A good Summary, biology homework help

User Generated

nmvm887

Science

Description

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

Unformatted Attachment Preview

Chapter 1: Scientific Thinking Your best pathway to understanding the world Lectures by Mark Manteuffel, St. Louis Community College Learning Goals • Describe what science is. • Describe the scientific method. • Describe key aspects of well-designed experiments. • Describe how the scientific method can be used to help make wise decisions. • Describe the major themes in biology. More than just a collection of facts, science is a process for understanding the world. Scientists  Are curious  Ask questions about how the world works  Seek answers • Does the radiation released by cell phones cause brain tumors? • Are anti-bacterial hand soaps better than regular soap? • Do large doses of vitamin C reduce the likelihood of getting a cold? “How do you know that is true?” The single question that underlies scientific thinking Scientific Literacy  how to think scientifically  how to use the knowledge we gain to make wise decisions  increasingly important in our lives  literacy in matters of biology is especially essential 1.2 Biological literacy is essential in the modern world. A brief glance at any newspaper will reveal  Biological Literacy The ability to: 1. use the process of scientific inquiry to think creatively about real-world issues, 2. communicate those thoughts to others, and 3. integrate them into your decisionmaking. 1.3 The scientific method is a powerful approach to understanding the world. Why and when do people develop superstitions? Can animals be superstitious? The Scientific Method  Observe a phenomenon  Propose an explanation for it  Test the proposed explanation through a series of experiments ↓ Accurate & valid, or… Revised or alternative explanations proposed Scientific Thinking Is Empirical… …based on experience and observations that are rational, testable, and repeatable. 1.4 Thinking like a scientist: how do you use the scientific method? The basic steps in the scientific method are:  Step 1: Make observations.  Step 2: Formulate a hypothesis.  Step 3: Devise a testable prediction.  Step 4: Conduct a critical experiment.  Step 5: Draw conclusions and make revisions. 1.5 Step 1: Make observations. Look for interesting patterns or cause-andeffect relationships. Does taking echinacea reduce the intensity or duration of the common cold? 1.6 Step 2: Formulate a hypothesis. A proposed explanation for observed phenomena To be most useful, a hypothesis must accomplish two things: 1. It must clearly establish mutually exclusive alternative explanations for a phenomenon. 2. It must generate testable predictions. Devising Testable Predictions • We can only evaluate the validity of a hypothesis by putting it to the test. • Researchers often pose a hypothesis as a negative statement, proposing that there is no relationship between two factors The Null Hypothesis  A negative statement that proposes that there is no relationship between two factors  These hypotheses are equally valid but are easier to disprove.  An alternative hypothesis  It is impossible to prove a hypothesis is absolutely and permanently true. Null and Alternative Hypotheses  Echinacea reduces the duration and severity of the symptoms of the common cold. Or as a null hypothesis: • Echinacea has no effect on the duration or severity of the symptoms of the common cold. Null and Alternative Hypotheses  Hair that is shaved grows back coarser and darker. Or as a null hypothesis: • There is no difference in the coarseness or color of hair that is shaved relative to hair that is not shaved. 1.7 Step 3: Devise a testable prediction. Suggest that, under certain conditions, we will make certain observations. Devising a Testable Prediction from a Hypothesis  Keep in mind any one of several possible explanations could be true. Devising a Testable Prediction from a Hypothesis The goal is to:  Propose a situation that will give a particular outcome if your hypothesis is true…  …but that will give a different outcome if your hypothesis is not true. Hypothesis: Eyewitness testimony is always accurate.  Prediction: Individuals who have witnessed a crime will correctly identify the criminal regardless of whether multiple suspects are presented one at a time or all at the same time in a lineup. Hypothesis: Echinacea reduces the duration and severity of the symptoms of the common cold. 1.8 Step 4: Conduct a critical experiment. an experiment that makes it possible to decisively determine whether a particular hypothesis is correct Hypothesis: Echinacea reduces the duration and severity of the symptoms of the common cold. 1.9 Step 5: Draw conclusions, make revisions. Trial and error Does echinacea help prevent the common cold? Hypothesis: Echinacea reduces the duration and severity of the symptoms of the common cold. 1.10 When do hypotheses become theories? Two distinct levels of understanding that scientists use in describing our knowledge about natural phenomena Hypotheses and Theories A hypothesis is a proposed explanation for a phenomenon. • a good hypothesis leads to testable predictions. Hypotheses and Theories A theory is a hypothesis for natural phenomena that is exceptionally wellsupported by the data. • a hypothesis that has withstood the test of time and is unlikely to be altered by any new evidence Theories vs. Hypotheses Repeatedly tested Broader in scope Well-designed experiments are essential to testing hypotheses. 