...Mark scheme January 2002 GCE Biology B Unit BYB1 The Assessment and Qualifications Alliance (AQA) is a company limited by guarantee registered in England and Wales 3644723 and a registered charity number 1073334 Registered address: Addleshaw Booth & Co., Sovereign House, PO Box 8, Sovereign Street, Leeds LS1 1HQ Kathleen Tattersall: Director General www.XtremePapers.net klm Question 1 (a) GCE: Biology B – BYB1 January 2002 Biuret reagent / Add NaOH and CuSO4; (ignore heated) Positive result = violet/mauve/lilac/purple coloration; (NOT blue) 2 1 1 (b) (i) (ii) (iii) Nitrogen / N; (NOT N2) Condensation; Must have box correct (allow HN / NH, but must have C=O correct) H H2N C H C O H N C CH2 SH O C OH Total 5 Question 2 (a) (i) (ii) (b) X 6.2; Active transport / active uptake; Ref. to carrier/intrinsic/pore/gate/transport/pump proteins; Ref. to different numbers of carrier proteins; Ref. to specificity / different types of carrier proteins; Ref. to charge / size of ion; For respiration; Energy for active transport; Total 1 1 2 max (c) 1 max 5 Question 3 (a) (b) (c) (i) A = Epithelium (ignore type of epithelium) / Endothelium; Muscle; X = Mitochondria; Y = Microvilli / brush border; X = Provide energy/for active uptake; Y = Increase surface area; Total 1 1 2 (ii) 2 6 www.XtremePapers.net klm Question 4 (a) (b) 82% GCE: Biology B – BYB1 January 2002 1 Concentration gradient maintained over...
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...ABSTRACT INTRODUCTION Many interesting biological facts but usually, when modifications or experiments are tried, the investigator has some reason for doing so. A substance in the gaseous or liquid state consists of molecules or atoms that are independent, rapid, and random in motion. These molecules frequently collide with each other and with the sides of the container. In a period of time, this movement results in a uniform distribution of the molecules throughout the system. This process is called diffusion (Everett and Everett, n.d.). Diffusion is defined as the movement of molecules away from the area of their highest concentration to an area of low concentration. Net diffusion can be restated as the movement of particles along the concentration gradient. According to Meyertholen (n.d.), there are several factors which may affect the rate of diffusion of a substance. These factors include the following: (1) Temperature: higher the temp-higher the rate of diffusion, (2) Size of particle: bigger the particle-higher the energy to diffuse , (3) State of matter: solid takes more time to diffuse compared to liquids, liquids take more time to diffuse compared to gases and gases take less time to diffuse compared to liquids and solids, (4) Nature of matter: denser the matter-slower the rate of diffusion. My objective was to determine the properties of ammonia (NH3) and of hydrochloric acid (HCl) that are related to diffusion. I hypothesized that ammonia diffuse...
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...ABSTRACT The effect of molecular weight on the rate of diffusion was assessed using two tests: the glass tube test and the agar-water gel test. In the glass tube set-up, two cotton plugs soaked in two different substances (HCl and NH4OH) were inserted into the two ends of the glass tube. The substance with the lighter molecular weight value (NH4OH, M = 35.0459 g/mole) diffused at a faster rate (dAve = 25.8cm), resulting in the formation of a white ring around the glass closer to the side of the heavier substance (HCl, M = 36.4611 g/mole; dAve = 10.8 cm). The agar-water gel set up was composed of a petri dish of agar-water gel containing three wells. Drops of potassium permanganate (KMnO4), potassium dichromate (K2Cr2O7) and methylene blue were simultaneously introduced to each well. Methylene blue, having the largest molecular weight, displayed the smallest diameter (18 mm) and diffused at the slowest rate (0.3668 mm/min.). Thus, the higher the molecular weight, the slower the rate of diffusion. INTRODUCTION A substance in the gaseous or liquid state consists of molecules or atoms that are independent, rapid, and random in motion. These molecules frequently collide with each other and with the sides of the container. In a period of time, this movement results in a uniform distribution of the molecules throughout the system. This process is called diffusion (Everett and Everett, n.d.). Diffusion occurs naturally, with the net movement of particles flowing from an area...
