Midterm 1 Study Guide BIO 1101
Midterm 1 Study Guide BIO 1101 BIOLOGY 1101 (Evan Waletzko)
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BIOLOGY 1101 (15989) Introduction to Biology Dr. Evan J. Waletzko The Ohio State University Notes by Sophie Chang Midterm 1 Study Guide for Biology 1101 What’s included in this document: • Carmen quizzes pre-1/19, 1/26, and 2/1 • Class notes –derived from PowerPoint slides • In-class activities and answers • TopHat questions –answered during class • Take-Home Messages for required readings and some suggested readings Carmen Quizzes Carmen Quiz 1 (Pre-1/19) Earned 5/5 points. 1. Which of the following IS a polysaccharide? a. Insulin (hormone) b. Cellulose c. Fructose (monosaccharide) d. Glucose (monosaccharide) 2. Which of the following is NOT a protein? a. Hemoglobin b. An enzyme c. Cholesterol d. Insulin e. An antibody 3. Energy used in cellular respiration can originate from: a. Carbohydrates, proteins, and fats. b. https://quizlet.com/5448377/final -review-multiple-choice-flash-cards/ c. https://quizlet.com/27094977/chapter-4-prepu-flash-cards/ 4. Glycogen belongs in the class of molecules known as: a. Polysaccharides. b. https://quizlet.com/9982201/bio -exam-1-chap-2-practice-test-flash-cards/ 5. What can happen if an enzyme is altered, even slightly? a. It won't work anymore. Carmen Quiz 2 (Pre-1/26) Earned 5/5 points. 1. Which statement is NOT part of the modern cell theory? a. Cellular reactions include both energy -releasing and biosynthetic types. b. Cells arise from other cells. c. All living organisms consist of one or more cells. d. The first cell arrived on earth from outer space. e. Cells contain hereditary information that passes from one generation of cells to the next. 2. Which of the following is a cellular characteristic of ALL eukaryotes? a. A nuclear membrane i. https://quizlet.com/9984445/bio -exam-1-chap-3-practice-test-flash-cards/ https://quizlet.com/20539723/bio -101-chapters-3-and-4-flash-cards/ ii. iii. http://classes.biology.ucsd.edu/bild10.WI14/BILD10/Problems_files/BILD%2010.Probl em%20Set%202%20KEY.pdf 3. A cell's interior is considered isotonic to the surrounding fluid when: a. The solute concentrations are the same within and outside the cell. i. https://quizlet.com/9984445/bio -exam-1-chap-3-practice-test-flash-cards/ 4. The primary function of molecular membranes is the transport of ions and molecules in and out of cells. The movem ent of molecules from areas of low concentration to those of high concentration against chemical gradients is best described as: a. Active transport 5. Which of the following is NOT true of ALL cells? a. They eliminate wastes, b. They assimilate nutrients. c. They move by means of flagella or cilia. https://quizlet.com/11972315/bio301l -homework-questions-flash-cards/ i. d. They have DNA as their genetic material. e. They synthesize new cellular material. 6. The principle components of cell membranes are… a. Lipids i. https://quizlet.com/4311426/ap -test-1-part-3-chapter-3-flash-cards/ 7. Sugar and CO2 are dissolved in water to make carbonated soft drinks. Which of the following is the solute? a. The water and the sugar b. The water and the CO2 c. The CO2 only d. The sugar and the CO2 e. The sugar only i. https://quizlet.com/32902069/taylor-chapter-3-test-flash-cards/ ii. https://quizlet.com/5448377/final -review-multiple-choice-flash-cards/ 8. Which of the following organelles are enclosed by a double membrane? a. Mitochondria and chloroplasts i. https://quizlet.com/9984445/bio -exam-1-chap-3-practice-test-flash-cards/ 9. Active transport, the movement of molecu les from areas of low concentration to areas of high concentration across the membrane, is often coupled with processes that… a. Gain energy (something like that) Carmen Quiz 3 (Pre-2/1) Earned 5/5 points. 1. Which of the following is NOT a product of photosynt hesis: a. Water b. Oxygen c. Sugars d. Carbon dioxide e. None of the above; all are products of photosynthesis 2. When energy is converted from one form to another: a. The quantity of energy in the universe changes. b. Some energy is converted to heat. c. It becomes more useful to organisms for fueling cellular activity. d. A small amount of energy is created. e. A small amount of energy is destroyed. 3. Which by-product of photosynthesis was important in altering the atmosphere of the earth so that aerobic organisms could evolve? a. Oxygen b. Air c. Carbon dioxide d. Methane gas e. Nitrogen 4. The graphs above show data relating to seasonal differences in the amount of pigment molecules present in leaves and how this is related to leaves changing colors. What is the dependent variable presented in these graphs? a. Time at which the amount of pigment was measured b. The wavelengths of light reflected by each photosynthetic pigment c. The seasons in which the measurements were taken d. The measure of the amount of each pigment molecule present in leaves e. The difference in pigment between spring and fall 5. Fermentation reactions generally occur under conditions of a. Low glucose levels b. High oxygen concentrations c. High temperatures d. Low methane concentrations e. Low oxygen concentrations Class Notes (Weeks 1-4) Week 1 Notes • Science as a philosophy o A process through which we can gain a better understanding of the world around us. o Science, however, is unlike other philosophies in that it is testable, falsifiable, and self-correcting. • Theory vs. Hypothesis o A theory is a blanket statement, or an explanation for a phenomenon or relationship of the natural world that has been extensively tested • Can still be falsified o A hypothesis is developed through experimentation and conclusion • The Scientific Method o Observe, hypothesize, prediction, design experiment, conduct experiment, conclude, review, redesign o Experimentation • 3 variables: § Standardized: variables the research tries to keep constant between all the treatments § Independent: variable you manipulate or change to determine if it affects the