Writing about scientific principles and phenomena is an increasingly important skill in the 21st century. This assignment is designed to help you understand a major concept covered in this unit while also helping you develop your science writing skills. One key to effective science writing is explaining how science can be used in everyday life. You’ll do this in a 500-600 word paper. You should:
1) Formulate and answer a question based on current media that focuses on LIFE SCIENCE.
Select a concept that was covered in this course and by current media and formulate a question. Use this question as the title of your essay.
2) Explain how this applies to your life Write a 500-600 word essay answering this question , and discuss
how the information could be useful to you in your own life. Be sure to include some concrete information that
was covered in this unit, explaining why the information is relevant to your life and useful for you. Be sure to explain how the information applies to you personally and give examples.
3) Structure your essay as suggested below • State your question in the title.
Give an overview of the answer to your question.
Provide the scientific details of the answer to your question. Be sure to select the
relevant information from class notes and
Make it personal. Explain why this information is relevant to your life or useful for
you and give examples.
Since you will be writing about science from a personal perspective, you can use personal
pronouns (I, we, you, etc.).
This assignment requires that you formulate your own question and approach, so do not use
the sample questions or specific examples provided
above for your paper. Great ways to start questions that will help you think deeply in this class
include: How do/does ______? Why is/are
______? What is the difference between ______?
For this assignment, work independently and do the best you can; you’ll receive feedback on
your work after it’s turned in.
two page for any topic about science life or biology
make sure to put question
Writing Assignment for Extra Credit/one per exam not including the final exam (worth 10 points each) Objective: Writing about scientific principles and phenomena is an increasingly important skill in the 21st century. This assignment is designed to help you understand a major concept covered in this unit while also helping you develop your science writing skills. One key to effective science writing is explaining how science can be used in everyday life. You’ll do this in a 500-600 word paper. You should: 1) Formulate and answer a question based on current media that focuses on LIFE SCIENCE. Select a concept that was covered in this course and by current media and formulate a question. Use this question as the title of your essay. 2) Explain how this applies to your life Write a 500-600 word essay answering this question, and discuss how the information could be useful to you in your own life.Be sure to include some concrete information that was covered in this unit, explaining why the information is relevant to your life and useful for you. Be sure to explain how the information applies to you personally and give examples. 3) Structure your essay as suggested below • State your question in the title. • 1st section: Give an overview of the answer to your question. • 2nd section: Provide the scientific details of the answer to your question. Be sure to select the relevant information from class notes and the textbook. • 3rd section: Make it personal. Explain why this information is relevant to your life or useful for you and give examples. Since you will be writing about science from a personal perspective, you can use personal pronouns (I, we, you, etc.). This assignment requires that you formulate your own question and approach, so do not use the sample questions or specific examples provided above for your paper. Great ways to start questions that will help you think deeply in this class include: How do/does ______? Why is/are ______? What is the difference between ______? For this assignment, work independently and do the best you can; you’ll receive feedback on your work after it’s turned in. The Working Cell: Energy Formation and Usage Energy—The capacity to perform work. Two Types: Potential- stored energy that is not doing work but can. Example: racehorse in starting gate, gas in car tank, couch potato watching tv Kinetic- energy of motion. Example: racehorse running down track, car moving down road, couch potato studying Biology Two Laws of Energy: 1. Energy cannot be created or destroyed, it can only be converted from one form to another. 