1.11 Controlling variables makes experiments more powerful. Elements Common to Most Experiments 1. Treatment • any experimental condition applied to individuals 2. Experimental group • a group of individuals who are exposed to a particular treatment 3. Control group • a group of individuals who are treated identically to the experimental group with the one exception: they are not exposed to the treatment 4. Variables • characteristics of your experimental system that are subject to change Controlling Variables  the most important feature of a good experiment  the attempt to minimize any differences between a control group and an experimental group other than the treatment itself Why does this experiment fall short of qualifying as a good example of the scientific method?  Experimental  Control design group with whom to compare the treatment group? The Placebo Effect  The phenomenon in which people respond favorably to any treatment  The placebo effect highlights the need for comparison of treatment effects with an appropriate control group. Clever Hans Experimental Designs  Blind experimental design • The experimental subjects do not know which treatment (if any) they are receiving.  Double-blind experimental design • Neither the experimental subjects nor the experimenter knows which treatment the subject is receiving. Hallmarks of an Extremely Well-designed Experiment  Blind/double-blind strategies  Randomized • The subjects are randomly assigned into experimental and control groups. 1·12 THIS IS HOW WE DO IT Is arthroscopic surgery for arthritis of the knee beneficial? How could you determine whether a particular type of surgery is effective? How does general scientific literacy—particularly among nonscientists such as the volunteers in this study—help in advancing our knowledge and understanding about a particular phenomenon? The Treatment Groups 1. Arthroscopic surgery with debridement 2. Arthroscopic surgery with lavage 3. Placebo surgery What is the take-home message from these two graphs? At two years, the pain scores were: Patient Group Mean Pain Score 1. Debridement 51 ± 23 2. Lavage 54 ± 24 3. Placebo 52 ± 24 What conclusions can you draw from these results? 1.13 Repeatable experiments increase our confidence. Can science be misleading? How can we know? Do megadoses of vitamin C reduce cancer risk? An experiment must be reproducible and repeatable. 1.14 We’ve got to watch out for biases. Can scientists be sexist? How would we know? Scientific thinking can help us make wise decisions. 1.15 Visual displays of data can help us understand and explain phenomena. Variables • Independent Variables – some measurable entity that is available at the start of a process and whose value can be changed as required. • Dependent Variables – created by the process being observed and whose value cannot be controlled. Take-home message 1.15 • Visual displays of data, which condense large amounts of information, can aid in the presentation and exploration of the data. Take-home message 1.15 • The effectiveness of such displays is influenced by the precision and clarity of the presentation, and it can be reduced by ambiguity, biases, hidden assumptions, and other issues that reduce a viewer’s confidence in the underlying truth of the presented phenomenon. 1.16 Statistics can help us in making decisions Statistics A set of analytical and mathematical tools designed to help researchers gain understanding from the data they gather. • Drawing conclusions based on limited observations is risky. • Measuring a greater number of people will generally help us draw more accurate conclusions about human height. Making Wise Decisions About Concrete Things  Does having access to a textbook help a student to perform better in a biology class? • Students who had access to a textbook scored an average of 81% ± 8% on their exams… • …while those who did not scored an average of 76% ± 7%. Statistics can also help us to identify relationships (or the lack of relationships) between variables. a positive correlation • meaning that when one variable increases, so does the other  “Correlation  Statistical is not causation.” analyses can help us to organize and summarize. 1.17 Pseudoscience and misleading anecdotal evidence can obscure the truth. 1. Pseudoscience: individuals make scientific-sounding claims that are not supported by trustworthy, methodical scientific studies. 2. Anecdotal observations: based on only one or a few observations, people conclude that there is (or is not) a link between two things. Anecdotal Observations  do not include a sufficiently large and representative set of observations of the world  data are more reliable than anecdotes 1.18 There are limits to what science can do. One of Several Approaches to the Acquisition of Knowledge  The scientific method is, above all, empirical.  