LAB REPORT Please fill the blanks tables in the experimental that attached as PDF file and do the report. The Lab report should be 2 pages exactly . TITLE: AUTHER: Name, Address # INTRODUCTION: – GENRAL BACKGROUND – MOTIVATION – PURPOSE – HYPOTHISIS DEVSION # EXPERMENTAL DESIGN AND PROCEDURE – APPARATUS – APPROACH # ANALYSIS – METHOD – RESULT # DISSCSSION AND CONCULSION Chapter 3: Cells The smallest part of you Lectures by Mark Manteuffel, St. Louis Community College Learning Objectives  Describe what a cell is and the two general types of cells.  Describe the structure and functions of cell membranes.  Describe several ways in which molecules move across membranes.  Describe how cells are connected and how they communicate with each other.  Describe nine important landmarks in eukaryotic cells. 3.1 All organisms are made of cells. The cell: the smallest unit of life that can function independently and perform all the necessary functions of life, including reproducing itself. Cells  Robert Hooke, a British scientist, mid-1600s  A cell is a three-dimensional structure, like a fluid-filled balloon, in which many of the essential chemical reactions of life take place.  Nearly all cells contain DNA (deoxyribonucleic acid). Cell Theory 1. All living organisms are made up of one or more cells. 2. All cells arise from other pre-existing cells. Take-home message 3.1  The most basic unit of any organism is the cell, the smallest unit of life that can function independently and perform all of the necessary functions of life, including reproducing itself.  All living organisms are made up of one or more cells and all cells arise from other preexisting cells. 3.2 Prokaryotic cells are structurally simple but extremely diverse. Every cell on earth falls into one of two basic categories: 1. 2. A eukaryotic cell • has a central control structure called a nucleus which contains the cell’s DNA. • eukaryotes A prokaryotic cell • does not have a nucleus; its DNA simply resides in the middle of the cell • prokaryotes Take-home message 3.2  Every cell on earth is either a eukaryotic or a prokaryotic cell.  Prokaryotes, which have no nucleus, were the first cells on earth. Take-home message 3.2  They are all single-celled organisms.  Prokaryotes include the bacteria and archaea and, as a group, are characterized by tremendous metabolic diversity. 3.3 Eukaryotic cells have compartments with specialized functions. Eukaryotic cells have organelles. Endosymbiosis Theory  Developed to explain the presence of two organelles in eukaryotes, chloroplasts in plants and algae, and mitochondria in plants and animals. Humans, deep down, may be part bacteria. How can that be? Take-home message 3.3  Eukaryotes are single-celled or multicellular organisms whose cells have a nucleus that contain linear strands of genetic material.  The cells also commonly have organelles throughout their cytoplasm, which may have originated evolutionarily through endosymbiosis or invagination, or both. Cell membranes are gatekeepers. 3.4 Every cell is bordered by a plasma membrane. Why are plasma membranes such complex structures? They perform several critical functions. • • • • • take in food and nutrients dispose of waste products build and export molecules regulate heat exchange regulate flow of materials in and out of cell Take-home message 3.4  Every cell of every living organism is enclosed by a plasma membrane, a twolayered membrane that holds the contents of a cell in place and regulates what enters and leaves the cell. 3.5 Molecules embedded within the plasma membrane help it perform its functions. There are four primary types of membrane proteins, each of which performs a different function. The Plasma Membrane “Fluid Mosaic” In addition to proteins, two other molecules are found in the plasma membrane: 1. Short, branched carbohydrate chains 2. Cholesterol Take-home message 3.5  The plasma membrane is a fluid mosaic of proteins, lipids, and carbohydrates. Take-home message 3.5  Proteins found in the plasma membrane enable it to carry out most of its gatekeeping functions.  The proteins act as receptors, help molecules enter and leave the cell, and catalyze reactions on the inner and outer cell surfaces. Take-home message 3.5  In conjunction with carbohydrates, some plasma proteins identify the cell to other cells.  And, in addition to the phospholipids that make up most of the plasma membrane, cholesterol is an important lipid in some membranes, influencing fluidity. 3.6 Faulty membranes can cause disease. Why do “beta blockers” reduce anxiety? Take-home message 3.6  Normal cell functioning can be disrupted when cell membranes—particularly the proteins embedded within them—do not function properly. Take-home message 3.6  Such malfunctions can cause health problems, such as cystic fibrosis.  