France Terminale STL (laboratory sciences) — Terminale specialties

Chapters: 11

1. Physics-chemistry: Matter and its transformations

Spatial structure of molecules · Acid–base reactions · Redox reactions · Reaction kinetics · Radioactivity

Stereochemistry: Chirality, R/S and Z/E – Stereochemistry studies how atoms sit in 3D space. A carbon with four different groups is chiral and has a non-overlapping mirror image (enantiomer). CIP rules rank groups by atomic number; with the lowest priority pointing away, 1 to 2 to 3 clockwise is R and anticlockwise is S. Around a double bond, the higher-priority groups on the same side give Z, on opposite sides E.
Acids and Bases: Properties, Indicators and Reactions – An acid gives H⁺ ions in water and a base gives OH⁻ ions. Indicators show which one is present by a colour or smell change, and when H⁺ meets OH⁻ they make water, leaving a salt behind.
Redox Reactions: From Oxygen to Electron Transfer – Oxidation first meant adding oxygen or removing hydrogen. Reduction meant the opposite. Today we use a bigger idea: oxidation is losing electrons and reduction is gaining electrons. Both always happen together, so we call them redox reactions. A more active metal gives electrons to the ion of a less active metal.
Rate of a Chemical Reaction – The rate of a reaction tells how fast a reactant is used up or a product is made, per unit time. Rate = −Δ[R]/Δt = +Δ[P]/Δt (unit mol L⁻¹ s⁻¹). The rate law, rate = k[A]^x[B]^y, is found by experiment; x + y is the order. Molecularity is the number of particles that collide in one elementary step.
Radioactivity: Alpha, Beta, Gamma and Half-Life – Some atomic nuclei are unstable. They give out radiation at random to become more stable. This is radioactive decay. Alpha (2 protons + 2 neutrons), beta (a fast electron) and gamma (a wave of energy) are the three main kinds. Half-life is the time for half of the unstable nuclei to decay.

2. Physics-chemistry: Motion and interactions

Motion · Interactions

Motion: Distance, Speed, Velocity, Acceleration and Graphs – An object is in motion when its position changes with time. Distance is the full path length (a scalar); displacement is the straight gap from start to finish with a direction (a vector). Speed = distance ÷ time; velocity = displacement ÷ time. Acceleration = change in velocity ÷ time. The slope of an s–t graph gives velocity, the slope of a v–t graph gives acceleration, and the area under a v–t graph gives the distance. For uniform acceleration: v = u + at, s = ut + ½at², v² = u² + 2as.
Force and Laws of Motion – A force is a push or a pull. Balanced forces (net force zero) do not change motion; an unbalanced force changes speed or direction. Friction opposes sliding. First law: a body keeps its state of rest or uniform motion unless an unbalanced force acts (inertia; heavier bodies have more inertia). Momentum p = mv. Second law: F = ma (rate of change of momentum), 1 N = 1 kg m/s². Third law: forces come in equal and opposite pairs acting on two different bodies. For a system with no outside force, internal forces cancel and total momentum is conserved.

3. Physics-chemistry: Energy conversions and transfers

Energy and its challenges · Mechanical energy · Chemical energy · Electrical energy · Energy and waves

