Bioknowledgy
questioning, investigating and understanding
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    • About
  • IB Biology
    • Syllabus
    • General Resources
    • Practical scheme of work >
      • Practical activities (Labs)
      • Individual investigation
      • IB Write
  • Core
    • 1. Cell biology >
      • 1.1 Introduction to cells
      • 1.2 Ultrastructure of cells
      • 1.3 Membrane structure
      • 1.4 Membrane transport
      • 1.5 The origin of cells
      • 1.6 Cell division
    • 2. Molecular biology >
      • 2.1 Molecules to metabolism
      • 2.2 Water
      • 2.3 Carbohydrates and lipids
      • 2.4 Proteins
      • 2.5 Enzymes
      • 2.6 Structure of DNA and RNA
      • 2.7 DNA replication, transcription and translation
      • 2.8 Cell respiration
      • 2.9 Photosynthesis
    • 3. Genetics >
      • 3.1 Genes
      • 3.2 Chromosomes
      • 3.3 Meiosis
      • 3.4 Inheritance
      • 3.5 Genetic modification and biotechnology
    • 4. Ecology >
      • 4.1 Species, communities and ecosystems
      • 4.2 Energy flow
      • 4.3 Carbon cycling
      • 4.4 Climate change
    • 5. Evolution and biodiversity >
      • 5.1 Evidence for evolution
      • 5.2 Natural selection
      • 5.3 Classification of biodiversity
      • 5.4 Cladistics
    • 6. Human physiology >
      • 6.1 Digestion and absorption
      • 6.2 The blood system
      • 6.3 Defence against infectious disease
      • 6.4 Gas exchange
      • 6.5 Neurons and synapses
      • 6.6 Hormones, homeostasis and reproduction
  • 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
      • 8.3 Photosynthesis
    • 9. Plant biology >
      • 9.1 Transport in the xylem of plants
      • 9.2 Transport in the phloem of plants
      • 9.3 Growth in plants
      • 9.4 Reproduction in plants
    • 10. Genetics and evolution >
      • 10.1 Meiosis
      • 10.2 Inheritance
      • 10.3 Gene pools and speciation
    • 11. Animal physiology >
      • 11.1 Antibody production and vaccination
      • 11.2 Movement
      • 11.3 The kidney and osmoregulation
      • 11.4 Sexual reproduction
  • Options
    • 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: There is an unbroken chain of life from the first cells on Earth to all cells in organisms alive today.

Above you can see fossilised images of cells. We know from such evidence that cells have always worked using the same basic principles.

Understandings, applications and skills:

1.5.U1 Cells can only be formed by division of pre-existing cells. [Students should be aware that the 64 codons in the genetic code have the same meanings in nearly all organisms, but that there are some minor variations that are likely to have accrued since the common origin of life on Earth.]
1.5.U2 The first cells must have arisen from non-living material.
1.5.U3 The origin of eukaryotic cells can be explained by the endosymbiotic theory. [Evidence for the endosymbiotic theory is expected. The origin of eukaryote cilia and flagella does not need to be included.]
1.5.A1 Evidence from Pasteur’s experiments that spontaneous generation of cells and organisms does not now occur on Earth.
[Text in square brackets indicates guidance notes]

Starters

This series of short programs considers the origin of life. If you enjoy the first episode watch episodes two and three to continue to increase your understanding.

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.
​Download presentation

 
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.
Download notes


Quick quiz

Quick quiz Use the BioK Quick Quiz on 1.5 The origin of cells  (as directed) to check your understanding of the topic.

Weblinks

Evidence against spontaneous generation
Science as a process: arriving at scientific insights by Sumanas Inc. looks at Pasteur's experiments

Rejecting spontaneous generation a simulated lab by PH School
​
Evolution of the first cells
Learn about the Miller-Urey experiment from Stanley Miller himself.
The origin of complex life: it was all about energy by Ed Yong

Endosymbiosis
The evolution of organelles by Sunamas Inc.
Endosymbiosis by McGraw and Hill
Evolution of the cell by learn.genetics

Nature of science:

Testing the general principles that underlie the natural world - the principle that cells only come from pre-existing cells needs to be verified. (1.9)

Theory of knowledge:

Biology is the study of life, yet life is an emergent property. Under what circumstances is a systems approach productive in biology and under what circumstances is a reductionist approach more appropriate? How do scientists decide between competing approaches?

This Science 2.0 article
Reductionism And Systems Thinking: Complementary Scientific Lenses is a good accessible read on how systems thinking complements the more traditional reductionist approach
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