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...Final report: Ultra Rapid Crack Propagation (This is a draft) * What is URCP? The Ultra Rapid Crack Propagation (URCP) phenomenon is a rare but significant phenomenon that may result in catastrophic damages. As the name suggests it results in a rapidly progressing crack in the PE tubes & pipes. The pressures (stresses) are usually distribution system pressures, below 100psi (as per CSA Z662). These cracks are initiated by a sudden or intense impact which propagates a crack in existing flaws such as a scratches, grooves or dents. The cracks are known to travel at speeds from 100-300 m/s and travel long distances. The main factors associated with URCP are susceptible material, stresses, temperature and environment. Since the stresses (pressures) required for the initiation of URCP are very small, the effect of predicting failures are very hard which leads to the URCP phenomenon resulting in more catastrophic failures. The characteristic of the crack follows a sinusoidal crack path with hackle marks that indicate the direction of the crack in the longitudinal crack path. Often times a crack may split in to more than one branch. Figure #2: URCP Crack Historical Issues As mentioned previously since the use of PE tubes & pipes has been a large part of the industry, the URCP phenomenon is becoming a more and more common problem in the industry. Over the course of a couple of decade the following issues have been documented. * In October 1985...
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...Checkpoint 5 Complete Exercise 9.13 (The Video Game Satisfaction Case) on page 357 in your textbook A. H0 ≤ 42 versus Ha >42 b: z = (42.954 - 42)/(2.64/√64) = 2.891 Z values at 0.10 = 1.28 - Reject 0.05 = 1.64 - Reject 0.01 = 2.33 - Reject 0.001 = 3.09 - Accept Since we are dealing with the right side of the curve the z values are positive. c: Z = 2.891 therefore right side = 0.0019 Left side = 0.9981 Since p is = 0.0019 it less than 0.10, 0.05. 0.01 but greater than 0.001 D. Very strong evidence Complete Exercise 9.19 on page 358 in your textbook. ( A. H0 = 16 versus Ha ≠ 16 b. α = 0.01 S = 0. 1 b.1 Xbar = 16.05 b.2 Xbar = 15.96 b.3 Xbar = 16.02 b.4 Xbar = 15.94 two tailed critical value rule requires we split α in 2, Therefore (Z 0.01/2)= 2.576 Z = (xbar – 16)/( 0.1/6) B.1 Critical Value Z = (16.05 – 16)/( 0.1/6) Z = 3.0 – therefore readjust P value = 2 time the area to the right of z 2(1- Z) = 2(1- 0.99865) = 0.027 0.027 < 0.01 – therefore reject and readjust CI Xbar ± (2.576)( 0.01/6) 16.05 ± 0.0429 = [16.007, 16.093] readjust B.2 Critical Value Z = (15.96 – 16)/( 0.1/6) Z = -2.40 – therefore do not reject do not readjust P value = 2 time the area to the right of z 2(1- Z) = 2(1- 0.9918) = 0.0164 0.0164 > 0.01 – therefore do not reject and do not readjust CI Xbar ± (2.576)( 0.1/6) 15.96 ± 0.0429 = [15.917,16.003] – reject and readjust B.3 Critical...