Work, Energy and Power – Work is done when a force moves an object: W = F × s, measured in joules (J). Energy is the ability to do work. A moving body has kinetic energy ½mv²; a raised body has potential energy mgh. Energy is never made or destroyed, only changed from one form to another. Power is how fast work is done: P = W ÷ t, in watts. Simple machines like levers and pulleys let a small effort move a big load.
First Law of Thermodynamics – Internal energy U is the total energy of the molecules inside a system. It changes in only two ways: by heat Q (energy that flows because of a temperature difference) and by work W (energy moved by a force, like a moving piston). First law: ΔQ = ΔU + ΔW. Heat given to a gas partly raises its internal energy and partly lets it do work. Work by a gas at constant pressure is PΔV. For an ideal gas Cp − Cv = R.
Electric Current, Potential Difference and Electric Circuits – Electric current is the rate of flow of charge, I = Q/t, measured in amperes with an ammeter joined in series. Potential difference is the work done to move a unit charge between two points, V = W/Q, measured in volts with a voltmeter joined in parallel. Charge flows only in a closed circuit.
Electromagnetic Waves – A changing electric field acts like a current, called the displacement current, and it makes a magnetic field. A changing magnetic field makes an electric field. Together they travel as an electromagnetic (EM) wave at c = 3 × 10⁸ m/s, even through empty space. E and B are at right angles to each other and to the direction of travel, so EM waves are transverse. Sorted by wavelength, they form the spectrum: radio, microwave, infrared, visible, ultraviolet, X-rays and gamma rays.

4. Mathematics

Integration · Exponential function · Natural logarithm · Differential equations · Composition of functions

Integrals – Integration undoes differentiation: if F′(x) = f(x), then ∫f(x) dx = F(x) + C. We integrate with standard formulas, substitution (replace an inside part by u), partial fractions (split a fraction) and by parts (∫u dv = uv − ∫v du). A definite integral ∫ₐᵇ f(x) dx is the signed area under the curve from a to b, and the fundamental theorem says it equals F(b) − F(a). Its properties make many hard integrals easy.
Exponential Functions – An exponential function has the form y = a·bˣ, where a ≠ 0 is the starting value and b > 0, b ≠ 1 is the growth factor. If b > 1 it grows; if 0 < b < 1 it decays. Each step of 1 in x multiplies y by b (a constant ratio), unlike a linear function which adds a constant. The graph of y = bˣ passes through (0, 1), has domain all real numbers, range y > 0, and the x-axis as a horizontal asymptote. The general form y = a·b^(k(x − d)) + c stretches, reflects and shifts it.
Logarithms – A logarithm tells you the power you need. log_b x = y means b^y = x. So log₂ 8 = 3 because 2³ = 8. Logs turn multiplying into adding: log(ab) = log a + log b, log(a/b) = log a − log b, log(aⁿ) = n log a. Base 10 is the common log, base e is the natural log (ln). Any base can be changed: log_b x = log x ÷ log b.
Differential Equations – A differential equation connects a function y with its derivatives. Its order is the highest derivative present and its degree is the power of that derivative (when the equation is a polynomial in derivatives). A general solution has arbitrary constants; a condition like y(0) = 1 fixes them to give a particular solution. Class 12 solves first-order equations of three kinds: variables separable, homogeneous (put y = vx) and linear dy/dx + Py = Q (multiply by the integrating factor e^∫P dx).
Functions: Composite, Inverse and Standard Graphs – A function is a rule that gives exactly one output for each allowed input. The allowed inputs are the domain; the outputs are the range. Two functions can be joined: g(f(x)) means do f first, then g. An inverse function f⁻¹ undoes f, and its graph is the mirror image of the graph of f in the line y = x. Only one-to-one functions have an inverse.

5. Part S: scientific concepts

Enzymes and metabolic pathways · Cellular and molecular immunity · DNA properties and replication · Microorganisms and biotech applications