outcome being tested (x variable) § Dependent: variable measured as the outcome of the experiment, or what is being affected by the experiment (y variable) • Biological fitness o Survival which will allow the organism to leave the most copies of itself in future generations • Correlation vs. Causation o Correlation is not causation • For example, in Evan's powerpoint, the graph on slide 57 illustrates that the per capita consumption of mozzarella cheese is correlated (connected) to the number of civil engineering doctorates awarded. The graph on slide 58 shows that the per capita cheese consumption correlates with the number of people who died by becoming tangled in their bedsheets. Does that mean that the increase in PhD graduates caused people to die from becoming entangled in their bedsheets? No. does that mean that people dying from becoming entangled in their bedsheets caused more engineers to get their PhDs? No! • Levels of Organization in Biology o Molecular o Cellular o Organ/organ system o Organism o Population o Community o Ecosystem Week 2 Notes • Chapter 2: Chemistry o Learning Objectives • Describe what atoms are, their structure, and how they bond • Understand water's features that help it support all life • Describe the structure and function of… § Carbohydrates § Lipids § Proteins § Nucleic acids o Overall theme: Molecular structure influences the properties of the chemical. • E.g. size, shape, polarity • Main 4 elements in the human body o Oxygen o Carbon o Hydrogen o Nitrogen • Properties of water that make it critical to life o Cohesion • Hydrogen bonds make water cohesive o Large heat capacity o Low density as a solid o Good solvent • Types of Macromolecules o Carbohydrates • C, H, and O • Primary fuel for organisms § Can be used as an energy source in the bloodstream § Can be stored as glycogen in the muscles and liver for later use § Can be converted to fat • Most carbohydrates are ultimately converted into glucose (a monosaccharide), which is blood sugar. • Complex Carbohydrates are "time-release" fuel pellets • Not all digestible § Cellulose -not digestible, but aids in digestion, because it contains fiber. § Chitin o Proteins • Essential dietary component for growth, repair, and replacement. • Amino acids are the building blocks for proteins. § 20 of them • 17,294 known gene codes for proteins § Each gene code can code for more than one protein. Therefore, there are a minimum of 17,294 proteins in the human body. • Types of Proteins § Complete: contain all essential amino acids § Incomplete: do not contain all essential amino acids § Complementary: incomplete proteins that when combined, have all essential amino acids • How to think of proteins: § Plants make amino acids. § Then they string them together to make proteins. § When you digest a protein, your body breaks it apart into individual amino acids again. § To make your own proteins, your cells string these amino acids back together in a new order. • Shape is important. § Sequence determines shape. § Shape determines properties. § When shape is deformed, protein cannot function. o Nucleic acids • Store info on how to build and run a body. • Examples § DNA • Nucleotides: • Adenine (A) • Guanine (G) • Cytosine (C) • Thymine (T) § RNA • Single-stranded • Nucleotides: • Adenine (A) • Guanine (G) • Cytosine (C) • Uracil (U) instead of thymine (T) o Lipids • Lipids do not follow the monosaccharide/polysaccharide relationship, but the other three types of macromolecules do. • Store energy not for immediate use/for a rainy day. • Contain more stored energy than carbohydrate molecules • Types § Saturated and unsaturated fats § Sterols • Cholesterol • Steroid hormones § Phospholipids • Characteristics § Non-soluble in water, greasy to the touch § Functions • Long-term energy storage • Insulation • Membrane formation • Hormones Week 3 Notes • Lecture 3: Cells o Learning Objectives • Describe what a cell is and the two general types of cells • Describe major differences between animal and plant cells • Cell Theory and Endosymbiotic Theory • Basic structure of membranes and their importance • The cell o Smallest unit of life that can function independently and perform al the necessary functions of life, including reproducing itself. o Nearly all contain DNA o Discovered by Robert Hooke in the mid-1600s when he was looking at cork • Cell Theory o All living organisms are made up of one or more cells. o All cells arise from other pre-existing cells. • Types of Cells o Prokaryotic -no nucleus o Eukaryotic -nucleus present Prokaryotic Eukaryotic Cells Single-celled Single to multi-celled Nucleus? No Yes DNA located Middle of the cell In the nucleus in… Noun Form Prokaryote Eukaryote Notes Structurally simple, extremely If you can see it, it's a diverse eukaryote. • Prokaryotes o Plasma membrane o Cytoplasm o Dna o Ribosomes -all cells that produce protein have ribosomes o Cell wall -protects and gives shape to cell • Basic Structure of Cells o Animal cells • Have centrioles, which aren't in plant cells o Plant cells • Chloroplast • Cell wall • Vacuole o In both animal and plant cells: • Nucleus • Plasma membrane • Ribosomes • Mitochondria • There are 2 organelles associated with energy in eurkaryotes o Chloroplast -convert solar energy into chemical energy (glucose) • Found in plant cells • Plant cell's energy collector/converter § Site of photosynthesis • Light --> chemical energy (glucose) o Mitochondria -convert chemical energy (glucose) into another form of energy (ATP) • Found in plant and animal cells • Convert glucose to ATP • Important o There are many forms of chemical energy, but Evan said that we're only considering glucose in this class. o ATP is like a common currency, but it can be used by all cells. o Glucose cannot be used by all cells. • Endosymbiotic Theory o Explains presence of 2 organelles in eukaryotes, chloroplasts in plants, and mitochondria in plants and animals o Double membranes o Own DNA like bacteria o Circular Week 4 Notes • Chapter 4: Energy o