Value judgments and subjective information  Moral statements and ethical problems On the road to biological literacy: what are the major themes in biology? • 1.19 Important unifying themes tie together the diverse topics in biology. What is Life? Try to define it Characteristics shared by all living organisms and living systems: • A complex, ordered organization consisting of one or more cells. • The use and transformation of energy to perform work. • Sensitivity and responsiveness to the external environment. Characteristics shared by all living organisms and living systems: • Regulation and homeostasis. • Growth, development, and reproduction. • Evolutionary adaptation leading to descent with modification over time. Two Unifying Themes  Hierarchical  The organization power of evolution 4 Chief Areas of Focus 1. The chemical, cellular, and energetic foundations of life 2. The genetics, evolution, and behavior of individuals 3. The staggering diversity of life and the unity underlying it 4. Ecology, the environment, and the subtle and important links between organisms and the world they inhabit Take-home message 1.19 • The characteristics shared by all living organisms include: – complex and ordered organization; – the use and transformation of energy; – responsiveness to the external environment. Take-home message 1.19 • The characteristics shared by all living organisms include: – regulation and homeostasis; – growth, development, and reproduction; – and evolutionary adaptation leading to descent with modification. Chapter 2: Chemistry Raw materials and fuel for our bodies Lectures by Mark Manteuffel, St. Louis Community College Learning Objectives  Describe what atoms are, their structure, and how they bond.  Understand water’s features that help it support all life.  Describe carbohydrates—their structure and function. Learning Objectives  Describe lipids—their structure and function.  Describe proteins—their structure and function.  Describe nucleic acids—their structure and function. Atoms form molecules through bonding. 2.1 Everything is made of atoms.  An element is a substance that cannot be broken down chemically into any other substances.  An atom is a bit of matter that cannot be subdivided any further without losing its essential properties. Atomic Structure: The nucleus, protons, and neutrons Atomic Structure: Electrons Atomic Numbers Isotopes Radioactive Atoms • A few atomic nuclei are not stable and break down spontaneously • These atoms are radioactive • They release, at a constant rate, a tiny, high-speed particle carrying a lot of energy. 25 Elements Found in Your Body and the Big 4 Electron Shells The Versatility of Carbon Ions Molecules Products of bonding! Bond Energy Ions and Ionic Bonds Hydrogen Bonds Water has features that enable it to support all life. 2.4 Hydrogen bonds make water cohesive. 2.5 Water has unusual properties that make it critical to life.  Cohesion  Large  Low heat capacity density as a solid  Good solvent Cohesion High Heat Capacity Why do coastal areas have milder, less variable climates than inland areas? Low Density as a Solid Why don’t oceans freeze as easily as fresh water lakes? 2.6 Living systems are highly sensitive to acidic and basic conditions. Hydrogen Ions and Hydroxide Ions pH Scale  The amount of H+ in a solution is a measure of its acidity and is called pH.  Acids  Bases H+ Ions and Acids  H+ very reactive  Acids can donate H+ to other chemicals  Stomach acids Bases  Low H+  High OH  Antacids  Baking soda, seltzer, milk of magnesia Blood pH  Buffers • can quickly absorb excess H+ ions to keep a solution from becoming too acidic, • and they can quickly release H+ ions to counteract any increases in OH concentration. 2·7 THIS IS HOW WE DO IT Do anti-acid drugs impair digestion and increase the risk of food allergies? Carbohydrates are fuel for living machines. 2.8 Carbohydrates include macromolecules that function as fuel. Health topics of the year  Low-carb diet?  Hi-carb diet?  “Carbo-loading”?  Fiber intake? What are carbohydrates? Four Types of Macromolecules  Carbohydrates  Lipids  Proteins  Nucleic acids Carbohydrates  C, H, and O  Primary fuel for organisms  Cell structure Energy is in the chemical bonds! 2.9 Glucose provides energy for the body’s cells  Fuel for cellular activity  Stored temporarily as glycogen  Converted to fat Glucose  Most carbohydrates — ultimately converted into glucose  Blood sugar What is “carbo-loading”? 2.10 Many complex carbohydrates are time-released packets of energy.  More than 1 sugar (monosaccharide) unit  Disaccharides • • sucrose lactose  Polysaccharides • • starch cellulose Chemical Fuel Preliminary Processing Starch > 100’s of glucose molecules joined together  Barley, wheat, rye, corn, and rice  Glycogen—“animal starch” Complex Carbohydrates “Time-release” fuel pellets 2.11 Not all carbohydrates are digestible.  Chitin  Cellulose Fiber  “Roughage”  Colon cancer prevention/reduction  Termites ecological role Lipids store energy for a rainy day. 2.12 Lipids are macromolecules with several functions, including energy storage. Why does a salad dressing made with vinegar and oil separate into two layers shortly after you shake it?  Hydrophobic  Hydrophilic 2.13 Fats are tasty molecules too plentiful in our diets.  Glycerol: region  Fatty “head” acid “tails”  Triglycerides Fat molecules contain much more stored energy than carbohydrate molecules. Saturated and Unsaturated Fats # of bonds in the hydrocarbon chain in a fatty acid  Health considerations  Chocolate chip cookie recipes call for some lipids.  