2. During conversion, some energy is lost as heat. This increases the “entrophy”, or disorder, of the universe. Ultimate source of all energy is the: SUN Nearly all energy processes can be traced back to the sun. plants start the process by absorbing the light and turning it into sugars that are passed down the food chain.ATP used to power cellular work. ATP = Adenosine Tri-Phosphate -nucleotide -energy is located between phosphate bonds -by removing a phosphate the ATP molecule releases energy much like a spring after you have compressed it. – ATP – P = ADP (Adenosine di-phosphate) + a free P Body recycles the entire supply of ATP about 1 x every minute. One teaspoon of ATP provides enough energy to do about 15 minutes of moderately strenuous activity. Average Joe uses about 408 lbs of ATP/24 hr period. We can recycle the free P, released when it is cleaved off the ATP for energy, by using some of the energy from this reaction to reattach it to an ADP molecule. This remakes ATP. We “spend energy to make energy.” This process is called “phosphorylation” and is important in helping keep the energy process in your body going. Build ATP with energy harvested from fuel molecules in the cell… like glucose. Break down ATP to provide the cell with energy to carry out various cell functions. Enzymes Review: -catalysts…speed up chemical reactions -belong to protein class of macromolecules -lower the activation energy of reactions -Less ATP is required to start a job with an enzyme than without an enzyme -Specific shapes of enzymes only allow them to catalyze one type of reaction. Discussion: Process of Respiration in Our LivesRemember…protein shape determines function. –ENZYMES ARE NOT INTERCHANGABLE. Sometimes products are formed by enzymesubstrate reactions like proteins formed by amino acids joining. Each reaction has a specific enzyme that will fit with a SUBSTRATE at the ACTIVE SITE and cause the reaction to happen. Enzyme/Substrate complex is much like a lock and key. Any change in the shape of the key prevents the lock from opening. Sometimes substrates are broken down by enzymesubstrate reactions (like complex carbohydrates such as table sugar being broken down to glucose) http://karimedalla.files.wordpress.com/2012/10/enzyme5.gif Inhibitors can block reactions from happening. Competitive Inhibition (a) -inhibitors take the place of the enzyme. They mimic the shape and combine with the substrate at the active site before the enzyme does preventing the enzyme and substrate to combine properly. Example: same key fits two different locks, but only turns one of them http://www.tokresource.org/tok_classes/biobiobio/biomenu/enzymes/competiti ve_inhibit_c_la_784.jpg Non-Competitive Inhibition (b) -inhibitors attach to the enzyme at a site remote to the active site which doesn’t affect the substrate but does change the shape of the active site so the substrate no longer fits the puzzle. Example: key gets smashed and no longer fits the lock so it cannot turn it Practical Application of Enzymes: Penecillin, the “wonder drug” produces an enzyme that inhibits the formation of a cell wall in bacteria. Discussion: Process of Respiration in Our LivesWithout the protection of a cell wall, white blood cells can attack the bacteria. Since humans don’t share enzymes with bacteria, we can use it without causing harm to any body cells. Cyanide inhibits O2 movement in all organisms. The cyanide ion halts cellular respiration by inhibiting an enzyme in the mitochondria called cytochrome c oxidase. http://www.thenutritionpost.com/w p-content/uploads/2011/08/bugspray.jpg Many insecticides used to kill insects are enzymes that inhibit various functions in the body, such as nervous system functioning. They can do the same thing to the human nervous system that they do to insect nervous systems. Using Energy to Move Things Into and Out of the Cell PASSIVE TRANSPORT -Movement is with the concentration gradient. No energy is needed to “go with the flow.” -Imagine rowing a canoe down river with the current. Different Types of PassiveTransport: DIFFUSION: -movement of molecules from areas of higher concentration to areas of low