Learning outcomes After studying this unit you should understand: that genes are the units of inheritance for individual characteristics and also may contribute to susceptibility to certain diseases; the number of chromosomes that make up the human genome and where they are located within the cell; something of the immense scale of the human genome project; how gametes are produced by the process of meiosis and how the full complement of 46 chromosomes
5 Where does transcription occur in the cell? Up to now we have described the processes of transcription without considering where each occurs within the cell. Given that transcription — the production of mRNA — requires a DNA template, where do you think this process occur 5 Summary Section 1 Superconductivity was discovered in 1911, and in the century since then there have been many developments in knowledge of the properties of superconductors and the materials that become superconducting, in the theoretical understanding of superconductivity, and in the applications of superconductors. Section 2 A superconductor has zero resistance to flow of electric current, and can sustain a current indefinitely. The magnetic flux remains constant in a completel 2.3 The Meissner effect The second defining characteristic of a superconducting material is much less obvious than its zero electrical resistance. It was over 20 years after the discovery of superconductivity that Meissner and Ochsenfeld published a paper describing this second characteristic. They discovered that when a magnetic field is applied to a sample of tin, say, in the superconducting state, the applied field is excluded, so that B = 0 throughout its interior. This property of the superconducting s References Optional reading If you are interested in considering the role of the internet on science communication practices, you may find the following references are of interest: Wulf (1999), Rzepa (1999) and Rowland (1999a). So far, you have been asked to reflect on your experiences of science communication both as a receiver and as a producer. You have also considered a definition for communication in terms of different types of media, noting how this influences the context for science communication (e.g. ‘f 3.1 Introduction In 2000, the House of Lords Select Committee on Science and Technology produced an influential report that highlighted the complex and increasingly problematic relationship between contemporary science and society, particularly in the field of biotechnology (House of Lords Select Committee on Science and Technology, 2000). The report argued that many of these concerns were seen by the public to be the result of a perceived lack of transparency in the relationship between science, industry, pu 1.5 Key dissertation ingredients A number of ingredients are essential for a satisfactory dissertation: a thesis, i.e. one coherent overriding ‘story’ or argument situation in existing knowledge, i.e. a critical review of prior research which motivates and justifies the research question contribution of something new appropriate voice and argument, i.e. the provision of clear and explicit evidence, substantiation, and chain of in 1.6.2 Metamorphic recrystallisation To consider metamorphic recrystallisation at its simplest, let's begin by imagining a sedimentary rock composed entirely of quartz grains – a quartz sandstone. Sandstone is a sedimentary rock and so has a fragmental texture (see Figure 7b). When it is subjected to high temperature and high pressure n 1.4 The formation of igneous rocks Igneous rocks are defined as having solidified from a molten state, either inside the Earth or on the surface at volcanoes. References 4.7 Ageing brains: hope for the future Due to the enormous progress in the field of molecular and cell biology, new avenues in brain research have opened up. 3.1.2. After reading this article: The chapter by Teesson et al. (2002) will have presented you with a clearly written initial orientation to addiction. The article introduced addiction at several different levels of explanation in what the authors term a ‘biopsy chosocial model’ (p. 47). Such an integrated model is at the heart of the app 2.2 Specific issues in addiction The term ‘addiction’ carries a number of different meanings. The word is generally used with reference to drugs (e.g. heroin, nicotine, alcohol), where a person is described as being ‘dependent on’ or ‘addicted to’ a substance. Also, substances are described as ‘addictive’ or ‘non-addictive’, implying that addiction is an intrinsic property of the substance. Some people are addicted to food. Given that food is necessary, in what sense is 2.4 Other spectrographs Although the simple, single-slit spectrograph described above is the type you are most likely to find on a small telescope, there are other more complex designs available. Each of these has its own role to play in astronomical observations. An echelle spectrograph has a second dispersing element, either a second grating or a prism, which disperses the light at right angles to the direction of dispersion produced by the main grating. Without going into details, the effect is to pr 1.4.5 Summary of Section 1.4 Deciduous trees avoid the problems of winter by shedding their leaves. Plants can store nutrients over winter in a variety of structures. Amphibians have evolved behavioural responses (e.g. burying themselves) and physiological responses (e.g. different types of antifreeze in the body fluids) to winter. Hibernation occurs only in certain small mammal species and one species of bird and is accompanied by marked phy 1.2.1 The molecular level It is common knowledge that the freezing point of pure water is 0°C. Often, however, the temperature of water can fall below 0°C without it freezing, for two reasons: Any solvent containing a dissolved substance has a lower freezing point than when pure, which is why the sea freezes at a lower temperature than clean freshwater. The occurrence of supercooling, the phenomenon by which a fluid remains liquid at a temperature below Learning outcomes After studying this unit you be able to: discuss the sequence of the events that are believed to have taken place in the history of the Universe, particularly the particle reactions that occurred in the first few minutes after the Big Bang, and the role of unified theories in explaining those events; manipulate large and small numbers in scientific notation, and calculate values for quantities when given appropriate numerical information. Introduction From the moment that Galileo dropped two cannonballs of different sizes and weights from the top of the Leaning Tower of Pisa mankind has been fascinated by the impact of gravity. This unit looks at gravity, its impact on objects and how the energy involved in the movement of objects is dispersed or stored. This unit is from our archive and is an adapted extract from How the universe works (S197) which is no longer taught by The Open University. If you want to study formally with us, yo 4.2 Earthquake magnitude The magnitude of an earthquake is a measure of the amount of seismic energy released by it, so it is a quantitative scale. The scale of earthquake magnitude is called the Richter scale. Its development is described in Box 4, Charles Richter and the Richter earthquake magnitude scale. The Richter magnitude
SAQ 5
