondria are thought to have formed from symbiotic bacteria Title: Sep 127:39 PM (44 of 65) Lysosomes Lysosomes appear to be bubbles floating in the cytoplasm. They are composed of a single membrane layer containing a fluid of water and digestive enzymes. When a lysosome attaches to a food vacuole, it releases the enzymes, breaking down the structure of the food into simpler molecules. Lysosome enzymes are also used to defend the cell against invading viruses or bacteria, and to remove and break down worn out cell organelles. Title: Sep 127:39 PM (45 of 65) cell membrane Golgi apparatus lysosome mitochondria nucleus nucleolus ribosome rough endoplasmic reticulum smooth endoplasmic reticulum Title: Sep 129:22 PM (46 of 65) Virtual Cell at "Cells Alive" Title: Sep 119:28 AM (47 of 65) Homework: Finish reading Section 1.3, pages 2933 Complete notes on this section, being sure to include information on the structure and function of all eukaryotic cell organelles, and the specialized structures of prokaryotic cells. *Review your notes, and list the typical structural differences between plant cells and animal cells. (In other words, what structures are found in plants that are not in animal cells, and what do animal cells have that are not found in most plant cells?) Title: Sep 129:33 PM (48 of 65) Peroxisome Peroxisomes are similar in appearance to lysosomes. They have a single membrane, surrounding strong enzyme contents. Formed in the cytoplasm, peroxisomes are most common in liver, kidney, and brain cells. They function to rid the cell of toxic substances, such as hydrogen peroxide that is formed during cell metabolism. In the liver, peroxisomes detoxify alcohol. Title: Sep 127:39 PM (49 of 65) Peroxisome The cytoskeleton provides support and shape to the cell, and allows movement of parts within the cell. There are three main strands that form the cytoskeleton: microfilaments (made of the protein actin, a major structural protein in muscle cells which can contract); intermediate filaments (which act as anchor points); and microtubules (composed of the protein tubulin). Title: Sep 127:39 PM (50 of 65) Centrosome The centrosome is composed of a pair of cylindrical centrioles. Each is made up of nine sets of three microtubules, arranged in a ring. During cell division, the centrioles move to opposite ends of the cell, and use microfilaments to pull the cell contents apart. Centrioles are normally found only in animal cells. Title: Sep 127:39 PM (51 of 65) Cilia and Flagella Cilia and flagella are used by several unicellular organisms for the same purpose: movement. They also have a similar structure, a ring of nine microtubule pairs forming a ring surrounding a tenth pair. The difference has to do with how long and numerous they are. One or two long "tails" are called flagella; shorter "hairs" covering the cell are called cilia. Cilia are also used to move fluid past the cell, and are found on the cells in structures of complex organisms (for example, in the trachea to remove particles from the lungs.) Title: Sep 127:39 PM (52 of 65) Cell Wall The cell wall provides strength and support for plant cells. It is composed of a tough, fibrous carbohydrate called cellulose. The cell wall lies outside of the cell membrane. The plant cells that form support structures, such as stems, have a secondary inner cell wall containing lignin, a complex chemical that acts as a binding agent (like glue) to add even more strength while remaining flexible. Title: Sep 127:39 PM (53 of 65) Central Vacuole central vacuole The central vacuole in plant cells stores water and other dissolved substances. This provides pressure (called turgor pressure) inside the cell, forcing the cytoplasm against the cell wall and giving the plant strength. (Think of what happens to a plant if it doesn't get enough water.) The central vacuole may also contain toxins produced by the plant making it taste bad to animals. *Animal cells also contain vacuoles; however, these are smaller, and appear as membrane bubbles in the cell, similar to lysosomes or peroxisomes. These animal cell vacuoles may contain food, wastes, etc. Title: Sep 127:39 PM (54 of 65) Chloroplast outer membrane inner membrane thylakoid granum stroma Plastids are specialized organelles found only in plants. Chloroplasts are the most familiar. They contain the pigment chlorophyll, which gives plants their green color and is responsible for photosynthesis. Another plastid, leucoplasts, are colorless and are used to store starches and other nutrients in plant cells. Like mitochondria, chloroplasts have a double membrane. They contain numerous stacks of membrane sacs called thylakoids (stacks of thylakoids are grana, singular granum ), and are filled with a fluid called the stroma. Title: Sep 127:39 PM (55 of 65) Prokaryotic Structure nucleoid capsule intercellular fluid plasma membrane ribosomes Prokaryotic cells are the bacteria. With no distinct organelles, they are simpler in structure than eukaryotic cells. Still, bacteria are successful, and can survive in extremely hostile environments. They are surrounded by a plasma membrane, often surrounded by a slime layer called the capsule. Bacteria contain DNA which forms a nucleoid region, and may contain plasmids , circular fragments of selfreplicating DNA. Ribosomes which are responsible for protein synthesis, float throughout the intercellular fluid filling the bacteria. Some may have flagella and pilli, which allow bacteria to exchange plasmids, and some form protective cell walls. Title: Sep 127:39 PM (56 of 65) What are the structural differences between plant cells and animal cells? Animal Cells Title: Sep 138:56 PM (57 of 65) Plant Cells Homework Review Section 1.3, pages 2333 Complete Questions #1, 4, 6, 8, 9, and 12 on page 34 Title: Sep 139:49 PM (58 of 65) Homework Title: Sep 139:49 PM (59 of 65) Virtual Cell at "Cells Alive" Title: Sep 138:06 PM (60 of 65) Label the following cell. Is this an animal cell or a plant cell? How do you know? Title: Sep 137:49 PM (61 of 65) Label the following cell. Is this an animal cell or a plant cell? How do you know? Title: Sep 139:47 PM (62 of 65) Section 1.2: Using a Microscope to Explore the Cell *Read pages 1213 and 2021, and take notes on the sections. *Label the parts of the microscope (handout sheet) using the diagram on page 16. *Read Investigation 1.A: Caring for and Using a Microscope. *Complete the prelab questions on page 15. Title: Sep 179:23 AM (63 of 65) Compound Light Microscope Title: Sep 179:17 AM (64 of 65) Compound Light Microscope condenser lens Title: Sep 179:17 AM (65 of 65)