Metabolism: How Cells Build, Break and Use Energy – Metabolism is the full set of chemical reactions inside a living thing. Breaking big molecules into small ones is catabolism; it gives out energy. Building big molecules from small ones is anabolism; it uses energy. ATP carries the energy between the two, like a rechargeable battery. Each reaction is sped up by its own enzyme, and the reactions link into chains called metabolic pathways.
Human Health and Disease – Health means the body, mind and social life all work well. Diseases can be caused by germs (pathogens) like bacteria, viruses, protozoa, worms and fungi. Our body fights them with two kinds of immunity: innate (we are born with it) and acquired (it learns and remembers). Vaccines use this memory. HIV destroys helper T cells and causes AIDS. Cancer is cells dividing without control. Drugs and alcohol harm the body and mind, especially in teenagers.
Molecular Basis of Inheritance – DNA is the genetic material in most living things (some viruses use RNA). It is a double helix: two antiparallel strands of nucleotides, A pairs with T by 2 hydrogen bonds and G with C by 3. Long DNA is packed on histones into nucleosomes and then chromatin. DNA copies itself semi-conservatively (Meselson–Stahl). The central dogma says DNA → RNA → protein. Transcription makes RNA from one strand; in eukaryotes the hnRNA is capped, tailed and spliced. The genetic code is a triplet, has 64 codons (61 for amino acids, 3 stops), starts with AUG, is nearly universal and degenerate. Ribosomes translate mRNA into protein with tRNA adaptors. Genes are switched on and off; the lac operon is the classic example. The Human and Rice Genome Projects read whole genomes, and DNA fingerprinting uses repeat DNA (VNTRs) to identify people.
Microbes in Human Welfare – Microbes are tiny living things: bacteria, fungi, some protozoa, algae and viruses. Many of them help us. They turn milk into curd, make dough rise, and produce drinks, acids, enzymes and medicines in big factories. They clean sewage, make biogas fuel, kill crop pests safely and add nutrients to soil. Antibiotics like penicillin come from microbes, but we must use them carefully so germs do not become resistant.

6. Part T: experimental technology

Observing living diversity · Culturing and controlling microbial growth · Identifying microorganisms · Counting microorganisms · Preparing lab solutions · Detecting biomolecules · Extracting and purifying · Assaying biomolecules · DNA technologies · Plant cell technologies

Microorganisms: The Tiny Living Things All Around Us – Microorganisms (microbes) are living things too small to see without a microscope. The main groups are bacteria, fungi, protozoa and algae; viruses are also studied with them but are not cells. Bacteria have no nucleus (prokaryotes); the others have one (eukaryotes). Bacteria multiply by splitting in two, so their number doubles again and again. Most microbes are harmless or helpful: our gut microbiota helps digestion, microbes make curd and bread, recycle dead matter and fix nitrogen. A few are pathogens that cause disease. Antibiotics kill bacteria but not viruses, and misusing them breeds resistant bacteria.
Microbiology: How to Grow, Identify and Count Microbes – In a microbiology lab we grow microbes on agar, choose the one we want with a selective medium, test drugs on them (antibiogram), identify them by shape, Gram stain and metabolic tests, and count them by microscope or by plate count (CFU/mL = colonies × dilution factor ÷ volume plated).
Solutions: Types, Concentration and Henry's Law – A solution is an even mix of two or more substances. The part in bigger amount is the solvent, the smaller part is the solute. We tell 'how strong' a solution is with concentration terms: mass %, volume %, ppm, mole fraction, molarity (per litre of solution) and molality (per kg of solvent). Solids usually dissolve more when hot. Gases dissolve more when their pressure is high (Henry's law, p = KH·x) and less when it is hot.
Biomolecules – A cell is mostly water, plus four big families of carbon compounds: proteins, carbohydrates, lipids and nucleic acids. Grinding tissue in acid separates small molecules (acid-soluble pool) from big ones – proteins, polysaccharides and nucleic acids (acid-insoluble pool). Proteins are chains of amino acids folded into four levels of structure. Polysaccharides are chains of sugars; lipids are fatty acids on glycerol; nucleic acids are chains of nucleotides. Enzymes are protein catalysts that bind a substrate at the active site, lower the activation energy, and are affected by temperature, pH, substrate level and inhibitors.
Purification and Analysis of Organic Compounds – A compound made in a lab or taken from a plant is never pure at first. We purify it by using a difference in properties: solubility (crystallisation), boiling point (distillation and its types), sublimation, solubility in two liquids (differential extraction) or how strongly it sticks to a surface (chromatography). A pure solid has a sharp melting point. Next we find which elements are present (qualitative analysis): carbon and hydrogen by heating with copper(II) oxide, and N, S, halogens and P by Lassaigne's sodium fusion test. Finally we find how much of each element is present (quantitative analysis): Liebig's method for C and H, Dumas and Kjeldahl methods for N, Carius method for halogens and S, and oxygen by difference. From the percentages we can get the empirical formula.
Enzymes – Enzymes are proteins that act as biological catalysts: they speed up reactions in cells without being used up. Each enzyme has an active site that fits only one kind of substrate (specificity). Enzymes work by lowering the activation energy. They work best at an optimum temperature and pH; too much heat or the wrong pH changes the active site's shape and denatures them.
Biotechnology: Principles and Processes (Recombinant DNA Technology) – Genetic engineering means changing the genes of a living thing on purpose. We cut the gene we want with restriction enzymes (molecular scissors), paste it into a carrier DNA called a vector using DNA ligase (molecular glue), put it into a host cell, pick out the cells that took it, and grow them in big tanks (bioreactors) to collect the product. PCR makes millions of copies of a gene, and gel electrophoresis sorts DNA pieces by size.
Plant Tissue Culture: Growing Many Plants From a Tiny Piece – Plant tissue culture means growing plant cells, tissues or organs on a clean jelly food in a closed glass jar. A tiny piece of the plant (the explant) is cleaned and placed on a medium with sugar, salts, vitamins and plant hormones. Its cells divide into a soft lump called callus. The hormone mix decides whether shoots or roots grow. Each new shoot can be cut and grown again, so one piece gives thousands of identical plants. This is micropropagation.

