Presentation on theme: "MID YEAR BIOLOGY REVIEW Excerpts from powerpoints used in class (with one exception) during the first semester. Review."— Presentation transcript:
MID YEAR BIOLOGY REVIEW Excerpts from powerpoints used in class (with one exception) during the first semester. Review
Scientific Method Scientific Method – way in which scientists gather information and answer questions. The goal of science is to investigate and understand the natural world, explain events, and use those explanations to make useful predictions. There are generally 7 steps to the scientific method. –This is a good flow chart of the scientific method. –Note: There are many versions of the steps of the scientific method, but they are essentially all the same!
1. Stating the problem 2. Gathering information on the problem 1. Stating the problem is something that you want to find out. –Example: Why did 10 people get sick with E.coli at Saturday’s picnic? 2. Gathering information on the problem? You must first Observe and gather facts! –Observation: Everyone who got sick with E. coli ate the chicken, potato salad and/or ate ice cream within 72 hours. –Inference: What does this suggest?
Observation Versus Inference There are two types of data scientists gather: quantitative and qualitative. When scientists gather information, they begin with observations or the process of recording information in a careful or orderly way. This is called Quantitative data. Scientists also use data to make inferences. This is a logical interpretation based upon prior knowledge or experiences. This is called Qualitative data. Let’s start out easy and then test your skills with a few observation versus inference games!
3.Forming a Hypothesis Hypothesis – proposed solution or educated guess to the problem. They must be proposed in such a way that they can be tested. (or testable.) There can be multiple hypotheses or many solutions to a scientific problem! –Example: Remember the bad picnic? 1. The chicken was bad (infected with E.coli) and made people sick. 2. The potato salad was bad (infected with E.coli) and made people sick. 3. The ice cream was bad (infected with E.coli) and made people sick. The Suspects!
4. Performing experiments to test the Hypothesis We must test the hypothesis to determine whether or not it is correct or explains what is going on in our problem. Testing is done through experiments. –Example: Compare the items that made people sick by growing samples of bacteria (E.coli) on culture plates resistant to other types of pathogen growth using sterile techniques. –Why is it important to have specific media? 12 345
4. Experiment: Controls Controls – There are two types of controls in every experiment used as a basis of comparison. –Positive Control: Your anticipated outcome of the experiment. This control ensures that your experiment is working properly and/or there are not any outside factors influencing the outcome of your experiment. Example: A pure sample of E.coli that made everyone sick from the picnic. Outcome: A sample of E.coli will grow on this plate. –Negative Control: Contains no variables and should have no effect or outcome in your experiment. This control ensures that no contamination has occurred in your experiment. Example: No sample of any food item added to the petri dish. Outcome: Nothing should grow on this plate. 1 E.coli 2 nothing
4. Experiment: Variables In designing an experiment, only one variable is tested at a time with your positive and negative controls. Variable – the factor being tested –Independent Variable – Factor you can manipulate –Dependent Variable – Factor that responds to the manipulation and can be measured. Example: Samples of the three food items from the picnic. 3 Chicken 4 Potato salad 5 Ice cream
5. Recording and Analyzing Data A) Data are Recorded observations and measurements. –Data is usually shown in a table or chart. B) Then data is made into a graph to show trends. –Makes information easier to see! –We’ll conduct a graphing experiment later…
6.Stating a conclusion 7.Repeating the experiment 6. Once you have looked at your data, you can draw conclusions. –Example: Which plate showed growth? What food was the culprit? What would you report based upon your outcome? Other Outcomes/Conclusions: –What if nothing was wrong with the food at all? How would you revise your hypothesis and conduct another experiment? –What if there was no growth on plate 1? –What is there was growth on plate 2? 7. In order to ensure your data is accurate AND to that your hypothesis accurately explains what is scientifically going on, experiments will be constantly repeated. –Why is this important?
Safety Goggles Used for Eye protection. The most common used safety item in the biology laboratory. Use when there are Chemicals, Flames or Heating. They give you protection against flying objects or toxic substances. If your eyes come into contact with a substance, use the eye wash immediately.
Poison Do not let it on your skin or inhale its vapor. Wash your hands after handling. Can cause death if eaten or drunk. Let your teacher know immediately if you come into direct contact. Always hold test tubes or flasks away from your nose and face and waft odors towards you.
Fire Hazard Wear safety goggles with fire hazards. Tie back loose hair and clothing. Ask your teacher about lighting and extinguishing fires during a lab.
Physical Safety This activity involves physical activity. Use caution to avoid injuring yourself and others. Follow all instructions from your teacher. Alert your teacher if there is any reason you should not participate in this activity.