Learning Objectives • Potential vs. kinetic energy • 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 • 2 key processes o Photosynthesis o Cellular respiration • Nearly all life depends on energy captured from the sun and converted into forms that living organisms can use. • Energy o The capacity to do work • Work is moving matter against an opposing force • Potential vs. Kinetic o Potential energy is stored energy • Types § Gravity gradient § Chemical bonds • Chemical energy is a form of potential energy stored in chemical bonds. • All food has potential energy, because the chemical energy stored in the chemical bonds in the food can be broken and the energy can be released during cellular respiration. § Concentration gradient o Kinetic energy • Energy of moving objects § Heat energy § Light energy • Made up of photons (like energy packets) • Thermodynamics o Study of the transformation of energy from one type to another o Laws • First Law of Thermodynamics § Energy can never be created or destroyed. § It can only change from one form to another. • Second Law of Thermodynamics § 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. o Heat is useless to living organisms in performing work, but it helps with homeostasis. • ATP is energy currency. o Energy is stored in the bond between the phosphate groups. o The potential energy can be converted to kinetic energy. • Electromagnetic Spectrum o Range of energy that is organized into waves of different lengths. o The shorter the wavelength, the higher the energy. o The longer the wavelength, the lower the energy. • Photosynthetic Pigments o Primary photosynthetic pigment is called chlorophyll a. • Chlorophyll a efficiently absorbs blue-violet and red wavelengths of light. • Can't efficiently absorb green light. Reflects the green back, so that's why we see them as green. o Chlorophyll b • Absorbs blue and red-orange wavelengths • Reflects back yellow-green wavelengths o Carotenoids • Absorbs blue-violet and blue-green wavelengths • Reflects yellow, orange, and red wavelengths • Photosynthesis o Energy of sunlight is captured and stored as chemical energy. o 2 steps: • Light reactions (photo-) -ATP § Make ATP from sunlight • Dark reactions (-synthesis) -Glucose § Make glucose from ATP o H2O + CO2 + Light Energy --> O2 + Glucose o 6H2O + 6CO2 + Light Energy --> 6O2 + C6H12O6 • Cellular Respiration o 2 steps: • Glycolysis § Occurs in cytoplasm § All organisms § Produces some ATP § Universal energy-releasing pathway § Just need to know that there's a net gain of ATP, not exact numbers. § Always the first thing organisms go through • Krebs Cycle + electron transport chain § Occurs in mitochondria § Produces waaaay more ATP than glycolysis § Needs oxygen § Most efficient method of producing ATP In-Class Activities & Answers In-class activity WEEK 2 1. What is the question the researchers asked before performing this experiment? a. Which sugar(s) do(es) the crab(s) respond to better? 2. If the crabs tasted a sugar, how did they predict they would respond? a. The researchers predicted that if the crabs tasted a sugar, they would release a feeding pellet. 3. What did the researchers find? a. The researchers found that the more complex the sugar, the more feeding pellets the crabs would release. 4. What is one characteristic of these sugars which could be influencing how the crabs responded? a. The complexity of the sugar. 5. Why did the researchers include a control group? a. It's part of the scientific method. b. It can't be a testable prediction if there's no control group. c. Also, to minimize the margin of error. d. Serves as a standard for comparison against the experimental group. 6. What is the benefit of having both a "male control" and a "female control" in this study? a. The benefit of having both a male control and a female control is that we can compare the sex hormones in each. 7. If indeed Atrazine facilitates the conversion of testosterone to estrogen, how do you predict estrogen levels would differ between these tr eatment groups? Draw another graph similar to the one above with Estrogen in the y -axis. Draw this in the margins of your worksheet. a. Estrogen in the atrazine males would equate to or exceed estrogen levels in control females. 8. In this study, frogs were exposed to Atrazine during development (as tadpoles). This study did not explicitly test whether it was the absence of testosterone, or the presence of estrogen which led to the hermaphrodite state in Atrazine -treated males. Generate two alternative hypothese s, one of which addresses each of these possibilities. a. Hypothesis 1: If frogs are exposed to increased levels of estrogen, then they will turn into hermaphrodite state. b. Hypothesis 2: The absence of testosterone in frogs will lead to a hermaphrodite state. 9. Are your hypotheses mutually exclusive (that is, does support for one mean the other is rejected)? Why would this be an important consideration in scientific investigations? a. No, they are not mutually exclusive. This is an important consideration in a scie ntific investigation because then each will have to be tested separately. 10. Bisphenyl A (BPA) is another known endocrine disruptor. BPA is structurally similar to estrogen, and can initiate some of the same biological responses as estrogen. Like Atrazine, BP A seems to have a greater effect on developing individuals than adults. Why might endocrine disrupters that influence sex hormones have a greater influence during development? Growth and development is highly influenced by endocrine signals, so endocrine d isrupters that influence sex hormones will interfere with development/have a greater negative effect during development. 