Investigating the relationship between diffusion and Size of the Cell
Investigating the relationship between diffusion and Size of the Cell Aim: To confirm the relationship that diffusion of chemicals depends on the ratio of surface area: volume. Hypothesis: I believe that the rate of diffusion will decrease with the increase in the volume of the cell. Fair Test: - Two agar cubes were used for each of the two volumes so that more accurate results could have been obtained. - All agar cubes were of the same size, this was done by using a ruler when cutting the agar. - All jelly samples were taken from one whole jelly container so the cells will be similar and the depth would remain the same. - The temperature will remain the same for all beakers. Safe Test: - We will be using scalpel to cut the jelly therefore we made sure we handled them with care - We made sure we used the beakers appropriately, so that they did not brake and cause any damage. Variables: Independent- size of the agar cube Dependent - Time taken for diffusion Controlled:- - Room Temperature - Concentration of the Acid - The amount of acid Apparatus: ) Jelly ( Agar in big Petri dish with phenolphthalein in it) 2) Two small Petri-dishes 3) Scalpel 4) Plastic ruler 15cm 5) Stop watch 6) Four Beakers 7) 0.1 m of hydrochloric acid Method: ) Obtain the Agar that is in the Petri dish. 2) Using the plastic ruler and the scalpel cut out two agar
Pill Bug lab. Question- What type of environment attracts the most amounts of pill bugs?
Dylane Jacobs Period 4 9/9/09 Pill Bug Vs Environment Lab Background Information- Pill Bugs are also known as wood lice. Pill Bugs are actually isopods and not bugs. They are dark brown or black and they have 7 legs. Pill Bugs mostly eat rotten vegetation such as vegetables. Pill bugs live in wet locations. They are found under damp objects or in organic garbage. If pill bugs enter a building, they will often dry out and die. There are 5 types of pill bugs, but are extremely similar. The pill bug has a tendency to roll up to protect them selves from harm; they were given the nickname "rollie pollies" because of this. They also are very active and love to try to escape. Question- What type of environment attracts the most amounts of pill bugs? Hypothesis- The pill bugs will be attracted to the soil more because it is closer in texture and make to their own natural habitat. Their natural habitat is under rocks, with soil and leaves. Variables- Manipulated Variable= Environment Responding Variable= Amount of pill bugs Controlled Variable= amount of environment ( 25 ml), amount of pill bugs (15), choice plate, temperature, and time of trials. Controlling Variables- The first variable that needed to be controlled was the amount of environment in each section of the choice plate, ultimately creating a necessity to make the choice plate a controlled variable. To control
Outline the use of polymerase chain reaction to copy and amplify minute quantities of DNA and Describe the application of DNA profiling to determine paternity and also in forensic investigations
Genetic engineering and biotechnology Outline the use of polymerase chain reaction to copy and amplify minute quantities of DNA: PCR basically gives researchers the opportunity to produce large amount of DNA sequence copies with out using up limited samples. This is done through 6 cycles where a piece of DNA is selected, raised to about 95 degrees Celsius, add primers, polymerase and nucleotides, allow the primers to bind to the DNA by lowering the temperature to 53 degrees and eventually repeat the cycle of temperature changes about 20 times. State that, in gel electrophoresis, fragments of DNA move in an electric field and are separated according to their size: Gel electrophoresis is a procedure utilized in biochemistry and molecular biology (also used in situations such as crimes scenes and DNA testing) to separate DNA molecules by size. In order to perform gel electrophoresis, DNA (which is negatively charged due to the phosphate groups in the backbone of DNA) and thus DNA will travel towards the positive electrode. During this procedure it is evident that as the pieces of DNA travel through the gel they will meet a resistance, meaning that it would be more difficult for larger pieces of DNA to move through the gel than smaller fragments, thus larger fragments move slower than smaller fragments. This is what allows the separation of all different sizes of DNA
investigating the action of pepsin on egg white