Glassware Hazard Glassware is present and can cause injury. Glassware should be cleaned with each use to avoid contamination. Alert your teacher if there is any broken glassware. Broken glass goes in a special “sharps” container, not in the regular trash.
Sharp Object Scissors, scalpels, razor blades, pins, and knives are sharp so use care. Always direct sharp edges and points away from yourself and others. If you are cut or bleeding, let your teacher know immediately. Use only as directed.
Heat Hazard Use an oven mitt or gloves when handling hot materials. Use clamps or tongs to hold hot objects. Always heat objects in a test tube away from you and others. Hot plates, hot water and hot glassware can cause burns. Glassware looks the same when hot or cold, so use care when heating any type of glass. Rapid changes in glass temperature can cause it to expand, crack and/or explode! Plastic tools should never be heated on a hot plate! –They will melt! Never touch hot objects with your bare hands.
Corrosive Chemical Indicates an acid or other corrosive chemical. Wear gloves at all times and safety goggles! Avoid getting in skin or eyes. Do not inhale vapors. Wash your hands after lab activity.
Electrical Hazard Avoid electric shock. Never use electrical equipment around water or when your hands are wet. Be sure cords are untangled and unplugged when not in use.
Animal Safety Treat live animals with care. Be careful when dissecting preserved animals. –Wear safety goggles! –Wear latex gloves! Wash your hands after lab.
Why Graph? When performing an experiment, a scientist must be able to record an immense amount of data and process that data into useful information. This is done by converting raw data into charts or tables. Then, the data must be graphed such that it can be interpreted by the public. Graphs are visual representations of data.
Part 1: Tables and Charts Tables and charts are created for organizing data from raw data. The chart should show how a trend occurs over several occurrences, (months, trials, categories, etc) or over time. Once data is organized, it can be graphed!
Part 2: Graphing Data A) Pie Graphs Pie graphs are useful in showing percentages. Displays how different categories are represented within a topic area. –Sample: How many land does Asia take up in the world?
Part 2: Graphing Data B) Bar Graphs A bar graph is a way of showing relationships between variables, typically items that being compared. It contains an x and y axis. –These are 2 lines that meet at a right angle. It uses a series of columns to display data. –Example, how does the number of farms in 1910 compare with 1990? Notice: –The x and y axis are always labeled. –The graph has a title. –The bars are vertical. –The numbers on the Y axis are in sequence for an accurate comparison.
Part 2: Graphing Data C) Line Graphs A line graph shows the best relationship between 2 variables. Along the x-axis (horizontal) is the manipulated or independent variable. Along the y-axis (vertical) is the responding or dependent variable. Has one or more lines connecting a series of points. Notice: –Time is on the x-axis (independent variable) –Distance is on the y-axis (dependent variable) –Distance and time are in sequence.
Constructing a graph Decide which variable to place along the x and y axis. Decide on a scale for your graph. –Must be as large as possible within the limits of the paper and still include the largest item of data. –Select your scale with ease of locating points, multiples of 1, 2, 5, or 10 are easiest. Your Turn! Flip on the back of your notes and let’s conduct a graphing experiment!
Organic Polymers Polymers – macromolecules made of repeating units called monomers. Four types: carbohydrates, lipids, nucleic acids, proteins. Polymer Monomers 2-3
Carbohydrates Carbohydrates – compounds made of carbon, hydrogen, and oxygen in a ratio usually 1 : 2 : 1. –Energy source!!! –Ex: sugars, starches, glycogen, cellulose –Monosaccharides (monomer) (glucose) –Polysaccharides (polymer) (starch) 2-3
What are Enzymes? Enzymes are proteins which act as biological catalysts. Their subunits are amino acids. Enzymes are used by cells to trigger and control chemical reactions. Without enzymes, several reactions in cells would never occur or happen to slowly to be useful.
What is activation energy? Activation energy is the amount of energy needed to start a chemical reaction.
Enzymes speed up chemical reactions by lowering their activation energy.
What is a substrate? Enzymes bind to molecules called substrates. These substrates are the reactants that are catalyzed by the enzyme.
Lock and Key Hypothesis Each protein has a specific shape, therefore enzymes bind to substrates based on shape. The site on the enzyme where the substrates bind is called the active site. Enzymes bind to the substrates based on their complementary shape.. The fit is so exact that the active site and substrates are compared to a “lock and key”.
How are enzymes affected by the reactions? Enzymes are NOT changed by the reactions they catalyze, therefore they are reusable!
Induce Fit Hypothesis Enzymes can change shape slightly to fit the substrate a little better (like a hand in glove).
