Bioknowledgy
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    • 1. Cell biology >
      • 1.1 Introduction to cells
      • 1.2 Ultrastructure of cells
      • 1.3 Membrane structure
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      • 1.5 The origin of cells
      • 1.6 Cell division
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      • 2.1 Molecules to metabolism
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      • 2.6 Structure of DNA and RNA
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  • Additional higher level (AHL)
    • 7. Nucleic acids >
      • 7.1 DNA structure and replication
      • 7.2 Transcription and gene expression
      • 7.3 Translation
    • 8. Metabolism, cell respiration and photosynthesis >
      • 8.1 Metabolism
      • 8.2 Cell respiration
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      • 9.1 Transport in the xylem of plants
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      • 10.1 Meiosis
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    • 11. Animal physiology >
      • 11.1 Antibody production and vaccination
      • 11.2 Movement
      • 11.3 The kidney and osmoregulation
      • 11.4 Sexual reproduction
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    • A. Neurobiology and behaviour >
      • A.1 Neural development
      • A.2 The human brain
      • A.3 Perception of stimuli
      • A.4 Innate and learned behaviour (AHL)
      • A.5 Neuropharmacology (AHL)
      • A.6 Ethology (AHL)
    • B. Biotechnology and bioinformatics
    • C. Ecology and conservation >
      • C.1 Species and communities
      • C.2 Communities and ecosystems
      • C.3 Impacts of humans on ecosystems
      • C.4 Conservation of biodiversity
      • C.5 Population ecology (AHL)
      • C.6 Nitrogen and phosphorus cycles (AHL)
    • D. Human physiology
  • Giving back - BioKQQAnswers

Essential idea: Information stored as a code in DNA is copied onto mRNA.

"The genetic code is frequently referred to as a blueprint because it contains the instructions a cell requires in order to sustain itself. We now know that there is more to these instructions than simply the sequence of letters in the nucleotide code, however. For example, vast amounts of evidence demonstrate that this code is the basis for the production of various molecules, including RNA and protein ... In transcription, a portion of the double-stranded DNA template gives rise to a single-stranded RNA molecule."
http://www.nature.com/scitable/topicpage/dna-transcription-426#
The image above shows how DNA is used as a template to create portable molecules of genetic code, i.e. mRNA, that can leave the nucleus for translation in other regions of the cell.

Understandings, applications and skills

7.2.U1 Transcription occurs in a 5’ to 3’ direction. [RNA polymerase adds the 5´ end of the free RNA nucleotide to the 3´ end of the growing mRNA molecule.]
7.2.U2 Nucleosomes help to regulate transcription in eukaryotes.
7.2.U3 Eukaryotic cells modify mRNA after transcription.
7.2.U4 Splicing of mRNA increases the number of different proteins an organism can produce.
7.2.U5 Gene expression is regulated by proteins that bind to specific base sequences in DNA.
7.2.U6 The environment of a cell and of an organism has an impact on gene expression.
7.2.A1 The promoter as an example of non-coding DNA with a function.
7.2.S1 Analysis of changes in the DNA methylation patterns.
[Text in square brackets indicates guidance notes]

Presentation and notes

The presentation is designed to help your understanding. The notes outline is intended to be used as a framework for the development of student notes to aid revision.
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Vocabulary

Correct use of terminology is a key skill in Biology. It is essential to use key terms correctly when communicating your understanding, particularly in assessments. Use the quizlet flashcards or other tools such as learn, scatter, space race, speller and test to help you master the vocabulary.
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Quick Quiz

Use the BioK quick quiz on 7.2 Transcription and gene expression (as directed) to check your understanding of the topic.

Weblinks

Transcription
Transcription by St. Olaf College

RNA Splicing
mRNA Splicing by Sumanas Inc
(contains more detail than you need)
3D Animation of RNA Splicing by the DNA Learning Center
RNA Splicing by McGraw and Hill (contains more detail than you need)
Alternative Splicing explained in this tutorial by Nobelprize.org
Nucleosomes and gene expression
Gene Control by Learn.Genetics


Epigenetics
Epigenetics resources from Learn.Genetics

Environment and gene expression

Coat color in the Himalayan rabbit by Cengage Learning

Nature of Science

Looking for patterns, trends and discrepancies—there is mounting evidence that the environment can trigger heritable changes in epigenetic factors. (3.1)

DNA and Genetics is fast evolving area of Biological research. One of the very interesting areas of current research is Epigenetics. How does this fit in with what you know about DNA and how is it contrary to accepted theory?

Learn more about Epigenetics by Learn.Genetics

Theory of knowledge

The nature versus nurture debate concerning the relative importance of an individual’s innate qualities versus those acquired through experiences is still under discussion. Is it important for science to attempt to answer this question?
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