How will the “chewy-ness” of the cookies differ depending on whether you use butter or vegetable oil as the lipid?  Which cookies will be healthier?  Many snack foods contain “partially hydrogenated” vegetable oils.  Why might it be desirable to add hydrogen atoms to a vegetable oil? What are trans fats?  Olestra is a recently developed “fake fat” chemical that gives foods the taste of fat, without adding the calories of fats.  What chemical structure might make this possible? 2.14 Cholesterol and phospholipids are used to build sex hormones and membranes.  Not all lipids are fats  The sterols Cholesterol  Important component of most cell membranes.  Can attach to blood vessel walls and cause them to thicken.  Cells in our liver produce almost 90% of the circulating cholesterol. Steroid Hormones  Estrogen  Testosterone • synthetic variants of testosterone Phospholipids and Waxes  Phospholipids are the major component of the cell membrane.  Waxes are strongly hydrophobic. Proteins are versatile macromolecules that serve as building blocks. 2.15 Proteins are bodybuilding macromolecules. Amino Acids  Twenty  Strung different amino acids together to make proteins 2.16 Proteins are an essential dietary component.  Growth  Repair  Replacement  Food labels indicate an item’s protein content.  Why is this insufficient for you to determine whether you are protein deficient, even if your protein intake exceeds your recommended daily amount? Complete Proteins  Have all essential amino acids  Incomplete proteins  Complementary proteins Study the table to answer the following 2 questions. What does the blue dot indicate in the figure below? 1. Presence of an amino acid in a food item. 2. Absence of an amino acid in a food item. 3. Essential vs. nonessential amino acids. 4. Absence of essential amino acids in a food Which combination of foods would contain all of the essential amino acids? 1. Apples and white rice 2. Almonds and lentils 3. White rice and lentils 4. Almonds and apples 2.17 A protein’s function is influenced by its three-dimensional shape.  Peptide bonds Primary Structure  The sequence of amino acids Secondary Structure  Hydrogen bonding between amino acids  The two most common patterns: • twist in a corkscrew-like shape • zig-zag folding Tertiary Structure  Folding and bending of the secondary structure  Due to bonds such as hydrogen bonds or covalent sulfursulfur bonds. Quaternary Structure  When two or more polypeptide chains are held together by bonds between the amino acids on the different chains.  Hemoglobin Egg whites contain much protein. Why does beating them change their texture, making them stiff?  Egg whites contain much protein.  Why does beating them change their texture, making them stiff? Why do some people have curly hair and others have straight hair? Activation Energy • Chemical reactions occurring in organisms can either release energy or consume energy. • In either case, the reaction needs a little “push” in order to initiate the reactioncalled activation energy. • Enzymes act as catalyst by lowering the activation energy An enzyme can reduce the activation energy in a variety of ways 1) By stressing, bending, or stretching critical chemical bonds 2) By directly participating in the reaction 3) By creating a microhabitat that is conducive to the reaction 4) By simply orienting or holding substrate molecules in place so that they can be modified. 2.19 Enzymes regulate reactions in several ways (but malformed enzymes can cause problems) The rate at which an enzyme catalyzes a reaction is influenced by several chemical and physical factors “Misspelled” Proteins  Incorrect amino acid sequence  Active site disruptions  Phenylketonuria Q Why do some adults get sick when they drink milk? Nucleic acids store information on how to build and run a body. 2.20 Nucleic acids are macromolecules that store information. Two Types of Nucleic Acids  Deoxyribonucleic acid (DNA)  Ribonucleic acid (RNA)  Both play central roles in directing the production of proteins. Information Storage  The information in a molecule of DNA is determined by its sequence of bases.  Adenine, guanine, cytosine, and thymine • CGATTACCCGAT 2.21 DNA holds the genetic information to build an organism. Base-Pairing A &T G &C  What is the complimentary strand to this strand: CCCCTTAGGAACC? 2.22 RNA is a universal translator, reading DNA and directing protein production. RNA differs from DNA in three important ways.  The sugar molecule of the sugarphosphate backbone  Single-stranded  Uracil (U) replaces thymine (T) 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. 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 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? Cell membranes are gatekeepers. 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 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 3.6 Faulty membranes can cause disease. Why do “beta blockers” reduce anxiety? Why is it extremely unlikely that a person will catch HIV from casual contact—such as shaking hands—with an infected individual? 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 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. 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. 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 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 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. 