How can enzymes be affected? Enzymes can be affected by temperature and pH. Temperatures outside the correct range can cause enzymes to break down or change shape. This break down is called denaturation. Therefore, enzymes in our body work best at 37°C (98.6°F) and at a pH between 6.5 to 7.5. Ex: Catalase is an enzyme that breaks down hydrogen peroxide. –H2O2 → H2O + O2 (gas) –A raw potato in H2O2 gives off O2. The boiled potato give no bubbles because the enzyme has changed due to heat.
Enzymes can turn On & Off Most cells contain proteins that turn enzymes on or off during critical stages of development.
Diffusion Diffusion – net movement of particles from an area of higher concentration to an area of lower concentration Caused by random movement Is a slow process because it relies on the random molecular motion of atoms
Rate of Diffusion Three key factors affect the rate of diffusion: –1. Concentration. The most important factor. The more the concentrated the substances, the faster diffusion occurs. –2. Temperature. Increased temperature can speed diffusion because of more rapid molecular movement –3. Pressure. Increased pressure will accelerate molecular movement and speed up diffusion.
The Result of Diffusion Eventually, the two different concentrations (the concentration gradient) will be distributed evenly. –This is called dynamic equilibrium. Diffusion is one of the methods that cells move substances in and out of the cell
Osmosis Osmosis – the diffusion of water across a selectively permeable membrane Regulating water is a very important factor in maintaining homeostasis in the cell.
What controls Osmosis? If two solutions are separated by a selectively permeable membrane… –Water will flow to the side of the membrane where the water concentration is lower –However, the substances in the water are prevented from moving and keep their original concentrations. Therefore, osmosis is controlled by a concentration gradient, that is an unequal distribution of particles across a membrane. –Movement from a low solute concentration (high water potential) to a solution with high solute concentration (low water potential)
Your Turn! Which way will the water go? On your sheet, record what will happen to the red blood cells in each of these three cases: Red Blood Cells (5% salt) in 40% Salt Solution Red Blood Cells (5% salt) in 5% Salt Solution Red Blood Cells (5% salt) in Pure Water (0% salt solution)
How Osmosis affects cells: Isotonic Solution All cells are subject to osmosis since they are surrounded by water. In an Isotonic Solution, the concentration of dissolved substances in the solution is the same as the concentration of dissolved substances inside the cell. There is equal flow and water goes in both directions. Therefore, cells retain their original shape since the water concentrations are equal.
How Osmosis affects cells: Hypotonic Solution In an Hypotonic Solution, the concentration of dissolved substances in the solution is lower than the concentration of dissolved substances inside the cell. Therefore, there is more water outside the cell than inside & water flows in! –Animal cells may burst –Plant cells become more rigid… how does this explain the misting machines in the produce section of grocery stores?
How Osmosis affects cells: Hypertonic Solution In an Hypertonic Solution, the concentration of dissolved substances in the solution is higher than as the concentration of dissolved substances inside the cell. Therefore, there is less water outside the cell than inside & water flows out! –Animal cells shrink –Plant cells become less firm called plasymolysis… How does this explain why plants will wilt without water?
Passive Transport Passive Transport When the cell uses NO ENERGY to move particles across the membrane via DIFFUSION Includes Water, Lipids, and Lipid- Soluble proteins Why? The membrane is attracted to them.
Viruses Viruses are non-living particles of nucleic acid, protein and some lipids that cause influenza. Composed of DNA or RNA in a protein coat called a capsid. Viruses that only infect bacteria are called bacteriophages. Named after their disease or discoverer. Likely evolved later since they are dependent on living things. Why Non-Living? –Cannot reproduce without infecting a host cell –Do not grow and develop –Do not respond to the environment.
Viral “Reproduction” Lysogenic cycle –Virus attaches to host cell –Inserts viral nucleic acid and inserts it into the host cell’s chromosome (prophage) –Gets replicated as host cell divides (through mitosis) –Can remain inactive for a long period of time. Like Bacteria, Viruses produce disease by disrupting the body’s normal equilibrium. They either directly attack cells or cause cells to change their patterns of growth or influence their function in the body.