But disruptions can also have beneficial therapeutic effects, such as in the treatments of high blood pressure and anxiety. 3.7 Membrane surfaces have a “fingerprint” that identifies the cell.  Cells with an improper fingerprint are recognized as foreign and are attacked by your body’s defenses. Why is it extremely unlikely that a person will catch HIV from casual contact—such as shaking hands—with an infected individual? Take-home message 3.7  Every cell in your body has a “fingerprint” made from a variety of molecules on the outside-facing surface of the cell membrane.  This molecular fingerprint is key to the function of your immune system. 3.8 Passive transport is the spontaneous diffusion of molecules across a membrane. There are two types of passive transport: 1. Diffusion 2. Osmosis Diffusion and Concentration Gradients • Solutes • Solvents Simple Diffusion Facilitated Diffusion  Most molecules can’t get through plasma membranes on their own.  Carrier • molecules transport proteins Defects in Transport Proteins  Can reduce or even bring facilitated diffusion to a complete stop  Serious  Many health consequences genetic diseases • Cystinuria and kidney stones Take-home message 3.8 For proper functioning, cells must acquire food molecules and/or other necessary materials from outside the cell. Similarly, metabolic waste molecules and molecules produced for use elsewhere in the body must move out of the cell. Take-home message 3.8 In passive transport—which includes simple and facilitated diffusion and osmosis—the molecular movement occurs spontaneously, without the input of energy. This generally takes place as molecules move down their concentration gradient. 3.9 Osmosis is the passive diffusion of water across a membrane. Cells in Solution  Tonicity • the relative concentration of solutes outside of the cell relative to inside the cell Hypertonic Hypotonic Isotonic Q How do laxatives relieve constipation?  Milk of magnesia and magnesium salts  Water moves via osmosis from the cells into the intestines. The Direction of Osmosis only by a difference in total concentration of all the molecules dissolved in the water  Determined  It does not matter what solutes they are. Take-home message 3.9  The diffusion of water across a membrane is a special type of passive transport called osmosis.  Water moves from an area with a lower concentration of solutes to an area with a higher concentration of solutes. Take-home message 3.9  Water molecules move across the membrane until the concentration of water inside and outside the cell is equalized. 3.10 In active transport, cells use energy to move small molecules into and out of the cell. Molecules can’t always move spontaneously and effortlessly in and out of cells. Two distinct types of active transport: 1. Primary 2. Secondary (differ only in the source of the fuel) Primary active transport: uses energy directly from ATP Secondary Active Transport  An indirect method many transporter proteins use for fueling their activities  The transport protein simultaneously moves one molecule against its concentration gradient while letting another flow down its concentration gradient. Secondary Active Transport  No  At ATP is used directly. some other point and in some other location, energy from ATP was used to pump one of the types of molecules involved against their concentration gradient. Take-home message 3.10  In active transport, moving molecules across a membrane requires energy.  Active transport is necessary if the molecules to be moved are very large or if they are being moved against their concentration gradient. Take-home message 3.10  Proteins embedded within the plasma membrane act like motorized revolving doors to actively transport the molecules. 3.11 Endocytosis and exocytosis are used for bulk transport of particles. Many molecules are just too big to get into a cell by passive or active transport. Three types of endocytosis: 1. Phagocytosis 2. Pinocytosis 3. Receptor-mediated endocytosis Pinocytosis: the process of cells taking in dissolved particles and liquid Q Faulty cell membranes are a primary cause of cardiovascular disease. What modification to them might be an effective treatment? Take-home message 3.11  When molecules cannot get into a cell via diffusion or a pump (e.g., when the molecules are too big), cells can engulf the materials with their plasma membrane in a process called endocytosis.  Similarly, molecules can be moved out of a cell via exocytosis. Take-home message 3.11  In both processes, the plasma membrane moves to surround the molecules or particles and forms a little vesicle that is pinched off inside the cell or fuses with the plasma membrane and dumps its contents outside the cell. 3.12 Connections between cells hold them in place and enable them to communicate with each other.  