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- Procedure a Hold the glass tubing vertically in a beaker so that one end of the tubing rests on the bottom of the beaker. Expected observations After some time, the purple colour of the potassium manganate VII spread throughout the water and...
- Most salts dissolve in soil water. For those salts whose concentration in soil water is higher that their concentration in the cell sap of root hair cells, they move into the root hair cells through diffusion. Plants require mineral salts for...
- Conversely, low surface area to volume ratio results in a low diffusion rate. This implies that diffusion rate is greater in small organisms than the large organisms. This is because the small organisms have a large surface area to volume ratio. As a result, most of their body parts are closer to the external surrounding leading to faster diffusion. Small organisms can, therefore, depend on diffusion alone as a means of transporting foods, respiratory gases and waste products. To large organisms, diffusion alone is inadequate as a means of transport of foods and excretion. They have an additional transport system. Organisms always lose heat to the surrounding through diffusion. This implies that small animals lose a lot of heat to the surrounding compared to the large animals. This is because the distance covered by the diffusing molecules is greater through the thicker membranes.
- The rate of diffusion is higher in thinner membranes. Osmosis Osmosis is a process by which solvent molecules move from a region of high concentration dilute solution to a region of low concentration concentrated solution through a semi permeable membrane. Osmosis can be described as a special type of diffusion since it involves movement of solvent Water particles from a region of high concentration to a region of low concentration.
- Demonstration of Osmosis Using a Visking Tubing Requirements 5OOcm3 beaker, visking tubing, a piece of thread, glass rod, concentrated sugar solution, cm3 distilled Water. Procedure 1. Into the beaker, put cm3 of the distilled water. Dip the visking tubing in water to moisten it. Open the visking tubing and tie one end with the thread provided. Half fill the visking tubing with the sugar solution provided and then tie the open end of the tubing. Ensure no sugar solution spills out of the tubing.
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Immerse the visking tubing into the distilled water in the beaker and suspend it using the glass rod provided. Leave the set up for about 30 minutes. Record your observations. Explain the observations made. Observations The visking tubing became swollen indicating that its cell contents increased. The amount of water in the beaker decreased. This implies that water moved from the beaker into the visking tubing. Explanation The visking tubing contains both sugar and water molecules. The beaker contains a higher concentration of water molecules than the visking tubing. The water molecules diffused from the beaker where they are highly concentrated into the visking tubing where they are lowly concentrated. Even though there is a higher concentration of sugar molecules in the visking tubing, they were not able to diffuse out of the visking tubing due to their large molecular sizes.- The visking tubing is semi permeable. Other than visking tubing, dialysis tubing or cellophane are also other semi permeable membranes that can be used in this experiment. Osmosis explained When two separate solutions are separated by a semi permeable membrane, there will be movement of water molecules from their region of high concentration dilute solution to a region of low concentration the highly concentrated solution across the semi permeable membrane. The semi permeable membrane does not allow movement of solute particles across it. The movement of the water molecules continues until the separate solutions have the same concentrations.
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Solutions with the same concentrations are referred to as isotonic solutions. The solutions are said to be isotonic to each other. A lowly concentrated solution dilute solution is referred to as a hypotonic solution. A hypotonic solution has less of the solute molecules but more of the solvent molecules. A highly concentrated solution with more of the solute particles but less of the solvent particles is referred to as a hypertonic solution. When isotonic solutions are separated with a semi permeable membrane, there will be no net movement of solvent molecules to any of the solutions since they have the same concentration of solvent molecules.- Osmotic pressure When a concentrated solution is separated from distilled water by a semi permeable membrane, the concentrated solution will develop a force with which it draws water through the semi permeable membrane from the distilled water. Osmotic pressure refers to the force with which a concentrated solution draws water to itself.
- An osmometer is an instrument used to measure the osmotic pressure. Osmotic potential This is a measure of the pressure a solution would develop to withdraw water molecules from pure water when separated by a semi permeable membrane. Water Relations in Animals As discussed earlier, the cell membrane is semi permeable. Let us discuss what would happen if an animal cell say red blood cell is placed in solutions of varying concentrations a Red blood cell in hypotonic solution e. When a red blood cell is placed in a hypotonic solution, water will move into the cell through osmosis. The cell will swell and burst. Swelling of red blood cell when placed in a hypotonic solution is referred to as haemolysis. The cell is said to be haemolysed. Water will, therefore, be drawn out of the cell into the hypertonic solution. The cell will shrink and become small. The cell is said to be crenated. The process by which animal cells shrink and become smaller when placed in hypertonic solutions is referred to as crenation.