Lytic Cycle Lytic cycle –Starts as the lysogenic cycle until triggered. –Takes over cell machinery to make virus only! (Chops up cell’s DNA to shut down all defenses.) –Viruses are assembled in the host cell –Burst out of the host cell releasing new virus 30 min = 200 viruses
Earth History Earth History: Evolution is studied using concepts about earth history. The earth is between 4.3 and 4.5 billion years old. Approximately 3.9 billion years ago, the surface was likely cool enough for water vapor to condense. (Oceans formed.) Many of these events and organisms are recorded on the geologic time scale. As geologists provided evidence about the age of the earth and the rate at which changes happened, biologists began to suspect that life, and life forms also changed over the same time. Geologic and evolutionary change is a long and slow process. People wondered, how did life arise? http://www.youtube.com/watch?v =QDqskltCixA
Key Scientists – Origin of Life Sidney Fox (1912- 1998) -Studied the development of the first cells; found structures that have some cell life characteristics. Microspheres – microscopic droplet enclosed by a membrane of organic molecules. (Predominantly proteins.) They can form buds, split and take up certain substances from surroundings. Sydney Fox produced protocells by heating solutions of amino acids. Coacervates – small organic droplet formed by different types of organic molecules. They can grow and take up substances from surroundings. (lipid bi-layer) NOTE: These are NOT ALIVE no heredity, instead of reproduction, they form spontaneously under proper conditions. Remember back to the Ecology unit, what are some of the criteria to be considered living? What is something else you know of that is not considered to be alive? Coacervates Microspheres
Key Scientists – Origin of Life Lynn Margulis (1938- ) Conducted experiments in the 1960’s Evidence: –1. Mitochondria and Chloroplast DNA is similar to bacterial DNA. –2. Mitochondria and Chloroplasts have ribosomes who size and structure resemble bacteria. –3. Mitochondria and Chloroplasts reproduce by binary fission like bacteria. She determined the endosymbiont theory that ancient prokaryotes became the first cellular organelles. This is significant because this was one of the first driving forces of the theory of evolution!
The Evolution of Cells 1 st cells were prokaryotic heterotrophs. Chemosynthetic bacteria came next like archaebacteria. Photosynthetic cells came later and added oxygen and the ozone to the atmosphere. Allowed for eukaryotes because the new ozone layer protected from UV rays and oxygen allowed for aerobic respiration.
Origin of Eukaryotic Cells Endosymbiont Theory: Eukaryotic cells arose from living communities formed by prokaryotic organisms. The evolution towards eukaryotic cells began between 1.5 and 2 billion years ago in what is known as “endosymbiosis”: an internal, mutually beneficial relationship. Small aerobic prokaryotes are thought to have entered and lived inside larger anaerobic prokaryotes. Later additional small photosynthetic prokaryotes are also thought to have entered and lived inside. This is huge! Chloroplasts!! Mitochondria!! What is some evidence that you know of that would lead you to think that chloroplasts and mitochondria are unrelated to our genetic history?
Early Life on Earth: What we know now! Early Life on Earth: It is known that at the beginning there was little to no oxygen available in the earth’s atmosphere. All living things must have been anaerobic. The small size of the microfossils found indicates early organisms were prokaryotes. Likely these were heterotrophs (does not make their own food) that ate spontaneously formed organic compounds. Supply and Demand: as the supply of these compounds became scarce, it became necessary to evolve. Became Autotrophs (can make own food).
Early Life on Earth: What we know now! -They learned to use chemosynthesis: CO2 is the carbon source for needed organic molecules, energy is obtained through chemical oxidation of inorganic molecules. The “archaebacteria” of today are likely similar organisms to those early life forms. Archaebacterium – Kingdom of unicellular organisms that live in anaerobic marine sediments. Oxygen, as it became present in the atmosphere was often harmful to early unicellular organisms, but by 3.5 billion years ago, some life forms had become photosynthetic and oxygen in the atmosphere increased. Evidence of a group similar to the cyanobacteria of today; Cyanobacteria – (blue green) a group of photosynthetic unicellular prokaryotes.
The Cell Theory Cell Theory:Cell Theory: 1.All living things are composed of cells 2.Cells are the basic living units of all organisms 3.New cells are produced from existing cells -a cell divides to form two identical cells Virchow 7-1
Cells are the basic unit of lifeCells are the basic unit of life –Unicellular Organisms: Bacteria –Multicellular Oganisms: Animal & Plant Cells Pancreatic cell Blood cell Muscle cell
All Cells have 3 characteristics: 1. surrounded by a barrier called a cell membrane 2. have biological information (DNA) 3. have cytoplasm
Two Main Groups of Cells ProkaryotesProkaryotes –NO membrane bound organelles –has circular DNA, no nucleus –cell functions carried out in cytoplasm –unicellular –Example: Bacteria
Eukaryotes:Eukaryotes: –membrane bound organelles –DNA is in the nucleus –cell functions carried out by organelles –Most multicellular –Example: Animal & Plant Cells
Eukaryotic Cell Structure Nucleus – contains DNA that codes for proteinsNucleus – contains DNA that codes for proteins Cytoplasm – the portion of the cell outside the nucleus; “jelly-like” fluidCytoplasm – the portion of the cell outside the nucleus; “jelly-like” fluid 7-2 www.nerdscience.com
Nuclear Membrane – surrounds the nucleus.Nuclear Membrane – surrounds the nucleus. Chromosomes – folded and twisted strands of DNA in the nucleus.Chromosomes – folded and twisted strands of DNA in the nucleus. Nucleolus – makes ribosomes.Nucleolus – makes ribosomes. 7-2 www.nerdscience.com Inside the Nucleus
Journey to the center of the cell! An explanation of the cell organelles. Use your paper to keep up and write down their functions.