11. A common saying by toxicologists is “the dose makes the poison.” How is this saying relevant to studies of endocrine disruptors such as Atrazine and BPA? a. There's a certain carrying capacity. b. This is relevant to studies involving endocrine disrupters because it's only harmful once it hits a certain level. In-Class Activity WEEK 3 Antibody Activity Membrane IN CLASS ACTIVITY (anti -body, antigen) 1st question Antigen-foreign Antibodies first line of defense in of immune system Antigens are substances that elicit an immune Antibodies are proteins which ID particular antigens and neutralize them by binding to the antigen and then calling other elements of the immune system into action. 1. Why is it important that antibodies not react to an organisms' own cells? a. If the antibodies reacted to its own organism's cells, then the organism would essentially self-destruct because the antibodies would be attacking its own cells. 2. The binding site of antibodies is highly variable (millions of possible forms). Why is it important for organisms to have many antibodies? a. So that they can identify the myriad antigens that could be detected in the body. 3. Some antibodies are on their own in blood plasma (the liquid portion of blood), but others are attached to B cells which either replicate or preserve themselves once “activated”. These B cells retain the antibodies on them and will remain in the body for the rest of the organism’s life. What advantage might organisms gain by having cells on hand with previous antibodies for antigens the organism has already encountered? a. Because then antibodies already know how to neutralize the antigens that the body has already encountered. 4. What is a real-life example of your response to #4 in action? a. Vaccinations, because the virus is already in your body so you don't get sick when you encounter it again. 5. When B cells replicate, is it making exact replicates of itself (mitosis), or slightly different varieties (meiosis)? How do you know? a. When B cells replicate, they are making exact replicates of themselves. I know this because that's the only way that these cells would have previous antibodies for antigens the organism has already encountered. Membrane IN CLASS ACTIVITY (blood type) 6. For each of the four ABO blood types, what are the antigens, and what types of antibodies would an individual of that blood type have? a. Type AB -A and B antigens, no antibodies b. Type A -A antigen, anti-B antibody c. Type B -B antigen, anti-A antibody d. Type O -no antigens, anti-A and anti-B antibodies 7. Individuals with type AB blood are often referred to as "universal recipients" and those with type O blood are often referred to as "universal donors." Explain the meaning of these descriptions. a. Individuals with type AB blood are "universal recipients" because they have no antibodies, so they can receive any type of blood without interference from antibodies. However, individuals with type O blood are "universal donors" because the blood cells have no antigens, so they can be accepted by any other blood cells. 8. If our bodies can mount an effective immune response towards red blood cells of the wrong ABO type, why is it so problematic for the recipient of the transfusion? a. Receiving the wrong blood type is problematic for the recipient of the transfusion, because the antibodies in its blood cells would attack the antigens and would reject the blood cells. For example, if someone with blood type O received a transfusion with blood type AB blood, the type O blood's anti-A and anti-B antibodies would attack the A and B antigens present in the type AB blood type. TopHat Questions No Top Hat questions for Weeks 1 or 4. Top Hat Questions WEEK 2 1. In general, why do coastal areas have milder, less variable climates than inland areas? a. Oceans have a high salt concentration b. Large bodies of water take a long time to change temperature c. Hydrogen-bonds (H-bonds) give water a high heat capacity d. H-bonds give water a low heat capacity e. Both B and C f. Both D and C--not possible because D and C are opposites 2. Why don't oceans freeze as easily as fresh water lakes? a. Salt prevents water from forming crystals easily b. Salt helps water form crystals more easily c. Salt absorbs heat d. Salt reduces melting point 3. What best describes glycogen? a. A large complex molecule, made from polymers --goes against the definition of what a polymer is, since a polymer is the result of many monomers put together. Monomer - polymer relationship. b. A large complex molecule, made from monomers c. A small simple molecule, made from one monomer d. A simple molecule, made from one polymer 4. What molecule is the arro w pointing to (the green thing)? (What is Life? 2.9, page 57 / Figure 2 -23 / IMG_6355) a. Glucose b. Unsure of name, a sugar monomer c. Glycogen d. Unsure of name, a sugar polymer 5. When we eat a simple sugar like white processed sugar (glucose) instead of a potato (starch) what step in the digestion process do we skip? a. The breaking down of glucose to get energy b. The breaking of bonds between glucose found within starch c. The breaking of bonds between starch found within glucose d. The formation of starch 6. Which type of carbohydrate will cause moderate, long term increases in blood sugar? a. Polysaccharide b. Disaccharide--digested quickly because there's only one bond to break c. Monosaccharide d. Both A and B 7. Cellulose is nearly identical to starch; however, we cannot digest cellulose. Why? a. Cellulose molecules have a different shape. b. Cellulose molecules are larger. c. Cellulose molecules are acidic. d. Cellulose molecules lack carbon -hydrogen bonds. e. Cellulose molecules are formed entirely from fructose. 8. Which combination of foods would contain all of the essential amino acids? a. Apples and white rice b. Almonds and lentils c. White rice and lentils d. Almonds and apples 9. Egg whites contain protein. Why does beating or heating eggs chang e their texture, making them stiff? a. The energy input (temp, beating) broke the protein into amino acids. b. The energy input (temp, beating) disrupted the H -bonds that create the 3 -D shape of the protein. (2.17 The heat breaks the hydrogen bonds that give the proteins their shape. Denaturation.) c. The energy input (temp, beating) changed the sequence of amino acids. 