- Note: When the cell becomes haemolysed or crenated, its functioning is impaired. This will prevent bursting or shrinking of the cells that would otherwise impair their physiology. The body has a mechanism through which these concentrations are maintained at a nearly same concentration. Water Relations in Plants Water relations in plant cells differ with that in animal cells. A plant cell has both a cellulose cell wall and cell membrane. The centre of the cell contains vacuole with sap. The sap is a solution of salts and sugars and is bound by a membrane, the tonoplast. The cell membrane and tonoplast are semi permeable while the cellulose cell wall is fully permeable. The cellulose cell wall is rigid and does not allow plant cells to burst as in the case of animal cells.
- As the cell gains more water, the vacuole enlarges and exerts an outward an outward pressure on the cell wall called turgor pressure. The turgor pressure increases as more water is taken into the vacuole causing the cell to stretch until the cell cannot stretch any more. The cell becomes firm and is said to be turgid. Turgor pressure is the outward pressure that the cell cytoplasm exerts on the cell wall as it gains more water through osmosis.
- When the cell wall is being stretched towards the outside, it will develop a resistant pressure to stretching that is equal and opposite to turgor pressure called wall pressure. It the cell loses more water, its contents reduce in size and the plasma membrane pulls away from the cell wall towards the centre. Wilting Plants always lose water to the atmosphere through transpiration and evaporation. Simultaneously, the plant cells lose water and draw more from the soil. Wilting is a phenomenon that occurs when plant cells lose more water than they draw from the soil making the plant cells to lose their turgor pressure and droop.
- To fit everything in, we often sacrifice sleep. But sleep affects both mental and physical health. Of course, sleep helps you feel rested each day. Internal organs and processes are hard at work throughout the night. Sleep helps you think more clearly, have quicker reflexes, and focus better. Tired people tend to be less productive at work and school. Lack of sleep also influences your mood, which can affect how you interact with others. A sleep deficit over time can even put you at greater risk for developing depression. Michael Twery, a sleep expert at NIH. Throughout the night, your heart rate, breathing rate and blood pressure rise and fall, a process that may be important for cardiovascular health. These hormone changes can affect your body weight. Recent studies also reveal that sleep can affect the efficiency of vaccinations. Twery described research showing that well-rested people who received the flu vaccine developed stronger protection against the illness.
- Each cycle includes periods of deep sleep and rapid eye movement REM sleep, when we dream. Sleep can be disrupted by many things. Stimulants such as caffeine or certain medications can keep you up. Distractions such as electronics—especially the light from TVs, cell phones, tablets and e-readers—can prevent you from falling asleep. Fatigue In , 11 million gallons of oil were spilled when the Exxon Valdez ran aground. Sara Mednick is a sleep researcher at UC Riverside. Video: Take a Nap! Studying is difficult, concentration is difficult, writing is difficult and taking an exam is difficult. This article, an interview with Czeisler and Scott Huettel, associate professor of psychology and neuroscience at Duke University links media with sleep interruption. These articles chronicle the benefits of getting adequate sleep and consequences of not getting adequate sleep along with questions and answers from the sleep specialists.
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The amount of sleep each person needs depends on many factors, including age, and getting a full night of quality sleep is important. Infants generally require about sixteen hours a day, while teenagers need about nine hours on average. For most adults, seven to eight hours a night appears to be the best amount of sleep. The amount of sleep a person needs also increases if he or she has been deprived of sleep in previous days. Eventually, your body will demand that the debt be repaid. People tend to sleep more lightly and for shorter time spans as they get older, although they generally need about the same amount of sleep as they needed in early adulthood. If you routinely fall asleep within five minutes of lying down, you probably have severe sleep deprivation, possibly even a sleep disorder.Campbell Biology Chapter 30 (powell_h) Flashcards | Easy Notecards
In many cases, people are not aware that they are experiencing microsleeps. Many studies make it clear that sleep deprivation is dangerous. Sleep-deprived people who are tested by using a driving simulator or by performing a hand-eye coordination task perform as badly as or worse than those who are intoxicated. Driver fatigue is responsible for an estimated , motor vehicle accidents and 1, deaths each year, according to the National Highway Traffic Safety Administration. Caffeine and other stimulants cannot overcome the effects of severe sleep deprivation. Directions Take a few minutes to review and assess your own sleep habits. Are you getting enough? Check the appropriate boxes:.If You Pass This Biology Test, You Are A Legit Biology Enthusiast!