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 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? 3.16 THIS IS HOW WE DO IT Can cells change their composition to adapt to their environment? 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? 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 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 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 3.20 The cell wall provides additional protection and support for plant cells 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 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 Chapter 4: Energy From the sun to you in just two steps Lectures by Mark Manteuffel, St. Louis Community College Learning Objectives Understand and be able to explain the following:  How energy flows from the sun and through all life on earth  How photosynthesis uses energy from sunlight to make food Learning Objectives Understand and be able to explain the following:  How cellular respiration converts food molecules into ATP, a universal source of energy  Alternative pathways to energy acquisition 4.1 Cars that run on french fry oil? Organisms and machines need energy to work. What are biofuels? Q Humans can get energy from food. Can machines? Biofuels and Fossil Fuels  Chains of carbon and hydrogen atoms • Energy is stored in the bonds  Animal fats and oils Energy Conversions  All life depends on capturing energy from the sun and converting it into a form that living organisms can use.  Two key processes • Photosynthesis • Cellular respiration 4.2 Energy has two forms. Kinetic and Potential What is energy?  The capacity to do work  Work • Moving matter against an opposing force Kinetic Energy  The energy of moving objects • Heat energy • Light energy Potential Energy A capacity to do work that results from the location or position of an object  Concentration energy  Food gradients and potential has potential energy  Chemical Energy 4.3 As energy is captured and converted, the amount of energy available to do work decreases. Energy Conversions Only ~1% of the energy released by the sun that earth receives is captured and converted by plants. • Converted into chemical bond energy  What happens to the other 99%?  Thermodynamics The study of the transformation of energy from one type to another First Law of Thermodynamics  Energy  It can never be created or destroyed. can only change from one form to another. Energy Tax!   Every time energy is converted from one form to another the conversion isn’t perfectly efficient. Some of the energy is always converted to the least usable form of kinetic energy: heat. Second Law of Thermodynamics  Every conversion of energy includes the transformation of some energy into heat.  Heat is almost completely useless to living organisms 4.4 ATP molecules are like free-floating rechargeable batteries in all living cells. How do cells directly fuel their chemical reactions?  None of the light energy from the sun can be used directly to fuel cellular work.  First it must be captured in the bonds of a molecule called adenosine triphosphate (ATP). Structure of ATP ATP Molecules  Cells cannot use light energy directly to do work.  First, the energy has to be converted into chemical energy in ATP molecules. Adenosine Triphosphate  Pop off the third phosphate group • ATP  ADP + Phosphate group + energy release  Release a little burst of energy!  Use this energy to drive chemical reactions necessary for cellular functioning. • Building muscle tissue • Repairing a wound • Growing roots Recycling in the Cell ADP + phosphate group + energy = ATP 4.5 Where does plant matter come from? Photosynthesis: the big picture. From a seed to a tree: Where does the mass come from? Photosynthetic Organisms Photosynthesis: The Big Picture 3 inputs 2 products 4.6 Photosynthesis take place in the chloroplasts Organelles found in plant cells A Closer Look at Chloroplasts 4.7 Light energy travels in waves: plant pigments absorb specific wavelengths Light Energy  A type of kinetic energy  Made up of little energy packets called photons Light Energy  Different photons carry different amounts of energy, carried as waves.  Length of the wave = amount of energy the photon contains. Electromagnetic Spectrum  Range of energy that is organized into waves of different lengths.  Shorter the wavelength, higher the energy. Visible Spectrum  Range of energy humans see as light  ROYGBIV  Pigments = molecules that absorb light Chlorophyll  Plant pigment  Absorbs certain wavelengths of energy (photons) from the sun  Absorbed energy excites electrons Plant Pigments  Plant pigments can only absorb specific wavelengths of energy  Therefore, plants produce several different types of pigments Plant Pigments  Chlorophyll a  Chlorophyll b  Carotenoids 4.8 Photons cause electrons in chlorophyll to enter an excited state. Electron Excitation  Conversion of electromagnetic energy into chemical energy of bonds between atoms  Photons of specific wavelengths bump electrons up a quantum level into an excited state Two Potential Fates of Excited Electrons (1) Electrons return to their resting, unexcited state. (2) Excited electrons are passed to other atoms. The Passing of Electrons in Their Excited State  Chief way energy moves through cells  Molecules