Investigating the action of pepsin on egg white Data Collection: The following table shows the lengths of egg white in a number of tubes before and after boiling: Contents The length before boiling(cm) The length after boiling(cm) Tube 1 HCL+Water 5.2 5.2 Tube 2 Pepsin+Water 4.7 4.7 Tube 3 HCL+Pepsin 5.5 5.2 Tube 4 HCL+Water+boiled Pepsin 4.9 4.9 Tube 5 Water 5.2 5.2 Table (1) Conclusion and Evaluation: While the food is in the stomach, it is mixed with acid, and enzymes, so chemical digestion takes place. During this, the peristaltic movements on the muscles in the wall of the stomach will mix the food until it is almost a fluid while is called chyme. After some, time the circular muscle between the stomach and the small intestine called pyloric sphincter opens briefly and a small amount of acid chyme is allowed into the duodenum. The wall of the stomach is made of protein, and pepsin works on proteins in order to avoid self-digestion of the stomach wall, pepsin is released as an inactive form (Pepsinosion), which is activated by the acidic environment that's why stomach secretes HCL In this experiment, we are investigating the action of the enzyme pepsin on the egg white (the protein). We know that enzymes are proteins that catalyze a reaction by lowering the activation energy. The substrate used in this experiment consists of the egg
Structure and functions of the human brain
a) Draw a diagram to show the structure of the human brain. b) Outline the function of the following regions of the human brain: medulla oblongata, cerebellum, hypothalamus, pituitary gland, cerebral hemisphere. Medulla oblongata: The medulla oblongata contains the neural centres of the autonomic nervous system and therefore controls automatic activities such as breathing, heart rate, blood pressure, swallowing digestion, production of saliva etc. Cerebellum: The cerebellum is responsible for unconscious functions such as movement and balance. It receives information from the balance organs in the ears and from receptors in muscles and tendons which indicate how stretched the muscles are. However, the cerebellum does not initiate movements but only controls them. Therefore, a damage of this part of the brain would result in uncoordinated movement. Hypothalamus: The hypothalamus basically is the link between the brain and the endocrine system. It produces the hormones which are later secreted by the posterior pituitary gland and stimulates the secretion of hormones from the anterior pituitary gland by nerve impulses. Pituitary gland: The pituitary gland is made up of two parts: the anterior pituitary gland and the posterior pituitary gland. The anterior pituitary gland consists of endocrine tissue and secretes hormones like FSH, LH, GH ect. These hormones produced in
Climate Crisis Lab Report
Human Impact on the Greenhouse Effect Research Question: How does petroleum emission affect the atmospheric carbon dioxide levels in the years 1959-1968 compared to 1997-2006? Hypothesis: Carbon dioxide levels are likely to rise in more recent years because the amount of machines that use petroleum has increased and so forming more pollution in the atmosphere. Variables: - Atmospheric carbon dioxide data is only from Mauna Loa Hawaii and not from the whole United States of America. - The petroleum data is from the United States of America so therefore it is a mean value and not specific amounts of petroleum emissions in a certain area. - Only the emission of petroleum is compared to the atmospheric carbon dioxide levels even though there are other carbon based substances that could have an effect on the carbon dioxide levels in the atmosphere. Therefore the amount of data that can be processed is limited to one sector of environmentally harmful materials. Data Selection: After taking a closer look at the data from Mauna Loa, Hawaii regarding the atmospheric carbon dioxide I decided to use the CO2 levels from the month of June for the first ten years from 1959 to 1968 and from 1997 to 2006 because I wanted a wide range of data selection so I chose the ten most recent years and the first ten years of data collected I Mauna Loa. I did not include the CO2 level from
Biology SL Conclusion and Evaluation on Oxygen Concentration Experiment
Conclusion and Evaluation The experiment carried out in class was designed to test: * How Oxygen concentration changes in lungs when a person's breath is held. * How hyperventilating lungs affects Oxygen concentration in lungs. Oxygen concentration in the air is 20.9%. The oxygen measuring device measured an 18% concentration in the air, which is perfectly acceptable. A plastic bag was wrapped around the end of the oxygen measuring apparatus and the air in it was removed. The plastic bag had a hole at its bottom. The person being tested held their breath for an extended period of time (about 60 seconds) and then exhaled into the plastic bag. The oxygen measuring device recorded a drop of 3% in Oxygen concentration. This means the concentration of oxygen in a person's lungs changed from 18% to 15% when their breath was held for about a minute. Therefore we can say that not much oxygen is used up by the lungs when your breath is held. In fact only about 16.6% of the all the Oxygen inspired is used when your breath is held. A problem that occurred frequently with other groups was that the hole at the bottom of the plastic bag was very big. This resulted in an unwanted exchange between oxygen richer and oxygen poorer airs and this made oxygen concentrations fluctuate. A simple reminder that could prevent mistakes like these from happening would be to add a reminder in the