concentration -Examples: iced tea in a pitcher of water, O2 and CO2 in the blood being exchanged, cologne scents diffusing from body into surrounding air Facilitated Diffusion: -movement of molecules from an area of high concentration to an area of low concentration with the aid of a transport protein in the cell membrane to provide passage for diffusing molecules. -each type of facilitated diffusion will have a different membrane protein to facilitate passage. Discussion: Process of Respiration in Our LivesRemember…protein shape determines function!! -still passive transport as no energy is used to move the molecules across the membrane. Only the protein is required for passage. ACTIVE TRANSPORT-NOT PASSIVE -use energy to push molecules against the concentration gradient …in other words…you are trying to fill up a space that is already full. -imagine rowing a canoe upriver, against the current -important in keeping the cell “balanced” with some molecules …Sodium/Potassium pump in muscle cells helps keep nerves going. -energy usually comes from ATP http://www.baileybio.com/plogger/images/anatomy___physiology/ 06._powerpoint_-_nervous_tissue/sodium-potassium_pump.jpg Water moves by diffusion in a class of it’s own. It is the only molecule that has free passage across the cell membrane. Thus: OSMOSIS -is the movement of water from areas of higher concentration to areas of lower concentration. -controls both solute concentration and volume in cells. Isotonic cells have equal amounts of solute and water both inside the cell membrane and outside the cell membrane. Thus, there is no net movement of water across the membrane.Most cells desire to be isotonic. APPLICATION: Blood has an isotonic saline concentration of 0.9%. When hospitals give you an I.V., they use 0.9% saline so they don’t upset the isotonicity of the blood. Isotonic Cell Fluid Exchange Solute=50% H2O=50% Equal exchange Solute=50% H2O=50% Cells that are: -HYPERTONIC have more solutes outside the cell than inside the cell. Example: salt water in ocean. -by osmosis, water must move from inside the cell to outside in order to balance the solution and volume. -loss of water will cause the cell to shrink or crenate -animal cells will lose shape and become limp -plant cells lose shape and become flaccid…this is when plants wilt Hypertonic Cell Fluid Exchange High solute conc. Low water conc. The cell will shrivel up or “crenate” due to a loss of water. Water will leave the cell in an attempt to create an isotonic situation. Low solute conc. High water conc. Cells that are: HYPOTONIC have more solutes on the inside of the cell than on the outside. Discussion: Process of Respiration in Our LivesThus, water moves into the cell by osmosis. Animal cells will swell and burst or lyse. Plant cells become “turgid” (develop turgor pressure) and look healthy. They cannot burst due to the strength of the cell wall. Hypotonic Cell Fluid Exchange Water will enter the cell very rapidly in an effort to provide an isotonic environment. Low water conc High solute conc Low water conc High solute conc Plant cells just become more turgid. Discussion: Process of Respiration in Our LivesThis will cause animal cells to swell and burst. High water conc Low solute conc Review: Can you identify the characteristics of each set of cells? Isotonic Hypotonic Hypertonic Explain how you can easily die of thirst if you get lost on the ocean? Sodas usually won’t quench your thirst. Why not? What organelle do plants store water in to make them turgid? How do protists that live in fresh water ponds and lakes avoid bursting because of the environment they live in? Respiration– AKA “breathing” Most associate respiration with the intake of Oxygen and exhaling of Carbon Dioxide. It is much more complicated than that!! After Oxygen enters your bloodstream it combines with sugar from your food intake to make ATP for energy. A by-product of all this activity is Carbon Dioxide. Respiration is called an AEROBIC process since it requires Oxygen to take place. ATP In order for sugar to provide energy, it requires 3 steps: 1. Glycolysis– “splitting the sugar” -happens in the cytoplasm of the cell -6 Carbon glucose molecule is split into 2, 3 Carbon molecules called “pyruvates” -NAD+, an enzyme, picks up high energy electrons of hydrogen to take to the next stage. This forms NADH. – some ATP is also made in this step -The “pyruvates” continue into step 2. 