that gain electrons always carry greater energy than before receiving them • Can view this as passing of potential energy from molecule to molecule 4.9 Photosynthesis in detail: the energy of sunlight is captured as chemical energy. FOLLOW THE ELECTRONS! The “Photo” Part    Sunlight ATP A high-energy electron carrier Electrons That Leave the Photosystem Are Replenished Where does oxygen come from? An Electron Transport Chain Connects the two photosystems Product #1 of the “Photo” Portion of Photosynthesis: ATP The Second Photosystem  Follow the electrons Product #2 of the “Photo” Portion of Photosynthesis: NADPH Products from the “Photo” Portion  ATP and NADPH  Time for the “synthesis” part! “SYNTHESIS” 4.10 Photosynthesis in detail: the captured energy of sunlight is used to make food. The Calvin Cycle  Series of chemical reactions  Occurs in stroma  Enzymes are recycled The Processes in the Calvin Cycle Occur in Three Steps: 4.11 The battle against world hunger can use plants adapted to water scarcity. Evolutionary Adaptations  Some plants thrive in hot, dry conditions  Adaptations that reduce evaporative water loss • How do plants use water? Stomata Pores for gas exchange How to get CO2 when stomata are shut? C4 Photosynthesis • C4 plants produce ultimate “CO2-sticky tape” enzyme. • C4 photosynthesis adds an extra set of steps. CAM Photosynthesis  Close stomata during hot dry days  At night, stomata open, CO2 let in and temporarily bound to a holding molecule  During day, CO2 gradually released and used while stomata are closed All Three Photosynthetic Pathways Cellular respiration converts food molecules into ATP, a universal source of energy for living organisms. 4.12 How do living organisms fuel their actions? Cellular respiration: the big picture. Cellular Respiration The big picture A Human Example Eat food  Digest it  Absorb nutrient molecules into bloodstream  Deliver nutrient molecules to the cells   At this point, our cells can begin to extract some of the energy • stored in the bonds of the food molecules 4.13 The first step of cellular respiration: glycolysis is the universal energy-releasing pathway. Glycolysis: the universal energy-releasing pathway Glycolysis Three of the ten steps yield energy – quickly harnessed to make ATP. High-energy electrons are transferred to NADH. Net result:  each glucose molecule broken down into two molecules of pyruvate  ATP molecules produced  NADH molecules store high-energy electrons 4.14 The second step of cellular respiration: the Krebs cycle extracts energy from sugar. The Preparatory Phase to the Krebs Cycle Payoff from the Krebs cycle:    ATP NADH FADH2 4.15 The third step in cellular respiration: ATP is built in the electron transport chain. Mitochondria  Two key features of mitochondria are essential to their ability to harness energy from molecules: • Feature 1: mitochondrial “bag-within-a-bag” structure • Feature 2: electron carriers organized within the inner “bag” The “bag-withina-bag” Follow the Electrons… (just as we did in photosynthesis) #2) This proton concentration gradient represents a significant source of potential energy! Proton Gradients and Potential Energy The force of the flow of H+ ions fuels the attachment of free-floating phosphate groups to ADP to produce ATP. 4.16 THIS IS HOW WE DO IT Can we combat the fatigue and reduced cognitive functioning of jet lag with NADH pills? Pure or Basic Science and Applied Science • What is jet lag and why is it of scientific interest? • How is jet lag related to cellular respiration? Why should NADH alleviate symptoms of jet lag? • If levels of NADH could be increased by taking the molecule in pill form, this might lead to increased production of usable energy through the electron transport chain. • Testable prediction: – “Supplementing NADH should counteract some of the effects of jet lag, including reduced cognitive functioning and fatigue.” Experimental Setup • The researchers used a randomized, controlled, double-blind experimental design. • 2 groups: Placebo or NADH • Battery of tests • Overnight “red-eye” flight • Retesting Did NADH reduce the symptoms of jet lag? 1. Vigilance  Placebo: 37% of subjects made omission errors.  NADH: 14% of subjects made omission errors. Did NADH reduce the symptoms of jet lag? 2. Working memory  Placebo: Subjects answered 6.8 more problems per minute than in the baseline test.  NADH: Subjects answered 13.2 more problems per minute than in the baseline test. Did NADH reduce the symptoms of jet lag? 3. Multi-tasking  Placebo: Subjects increased performance by 19.2 points over baseline.  Subjects’ reaction time was slower than baseline by 0.44 seconds.  NADH: Subjects increased performance by 77.5 points over baseline.  Subjects’ reaction time was faster than baseline by 0.15 seconds. Did NADH reduce the symptoms of jet lag? 4. Visual perception  Placebo: Subjects completed 1.4 more items per minute than at baseline.  NADH: Subjects completed 5.4 more items per minute than at baseline. Did NADH reduce the symptoms of jet lag? 5. Sleepiness  Placebo: 75% of subjects reported increased sleepiness.  NADH: 25% of subjects reported increased sleepiness What conclusions can we draw from these results? • The researchers’ conclusion, supported by the evidence, was that “NADH appears to be a suitable short-term countermeasure for the effects of jet lag on cognition and sleepiness.” There are alternative pathways to energy acquisition. 