Stem Cell Reflection
Stem Cell Debate Reflection Over many years the use of stem cell research has been debated over, and it is yet inconclusive. My personal opinion on the use of stem cell research, highly regards the potential it holds to unveil a new beginning in the world of science. Imagine a world where one no longer has to suffer from their severe illness, or where someone is told that they will complete a miraculous recovery. This world is in our reach, and if we don't act upon it, we could be missing the opportunity of a lifetime. Summarizing the main points from the debate, the pro side said that stem cell research allows scientists to analyze different stem cells, and be able to replicate them for humans that are in need. It attempts to create a solution from different types of stem cells to heal the body and the organs that suffer. There are a variety of different kinds of stem cells in our body. The ability to be able to provide someone with aid from a serious disease like Parkinson's, is truly a miraculous discovery. By researching these stem cells, humans will no longer be at risk. We will be able to have organs and limbs grown from scratch rather than having a donor. The con side said that religious figures claim that the use of stem cell research would be immoral and would be playing "God". They feel that only God can determine how long one should live, or how they should die.
Radioactive Lab
Radioactive Lab Data: 00 Pennies Number Of Trial Amount Of Pennies Left 47 2 21 3 6 4 7 5 5 6 3 7 2 8 0 0 Pennies, 1 Minute Number Of Trial Amount Of Pennies Left 3 2 6 3 0 4 Graphs: Conclusion: Radiometric dating attempts to use the constant decay of radioactive substances as a way to measure the age of rocks and minerals. Scientists attempt to deduce time for events in the past, using the presently determined rate of disintegration of unstable forms of atoms. The techniques are varied and complex. The methods involve a number of assumptions with varying degrees of certainty. The most common dating methods are radiocarbon (often called carbon-14), used for dating materials of biological origin. Half-life is the amount of time it takes for half of the atoms in a sample to decay. How accurate is radiometric dating? I don't believe it is that accurate and it is unreliable. The interpretation of these ratios, in terms of age, depends upon theories. Theories are just assumptions that are not necessarily true or valid. The nuclear decay process seems to be random yet predictable. The shaking of the cup is random and which pennies come up heads is also random. What can be predicted is the amount of pennies that will decay. For each trial the amount of decayed pennies should decrease by half. The experiment achieved the radioactive decay curve. The
The Food of the Gods
Drew Chambers Paper #2 Re- Write Monday, December 8, 2008 Purcellville Effective Writing The Food of the Gods Three Reasons Why Dark Chocolate Is Good for You For centuries Theobroma Cacao has been considered luxurious, coveted, and heavenly. In fact according to Aztec mythology, chocolate was brought down from the heavens by a god named Quetzacoatl. Chocolate may be delicious and mouth-watering, but other than its taste does it have any other real benefits? Going against the popular opinion, the answer is surprisingly, yes. Hold on though, only dark chocolate has these hidden benefits. Milk and white chocolate have no other perks to them, but actually have downsides. What extra advantages does dark chocolate really have? Well, primarily health benefits. Dark chocolate can help lower your blood pressure, increase your heart health, and help the battle against diabetes and cancer. Dr. Dirk Taubert, MD, PhD, conducted a study in Cologne, Germany, to observe whether or not dark chocolate really did lower blood pressure. Dr. Taubert gathered 44 men and women with hypertension, or high blood pressure, and commanded that 22 adults eat one dark chocolate Hershey's Kiss two hours after dinner each night for 18 weeks. The other 22 did the same except with a white chocolate Kiss instead of dark chocolate. After the 18 weeks the results where in, those eating the dark chocolate
