A Level Biology 9700 lectures
56 short lectures, one for each part of the syllabus, in the order it is taught. Each one teaches a topic on the board in a few minutes. The teaching part is free to watch; a free account opens the rest of every lecture: worked examples, practice questions and real past-paper questions answered.
Chapter 1 Cell structure
Chapter 2 Biological molecules
- Monomers, sugars and Benedict's testBig biological molecules are built like a Lego model.6 min
- Polysaccharides, lipids and waterA plant needs to store energy, build a strong wall, keep cell membranes together and move materials around.6 min
- Amino acids, protein structure, haemoglobin and collagenOnly twenty different amino acids build every protein in your body.6 min
Chapter 3 Enzymes
- Enzyme action, the factors and progress curvesSugar can sit in a bowl for years without turning into carbon dioxide.6 min
- Enzyme inhibitors, Vmax and KmMany drugs and poisons work by switching off one enzyme.6 min
- Immobilised enzymes and where enzymes workMaking lactose free milk needs an enzyme called lactase.6 min
Chapter 4 Cell membranes and transport
Chapter 5 The mitotic cell cycle
Chapter 6 Nucleic acids and protein synthesis
- DNA, RNA, ATP and the genetic codeA whole human being is described using just four letters.6 min
- DNA replication and gene mutationsBefore a cell divides, it must copy three billion base pairs.5 min
- Transcription, RNA processing and translationThe D N A never leaves the nucleus, yet its instructions end up building proteins out in the cytoplasm.6 min
Chapter 7 Transport in plants
Chapter 8 Transport in mammals
- The heart, double circulation and the heartbeatYour heart beats about seventy times a minute, every minute, for your whole life.5 min
- The cardiac cycle and blood cellsIn less than a second, your heart fills, squeezes and relaxes.5 min
- Blood vessels, tissue fluid and lymphBlood leaves the heart through arteries, travels through tiny capillaries, and returns in veins.6 min
- The oxygen dissociation curve, the Bohr shift and carbon dioxide transportHaemoglobin has a hard job.6 min
Chapter 9 Gas exchange
Chapter 10 Infectious diseases
Chapter 11 Immunity
Chapter 12 Energy and respiration
- ATP, coenzymes and glycolysisA cell cannot spend glucose directly.6 min
- The link reaction, Krebs cycle and oxidative phosphorylationAfter glycolysis, the pyruvate has only released a small part of the energy in glucose.6 min
- Anaerobic respiration, RQ and riceA sprinter, a diving seal and a rice plant with its roots under water all share one problem.6 min
- Respirometers and redox indicatorsYou cannot watch respiration happen.5 min
Chapter 13 Photosynthesis
Chapter 14 Homeostasis
Chapter 15 Coordination
- Stomata, auxin and gibberellinA plant cannot run from drought or reach for light with a muscle.6 min
- Receptors, neurones and the Venus fly trapYou pull your hand away from a hot pan before you even feel the pain.6 min
- Resting potential, action potentials and myelinA nerve impulse is not electricity flowing down a wire.6 min
- Cholinergic synapses, drugs and toxinsAn action potential cannot jump from one neurone to the next, because there is a tiny gap between them.6 min
- The endocrine system compared with the nervous systemYour body has two long distance messaging systems.6 min
- Striated muscle and the sliding filament modelWhen you bend your arm, no filament shortens.5 min
Chapter 16 Inheritance
- Meiosis and how genes make phenotypesA human cell has forty-six chromosomes, but a sperm or an egg must have only twenty-three.5 min
- Monohybrid crosses, codominance and sex linkageTwo brown eyed parents can have a blue eyed child.5 min
- Dihybrid crosses, linkage and epistasisMendel did not stop at one gene.6 min
- The chi-squared test and the gibberellin geneA genetic cross gives results that are close to the expected ratio, but never exactly on it.5 min
- The lac operon and transcription factorsEvery cell in your body has the same D N A, yet a muscle cell and a nerve cell are very different.6 min
Chapter 17 Selection and evolution
- Variation, the t-test and natural selectionLook around a classroom: no two people are the same height.6 min
- Types of selection, selective breeding and antibiotic resistanceImagine the beak sizes in a population of finches plotted as a bell shaped curve.6 min
- Genetic drift, Hardy-Weinberg and molecular evidenceNatural selection is not the only thing that changes a population's alleles.6 min
- Speciation and species conceptsBiologists name over a million species, yet they argue about what a species actually is.6 min
Chapter 18 Classification, biodiversity and conservation
- Classification, the three domains and the kingdomsThere are millions of species, and biologists need a way to talk about them all.6 min
- Sampling, biodiversity and Simpson's indexYou cannot count every frog in a rainforest, or every plant in a meadow.6 min
- Threats, conservation, invasive species and assisted reproductionSpecies have always gone extinct, but humans are now speeding the rate up enormously.6 min
Chapter 19 Genetic technology
- Genetic engineering tools, recombinant proteins and GM organismsGenetic engineers work like molecular editors.7 min
- PCR, gel electrophoresis and genetic screeningA crime scene yields a speck of blood, far too little D N A to analyse.7 min
- Gene therapy, gene editing, microarrays and bioinformaticsMost medicines treat symptoms.7 min
Also for A Level Biology 9700
Which topics come up most in A Level Biology 9700 past papers, counted from every paper since 2004: Paper 1 topic frequency, Paper 2 topic frequency, Paper 4 topic frequency.