Page 1: Once Upon a time… There was a young girl named Samantha. She lived in a little town called Carrboro. She lived there with her little dog Auggie. One day there was a big tornado and she and her dog got whisked into the air and transported to a strange new world!
Page 2: Where am I? Samantha awoke in a crazy new world and said, “where am I?” She felt that she was stuck in some gooey liquid and saw that her dog was too although Auggie looked very different than before. Then Auggie spoke and she said, “this goo is likely cytoplasm, the liquid gel inside of all eukaryotic cells. It acts as a cushion and support for the organelles!” She continued, “kind of like the packing popcorn in shipping boxes.”
Page 3: Who am I? Shocked that her dog spoke, Sam looked and saw that she was made of stacks and green. “You’re one of us,” a mysterious voice said. “You’re a chloroplast! Chloroplasts trap light energy to be used by plant cells.” “Kind of like how solar panels collect the sun energy to be used later.” The voice continued. “Chloroplasts are only found in plant cells, Auggie exclaimed, “so that helps in our mystery!” What happene d to me? Cool! I mean “Woof!” Hi there!
Page 4: What happened to my Dog!? Samantha was a bit concerned about being turned into a chloroplast, but she was a bit more curious about her dog. Knowing now her dog could talk, she asked her, “Auggie, what the biscuits happened to you?” “I believe I am a Ribosome. I help read DNA and make it into protein for the cell. We’re kind of like the workers of the cell; the cell’s best friend!” Ribosome is my name and Protein is my game!
Page 5: Okay, now let’s get out of here! As Sam and Auggie swam through the cytoplasm, they headed past all of these tubes and filaments that kept getting in their way. “What is all of this stuff Auggie?” Sam asked. “This is likely parts of the cytoskeleton that acts to help support the cell. Kind of like the concrete blocks and structural supports.” Auggie replied. It’s like our own skeletons!
Page 6: Leaving is not so easy! Samantha and Auggie reached the end of the cell and found a security guard at the cell boundary. “Who are you?” asked Samantha. “I’m the plasma membrane and I act as the bouncer for the cell. I say who goes in and who goes out.” He continued, “Since this is a plant cell, there is also another layer outside of the membrane called the cell wall which acts like a city wall around a city. There are not present in animal cells.” “You two, my friends, are not leaving.” The membrane added. “If we want to leave, we’re going to have to see the wizard or the nucleus of the cell!” Said Auggie. Come on Sam, let’s go see the wizard. I had a feeling that this wasn’t going to be easy.
Page 7: A new friend who needs some heart. On the way we bump into an organelle that seemed unhappy. “Hi, I’m a mitochrondrion, I make energy for the cell, kind of like the power plant for a factory.” “Lately I haven’t had the heart to do it anymore and I don’t know what to do!” Auggie added, “I know! Let’s all go see the Nucleus and he’ll tell us what to do!” The three then set off looking for the Nucleus. Let’s keep going! I just need the heart to start making energy again! I wonder who else we will meet?
Page 8: A new friend who needs a brain. While traveling with their new friend, they passed by another organelle with obvious issues. “And who are you that is so blue?” Auggie asked. “I’m the Golgi Apparatus, I package proteins from Ribosomes and send them out the rest of the cell, kind of like the post office does for letters in a town.” “What are those weird little things coming off of you?” asked Samantha. “Those are called Vesicles. This is the transport method I move out processed proteins. They are like the letters from the post office. “However, lately I’ve forgotten how to package all these proteins so I haven’t been doing my job and I don’t know what to do!” He exclaimed. I need a brain to figure out what to do! How do you do? Cool! Another friend! Oh dear, who else? Samantha told him, “Well, we’re all off to see the Nucleus to get his guidance, do you want to come?” “Sure!” The Golgi Apparatus exclaimed and happily joined the gang.