2. The Krebs Cycle—happens inside the mitochondria –”fuel” in the form of pyruvic acid is modified for use and becomes Acetyl CoA. –the Acetyl CoA is completely broken down into Carbon Dioxide, ATP and enzymes NAD+ and FAD++ that become NADH and FADH2 –Carbon Dioxide becomes a by-product that you breath out during respiration. –The enzymes carry the high energy H+ into the next and final step. 3.The Electron Transport System or ETS– in the mitochondria cristae. -Enzymes drop off Hydrogen at the beginning of the ETS and then return to Glycolysis or Krebs for another H ion. -Oxygen is key ingredient in ETS FADH2 -it pulls the H down the cristae to the end of the chain. -H releases energy each time it jumps down the pump -end result is water and Lots of ATP energy Total energy output from Aerobic Respiration: Glycolysis…………………..2 ATP Kreb’s Cycle………………..2 ATP Electron Transport Chain…32 ATP Total…36 ATP (38) These numbers are only true of respiration when oxygen is present in the reaction. If no oxygen is present, the cell must use an alternate form of respiration: ANAEROBIC RESPIRATION or FERMENTATION Anaerobic Respiration cannot use the same 3 steps that aerobic respiration uses because no oxygen is present to run the ETS. Instead, anaerobic respiration relies on the first step, Glycolysis, to supply the cell with energy. Recall how many ATP are produced by the glycolysis process. Discussion: Process of Respiration in Our LivesGlycolysis…………………..2 ATP This is the Total Energy output for fermentation. Although energy production isn’t great, it is better than the alternative…nothing at all!!! Although fermentation seems like a simple process, it must be able to recycle the NADH in order to keep the process going. This is done by the pyruvic acid accepting the H+ ion to make by-products allowing the NAD+ to return for more H+. http://www.uic.edu/classes/bios/bios100/lectures/09_25a_fermentation-L.jpg Two types of by-products are produced, depending on the organism using the fermentation process: Lactic Acid—found in human muscles and microorganisms Ethyl Alcohol—found in yeast These by-products may provide benefits to society in the form of alcohol products, canning process benefits and production of yeasty bread products. http://1.bp.blogspot.com/KwCaCv69Gsk/T0vbrrfXQRI/AAAAAAAA Byk/S41salirjto/s1600/alcoholic_fermenta tion.jpg Lactic Acid build-up in human muscle cells causes muscle soreness after strenuous exercise. Think about what you do when you exercise (die is not a good answer here!!) You start out pretty good, then begin to breathe faster, then start to feel muscle fatigue, then run out of energy. Muscle cells are forced to revert to anaerobic respiration when Oxygen supplies cannot meet energy demand. This is what results in fatigue and soreness after exercise is attributed to lactic acid (a poison) build-up in muscle cells. How most of you would look! —How your instructor would look!! —→ Lactic acid is also produced by microorganisms in Oxygen free environments. –canning process produces anaerobic conditions –necessary to get “good” seal on cans or must eat food right away –correctly canned, food can last a long time –best canned foods are the oldest…lactic acid becomes a flavoring agent –build-up will eventually create high acid environment and Cheese is continually microorganisms cannot survive pressed and sealed to here create the anaerobic process necessary to –cheese and yogurt, olives and produce the different Kraut, soy sauce all employ flavors of cheese. Discussion: Process of Respiration in Our LivesThe aging process also same process contributes to flavor. Soy sauce is fermented juice from the soybean. It cannot even be placed on the market shelf until it is at least one year old!! Kraut lovers of the world… Unite!!! Kraut is NOT rotten cabbage!! It is fermented cabbage and we love it!! Ethyl Alcohol is a by-product released during fermentation of sugar products by yeast cells. This process is economically important for several reasons: Bread relies on this process. Yeast “breaks down” the sugar and flour carbohydrates. The by-products released during the “rising” period help create fluffy bread. Which by-product besides ethyl alcohol is produced? What does it do? How can you eat bread and not become inebriated? The brewing industry also relies on yeast fermentation of