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Edexcel International AS Level Biology revision notes

Short notes for every spec point. Pick a topic, then a note.

1

Molecules, Transport and Health

4 subtopics · 24 notes

Water, carbohydrates and lipids
  1. Subtopic overview: questions, flashcards and PDFs
  2. Water as a solvent in transport
  3. Monosaccharides, disaccharides and polysaccharides
  4. Glycosidic bonds: condensation and hydrolysis
  5. Core practical 1: Benedict’s reagent and iodine solution
  6. Triglycerides and ester bonds
  7. Saturated and unsaturated lipids
The heart, blood vessels and haemoglobin
  1. Subtopic overview: questions, flashcards and PDFs
  2. Why many animals have a heart and circulation
  3. Arteries, veins and capillaries
  4. Structure of the mammalian heart
  5. The cardiac cycle
  6. Haemoglobin and the transport of oxygen and carbon dioxide
  7. The oxygen dissociation curve, the Bohr effect and fetal haemoglobin
Cardiovascular disease and its causes
  1. Subtopic overview: questions, flashcards and PDFs
  2. Atherosclerosis
  3. Blood clotting and cardiovascular disease
  4. Risk factors for cardiovascular disease
  5. Dietary antioxidants and the risk of CVD
  6. Core practical 2: vitamin C content of food and drink
Health risks, evidence and treatment
  1. Subtopic overview: questions, flashcards and PDFs
  2. Analysing data on illness and mortality
  3. Evaluating the design of studies
  4. Perception of risk
  5. Blood cholesterol, HDL and LDL
  6. Evidence linking cholesterol and CVD
  7. Using scientific knowledge to reduce the risk of CHD
  8. Treatments for cardiovascular disease
All molecules, transport and health notes (PDF)Download all notes (PDF)28 pages
2

Membranes, Proteins, DNA and Gene Expression

4 subtopics · 27 notes

Gas exchange, membranes and transport
  1. Subtopic overview: questions, flashcards and PDFs
  2. Gas exchange surfaces and Fick's law
  3. The mammalian lung
  4. The structure and properties of cell membranes
  5. Models of membrane structure and the evidence for them
  6. Core practical 3: membrane permeability, alcohol and temperature
  7. Osmosis and water potential
  8. Passive transport: diffusion, facilitated diffusion, channel and carrier proteins
  9. Active transport, endocytosis and exocytosis
Proteins and enzymes
  1. Subtopic overview: questions, flashcards and PDFs
  2. Amino acids, peptide bonds and polypeptides
  3. Levels of protein structure and the bonds involved
  4. Globular and fibrous proteins: haemoglobin and collagen
  5. Enzymes: mode of action and specificity
  6. Factors affecting the rate of enzyme-catalysed reactions
  7. Core practical 4: the initial rate of enzyme-catalysed reactions
DNA, the genetic code and gene expression
  1. Subtopic overview: questions, flashcards and PDFs
  2. The structure of mononucleotides, DNA and RNA
  3. DNA replication and the role of DNA polymerase
  4. The Meselson–Stahl experiment
  5. The genetic code and the gene
  6. Transcription
  7. Translation, tRNA and ribosomes
  8. Gene mutations
Inheritance, cystic fibrosis and genetic screening
  1. Subtopic overview: questions, flashcards and PDFs
  2. Genetic terms
  3. Monohybrid inheritance and pedigree diagrams
  4. Sex linkage and red-green colour blindness
  5. Cystic fibrosis
  6. Genetic screening: carriers, PGD and prenatal testing
  7. Ethical and social issues of genetic screening
All membranes, proteins, dna and gene expression notes (PDF)Download all notes (PDF)42 pages
3

Cell Structure, Reproduction and Development

5 subtopics · 23 notes

Cells, tissues and organelles
  1. Subtopic overview: questions, flashcards and PDFs
  2. Features common to all living cells
  3. Tissues, organs and organ systems
  4. Ultrastructure of eukaryotic cells
  5. Protein transport and extracellular enzymes
  6. Ultrastructure of prokaryotic cells
  7. Recognising organelles in electron micrographs
Microscopy and measuring cells
  1. Subtopic overview: questions, flashcards and PDFs
  2. Magnification and resolution
  3. Staining specimens
  4. Core Practical 5: observing, drawing and measuring cells
Chromosomes, meiosis and gametes
  1. Subtopic overview: questions, flashcards and PDFs
  2. Gene loci and linkage
  3. Meiosis and genetic variation
  4. Specialised mammalian gametes
  5. Fertilisation in mammals
  6. Fertilisation in flowering plants
Mitosis and the cell cycle
  1. Subtopic overview: questions, flashcards and PDFs
  2. The cell cycle and mitosis
  3. Core Practical 6: root tip squash
  4. Calculating the mitotic index
Stem cells, gene expression and phenotype
  1. Subtopic overview: questions, flashcards and PDFs
  2. Stem cells and potency
  3. Using stem cells in medical therapies
  4. Differential gene expression and specialisation
  5. One gene, more than one protein
  6. Genotype, environment and epigenetics
  7. Multiple alleles, polygenic inheritance and variation
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4

Plant Structure and Function, Biodiversity and Conservation

5 subtopics · 20 notes

Plant cells and cell walls
  1. Subtopic overview: questions, flashcards and PDFs
  2. Plant cell ultrastructure and its functions
  3. Starch and cellulose
  4. Cell wall structure, secondary thickening and plant fibres
Plant tissues, fibres and mineral nutrition
  1. Subtopic overview: questions, flashcards and PDFs
  2. Sclerenchyma fibres, xylem vessels and phloem
  3. Core practical 7: plant tissues under the light microscope
  4. Plant fibres, starch and sustainability
  5. Water and inorganic ions in plants
  6. Core practical 8: tensile strength of plant fibres
Bacterial growth, plant medicines and drug testing
  1. Subtopic overview: questions, flashcards and PDFs
  2. Conditions required for bacterial growth
  3. Antimicrobial and therapeutic substances from plants
  4. Core practical 9: antimicrobial properties of plants and aseptic technique
  5. The development of drug testing
Classification and biodiversity
  1. Subtopic overview: questions, flashcards and PDFs
  2. Classification and the three-domain system
  3. Biodiversity, endemism and human threats
  4. Measuring biodiversity: species richness and heterozygosity index
  5. Comparing habitats: index of diversity (D)
Niche, allele frequency and conservation
  1. Subtopic overview: questions, flashcards and PDFs
  2. Niche and adaptations to the environment
  3. The Hardy-Weinberg equation, mutation and natural selection
  4. Reproductive isolation and the formation of new species
  5. Evaluating zoos and seed banks in conservation
All plant structure and function, biodiversity and conservation notes (PDF)Download all notes (PDF)32 pages