Page 9: A new friend who needs some courage! “I used to be scary,” said the Lysosome. “I’m filled with digestive enzymes and my job is to digest and eat old cell parts and microbes that enter the cell. I’m kind of like the garbage disposal of the cell. Everyone fears me, but lately I haven’t had the courage to go out and eat anything!” “Well,” Auggie started and then was cut off by Samantha. “Blah, blah, you wanna see the Nucleus and try to solve your problem?” Sam interjected. “Sure!” the Lysosome replied and off they went. I need the courage to do my job again! We’re going to see the nucleus! I bet he can help us! Alright, it’s getting crowded here, let’s go! As the foursome moved towards the nucleus, they encountered a dangerous foe! “Who are you?” Auggie timidly asked. “I’m the … uh, the Lysosome.” It replied fearfully. “Oh, he’s not scary, just scared!” exclaimed Sam.
Page 10: Follow the Yellow Brick ER As our heroes went further to the nucleus, they found a road that led straight to it! “What is this strange place?” asked Sam. Just then, Auggie perked up, starting barking and ran straight to it. Follow that dog! “Oh, I get it,” said the mitochrondrion. “This is the Endoplasmic Reticulum or ER. It is the site of all chemical reactions. It is like the assembly line for the cell. The Smooth ER doesn’t have any ribosomes, but the Rough ER contains most of the Ribosomes. Maybe that’s what Auggie went to go see, the other Ribosomes.” “WAIT! Auggie, come back!” Shouted Sam. It was too late, Auggie had ran ahead on the ER right to the exterior of the Nucleus.
Page 11: Get Auggie Back! “We have to sneak in, we have to get Auggie back!” Sam cried. “The Nuclear membrane is just a membrane that separates the DNA from the rest of the cell so it doesn’t get damaged. It is kind of like a plastic holder around a cell phone or plastic shrink wrap! So it won’t be so bad to go through, we’ll just have to push through one at a time!” Said the Lysosome. The group snuck into the nucleus and continued their search for Auggie and the Wizard inside the Nucleus. We can sneak in through one of those nuclear pores! The group chased after Auggie up until they reached the nuclear membrane where Auggie (because she is a small ribosome) jumped in through one of the small holes.
Page 12: Inside the Nucleus… “Auggie, Auggie, come here girl! Where are you?” Called Samantha. “There she is!” said the Golgi Apparatus. “Over there with the Nucleolus!” “What’s a nucleolus?” asked Samantha. “The Nucleolus is the organelle inside the nucleus that makes Ribosomes. It is kind of like the Boss of all the Ribosomes.” Sure enough, Auggie was wagging her tail next to the Nucleolus which was giving her some treats. Treats are so awesome! You are such a bad dog! We were so worried!
Page 13: Auggie & the Nucleolus “Wait, so exactly who is the wizard of the cell?” asked Sam. “That would be the DNA of the cell,” the Mitochondria replied. “The DNA is the genetic code that makes all the organelles and enzymes inside the cell. It acts as the brain of the cell, directing all of the cell activities. The DNA lives inside of the Nucleus. All Plant and Animal cells have DNA in their nucleus.” “Even prokaryotic cells have DNA.” added the Lysosome. We’ve got to be getting close to the Wizard! About time! Ugh, I’m not feeling so good… Yeah! Cool! “Auggie, there you are! You had us so worried!” exclaimed Samantha. “Sorry,” Auggie said, “I knew if I found the Nucleous, then the wizard would be close by!”
Page 14: Meeting the “Wizard.” Finally, the group with Auggie back, reached the DNA at the center of the Nucleus. Timidly, they approached the DNA wizard and each organelle with the group asked the wizard for what they needed. The Mitochondria went first and got the heart to make energy again. The Golgi Apparatus went next and got the brain he needed to package and sort proteins again. The Lysosome went last and got the courage to hunt down old organelles, bacteria and viruses to digest again. Lastly, Samantha and Auggie went before the DNA to ask their question about why they were inside the cell. I’ve found my brain to package proteins! I’ve found my heart to make energy! I’ve found my courage to digest things, but I still don’t feel good…
Page 15: The Test! Wait, how can we find the vacuole?” Samantha asked. The mitochrondrion replied, “The vacuole is like a storage area of the cell for water or food items. It is kind of like a giant storage unit like a trunk or closet. It’s huge in plant cells, you can’t miss it. In animal cells there are more of them, but not as large.” “Okay,” said Auggie. “Let’s ace this test!” “Um, all knowing Wizard, I mean DNA, sir…” Sam stammered, “could you help us find our way back home?” she pleaded. “DEPENDS,” boomed the DNA. “YOU MUST PASS MY TEST ON CELL ORGANELLES TO SEE IF YOU ARE WORTHY TO GO TO THE VACUOLE AND RETURN TO YOUR NORMAL LIVES!”
