2.7 Summary

  1. Eukaryotic cells contain numerous distinct types of membrane-bound compartment. Transport vesicles move proteins and other molecules between the compartments.

  2. Proteins contain signalling sequences or patches that specify their destination compartment.

  3. Proteins destined for lysosomes, secretion or the plasma membrane are synthesised in the ER, transported to the cis Golgi, modified in the Golgi apparatus, and sorted and pa
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1.7 Localization of signalling proteins

Since signalling proteins cannot diffuse as rapidly as small second messengers, they need be close to their downstream target in order to be able to function. Where they are located with respect to both their subcellular position and their immediate neighbours is therefore vitally important. The plasma membrane is usually the initial location, and proteins can be attached to the plasma membrane in various ways (Author(s): The Open University

Learning outcomes

By the end of this unit you should be able to:

  • recognise the terminology which is used to describe the properties and behaviour of active galactic nuclei (AGN);

  • manipulate numbers, algebraic symbols and mathematical functions in equations.


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1.3.1 Inheritance of colour in maize

We can trace the inheritance of characters in animals and plants by following the phenotype from generation to generation, in breeding experiments. We will describe work with maize (Zea mays), alternatively called corn (sweetcorn, or corn on the cob), which occurs throughout the world as an extremely important commercial crop plant, and which is used extensively in genetic research. We can also study the inheritance of characters at the level of the genotype. In this section we will ju
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1.2 Like begets like

It is possible to follow a character, such as eye colour or hair colour in humans, that is handed down from generation to generation. Such characters are said to be inherited characters (or heritable characters) and are determined by genes. A gene can be considered as a unit of inheritance, which determines a particular character and which is passed on from parent to offspring.

Genes maintain the differences between species, such as oak and human, but they also contribute
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Learning outcomes

After studying this unit you should know:

  • the number of chromosomes is characteristic of each species and can vary enormously between species

  • genetics is based on the concept of the gene as the unit of inheritance

  • that sexual reproduction always includes two distinctive processes: the production of gametes, which involves meiosis, and fertilisation. The two processes are accompanied by changes in the chromosome number, from diploid to haploid and fr
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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 acknowledgement is made to the following sources for permission to reproduce material in this unit:

The content acknowledged be
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5.2 Madagascan diversity

Activity 7

Watch the video sequence below, which focuses on just three lemur species – the ring-tailed (in a very brief sequence, leaping from one tree to another), the golden bamboo lemur, already mentioned, and the sifaka, plus the
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4.2 Other members of the bear family

Other omnivorous species of bear include the Asian black bear, the North American black bear and the Andean spectacled bear. Although polar bears spend their winters hunting seals out on the Arctic sea-ice, they have to come ashore when the ice melts in spring and find other sources of food.

Activity 2
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3.3 Variation

Fossil rodents are first found in rocks that date from around 65 million years ago (from the Eocene) and are thought to have evolved from insectivore/omnivore-type mammals that lived 100 million years ago (in the Cretaceous period). To say that they evolved from simply means that there probably is a direct line of descent but that the descendants have changed from their forebears. One of the most significant ways that evolutionary change can be brought about is by a process known as na
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1 Overview

As you walk down the street one day, you hear a voice from somewhere behind you that seems to be discussing this unit. It says:

‘My dad's tutor's no joker, and he told me the TMA's going to hit home with a bang.’

You turn to find the face behind the voice, which is a gravelly Glaswegian baritone, but the man has gone, leaving you to ponder what he has said. Let us call his sentence exam
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2.2 Why study ecology?

These days, bird watching is a popular leisure activity and in the past so were collecting insects, wild flowers and birds’ eggs (although such activities are not now recommended – indeed, they are often illegal – because of the potential damage they cause to flora and fauna). Some amateurs are or were truly experts in their fields. In fact, much of the original identification of the British flora and fauna was done by amateur naturalists. Many a Victorian vicar or other self-taught nat
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1.5.2 Sedimentary processes

Sedimentary grains are formed when the rocks at the Earth's surface are slowly broken up physically by exposure to wind and frost, and decomposed (chemically) by rainwater or biological action. These processes are collectively termed weathering. Once a rock has been broken up by weathering, the small rock fragments and individual mineral grains can be eroded from their place of origin by water, wind or glaciers and transported to be deposited elsewhere as roughly horizontal layers of sediment
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1.4.4 O is for Objectivity

One of the characteristics of ‘good’ information is that it should be balanced and present both sides of an argument or issue. This way the reader is left to weigh up the evidence and make a decision. In reality, we recognise that no information is truly objective.

This means that the onus is on you, the reader, to develop a critical awareness of the positions represented in what you read, and to take account of this when you interpret the information. In some cases, authors may be
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13 Post-compulsory science education

In a speech to the Institute of Economic Affairs in 2001, the then UK Secretary of State for Education said:

Young people choosing vocational study will be able to see a ladder of progression that gives structure, purpose and expectation to their lives, in the same way that a future pathway is clear to those who leave school to gain academic A-levels and enter university. Over-16s in full-time education will be abl
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Europe and the law
This unit will give you a basic understanding of EU law and the interaction between EU and domestic law. It will provide a brief explanation of the European Convention on Human Rights and other European legislation, as well as the background to such institutions as the European Council, the European Commission, the European Parliament and the European Court of Justice. First publish
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1.2 The growth of the legal system

The legal system plays a significant and growing role in society as our lives become governed by an increasing number of laws. As our society has become more sophisticated, a greater number of laws have been required. This in turn has resulted in our legal system becoming increasingly more complex. Changes in technology, the way in which we live and the types of relationships we have are all reflected by the law. Society expects the law to reflect its ideas, values and culture, so the law has
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4.3 Summary of accurate law reporting

This section stressed the importance of accurate law reporting which allows for legal principles to be collated, identified and accessed. I examined where you might locate case reports on particular areas of the law. These are:

  • Year Books (1275–1535)

  • Private reports (1535–1865)

  • Modern reports (1865 to present)

  • The Law Reports

  • Weekly Law Reports (citation WLR)

  • All
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4.2.10 DVD-ROMs and internet facilities

As in most other fields, the growth of information technology has revolutionised law reporting and law finding. Many of the law reports mentioned above are available both on DVD-ROM and via the internet through legal databases such as Justis, Lawtel, Lexis-Nexis and Westlaw UK. Many such databases, however, require you to complete a registration process and there may be a charge for the service. Altrnatively they may be available, for free, to registered university or college students studyin
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1.4: Price ratios and price indices

Aims The main aim of this section is to look at some different ways of measuring price increases.

In this section you will be looking at measuring price changes using price indices. In order to do this you will need to understand the concept of a price ratio. Price ratios are another way of looking at price increases or decreases, related to the proportional and percentage increases and decreases you have seen before.


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