Involves numerous types of protein and glycoprotein adhesion molecules Tight Junctions  form continuous, water-tight seals around cells and also anchor cells in place  particularly important in the small intestine where digestion occurs Desmosomes  are like spot welds or rivets that fasten cells together into strong sheets  function like Velcro: they hold cells together but are not water-tight  found in much of the tissue-lining cavities of animal bodies Gap Junctions pores surrounded by special proteins that form open channels between two cells Gap junctions are an important mechanism for cell-to-cell communication. Q Is a breakdown of cell-to- cell communication related to cancer?  Contact inhibition  Tumors Take-home message 3.12  In multicellular organisms, most cells are connected to other cells. Take-home message 3.12  The connections can form a water-tight seal between the cells (tight junctions)… Take-home message 3.12  …can hold sheets of cells together while allowing fluid to pass between the cells (desmosomes)… Take-home message 3.12  …or can function like secret passageways between cells, allowing the movement of cytoplasm, molecules, and other signals (gap junctions). Nine important landmarks distinguish eukaryotic cells. 3.13 The nucleus is the cell’s genetic control center.  The nucleus—the largest and most prominent organelle in most eukaryotic cells.  The nucleus has two primary functions: • genetic control center • storehouse for hereditary information Chromatin a mass of long, thin fibers consisting of DNA with some proteins attached Nucleolus  an area near the center of the nucleus where subunits of the ribosomes are assembled  Ribosomes are like little factories. Take-home message 3.13  The nucleus is usually the largest and most prominent organelle in the eukaryotic cell.  It directs most cellular activities by controlling which molecules are produced and in what quantity.  The nucleus is the storehouse for hereditary information. 3.14 Cytoplasm and cytoskeleton form the cell’s internal environment, provide its physical support, and can generate movement. Cytoskeleton: Three Chief Purposes Cilia and Flagellum Take-home message 3.14  The inner scaffolding of the cell, which is made from proteins, is the cytoskeleton.  It consists of three types of protein fibers: microtubules, intermediate filaments, and microfilaments Take-home message 3.14  It gives animal cells shape and support.  It gives cells some ability to control their movement.  It serves as a series of tracks on which organelles and molecules are guided across and around the inside of the cell. 3.15 Mitochondria are the cell’s energy converters Bag-within-a-Bag Structure: the intermembrane space and the matrix Endosymbiosis  Mitochondria may have existed as separate single-celled, bacteria-like organisms billions of years ago.  Mitochondria have their own DNA! We all have more DNA from one parent than the other. Who is the bigger contributor: mom or dad? Why? Take-home message 3.15 In mitochondria, the energy contained within the chemical bonds of carbohydrate, fat, and protein molecules is converted into carbon dioxide, water, and ATP, the energy source for all cellular functions and activities. Mitochondria may have their evolutionary origins as symbiotic bacteria living inside other cells. 3.16 THIS IS HOW WE DO IT Can cells change their composition to adapt to their environment? Why did the researchers use multiple cats from each litter? What was the purpose of counting the capillaries? Why do you think the fat cells in the cats exposed to cold shrank so much? What change in the study would increase your confidence in the conclusions? Take-home message 3.16 • Form follows function in an organism’s cells and reflects their environment. • When cells must perform intensive heat production, they significantly increase the number and size of their mitochondria. Take-home message 3.16 • They also increase the blood supply to the tissue and make use of existing stores of energy. 3.17 Lysosomes are the cell’s garbage disposals Lysosomes round, membrane-enclosed, acid-filled vesicles that function as garbage disposals Why is Tay-Sachs disease like a strike by trash collectors?  50 different enzymes necessary  Malfunctions  Genetic sometimes occur. disorder Take-home message 3.17  Lysosomes are round, membraneenclosed, acid-filled vesicles that function as a cell’s garbage disposal.  They are filled with about 50 different digestive enzymes and enable a cell to dismantle macromolecules, including disease-causing bacteria. 