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Edexcel International AS Level Biology, topic 2

Membranes, Proteins, DNA and Gene Expression

Membranes, Proteins, DNA and Gene Expression is topic 2 of Pearson Edexcel International AS / A Level Biology (XBI11 / YBI11) and is examined in Unit 1. It covers gas exchange surfaces and the lung, membrane structure and transport, proteins and enzymes, DNA and protein synthesis, and inheritance, cystic fibrosis and genetic screening. It includes core practical 3 (membrane permeability) and core practical 4 (the initial rate of enzyme-catalysed reactions).

Subtopics

Work through them in order. Each one has notes, exam questions and flashcards, and a PDF of each.

  1. 1Gas exchange, membranes and transport Spec 2.1–2.5Gas exchange surfaces and Fick's law, the mammalian lung, membrane structure, osmosis and the ways substances cross membranes.NotesQuestions 8Flashcards 23
    1. Gas exchange surfaces and Fick's law
    2. The mammalian lung
    3. The structure and properties of cell membranes
    4. Models of membrane structure and the evidence for them
    5. Core practical 3: membrane permeability, alcohol and temperature
    6. Osmosis and water potential
    7. Passive transport: diffusion, facilitated diffusion, channel and carrier proteins
    8. Active transport, endocytosis and exocytosis
  2. 2Proteins and enzymes Spec 2.6–2.8Amino acids, peptide bonds and protein structure; globular and fibrous proteins; how enzymes work and the factors that change their rate.NotesQuestions 8Flashcards 18
    1. Amino acids, peptide bonds and polypeptides
    2. Levels of protein structure and the bonds involved
    3. Globular and fibrous proteins: haemoglobin and collagen
    4. Enzymes: mode of action and specificity
    5. Factors affecting the rate of enzyme-catalysed reactions
    6. Core practical 4: the initial rate of enzyme-catalysed reactions
  3. 3DNA, the genetic code and gene expression Spec 2.9–2.14The structure of DNA and RNA, semi-conservative replication, the genetic code, transcription, translation and gene mutations.NotesQuestions 8Flashcards 23
    1. The structure of mononucleotides, DNA and RNA
    2. DNA replication and the role of DNA polymerase
    3. The Meselson–Stahl experiment
    4. The genetic code and the gene
    5. Transcription
    6. Translation, tRNA and ribosomes
    7. Gene mutations
  4. 4Inheritance, cystic fibrosis and genetic screening Spec 2.15–2.18Genetic terms, monohybrid inheritance, pedigrees and sex linkage, the effects of cystic fibrosis, genetic screening and the ethical issues it raises.NotesQuestions 7Flashcards 20
    1. Genetic terms
    2. Monohybrid inheritance and pedigree diagrams
    3. Sex linkage and red-green colour blindness
    4. Cystic fibrosis
    5. Genetic screening: carriers, PGD and prenatal testing
    6. Ethical and social issues of genetic screening

Whole topic

When you have done the subtopics: test yourself on everything, or print the lot.

Revision notesAll revision notesEvery subtopic in one PDF · 42 pagesDownload PDFWorksheetTopic testAll 31 questions (107 marks) with the mark scheme · 18 pagesDownload PDF
FlashcardsAll flashcards84 cards from every subtopicPractisePrint
Mind mapMind mapThe whole topic on one pageViewPDF