7. Part L: working together in the lab

Project approach in biotechnology · Lab risk prevention · Reliable measurement results · Digital tools in biotechnology

Project Management – A project is a one-time piece of work with a clear goal, a start and an end. Project management means planning and controlling it so it meets its scope on time and within cost. The life cycle runs initiate, plan, execute, monitor and close. Planners break the work into tasks (WBS), place them on a Gantt chart, find the critical path, manage risks and review lessons learned at the end.
Lab Safety and Safe Experiments – Dress for safety (goggles, coat, closed shoes, hair tied). Read labels and hazard pictograms. Heat gently with the mouth of the tube pointing away. Add acid to water, waft smells, never taste. Report every accident at once. Plan experiments step by step, assess the risks first and dispose of waste correctly.
Matter and Its Measurement – Matter is anything that has mass and takes up space. It can be solid, liquid or gas, and it can be an element, a compound or a mixture. Chemists measure matter in SI units. Every measurement has some doubt, so we write it with the right number of significant figures, use scientific notation for very big or small numbers, and change units with conversion factors.
Bioinformatics: Computers in Biology – Bioinformatics uses computers to store, search and compare biological data. Lab results go into spreadsheets; DNA and protein sequences go into online databases; alignment tools compare sequences to find matches, differences (like SNPs) and relatives; image software measures what a microscope camera sees. Data about people must be kept private and used fairly.

8. Lab sciences: Chemistry and sustainable development

Composition of chemical systems · Synthesis: macroscopic aspects · Synthesis: reaction mechanisms

Titration: Finding an Unknown Concentration – Titration finds the unknown concentration of a solution. A solution of known concentration (the titrant) is added slowly from a burette to a measured volume of the unknown (the analyte) until the reaction is just complete. An indicator or a meter shows this point. At the equivalence point the moles react in the ratio of the equation, so for a 1 : 1 reaction C₁V₁ = C₂V₂.
Carbon and Its Compounds: Bonding, Hydrocarbons and Naming – Carbon has 4 outer electrons, so it shares electrons (covalent bonds) instead of gaining or losing them. Because it bonds to itself (catenation) and always makes 4 bonds (tetravalency), it forms millions of compounds: chains, branches and rings, saturated or unsaturated. Compounds with the same functional group form a homologous series that differs by –CH₂–, and IUPAC names are built from the number of carbons + a suffix or prefix for the functional group.
Basics of Organic Reaction Mechanism – A reaction mechanism is the step-by-step story of which bonds break, which form, and where the electrons move. A covalent bond can break in two ways. In homolysis each atom takes one electron and free radicals form. In heterolysis one atom takes both electrons, giving a carbocation (C with + charge) and a carbanion or an anion. Electron-poor species that seek electrons are electrophiles; electron-rich species that give electrons are nucleophiles. The movement of electrons inside a molecule is controlled by four effects: the inductive effect (pull along σ bonds), the resonance effect (spreading of π electrons), the electromeric effect (a temporary full shift when a reagent attacks) and hyperconjugation (σ C–H electrons spreading into a nearby empty p orbital or π bond). These effects decide how stable an intermediate is and where a reagent attacks.

