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References

Bindon, J. R. and Baker, P. T. (1997) Bergmann's rule and the thrifty genotype. American Journal of Physical Anthropology, 104, 201–210.
Blundell, J. E., Stubbs, R. J., Hughes, D. A., Whybrow, S. and King, N. A. (2003) Cross talk between physical activity and appetite control: does physical activity stimulate appetite? Proceedings of the Nutrition Society, 62, 651–661.

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2.9 Summary of Section 2

  1. Obesity is determined by a number of factors including environmental variables, such as the macronutrient content, energy density and fat content of available diets. Using whole room indirect calorimetry it has been found that humans are not good at recognizing the difference between low and high energy diets. Furthermore fat is less good at inducing satiety than are either carbohydrate or protein.

  2. An evolutionary perspective offers an explana
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1.5 Obesity

At the time of writing (2004) 20% of the adult population of the UK is classified as obese. The number of obese children has doubled since 1982, 10% of six year olds and 17% of fifteen year olds are now classified as obese. As shown in Table 4, obesity is recognized when the BMI exceeds 30 and occurs quite simply wh
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1.3 Balanced energy intake

There is a need for a certain daily energy intake to allow metabolism to occur in the body. Metabolism means all the chemical reactions occurring in the body and there are two types of process involved: catabolism breaks down larger molecules into smaller ones often with energy release and anabolism is the building up of larger molecules from smaller precursors, often requiring energy. The body requires energy to power anabolic, mechanical (for example, muscle contraction
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1.2 Summary of Section 1.1

  1. A balanced diet consists of six main nutrient groups; proteins, carbohydrates, lipids, vitamins, minerals and water.

  2. Dietary reference values (DRVs) comprise a range and an estimated average of recommended daily intake levels for nutrients and energy for males and females at different stages of their life.


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7.3 The central engine

  • An object that fluctuates in brightness on a timescale Δt can have a radius no greater than RcΔt.

  • The point-like nature of AGNs and their rapid variability imply that the emitting region is smaller than the size of the Solar System.

  • The central engine of a typical AGN is believed to contain a supermassive black hole of mass ∼108M and Schwarzschild radius
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5 How might dialogue move on from GM Nation?

There is a widespread optimism that ‘lessons have been learnt from the GM Nation? Debate’ – indeed the government's response to the exercise was couched in just those terms (DEFRA, 2004). One concern has been touched on already – many felt that the debate took place too late, on a rushed timetable, at a time in the controversy when the debate had become highly polarised and divisive ‘pro’ or ‘anti’ stances already embedded. This late in the day, questions for public discussion
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3.4 Consensus conference on plant biotechnology

The first UKNCC (at Regent's College) was hosted by the Science Museum and funded by the Biotechnology and Biological Sciences Research Council (BBSRC). The conference was based on a procedural model developed by the Danish Board of Technology. In Denmark, consensus conferences are held regularly and can be seen to have had unequivocal effects on policy making. Indeed, in a number of instances, Parliament has explicitly incorporated lay-panel recommendations in legislation. For example, lay-p
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References

Sheldon, P. (2005) Earth’s Physical Resources: An Introduction (Book 1 of S278 Earth’s Physical Resources: Origin, Use and Environmental Impact), The Open University, Milton Keynes
Smith, S. (2005) Water: The Vital Resource (Book 3 of S278 Earth’s Physical Resources: Origin, Use and Environmental Impact), The Open University, Milton Keynes

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3.2 Uranium occurrence and ore deposits

In igneous rocks, uranium is more abundant in granites (~3.5 ppm) than in basalts (~1 ppm). The large size of the uranium atom prevents it from easily entering the structures of common rock-forming minerals, so it is an incompatible element that tends to remain in magmas until a late stage of crystallisation, when it enters minor minerals, or even the uranium oxide, uraninite (UO2). In suitable circumstances, following fractional crystallisation of uranium-rich granitic magm
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Acknowledgements

The content acknowledged below is Proprietary (see terms and conditions). this content is made available under a Creative Commons Attribution-NonCommercial-ShareAlike 2.0 Licence.

Grateful thanks is made to the pupils and staff of: The Henley College, Oxon; Langtree School, Woodcote, Oxon and The Hill Primary School, E
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Acknowledgements

Grateful acknowledgement is made to the following sources for permission to reproduce material in this unit:

This content is made available under a Creative Commons Attribution-NonCommercial-ShareAlike 2.0 LicenceSee Terms and Conditions

Figures

Figure: 1 Copyright
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2.1 Introduction

Every receptor has to be able to recognize its particular ligand in a specific manner, and become activated by it in such a way that it transmits the signal to the cell. We shall deal with receptor specificity and activation mechanisms. Then we shall see how the same principles of specificity and activation also apply to intracellular receptors.


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7.4 Proteomics

Traditionally, the study of the biochemistry or structure of a protein necessitated its purification to a high degree. The development of protocols for cloning, manipulation and expression of genes greatly facilitated this kind of study, as will be clear to you from the previous section. In recent years, a number of high-throughput techniques have, to an extent, obviated traditional approaches and permit simultaneous analysis of all the expressed proteins in a cell or organism, known as the <
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7.3 Studying protein–protein interactions

The investigation of protein–protein interactions is a very important aspect of understanding proteins. Identifying binding partners can give insight into a protein's function. Many different methods and technologies have been developed to identify and characterise interactions between proteins, a few of which are described here.


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7.2 Site-directed mutagenesis

The application of site-directed mutagenesis (SDM) to the study of protein function has been illustrated with the enzyme lysozyme, as described previously. SDM is a very powerful technique in the study of protein function, allowing the experimenter to assess the importance of particular amino acid side-chains in a protein. It is most commonly used in the study of enzymes; however, it is also very useful in identifying key residues in protein–protein interactions. In this section, we will co
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1.4.4 Covalent cross-linkages stabilise protein structure

Proteins that are secreted by the cell, or are attached to the extracellular surface of the plasma membrane, can be subject to more extreme conditions than those experienced by intracellular proteins. Often, covalent cross-linkages stabilise these proteins by connecting specific amino acids within a polypeptide or between polypeptide chains in multisubunit proteins (see below). Typically such a linkage will be a covalent sulfur–sulfur bond which forms between the –SH groups of two cystein
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6.3 Risk

Risk is a difficult concept. Most of what we do in life involves making choices and taking risks. Sometimes the risks are small, and sometimes they are large. It can be difficult sometimes to know what the risk of doing something is. Past experience can also influence the way we think about risk. If one was knocked over by a car crossing the road, then even though the risk of it happening again is small we may remain worried and concerned about crossing the road.

How you explain risk is
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6 Thermoregulation and mammalian fur

A coat of profuse mammalian body hair is commonly called fur. Fur provides insulation, which is a property that one first thinks of as useful for mammals to help retain body heat. Fur is a unique and fundamental feature of mammals, though not all living species possess it.

Question 12

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