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...Quantum-Criticality in Dissipative Quantum Two-Dimensional XY and Ashkin-Teller Models: Application to the Cuprates Vivek Aji and C. M. Varma Physics Department, University of California, Riverside, CA 92507 In a recent paper1 we have shown that the dissipation driven quantum phase transition of the 2D xy model represents a universality class where the correlations at criticality is local in space and power law in time. Here we provide a detailed analysis of the model. The local criticality is brought about by the decoupling of infrared singularities in space and time. The former leads to a Kosterlitz Thouless transition whereby the excitations of the transverse component of the velocity field (vortices) unbind in space. The latter on the other hand leads to a transition among excitations (warps) in the longitudinal component of the velocity field, which unbind in time. The quantum Ashkin-Teller model, with which the observed loop order in the Cuprates is described maps in the critical regime to the quantum xy model. We also discuss other models which are expected to have similar properties. arXiv:0901.4758v2 [cond-mat.supr-con] 29 Apr 2009 The dissipative quantum 2D xy model was introduced2,3 to describe experiments on ultrathin granular Superconducting films, where it was observed that above a normal-state sheet resistance of order RQ = h/4e2 the resistivity does not decrease towards 0 even at the lowest temperatures studied.4 . The granular superconductor is represented...
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...Negative Interest Rates Nominal interest rates are normally positive, but not always. Given the alternative of holding cash, and thus earning 0%, rather than lending it out, profit-seeking lenders will not lend below 0%, as that will guarantee a loss, and a bank offering a negative deposit rate will find few takers, as savers will instead hold cash. During the European sovereign-debt crisis, government bonds of some countries (Switzerland, Denmark, Germany, Finland, the Netherlands and Austria) have been sold at negative yields. Suggested explanations include desire for safety and protection against the Eurozone breaking up. More often, real interest rates can be negative, when nominal interest rates are below inflation. When this is done via government policy (for example, via reserve requirements), this is deemed financial repression, and was practiced by countries such as the United States and United Kingdom following World War II (1945) until the late 1970s or early 1980s (during and following the Post–World War II economic expansion). In the late 1970s, United States Treasury securities with negative real interest rates were deemed certificates of confiscation. Negative interest rates have been proposed in the past, notably in the late 19th century by Silvio Gesell. To prevent people from holding cash (and thus earning 0%), Gesell suggested issuing money for a limited duration, after which it must be exchanged for new bills; attempts to hold money thus result in...
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...Phase diagram When f assumes a double-well form a miscibility gap which is a situation where the systems cannot take any arbitrary concentrations is observed. Figure 1 is a phase diagram which relates to the final form of f. The common tangent f defines the points of concentration with the ce1 and ce2 as the values, which is used to establish the coexistence curve in the Tc-plane as illustrated in the bimodal. The positions of concentrations are defined by equal chemical potentials which are the slope of the tangent. The stable single phase is above the bimodal area, the supplement of this area is known to states that are unstable thermodynamically. The curve indicated by spinodal is determined by inflection points cs1, cs2 of f. Metastable (f”> 0 ) and unstable (f”< 0)subareas of the curve are separated with the spinodal. If the systems is reduced below a critical temperature, it undergoes a split into two phases this is known as a homogeneous state. The path to phase division conventionally is referred as spinodal decomposition if it is an inner state of the spinodal and nucleation if it is in a metastable area or region. Phase transition The qualitative changes that occur in equilibrium state of a system and those changes act as externally imposed constraints is referred to as phase transition. The constraints may be physical quantities such as pressure, temperature, concentration or any other. In the subsequent section, I will bear in mind that a transition...
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...For office use only T1 Team Control Number 43689 T2 For office use only F1 F2 T3 Problem Chosen F3 T4 D F4 2016 MCM/ICM Summary Sheet Macroscopic and Microscopic Models of Measuring the Efficiency of Information Networks Summary In this paper, we build a macroscopic model to determine the structure of the information networks in society, and a microscopic model to determine the probability of information diffusion between any two neighboring nodes. We use the macroscopic model to simulate the process of information finding its way, considering spread medias as the nodes. Assuming that the public medias and personal medias which first send a new and same information are the source nodes, and in order to simplify the model, we simplify these nodes as one node. Then we combine series model and parallel model of information diffusion building the macroscopic model. We draw a conclusion that when information networks become extremely developed, information networks have the ability to connect the source node to anyone in society. Moreover, based on the macroscopic model we build the microscopic model to measure the probability of information diffusion of any two neighboring nodes. We conclude that factors determining the probability of information diffusion contain two kinds: features of nodes and features of edges. We use the Fitting Method to determine the calculation model of the probability of information diffusion. We use our algorithm validate the probability of information...