10. Why does a misspelling in the primary structure of phenylalanine hydroxylase inhibit its function? a. Enzyme shape is incorrect b. Enzyme fails to bind phenylalanine c. Enough tyrosine is produced elsewhere d. Tyrosine now binds to the enzyme e. Both A and B TopHat Questions WEEK 3 1. Which type of fat would be liquid at room temperature? a. Saturated fat (like animal fat) b. Unsaturated fat (like canola oil) c. Trans fat (like margarine) d. Both 1 and 3 are correct. 2. What is the molecule surrounding grease? Enter your answer below. a. Soap. i. The area that hates water is the part that attaches to grease. Soap has a part that sticks to the grease but also a part that doesn't mind the water. Hence, it washes away. 3. When a manufacturer hydrogenates an oil, they make ____ more _____. a. Animal fat; like vegetable fat b. Animal fat; healthy c. Vegetable fat; like animal fat d. Vegetable fat; healthy 4. Why is our understanding of cells called a "theory" rather than a "hypothesis"? a. Observations are well -supported by empirical data. i. Only seen cells from other cells b. Observations are viewed with confidence by the scientific community. i. Confident with observing and reporting. c. Observations are a proposed explanation for a phenomenon. (Definition of hypothesis) d. 1 and 2. e. All of the above. 5. What is the independent variable in this graph? a. Cell number b. Mitochondria number c. Metabolic rate d. Cell type 6. Which can be found in BOTH eukaryotic and prokaryotic cells? a. Nucleus b. Mitochondria c. Ribosomes d. Membrane-bound organelles 7. What two pieces of evidence found in mitochondria and chl oroplasts support the endosymbiotic theory of Eukaryote evolution? (Choose two) a. Presence of a nucleus b. Presence of DNA c. Presence of double membranes d. Presence of cytoplasm e. Presence of a single membrane 8. What is the best answer to describe the molecule responsible for letting things into and out of the cell? a. The cell membrane b. Proteins embedded in the cell membrane i. Take-Home Message 3.5: Proteins found in the plasma membrane enable it to carry out most of its gatekeeping functions. c. Carbohydrates embedded in the cell membrane d. Proteins Take-Home Messages Week 1 1.4 Thinking like a scientist: how do you use the scientific method? 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. The scientific method tells us when we should change our minds. If something you believe turns out to be wrong, formulate a new hypothesis. Take-Home Message 1.4 The scientific method (observation, hypothesis, prediction, test, and conclusion) is a flexible, adaptable, and efficient pathway to understanding the world, because it tells us when we must change our beliefs. 1.5 Step 1: Make observations. Sample observation: To many people, consuming echinacea extract seems to reduc e the intensity or duration of symptoms of the common cold. Sample question: Does taking echinacea reduce the intensity or duration of the common cold? Take-Home Message 1.5 The scientific method begins by making observations about the world, noting appare nt patterns or cause-and-effect relationships. 1.6 Step 2: Formulate a hypothesis. Hypotheses: a proposed explanation for observed phenomena. Sample prelim hypothesis: Eyewitness testimony is always accurate. To be useful, a hypothesis must accomplish tw o things. 1. It must establish an alternative explanation for a phenomenon. That is, it must be clear that if the proposed explanation is not supported by evidence or further observations, a different hypothesis is a more likely explanation. 2. It must generate testable predictions. This characteristic is important because we can evaluate the validity of a hypothesis only by putting it to the test. For example, we could disprove the "Eyewitness testimony is always accurate" hypothesis by demonstrating that, in ce rtain circumstances, individuals who have witnessed a crime might misidentify someone as the criminal when asked to select the suspect from a lineup. Researchers often pose hypotheses as negative statements, proposing that there is no relationship between two factors. E.g.: Echinacea has no effect on the duration and severity of cold symptoms. There is no difference in the coarseness or darkness of hair that grows after shaving. A hypothesis that states a lack of relationship between two factors is called a null hypothesis. Null hypotheses are easier to disprove , because…a single piece of evidence can disprove it. Examples… Hypothesis: Echinacea reduces the duration and severity of the symptoms of the common cold. Null hypothesis: Echinacea has no effect on the duration or severity of the symptoms of the common cold. Hypothesis: Hair that is shaved grows back coarser and darker. Null hypothesis: There is no difference in the coarseness or color of hair that is shaved relative to hair that is not shaved. Take-Home Message 1.6 A hypothesis is a proposed explanation for an observed phenomenon. 1.7 Step 3: Devise a testable prediction. For a hypothesis to be useful, it must generate a prediction. In devising a testable prediction from a hypothesis, the goal is t o propose a situation that will give a particular outcome if your hypothesis is true, but 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 subjects are presented one at a time or all at the same time in a lineup. This is a good, testable prediction because if our hypo is true, then our prediction will always be true. BUT, if our hypothesis is incorrect, the hypothesis cannot be true and must be revised or discarded. Take-Home Message 1.7 For a hypothesis to be useful, it must generate a testable prediction. 1.8 Step 4: Conduct a critical experiment. A critical experiment is one that makes it possible to decisively determine whether a particular hypothesis is correct. Echinacea experiment details Shaving hair experiment details Take-Home Message 1.8 A critical experiment is one that makes it possible to decisively determine wh ether a particular hypothesis is correct. 