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3.6.4 Vitamin B6 (pyridoxine)

Vitamin B6 is composed of pyridoxine and two closely related compounds. It is found in small quantities in many foods, though it can be destroyed in the cooking process. No clear deficiency disease has been recognised in humans as being directly caused by lack of this vitamin, since it is often found in conjunction with other B vitamins and their absence has greater effects. Its main role is in the conversion of some amino acids into other ones, depending on the requirements of the
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3.6.1 Thiamin (or thiamine, also known as vitamin B1)

The deficiency disease beriberi has been known for thousands of years. The name literally means ‘I can't, I can't’ in Sinhalese (a major language in Sri Lanka), and reflects the crippling effect on its victims, who suffer from neurological symptoms, including pain, fatigue and paralysis, and cardiovascular disease. The disease was most common in southeast Asia, where white or ‘polished’ rice was a major part of the diet. The main source of thiamin is in the outer layers of the grain,
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3.6 Vitamin B

Vitamin B, often called the vitamin B complex, consists of a whole range of different compounds, some of which have similar functions and work together. However, unlike the families of compounds forming vitamins E and K, the B vitamins are sufficiently different from one another to be given individual names or numbers, and to be listed separately on many food labels. Except for vitamin B12, the body can only store limited amounts of B vitamins and because they are all water-soluble
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3.5 Vitamin K

Like vitamin E, vitamin K is fat-soluble and composed of a series of related compounds. Vitamin K is widely distributed in the diet (see Table 1) and it is absorbed from the small intestine with the assistance of bile acids. Vitamin K is also manufactured by the bacteria that inhabit the human large intestine and appears to be absorbed there too. The main role of vitamin K is in blood clotting. This process requires the presence of a number of different chemicals, called clotting factors, in
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1.5 Some chemistry involving esters

Esters are produced by the reaction of a carboxylic acid with an alcohol and result from the formation of a new bond (Reaction 2.1). For example, ethyl butanoate, the major constituent of artificial pineapple flavouring, is made from the reaction of butanoic acid with ethanol.

There is a certain l
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1.4.3 Aspirin

Compare the structure of aspirin, 2.8, with that of salicylic acid, 2.7. What similarities and differences can you see?

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1.1 Why does it hurt?

The relief or avoidance of pain must be one of the major driving forces behind medical research. In this unit we start the discussion about relief of pain.

When we experience the sensation of pain it is likely that something is happening that the brain needs to know about, so it can direct us to whatever damage-limiting action is needed. We hurt because we have genes that constructed a body able to feel pain.

Without such a mechanism it is likely that life would be much shorter, w
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Acknowledgements

The content acknowledged below is Proprietary (see terms and conditions) and is used under licence.

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

Unit Image

Chaserpaul

All other materials included in this unit are derived from content originated at the Open University.
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3.3 Producing a scientific paper: science communication as knowledge production and exchange

As with all other communication, the production of science communication does not exist in a social vacuum. It involves norms and conventions that science communicators learn as part of the process of becoming a scientist. As you have seen, in taking on this social role scientists are both motivated and constrained in how they communicate, depending on the content and context of the communication. Indeed, part of the remit of this course is to develop your skills as scientists, to ensure that
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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
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Optional reading

If you are interested in investigating the issues raised by the House of Lords Select Committee report in more detail, you will find a copy of the full report on the web at:

http://www.publications.parliament.uk/pa/ld199900/ldselect/ldsctech/38/3801.htm

The following references also discuss issues related to key findings from this report: Irwin and Michael (2003, particularly pp. 19–40), Miller (2001) and Gibbons (1999).

This overall picture places demands on you as a co
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1.7 Interlude

Now that we have covered the features found in igneous, sedimentary and metamorphic rocks, and seen how these features can be explained by the processes that formed the rocks, here is a useful point at which to have a break before continuing with the next section. Before returning, you might like to see for yourself what types of rock you can find in your area. Can you identify their texture, or spot any fossils? Surfaces that haven't been obscured by grime or lichens are by far the best, as
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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
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3.1.1 Before reading this article:

Take some time to think about what ‘addiction’ means to you – how chemical and non-chemical substances can be abused and how they can lead to dependent behaviour that can affect individuals and the society in which they live. Write down your ideas.

This short exercise may be useful to establish
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1.2.3 The physiological and behavioural levels

Anticipation of winter

If organisms are to survive winter, they must be well prepared for cold weather and sometimes for reduced supply of food. Physiological changes such as shedding leaves and building up fat reserves, and behaviours such as hoarding food, must be completed before winter begins. In order to be prepared, organisms need to anticipate the onset of winter, which is done in two ways, each of which has its own associated physiological mechanisms. First, they could re
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1.2 Response to winter: understanding at different levels

Winter in a temperate region poses a number of environmental problems for organisms. Most obviously, average temperatures are lower than at other times of year and there are frequent frosts. Frost is highly significant for living organisms because water forms such a large proportion of their body tissues; for the great majority of organisms, freezing of their tissues leads to death. Secondly, because, as shown in Table 1.1, many adult organisms die, go into hiding or migrate in winter, many o
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1.8 Primordial nucleosynthesis

Time: 100 s to 1000 s

Temperature: 109 K to 3 × 108 K

Energy: 300 keV to 100 keV

As the temperature continued to decrease, protons and neutrons were able to combine to make light nuclei. This marked the beginning of the period referred to as the era of primordial nucleosynthesis (which literally means ‘making nuclei’). The first such reaction to become energetically favoured was that of a single proton and neutron comb
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1.6 The quark-lepton era (contd)

The next stage of the story is to look at how and when the original mixture of all types of quark and lepton that were present when the Universe was 10−11 s old, gave rise to the Universe today, which seems to be dominated by protons, neutrons and electrons.

Question 8

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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.


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Introduction

This unit explores origins of the Universe by looking in detail at events immediately following the Big Bang. Starting with looking at the cooling of the very early Universe, the unit then moves on to the inflation era, the quark-lepton and the hadron era. Then the unit looks at how fundamental particles began to synthesise to form nuclei, and from here it discusses the development of larger structures like stars and galaxies. By examining closely the forces in play and the interactions of fu
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