3.18 In the Endoplasmic reticulum, cells build proteins and disarm toxins Rough Endoplasmic Reticulum The Smooth Endoplasmic Reticulum Critical Responsibilities of the Smooth ER Take-home message 3.18  The production and modification of biological molecules within eukaryotic cells occurs in a system of organelles called the endomembrane system, which includes, among other organelles, the rough and smooth endoplasmic reticulum. Take-home message 3.18  In rough ER, proteins that will be shipped elsewhere in the body are folded and packaged.  In the smooth ER, lipids and carbohydrates are synthesized and alcohol, antibiotics, and other drugs are detoxified. 3.19 The Golgi apparatus processes products for delivery throughout the body 3.19 Golgi apparatus: Where the cell processes products for delivery throughout the body Take-home message 3.19  The Golgi apparatus—another organelle within the endomembrane system— processes molecules synthesized within a cell and packages those that are destined for use elsewhere in the body. 3.20 The cell wall provides additional protection and support for plant cells Take-home message 3.20  The cell wall is an organelle found in plants (and some other non-animal organisms).  It is made primarily from the carbohydrate cellulose and it surrounds the plasma membrane of a plant cell. Take-home message 3.20   The cell wall confers tremendous structural strength on plant cells, gives plants increased water resistance, and provides some protection from insects and other animals that might eat them. In plants, plasmodesmata connect cells and enable communication and transport between them. 3.21 Vacuoles are multipurpose storage sacs for cells The central vacuole can play an important role in five different areas of plant life: 1. 2. 3. 4. 5. Nutrient storage Waste management Predator deterrence Sexual reproduction Physical support Take-home message 3.21  In plants, vacuoles can occupy most of the interior space of the cell.  Vacuoles also appear in some other eukaryotic species.  They function as storage space and play a role in nutrition, waste management, predator deterrence, reproduction, and physical support. 3.22 Chloroplasts are the plant cell’s power plant The stroma and interconnected little flattened sacs called thylakoids Endosymbiosis Theory Revisited  Chloroplasts bacteria.  Circular  Dual resemble photosynthetic DNA outer membrane Take-home message 3.22  The chloroplast is the organelle in plants and algae that is the site of photosynthesis—the conversion of light energy into chemical energy, with oxygen as a by-product.  Chloroplasts may have originally been bacteria that were engulfed by a predatory cell by endosymbiosis. Chapter summery instructions 2 pages max, font size 12 *GENERAL GUIDELINES FOR SUMMARY WRITING: 1. Overall summary should be the first paragraph: possible points 20 2. Remaining write it after the bullets: possible points 5 3. Write efficiently – extract main ideas, points, reasoning, etc. from the text: possible points 10 4. Concise – whether it is shorter than original article: possible points 5 5. Own words- write your own language which will be easy to understand: possible points 5 6. Covers all the necessary information: possible points 5 Chapter #3 (CELL) Learning Objectives           What is cell theory Difference between prokaryotic and eukaryotic cell structure Organelle biogenesis: endosymbiosis and invagination Cell boundary: plasma membrane as well as the structure of individual phospholipids Passive transport methods: diffusion, facilitated diffusion, osmosis Tonicity: isotonic, hypertonic, and hypotonic solutions Active transport methods Structures that allow for connection and communication between cells Major landmarks of eukaryotic cells Major structural differences between animal and plant cells Chapter Outline 1 What is a cell? 3.1 Cell is the smallest unit of life and functions independently and performs reproduction. Every organism is composed of one or more cells. The continuity of life arises from growth and division of single cells exists from preexisting cell. Cells differ in size, shape and activities. Each cell is composed of: (i) Cell Boundary or Plasma Membrane, (ii) Nucleus (Eukaryote) or Nucleoid (Prokaryote) and (iii) cytoplasmic contents Cell Theory: i. Cell is the smallest unit of life ii. Each cell arise from the pre-existing cell iii. All organisms consist of one or more cells 3.2 Prokaryotic cells are structurally simple (no membrane bound organelles and no nucleus but circular chromosome also contain extra-chromosomal DNA called Plasmid) and single-celled organisms. Bacteria and archaea belong to prokaryote. General Structure of Bacteria Consists of: A. Cell Envelop: i. Glycocalyx: gel-like coating outside the cell wall made up of polysaccharide ii. Cell wall: mad ..