Your Turn! Identify the Letters to the Organelles! The group put all their heads together and came up with a list of answers to DNA’s test. Luckily, since Samantha and Auggie went around and made friends with all the organelles, it was an easy job! Help the group by identifying the organelles in your notes!
Page 16: Answers to DNA’s Test The group put all their heads together and came up with a List of Answers. Double check with your list in your notes and see how you did! Correct any answers you did not get the first time! A – Nucleus B – DNA C – Nucleolus D – Nuclear Membrane E – Rough ER F – Smooth ER G – Vacuole H – Cytoskeleton I – Chloroplast J – Cell Wall K – Plasma Membrane L – Mitochondrion M – Vesicle N – Golgi Apparatus O – Lysosome P – Cytoplasm Q - Ribosome
Page 17: One Last Question!? “BEFORE I CAN LET YOU GO, I WANT TO SEE IF YOU HAVE TRUE KNOWLEDGE OF ORGANELLES.” The DNA demanded. “WHICH ORGANELLE IS NOT FOUND IN PLANT CELLS, BUT ONLY IN ANIMAL CELLS THAT HELPS IN CELL DIVISION?”
Page 18: The last question… answered! The group was dumbfounded, all of them had spent their entire lives inside of a plant cell and had no idea what was the unique organelle of an animal cell. The Lysosome got so nervous, he vomited on the floor all of the contents in his gut! Then, up popped an undigested bacterium that must have escaped death due to the previous lack of courage from the lysosome. “I know the answer you seek!” cried the bacterium. “It’s a Centriole! Centrioles are only found in animal cells and act as fishing poles to separate the chromosomes in cell division!” Oh, excuse me! Ugh, it was getting stuffy in there! Eww! Hmm.. Hey are you going to eat that?
Page 19: Onto the Vacuole and Home! “NOW IF YOU WISH TO GO HOME, FIND THE CENTRAL VACUOLE OF THE CELL AND SAY THE MAGIC WORDS, “THERE’S NO PLACE LIKE CARRBORO! “What are we waiting for?” exclaimed Samantha. “Come on Auggie, let’s go home!” And with that, the group went to the Vacuole! There’s no place like Carrboro, there’s no place like Carrboro! Onto the vacuole ! “YES, THAT IS CORRECT.” Stated the DNA.
Page 20: Home Sweet Home The group rushed to the vacuole and said their tearful goodbyes. Samantha had learned a lot from her organelle friends and she would never forget them. Sam and Auggie entered into the vacuole, said the magic words and then felt like they were in a terrible storm! We sure are going to miss you! Thanks Samantha and Auggie! We couldn’t have done it with you!
Epilogue “No, no Samantha,” her mother told her. “A tree branch hit you on the head during the storm and we found you when Auggie was barking and licking your face. It was all just a dream.” Her mother left the room and Auggie jumped on her bed and said, “It was all a dream so just go back to sleep.” I bet she doesn’t suspect a thing! “Where am I? Who am I? Am I still a chloroplast? Is Auggie a talking Ribosome?” Samantha said with a jolt upright in her bed.
Photosynthesis Overview Photo = light Synthesis = putting together Photosynthesis is the process that plants use to trap the sun’s energy and build carbohydrates (called glucose) that store energy Happens in 2 phases: –1) The Light (light dependent) reaction creates ATP –2) The Dark (light independent) reaction uses those ATP molecules (from the light reaction) to make glucose
The Role of Chlorophyll The Chloroplast is the cell organelle where photosynthesis occurs In the chloroplasts are pigments that absorb wavelengths of light Chlorophyll (a and b) absorb all colors except green so it is reflected In Fall, trees reabsorb chlorophyll leaving the other pigments visible
Summary: The light reaction converts ADP and NADP+ into ATP and NADPH with Oxygen gas.
Light-Independent Reactions Does not need light Called the Calvin Cycle Uses CO 2 to form Carbohydrates Takes place in the stroma of the chloroplast Called a Cycle because the end products can be used again to initiate the process Uses the NADPH and ATP produced in the earlier light reactions
Calvin Cycle The Calvin cycle uses the ATP and NADPH from the light dependent reaction to create sugar. Reactant: Carbon Dioxide Product: a 6 Carbon Sugar Calvin is in the dark about photosynthesis! http://www.tracy.k12.ca.us/thsadvbio/animat ions/Photosynthesis.swf
What’s the big deal about Photosynthesis? The Calvin Cycle removes Carbon Dioxide from the Earth’s atmosphere and creates sugars. Plants can use those sugars for food or to make larger molecules like cellulose for growth and development. When we eat plants (or herbivores) eat plants, we use the energy stored in the carbohydrates. A byproduct of our breathing is Carbon Dioxide, which is used by plants for photosynthesis. It is also a greenhouse gas contributing to global warming. Without plants to harvest the sun’s energy, there would be no life for animals on Earth!