The graph below shows the rate of a reaction as the concentration of ATP is increased while substrate concentration remains constant. How is the reaction between enzyme and substrate modified by the different temperatures? This reduces the rate of random collisions and therefore the rate of the reaction. The excess kinetic energy makes it harder for the substrate to bind to the enzyme.Chapter 30 - Test Your Understanding - Level 1 - Knowledge/Comprehension - Page 647: 5
This allows the reaction to proceed more rapidly. Answer 1 A: A certain amount of energy the activation energy is needed for the reaction to take place. At higher temperatures, there is more kinetic energy and the increased rate of random collisions between molecules increases the probability that they will collide in the right way to react. Thus, A correctly characterizes this relationship.- B is incorrect because there is more kinetic energy at higher temperatures, not at lower temperatures, and because increased kinetic energy actually raises the likelihood that the substrate will bind to the enzyme. Question 2 Dichlorophenolindophenol DPIP , an electron acceptor that changes from blue to clear when reduced, can be used to visually determine the rate of photosynthesis. In an experiment, a solution of chloroplasts containing DPIP was divided among 4 tubes. Higher transmittance is correlated to lighter color. The results of the experiment are provided. Which of the following can be reasonably concluded from the experimental results?
- The onset of photosynthesis is visible when DPIP is oxidized and changes from clear to blue. Chloroplasts exposed to heat had the highest rate of photosynthesis. Photosynthesis is stimulated when chloroplasts are exposed to light only. The solution in all four tubes was clear at time 0. During photosynthesis, DPIP is reduced and becomes colorless, which results in an increase in light transmittance. According to the data, an increase in light transmittance over time is found for the tube exposed to light only. The correct answer is C. Choice B is incorrect because the tube exposed to light only had the highest rate of photosynthesis increasing percent transmittance.
- Choice D is incorrect because the solution in all four tubes was blue at time 0. The administration of the solution caused severe damage to the patient. How can the consequence of the administration of substitute plasma be explained? The dilution was incorrect, resulting in an excessive concentration of albumin that led to the shriveling of the red blood cells. The dilution was incorrect, resulting in a deficient concentration of albumin that led to the bursting of the red blood cells. The dilution of albumin in distilled water caused the bursting of red blood cells because the solution was hypotonic to the red blood cells. The dilution of albumin in distilled water caused the shriveling of the red blood cells because the solution was hypertonic to the red blood cells.
- However, the pharmacist should have used sterile saline solution instead of the distilled water, to ensure that there was an adequate concentration of NaCl. Because the resulting solution was hypotonic to the red blood cells, water from the solution osmosed into the cells, causing them to burst, as in C. A and B are incorrect because the pharmacist did not err in his dilution of the albumin. D is incorrect because the solution is hypo- tonic to the red blood cells, not hypertonic. Blue colonies indicate that lactose is being fermented. Colorless colonies indicate that the cells cannot ferment lactose. Which of the following would most likely be observed after growing the cultures? Only colorless colonies appear from cells incubated with extract A. Only colorless colonies appear from cells incubated with extract B. Only colorless colonies appear from cells incubated with extract C.
- Blue colonies appear from cells grown with all three extracts. Because those cells would be unable to ferment lactose, they would appear as colorless. B is thus correct. D is incorrect because the cells incubated with extract B will appear colorless, as explained above. Question 5 In a respiration experiment, transgenic mice those possessing a particular genetic mutation were compared to wild type normal mice.
Chapter 30 - Plant Diversity II: The Evolution Of Seed Plants | CourseNotes
The ADP levels in the transgenic mice were found to be higher than those in the wild type. Which of the following is the most plausible explanation for this finding? The rate of oxygen consumption in mitochondria was higher in transgenic mice. The transgenic mice are unable to utilize ATP in the cytoplasm for metabolism. The rate of carbon dioxide consumption in cells was lower in transgenic mice. Choice D is incorrect because carbon dioxide is released, not consumed, in cellular respiration.- Campbell biology in focus study guide answers 1. The "9e" goes with Campbell Biology 9th Edition. Biology in Focus Chapter The Molecular Basis of Inheritance by Science Edu-cate-tion 1 year ago 1 hour, 29 minutes 5, views This lecture covers , chapter , 13 from Campbell's , biology , in focus over the molecular basis of inheritance. Exercises include concept maps, chapter summaries, word roots, chapter tests, and a variety of interactive questions in various formats. Thus, where oxygen is at high levels, such as in the lungs or gills, hemoglobins affinity for oxygen increases as more binding sites are filled. Students in more of a time crunch will be better off with AP Biology Crash Course, which cuts out a lot of the fluff and keeps a narrow focus on the exam contents.
- Streamlined content enables students to prioritize essential biology content, concepts, and scientific skills that are needed to develop conceptual understanding and an ability to apply their knowledge in future courses. Biology is the scientific study of life. Answer: B Topic: Concept 9. Choose from different sets of campbell biology 9th edition flashcards on Quizlet. Adapted from Pearson Education, Inc. In text pages, Campbell Biology in Focus emphasizes the essential content and scientific skills needed for success i. Download our chapter 5 active reading guide membrane transport and cell signaling campbell biology in focus answers eBooks for free and learn more about chapter 5 active reading guide membrane transport and cell signaling campbell biology in focus answers.
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