4.17 Beer, wine, and spirits are byproducts of cellular metabolism in the absence of oxygen. 4.18 Eating a complete diet: cells can run on protein and fat as well as on glucose. Learning Objectives Understand and be able to explain the following:     How energy flows from the sun and through all life on earth How photosynthesis uses energy from sunlight to make food How cellular respiration converts food molecules into ATP, a universal source of energy Alternative pathways to energy acquisition Chapter 5: DNA, Gene Expression, and Biotechnology What is the genetic code, and how is it harnessed? Lectures by Mark Manteuffel, St. Louis Community College Learning Objectives  Describe what DNA is and what it does.  Explain the process of gene expression involving transcription and translation.  Explain the causes and effects of damage to the genetic code.  Discuss biotechnology in agriculture.  Describe biotechnology and its implications for human health. DNA: what is it, and what does it do? 5.1 Knowledge about DNA is increasing justice in the world. Q What is the most common reason why DNA analyses overturn incorrect criminal convictions? Selfish dictators may owe their behaviour partly to their genes, according to a study that claims to have found a genetic link to ruthlessness. –Nature, April 2008 Too Many One-Night Stands? Blame Your Genes . . .according to a new study, it may be fair to say that while you jolly well could help cheating, your particular genes did make things more difficult. — Time magazine, December 2010 5.2 The DNA molecule contains instructions for the development and functioning of all living organisms. DNA “Double Helix” Nucleic acids and nucleotides Sugars, Phosphates, and Bases A, T, C, and G The Base pairs Base-pairing rules 5.3 Genes are sections of DNA that contain instructions for making proteins. Why is DNA considered the universal code for all life on earth? Genes A sequence of bases in a DNA molecule that carries the information necessary for producing a functional product, usually a protein molecule or RNA.  Locus: the location or position of a gene on a chromosome. Genetic Information • The sequence of bases in DNA carries information. • “AAAGGCTAGGCC…” continuing on for another 3,000 or so bases. 5.4 Not all DNA contains instructions for making proteins. An onion has five times as much DNA as a human. Why doesn’t that make them more complex than us? The Proportion of the DNA That Codes for Genes Introns  Non-coding regions of DNA  May take the form of short (or long) sequences that are repeated thousands of times  May also consist of gene fragments, duplicate versions of genes, and pseudogenes 5.5 How do genes work? An overview  Genotype • all of the genes contained in an organism  Phenotype • the physical manifestations of the instructions Building organisms: information in DNA directs the production of the molecules that make up an organism. 5.6 In transcription, the information coded in DNA is copied into mRNA. 5.7 In translation, the mRNA copy of the information from DNA is used to build functional molecules. Several ingredients must be present in the cytoplasm for translation to occur.  Free amino acids  Ribosomal  Transfer units RNA The Genetic Code 5.8 Genes are regulated in several ways Gene Expression & Gene Regulation Microarrays • A powerful tool used to monitor the expression levels of thousands of genes simultaneously • Particularly useful in exploring how gene expression differs in response to an illness, or the treatment of an illness, or in response to aging Controlling Gene Expression • Transcription factors – proteins that bind to specific regulatory sites on the DNA • “positive control” & • “negative control” Prokaryotic Gene Control and the lac operon Elements of Gene Control • Promoter • Operator • Regulatory Gene Eukaryotic Gene Control • There are many other ways that genes can be regulated, besides operons. • Transcription Regulation – Activators & Repressors – Enhancer Sequences – Chemical interference • Post-Transcription Regulation Damage to the genetic code has a variety of causes and effects. 5.9 What causes a mutation, and what are its effects?  Alteration DNA of the sequence of bases in • can lead to changes in the structure and function of the proteins produced • can have a range of effects Breast Cancer in Humans  Two human genes, called BRCA1 and BRCA2  More than 200 different changes in the DNA sequences of these genes have been detected,  each of which results in an increased risk of developing breast cancer. Mutations in Sex Cells & Non-Sex Cells • Differences? • Which may get passed on to offspring? Q Why do dentists put a heavy apron over you when they X-ray your teeth? Ionizing Radiation Q Why is it dangerous to be near the core of a nuclear power plant? 