1.9 Step 5: Draw conclusions, make revisions. Witnesses are less likely to make misidentifications when viewing suspects one at a time. Echinacea had no effect at all on any subjects in the experiment. Take-Home Message 1.9 Based on the results of the experimental tests, we can revise a hypothesis and explain the observable world with increasing accuracy. A great strength of scientific thinking, therefore, is that it helps us understand when we should change our minds. 1.12.16 Suggested 1.11-15 1.11-1.14 Well-designed experiments are essential to testing hypotheses. 1.11 Controlling variables makes experiments more powerful. Some elements common to most experiments: 1. Treatment. Any experimental condition applie d to the research subjects. E.g. shaving an individual's eyebrows, pattern used to show "suspects" to witness of staged crime, dosage of echinacea given to an individual. 2. Experimental group/treatment group . A group of subjects who are exposed to a particul ar treatment (e.g. the indivs given echinacea rather than placebo in the experiment above). 3. Control group. A group of subjects treated identically to the experimental group, with one exception: they are not exposed to the treatment. E.g. indivs given plac ebo rather than echinacea. 4. Variables. Characteristics of an experimental system that are subject to change, e.g. the amount of echinacea a person is given, or measure of coarseness of individual's hair. Ulcer experiment example. Placebo effect is the frequently observed, poorly understood phenomenon in which people respond favorably to any treatment. Blind experimental design , in which the experimental subjects do not know which treatment, if any, they are receiving. Double-blind experimental design , in which neither the experimental subjects nor the experimenter know which treatment a subject is receiving (echinacea experiment). Randomized -subjects are randomly assigned into experimental and control groups. Researchers and subjects have no influence on the composition of the two groups. The use of randomized, controlled, double-blind experimental design can be thought of as an attempt to imagine all the possible ways that someone might criticize an experiment and to design the experiment so that the results cannot be explained by anything other than the effect of the treatment. Take-Home Message 1.11 To draw clear conclusions from experiments, it is essential to hold constant all those variables we are not interested in. Control and experimental groups shoul d differ only with respect to the treatment of interest. Differences in outcomes between the groups can then be attributed to the treatment. 1.12 This is How We Do It Is arthroscopic surgery for arthritis of the knee beneficial? Take-Home Message 1.12 1.13 Repeatable experiments increase our confidence. Take-Home Message 1.13 1.14 We've got to watch out for our biases. Take-Home Message 1.14 1.15-1.18 Scientific thinking can help us make wise decisions. 1.15 Visual displays of data can help u s understand and explain phenomena. 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. 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. 1.19.16 Required 2.1,3-5,8-22; Suggested 2.2,6 Chapter 2: Raw Materials and Fuel for our Bodies 2.1-2.3 Atoms form molecules through bonding. 2.1 Everything is made of atoms. Take-Home Message 2.1 Everything around us, living or not, is made up of atoms, the smallest unit into which material can be divided without losing its essential properties. All atoms have the same general structure. They are made up of protons and neutrons in the nucleus, and electrons, which circle far and fast around the nucleus. 2.3 Atoms can bond together to form molecules or compou nds. Take-Home Message 2.3 Atoms can be bound together in three different ways. Covalent bonds are formed when atoms share electrons. In ionic bonds, one atom transfers its electrons to another and the two oppositely charged ions are attracted to each other, forming an ionic compound. Hydrogen bonds, which are weaker than covalent and ionic bonds, are formed from the attraction between a hydrogen atom and another atom with a slight negative charge. 2.4-2.7 Water has features that enable it to support all life. 2.4 Hydrogen bonds make water cohesive. Take-Home Message 2.4 Water molecules easily form hydrogen bonds, giving water great cohesiveness. 2.5 Water has unusual properties that make it critical to life. Take-Home Message 2.5 The hydrogen bonds between water molecules give water several of its most important characteristics, including cohesiveness, reduced density as a solid, the ability to resist temperature changes, and broad effectiveness as a solvent for ionic and polar substances. 2.8-2.11 Carbohydrates are fuel for living machines. 2.8 Carbohydrates include macromolecules that function as fuel. Take-Home Message 2.8 Carbohydrates are the primary fuel for running all cellular machinery and also form much of the structure of cells in all life forms. Carbohydrates contain carbon, hydrogen, and oxygen, and generally have the same number of carbon atoms as they do H2O units. The simplest carbohydrates, including glucose, are monosaccharides or simple sugars. They contain from three to six carbon atoms. As the chemical bonds of carbohydrates are broken down and other more stable bonds are formed, a great deal of energy is released that can be used by the organism. 2.9 Glucose provides energy for the body's cells. Take-Home Message 2.9 Glucose is the most important carbohydrate to living organisms. Glucose in the bloodstream can be used as an energy source, can be stored as glycogen in the muscles and liver for later use, or can be converted to fat. 2.10 Many complex carbohydrates are time -release packets of energy. Take-Home Message 2.10 Multiple simple carbohydrates are sometimes linked together into more complex carbohydrates. Types of complex carbohydrates include starch, which is the primary form of energy storage in plants, and glycogen, which is a primary form of energy storage in animals. 