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...ABSTRACT The effect of molecular weight on the rate of diffusion was assessed using two tests: the glass tube test and the agar-water gel test. In the glass tube set-up two cotton plugs soaked in twodifferent substances (HCl and NH4OH) were inserted into the two ends of the glass tube.The substance with the lighter molecular weight value (NH4OH, M = 35.0459 g/mole) diffused at a faster rate (dAve = 25.8cm), resulting in the formation of a white ring around the glass closer to the side of the heavier substance (HCl, M = 36.4611 g/mole; dAve = 10.8 cm). The agar-water gel set up was composed of a petri dish of agar-water gel containing three wells. Drops of potassium permanganate (KMnO4), potassium dichromate (K2Cr2O7) and methylene blue were simultaneously introduced to each well. Methylene blue, having the largest molecular weight, displayed the smallest diameter (18 mm) and diffused at the slowest rate (0.3668 mm/min.). Thus, the higher the molecular weight, the slower the rate of diffusion. INTRODUCTION A substance in the gaseous or liquid state consists of molecules or atoms that are independent, rapid, and random in motion. These molecules frequently collide with each other and with the sides of the container. In a period of time, this movement results in a uniform distribution of the molecules throughout the system. This process is called diffusion (Everett and Everett, n.d.). Diffusion occurs naturally, with the net movement of particles flowing...
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...2 ABSTRACT The effect of molecular weight on the rate of diffusion was assessed using two tests: the glass tube test and the agar-water gel test. In the glass tube set-up, two cotton plugs soaked in two different substances (HCl and NH4OH) were inserted into the two ends of the glass tube. The substance with the lighter molecular weight value (NH4OH, M = 35.0459 g/mole) diffused at a faster rate (dAve = 25.8cm), resulting in the formation of a white ring around the glass closer to the side of the heavier substance (HCl, M = 36.4611 g/mole; dAve = 10.8 cm). The agar-water gel set up was composed of a petri dish of agar-water gel containing three wells. Drops of potassium permanganate (KMnO4), potassium dichromate (K2Cr2O7) and methylene blue were simultaneously introduced to each well. Methylene blue, having the largest molecular weight, displayed the smallest diameter (18 mm) and diffused at the slowest rate (0.3668 mm/min.). Thus, the higher the molecular weight, the slower the rate of diffusion. INTRODUCTION A substance in the gaseous or liquid state consists of molecules or atoms that are independent, rapid, and random in motion. These molecules frequently collide with each other and with the sides of the container. In a period of time, this movement results in a uniform distribution of the molecules throughout the system. This process is called diffusion (Everett and Everett, n.d.). Diffusion occurs naturally, with the net movement of particles flowing from...
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...How surface area affects the rate of diffusion. Hypothesis – the larger the surface area the faster the rate of reaction Why did you choose your hypothesis? The reason I have chosen my hypothesis is because large surface area of the tea bag will contain more molecules which means the rate of reaction will happen faster. For example the pyramid due to it 3D shape provides more sides for diffusion to take place and more area in the middle for the tea molecules to move around which will make them escape quicker so the reaction will happen faster. 2 web sites I have done my research, a) http://www.mylearning.org/learning/investigate/Tea%20Bag%20Trials.pdf b) http://www.science-sparks.com/2012/01/02/get-the-kids-to-make-your-cuppa-investigating-teabags/ I prefer website science-sparks because I found it easier to follow and also it was more useful was because it’s a scientific website therefore it was more accurate than mylearing. It also appeared to make more sense to me. Therefore website science-sparks was more detailed and had a diagram whereas website mylearning didn’t have one so it was hard to understand how to do the experiment and how to set it all up. Equipment: Circle, square and pyramid tea bags 4 pieces of white paper A black pen or a marker Kettle with hot water (70°c) A stopwatch/timer 3 Clear glass cups Thermometer Method: On the piece of 4 white paper that are going to be used as part...