Cellular Respiration Cellular Respiration = Process by which mitochondria break down food molecules to produce ATP Does not use Oxygen is called Anaerobic Does use Oxygen is called Aerobic There are 3 stages of Cellular Respiration: 1) Glycolysis (Anaerobic) 2)Citric Acid Cycle (Aerobic) 3)Electron Transport Chain (Aerobic)
Glycolysis - Anaerobic Glycolysis = series of chemical reactions in the cytoplasm of a cell that break down glucose (a 6 Carbon compound) into 2 molecules of pyruvic acid (a 3 Carbon compound) NAD+ accepts a pair of high energy electrons to pass that energy to other pathways in the cell. 2 Molecules of ATP are used to start Glycolysis and only 4 ATPs are produced Net only 2 ATP Then pyruvic acid proceeds to the Mitochondria to begin the Citric Acid Cycle and the Electron Transport Chain (in the presence of Oxygen)
Anaerobic Processes Sometimes your cells are without Oxygen for short periods of time (during strenuous exercise, etc) In order to make ATP, the process of Fermentation occurs after Glycolysis until Oxygen becomes available again. During fermentation, cells convert NADH to NAD+ by passing high energy electrons back to pyruvic acid. This action converts NADH back into the electron carrier NAD+ allowing glycolysis to continue producing a steady supply of ATP. Some organisms simply live in areas without Oxygen and must produce their ATP this way. http://www.youtube.com/watch?v= y_k8xLrBUfghttp://www.youtube.com/watch?v= y_k8xLrBUfg
2 Anaerobic Processes: Lactic Acid Fermentation & Alcoholic Fermentation Without Oxygen, the Electron Transport Chain becomes backed up since no Oxygen is there to be the final electron acceptor Pyruvic Acid + NADH → lactic acid + NAD+ Lactic Acid is the cause of sore muscles. Certain organisms living in anaerobic environments will rely on this type of ATP synthesis. Pyruvic acid + NADH → alcohol + CO 2 + NAD+ Yeast use this type of fermentation to create C02 and ethyl alcohol.
Aerobic Respiration Most efficient type of Cellular Respiration Requires Oxygen Occurs in 3 steps: –1) Glycolysis –2) Citric Acid Cycle –3) Electron Transport Chain Glycolysis is the only step that is Anaerobic The other Anaerobic process was fermentation
Aerobic Respiration - Mitochondria Remember, Glycolysis breaks down 1 glucose into 2 pyruvic acid molecules Heads to Mitochondria for Aerobic Respiration Citric Acid Cycle occurs in the outer mitochondrial membrane Calvin Cycle – glucose was formed Citric Acid Cycle – glucose is being broken down For 1 Glucose molecule, 1 ATP is made for every turn of the cycle. http://www.wiley.com/college/pra tt/0471393878/student/animation s/citric_acid_cycle/index.htmlhttp://www.wiley.com/college/pra tt/0471393878/student/animation s/citric_acid_cycle/index.html
Electron Transport Chain 1:2 Very Similar to the ETC of the thylakoid in plants NADH and FADH 2 pas energized electrons from protein to protein releasing small amounts of energy A Concentration gradient forms in the mitochondria –Hydrogen ions inside –Lack of Hydrogen ions outside An Electrical gradient forms in the mitochondria (H + ions pumped inside) –Positive in the center –Negative on the outside
Electron Transport Chain 2:2 The final electron acceptor is Oxygen Yields Carbon Dioxide (CO 2 ), 2 Water, and 36 ATP Most efficient process since anaerobic respiration only yields 2 ATP. http://www2.nl.edu/jste/electron_transport_system.ht mhttp://www2.nl.edu/jste/electron_transport_system.ht m
Comparing Photosynthesis & Respiration PHOTOSYNTHESIS –Food accumulated –Energy from the Sun stored in Glucose –CO 2 taken in –Oxygen given off –Produces Glucose from PGAL –Goes on only in Light –Occurs in the presence of Chlorophyll of Plants only –Chloroplasts RESPIRATION –Food Broken Down –Energy of Glucose Released –CO 2 given off –Oxygen taken in –Produces Carbon Dioxide, Water & ATP –Goes on Day & Night –Occurs in all Living Cells (Plants and Animals) –Mitochondria