2.11 Not all carbohydrates are digestible. Take-Home Message 2.11 Some complex carbohydrates, including chitin and cellulose, cannot be digested by most animals. Such indigestible carbohydrates in the diet, called fiber, aid in digestion and have many health benefits. 2.12-2.14 Lipids store energy for a rainy day. 2.12 Lipids are macromolecules with several functions, including energy storage. Take-Home Message 2.12 Lipids are insoluble in water and greasy to the touch. They are valuable to organisms for long -term energy storage and insulation, in membrane formation, and as hormones. 2.13 Fats are tasty molecules too plentiful in our diets. Take-Home Message 2.13 Fats, including the triglycerides co mmon in the food we eat, are one type of lipid. Characterized by long hydrocarbon tails, fats effectively store energy in the many carbon -hydrogen and carbon-carbon bonds. Their caloric density is responsible for humans' preferring fats to other macromolec ules in the diet, and is also responsible for their association with obesity and illness in the modern world. 2.14 Cholesterol and phospholipids are used to build sex hormones and membranes. Take-Home Message 2.14 Cholesterol and phospholipids are lipids that are not fats. Both are important components in cell membranes. Cholesterol also serves as a precursor to steroid hormones, important regulators of growth and development. 2.15-2.19 Proteins are versatile macromolecules that serve as building blocks . 2.15 Proteins are bodybuilding macromolecules. Take-Home Message 2.15 Unique combinations of 20 amino acids give rise to proteins, the chief building blocks of the physical structures that make up all organisms. Proteins perform myriad functions, from assisting chemical reactions to causing blood clotting to building bones to fighting microorganisms. 2.16 Proteins are an essential dietary component. Take-Home Message 2.16 Twenty amino acids make up all the proteins necessary for growth, repair, and re placement of tissue in living organisms. Of those amino acids, about half are essential for humans: they cannot be synthesized by the body so must be consumed in the diet. Complete proteins contain all essential amino acids, while incomplete proteins do not. 2.17 A protein's function is influenced by its three -dimensional shape. Take-Home Message 2.17 A protein's particular amino acid sequence determines how it folds into a particular three -dimensional shape. This shape determines many of the protein's pr operties, including which molecules it will interact with. When a protein's shape is deformed, the protein usually loses its ability to function. 2.18 Enzymes are proteins that speed up chemical reactions. Take-Home Message 2.18 Enzymes are proteins that help initiate and speed up chemical reactions. They aren't permanently altered in the process, but rather can be used again and again. 2.19 Enzymes regulate reactions in several ways (but malformed enzymes can cause problems). Take-Home Message 2.19 Enzyme activity is influenced by physical factors such as temperature and pH, as well as chemical factors, including enzyme and substrate concentrations. Inhibitors and activators are chemicals that bind to enzymes and, by blocking the active site or altering the shape or structure of the enzyme, can change the rate at which the enzyme catalyzes reactions. 2.20-2.22 Nucleic acids store information on how to build and run a body. 2.20 Nucleic acids are macromolecules that store information. Take-Home Message 2.20 The nucleic acids DNA and RNA are macromolecules that store information in their unique sequences of bases contained in nucleotides, their building -block molecules. Both nucleic acids play central roles in directing protein production in organisms. 2.21 DNA holds the genetic information to build an organism. Take-Home Message 2.21 DNA is shaped like a ladder in which the long, vertical sides of the ladder are made from a sequence of sugar-phosphate-sugar-phosphate molecules and the rungs are pairs of nucleotide bases. The sequence of nucleotide bases contains the information about how to produce a particular protein. 2.22 RNA is a universal translator, reading DNA and directing protein production. Take-Home Message 2.22 RNA acts as a middleman mol ecule--taking the instructions for protein production from DNA to another part of the cell, where, in accordance, with the RNA instructions, amino acids are linked together into proteins. Suggested 2.2,6 2.2 An atom's electrons determine whether (and h ow) the atom will bond with other atoms. Take-Home Message 2.2 The chemical characteristics of an atom depend on the number of electrons in its outermost shell. Atoms are most stable and least likely to bond with other atoms when the outermost electron she ll is filled to capacity. 2.6 Living systems are highly sensitive to acidic and basic conditions. Take-Home Message 2.6 The pH of a fluid is a measure of how acidic or basic the solution is and depends on the concentration of dissolved H+ ions present; t he lower the pH, the more acidic the solution. Acids, such as vinegar, can donate protons to other chemicals; bases, including baking soda, bind with free protons. Week 2 What I read for this quiz: 1.26.16 Required 3.1-4, 8-10, 22 1.26.16 Suggested 3.5-6,13,15-16,20-21 Chapter 3 Cells: The Smallest Part of You 3.1-3.3 What is a cell? 3.1 All organisms are made of 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. 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. They are 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. Take-Home Message 3.3 Eurkaryotes are single-celled or multicellular organisms consisting of cells with a nucleus that contains linear strands of genetic material. The cells also commonly have organelles throughout their cytoplasm; these organelles may have originated evolutionarily through endosymbiosis or invagination, or both. 3.4-3.7 Cell membranes are gatekeepers. 