5.10 THIS IS HOW WE DO IT Does sunscreen use reduce skin cancer risk? What happens when our skin cells are exposed to the sun? • UVB radiation • Inflammation • Skin cancer? – melanoma Why would anyone question whether sunscreen has a positive effect? • 1960s and 1970s: sunscreens widely available • Increase in incidence of melanoma • Swedish study Sunscreen users were at greater risk for cancer! How can that be? • False sense of security • UVA & UVB How can you figure out whether sunscreen users are actually protected from cancer? • Case-controlled studies • Assumptions and confounding variables “Randomized controlled trials.” Why are they better than casecontrolled studies? • Randomly assigned 1,621 adults to one of two groups: 1) regular sunscreen use and 2) discretionary sunscreen use. Results? • Sunscreen-use group • 11 melanoma detects • Discretionary-use group • Twice as many new melanomas detected! • Invasive melanomas 4x more frequent! If randomized controlled studies are so much better, why would anyone bother doing case-controlled studies? • Difficult to conduct • Relatively expensive • Compliance issues 5.11 Faulty genes, coding for faulty enzymes, can lead to sickness.  How can people respond so differently to alcohol? A single difference in a single pair of bases in their DNA. A “fast-flush” response Q Why do many Asians have unpleasant experiences associated with alcohol consumption? From mutation to illness in just four steps: (1) A mutated gene codes for a nonfunctioning protein, usually an enzyme. (2) The non-functioning enzyme can’t catalyze the reaction as it normally would, bringing it to a halt. From mutation to illness in just four steps: (3) The molecule with which the enzyme would have reacted accumulates, like a blocked assembly line. (4) The accumulating chemical causes sickness and/or death. Biotechnology is producing improvements in agriculture. 5.12 What is biotechnology? And What Is Genetic Engineering?  Adding, deleting, or transplanting genes from one organism to another, to alter the organisms in useful ways 5.13 Biotechnology can improve food nutrition and make farming more efficient and eco-friendly Q How might a genetically modified plant help 500 million malnourished people? Nutrient-rich “golden rice” Almost everyone in the U.S. uses genetically modified crops regularly without knowing it. What crops are responsible for this? Insect Resistance Q How can genetically modified plants lead to reduced pesticide use by farmers? Herbicide Resistance Faster Growth and Bigger Bodies 5.14 Fears and risks: are genetically modified foods safe? Concern#1. Organisms that we want to kill may become invincible.  Concern#2. Organisms that we don’t want to kill may be killed inadvertently.  Concern#3. Genetically modified crops are not tested or regulated adequately.  Concern#4. Eating genetically modified foods is dangerous.  Concern#5. Loss of genetic diversity among crop plants is risky.  Concern#6. Hidden costs may reduce the financial advantages of genetically modified crops.  Biotechnology has the potential for improving human health (and criminal justice). 5.15 The treatment of diseases and production of medicines are improved with biotechnology  Prevent  Cure diseases diseases  Treating diseases • The treatment of diabetes Q Why do some bacteria produce human insulin? Recombinant DNA technology Several important achievements followed the development of insulin-producing bacteria, including: (1) Human growth hormone (HGH) (2) Erythropoietin What is “blood doping”? How does it improve some athletes’ performance? 5.16 Gene Therapy: biotechnology can help diagnose and prevent diseases But has had a limited success in curing them 1) Is a given set of parents likely to produce a baby with a genetic disease? 2) Will a baby be born with a genetic disease?  cystic fibrosis  sickle-cell anemia  Down syndrome  others 3) Is an individual likely to develop a genetic disease later in life?  breast cancer  prostate  skin cancer cancer Ethical Dilemmas  Discrimination  Health  How insurance to proceed with the information? Q Why has gene therapy had such a poor record of success in curing diseases? Gene Therapy Difficulties (1) Difficulty getting the working gene into the specific cells where it is needed. (2) Difficulty getting the working gene into enough cells and at the right rate to have a physiological effect. Gene Therapy Difficulties (3) Difficulty arising from the transfer organism getting into unintended cells. (4) Difficulty regulating gene expression. 5.17 Cloning—ranging from genes to organs to individuals—offers both promise and perils Are there any medical justifications for cloning? Can a human be cloned (and should they be)? 5.18 DNA as an individual identifier: the uses and abuses of DNA fingerprinting DNA From Different Humans • 99.9% identical • So what differs? • Highly variable regions • STRs What is a DNA fingerprint?
Purchase answer to see full attachment
User generated content is uploaded by users for the purposes of learning and should be used following Studypool's honor code & terms of service.

Explanation & Answer

Attached.

Chapter one summary
Scientific thinking
The summary gives a description of what science is as well as the scientific method.
Besides, the chapter covers the key characteristics of well-designed experiments and the ways
through which the scientific method can be utilized in aiding to make wise decisions. Finally, the
chapter describes the major themes in biology.
First, it is particular that scientists are inquisitive and try t...


Anonymous
I was stuck on this subject and a friend recommended Studypool. I'm so glad I checked it out!

Studypool
4.7
Trustpilot
4.5
Sitejabber
4.4

Related Tags