carbohydrates. They use the sugar in grains and fruits to produce ethyl alcohol and carbon dioxide. Instead of “driving off” the alcohol, it is bottled and marketed. Beer is the result of yeast fermenting hops and different grain products. Different grains produce different flavors of light and dark brews. Wine and champagne are the result of fruit fermentation. Discussion: Process of Respiration in Our LivesAging contributes greatly to the flavor of wines. Champagne bubbles come from the addition of Carbon dioxide. It is easy when talking about bread and brew making to forget the concept behind the process relies on no oxygen being present. What happens if oxygen is present in wine or brewing processes? How can you check and make sure sufficient anaerobic conditions are being met? What ingredients would you consider essential if you wanted to make your own brew or wine? Saccromyeces cerivasae “brewers yeast”, an facultative anaerobe Humans tend to be obligate aerobes because we depend so much on oxygen. E. aerogenes, a obligate anerobe. Photosynthesis -energy producing process in AUTOTROPHS -autotrophs are organisms that produce their own food they are “self feeding”, ex: plants, algae, some bacteria Making Your Own Food Requires: -the intake of sunlight energy -pigments (specifically Chlorophyll) found in cells of autotrophs capture the light and use it to start the photosynthesis reaction The overall reaction for photosynthesis requires: sunlight water carbon dioxide (you exhale during respiration) And produces: sugar water oxygen (you inhale during respiration) Here’s how it all happens: And you From sun http://hosho.ees.hokudai.ac.jp/~tsuyu/figs/photosynthesis.gif -Chlorophyll is found in chloroplasts and is what makes the plant green. -Most chlorophyll is found in leaf material so most of the photosynthesis that takes place happens in the leaf in the mesophyll area http://www.bbc.co.uk/bitesize/standard/biology/images/leaf_struct ure_al.gif Parts of a Chloroplast: Thylakoids are responsible for the capture of sunlight as they contain chlorophyll. Granum are stacks of thylakoids Stroma serves much like the cytoplasm of the cell. http://3.bp.blogspot.com/_FLSPZURcXIQ/TIfCswCmXWI/AAAAAAAAANQ/i UlQZBRAc0E/s1600/structureofchloroplast.gif Notice how there is also an inner and outer membrane similar to a prokaryotic cell?? First step is called the LIGHT REACTION: -as it’s name implies…it requires light!! -not just any light will do…it has to be a specific wavelength -white light colors are the colors of the rainbow…red, orange, yellow, green, blue, indigo and violet…ROYGBIV -notice how light in the 500 to 600 nm range is not absorbed in any great amount…WHY? –green plant pigment prefers light in the 400450 nm range and the 600-680 range. http://1.bp.blogspot.com/_dB8l7L29Rvc/TTwNMD9gXeI/AAAAAAAAABg/RQt motqGgDk/s1600/Chlorophyll-Absorption-Spectrum.jpg -chlorophyll in plants absorbs the ends of the spectrum better and reflects the green in the middle. That is why we see plants as being green…they reflect the green wavelength Light reaction: -uses sunlight to split water into H and O -sunlight is captured by the chlorophyll in a chloroplast -the energy in the light is used to break apart water molecules and releases some heat -Oxygen that results from this split is given off as a by-product that you use to breathe -the Hydrogen is “captured” by an enzyme, NADP+ in the plant cell and transported to the next step of the photosynthesis reaction as NADPH -some ATP is made -happens in the thylakoids http://www.uic.edu/classes/bios/bios100/lecturesf04am/lightrxn.gif The Dark Reaction (or Calvin Cycle) is the 2nd step in PS: -NADPH comes from the Light reaction to the site of dark reaction to “drop off” the hydrogen collected -CO2 from the air is used to combine with the H and produce a sugar molecule (CH2O)n -the NADP+ returns to the light reaction to get another H -ATP is used to provide some energy to make the sugar -If the Calvin Cycle does not happen, no sugar is made http://2.bp.blogspot.com/_ADtjVgTw6Q/TSjL4DyUnhI/AAAAAAAAACs/xg261s8seQM/s1600/calvin_cycle.jpg Just a few notes… -the light reaction must have light to occur…this means plants do not photosynthesize at night -plants must have chlorophyll to photosynthesize…this means that flowers, red, orange and yellow leaves, etc.
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