3.4 Every cell is bordered by a plasma membrane. Take-Home Message 3.4 Every cell of every living organism is enclosed by a plasma membrane, a two -layered membrane that holds the contents of a cell in place and regulates what enters and leaves the cell. 3.8-3.11 Molecules move across membranes in several ways. 3.8 Passive transport is the spontaneous diffusion of molecules across a membrane. 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. 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. Take-Home Message 3.9 The diffusion of water across a membrane is a special type of pas sive transport called osmosis. Water moves from an area with a lower concentration of solutes to an area with a higher concentration of solutes. Water molecules move across the membrane until the concentration of water inside and outside the cell is equali zed. 3.10 In active transport, cells use energy to move small molecules into and out of the cell. Take-Home Message 3.10 In active transport, movement of molecules across a membrane requires energy. Active transport is necessary if the molecules to be mo ved are very large or if they are being moved against their concentration gradient. Proteins embedded in the plasma membrane act like motorized revolving doors to actively transport (pump) the molecules. 3.22 Chloroplasts are the plant cell's solar powe r plant. 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 originally have been bacteria that were engulfed by a predatory cell by endosymbiosis. Week 3 What I read for this quiz: 2.1.16 Required 4.1-8, 12, 17-18 2.1.16 Suggested 4.9-11, 13 Chapter 4 Energy: From the sun to you in just two steps 4.1-4.4 Energy flows from the sun and through all life on earth. 4.1 Cars that run on french fry oil? Organisms and machines need energy to work. Take-Home Message 4.1 The sun is the source of the energy that powers most living organisms and other "machines." The energy from sunlight is stored in the chemical bonds of molecules. When these bonds are broken, energy is released, regardless of whether the bond is in a molecule of food, of a fossil fuel, or of a biofuel such as the oil in which french fries are cooked. 4.2 Energy has two forms: kinetic an d potential. Take-Home Message 4.2 Energy, the capacity to do work, comes in two forms. Kinetic energy is the energy of moving objects, while potential energy, such as chemical energy, is stored energy that results from the position or location of an object. 4.3 As energy is captured and converted, the amount of energy available to do work increases. Take-Home Message 4.3 Energy is neither created nor destroyed but can change form. Each conversion of energy is inefficient, and some of the usable energy is converted to less useful heat energy. 4.4 ATP molecules are like free -floating rechargeable batteries in all living cells. Take-Home Message 4.4 Cells temporarily store energy in the bonds of ATP molecules. This potential energy can be converted to kinetic energy and used to fuel life-sustaining chemical reactions. At other times, inputs of kinetic energy are converted to the potential energy of the energy -rich but unstable bonds in the ATP molecule. 4.5-4.11 Photosynthesis uses energy from sunlight to make food. 4.5 Where does plant matter come from? Photosynthesis: the big picture. Take-Home Message 4.5 Through photosynthesis, plants use water, the energy of sunlight, and carbon dioxide gas from the air to produce sugars and other organic materials. In the process, photosynthesizing organisms also produce oxygen, which makes all animal life possible. 4.6 Photosynthesis takes place in the chloroplasts. Take-Home Message 4.6 In plants, photosynthesis occurs in chloroplasts, green organelles packed in cells near the plants' surfaces, especially in the leaves. 4.7 Light energy travels in waves: plant pigments absorb specific wavelengths. Take-Home Message 4.7 Photosynthesis is powered by light energy, a type of kinetic energy made of energy packets ca lled photons. Photons hit chlorophyll and other light -absorbing molecules in the chloroplasts of cells near the green surfaces of plants. These molecules capture some of the light energy and harness it to build sugar from carbon dioxide and water. 4.8 Photons cause electrons in chlorophyll to enter an excited state. Take-Home Message 4.8 When chlorophyll is hit by photons, the light energy excites an electron in the chlorophyll molecule, increasing the chlorophyll's potential energy. The excited electrons can be passed to other molecules, moving the potential energy through the cell. 4.12-4.16 Living organisms extract energy through cellular respiration. 4.12 How do living organisms fuel their actions? Cellular respiration: the big picture. Take-Home Message 4.12 Living organisms extract energy through a process called cellular respiration, in which the high -energy bonds of sugar and other energy -rich molecules are broken, releasing the energy that went into creating them. The cell captures the food molecules' stored energy in the bonds of ATP molecules. This process requires fuel molecules and oxygen, and it yields ATP molecules, water, and carbon dioxide. 4.17-4.18 There are alternative pathways to energy acquisition. 4.17 Beer, wine, and spirits a re by-products of cellular metabolism in the absence of oxygen. Take-Home Message 4.17 Oxygen deficiency limits the breakdown of fuel because the electron transport chain requires oxygen as the final acceptor of electrons during the chemical reactions of g lycolysis and the Krebs cycle. When oxygen is unavailable, yeast resort to fermentation, in which they use a different electron acceptor, acetaldehyde, and in the process generate ethanol, the alcohol in beer, wine, and spirits. 4.18 Eating a complete di et: cells can run on protein and fat as well as on glucose. Take-Home Message 4.18 Humans and other organisms have metabolic machinery that allows them to extract energy and other valuable chemicals from proteins, fats, and carbohydrates in addition to the simple sugar glucose.
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