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...Corrected sunspot history suggests climate change not due to natural solar trends In a recent study by The International Astronomical Union (IAU), a long time discrepancy between two different models dealing with climate change and its direct correlation to solar activity or flares has been found to be somewhat inconclusive now after one of the longest going scientific experiments on the subject. Based on the 70 plus year period of the Maunder Minimum which has shown through data that earth’s harsh winters coincided with a higher frequency of sunspots has been believed to been a large factor in what we today believe has to do with climate change. The Maunder Minimum is a measurement of the suns activities between the years of 1645 and 1715. Basically, some scientists have believed that global warming has been connected to this effect and the fact that since this time, solar activity has increased and especially in the 20th century. According to EScienceNews.com, ‘The two methods of counting the sunspot number -- the Wolf Sunspot Number and the Group Sunspot Number [2] -- indicated significantly different levels of solar activity before about 1885 and also around 1945. With these discrepancies now eliminated, there is no longer any substantial difference between the two historical records’. These new findings were disclosed on August 10th at the IAU XXIX General Assembly in Honolulu, Hawaii. Also according to the same article, ‘The new correction of the sunspot number, called...
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...Observations on the Characteristics of Diffusion A Scientific Paper Submitted to Professor Christina Barazona College of Science and Mathematics - Department of Biological Sciences Mindanao State University – Iligan Institute of Technology Andres Bonifacio Avenue, Tibanga, 9200 Iligan City, Philippines By Janna R. Andalan August 2013 ABSTRACT The Experiment conducted involves diffusion. The point of this experiment was to know the characteristics of diffusion and to formulate hypothesis based on diffusion. It has also a purpose to see whether the diffusion is dependent on distance, rate and molecular weight of the substance. The estimation of distance is predicted by getting the average of the substance. Rate is predicted by subtracting the final diameter to initial diameter and dividing it by time. It is determined that there are three things which influence the movement of molecules such as kinetic energy, nature of the environment and size of the molecules. By this, we know which dye diffused at the fastest rate by measuring the diameter of the colored area immediately after adding the substance to the agar plate. After one hour of measuring the methylene blue by 15 minutes interval, the substance moved immediately in 0min until 45minutes, the remaining minutes remains the same. While on the potassium permanganate, the substance moved from 0minutes to 1hour. These happened because they had different molecular weight and also the size of the substance...
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...Week 3: Membrane Transport The Pre-Reading assignment lists the overall chapters and sections of the textbook you will need to refer to. The Targeted Reading is created to guide your reading – directing your attention (Focus) to the content that will help you meet the learning objectives. For example, not every paragraph in a chapter section is required reading. This document will tell you when you Pre-Reading Assignment See your Targeted reading for details… Chapter 5: Section 5.2 Membrane transport Pre-Reading Assignment See your Targeted reading for details… Chapter 5: Section 5.2 Membrane transport could Skip a paragraph/subtopic to save you time! Targeted Reading: Topic: Membrane Transport * Section 5.2 – pages 5-8 to 5-12 Subtopics: Passive transport involves diffusion + Primary active transport uses the energy of ATP + Secondary active transport is driven by an electrochemical gradient. Focus compare and contrast between diffusion versus facilitated diffusion and osmosis; passive versus active transport; primary active transport versus secondary active transport. Terminology Alert Diffusion, facilitated diffusion, osmosis, passive transport, active transport, primary active transport, secondary active transport, concentration gradient, electrochemical gradient. * Fig. 5.10: compare between simple diffusion and facilitated diffusion, and between channel-mediated and carrier-mediated diffusion. * Fig. 5.12: concentration...
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