9. Lab sciences: Waves

Mechanical and electromagnetic waves · Waves for measuring · Waves for observing · Transmitting, storing and displaying

Simple Harmonic Motion (SHM) – A motion that repeats after a fixed time is periodic. If the object goes to and fro about a middle point and the force pulling it back is proportional to its distance from the middle (F = −kx), the motion is simple harmonic. Its position is x = A sin(ωt + φ), with ω = 2π/T = 2πf. Speed is largest in the middle, acceleration is largest at the ends, and total energy ½kA² stays constant.
Refraction of Light: Laws, Refractive Index and the Glass Slab – Light changes speed when it goes from one transparent medium to another, and so it bends at the boundary (unless it hits along the normal). Going into an optically denser medium it slows down and bends toward the normal; coming out it speeds up and bends away. For a pair of media, sin i / sin r stays constant (Snell's law); this constant is the refractive index, which also equals the ratio of the speeds of light, n = c/v. In a rectangular glass slab the emergent ray is parallel to the incident ray but shifted sideways (lateral displacement).
Spherical Lenses: Images, Lens Formula and Power – A convex lens is thick in the middle and bends parallel light to meet at its focus; a concave lens is thin in the middle and spreads light out as if from its focus. With two simple rays (one parallel to the axis, one through the optical centre) you can find the image for any object position. A convex lens gives real, inverted images when the object is beyond F₁ and a virtual, erect, enlarged image inside F₁; a concave lens always gives a virtual, erect, diminished image. The lens formula 1/v − 1/u = 1/f, magnification m = v/u and power P = 1/f (in metres, unit dioptre) let you solve lens numericals.
Data Representation: How Computers Store Numbers, Text, Images and Sound – Data is raw facts; information is data given meaning; knowledge is information we can use. A computer stores all data as bits (0 or 1). 8 bits make a byte, and 1 kB = 1000 bytes, 1 MB = 1000 kB, 1 GB = 1000 MB, 1 TB = 1000 GB. Numbers are stored in binary, where place values double: 1, 2, 4, 8 and so on. Text uses a character set: in ASCII 'A' is 65; Unicode covers every script. A bitmap image is a grid of pixels; size = width × height × colour depth. Sound is sampled: size = sample rate × bit depth × seconds. Vector images store shapes instead of pixels. Compression makes files smaller: lossless keeps every bit, lossy throws some detail away.

10. Lab sciences: Systems and processes

Information flow and control · Energy flow conversions · Matter flow transport

Control Systems and Feedback – A control system makes a machine or process behave the way we want. Every system has input → process (controller) → output. In an open-loop system the controller does not check the result (a toaster on a timer). In a closed-loop system a sensor measures the output and feeds it back; the controller compares it with the set point and corrects the error (a thermostat, cruise control). Real systems are built from sensors, a controller (electronic circuit, microcontroller or PLC) and actuators (motors, heaters, valves, pneumatic cylinders). Many are now networked (IoT, SCADA) so they can be watched and controlled from far away.
First Law of Thermodynamics – Internal energy U is the total energy of the molecules inside a system. It changes in only two ways: by heat Q (energy that flows because of a temperature difference) and by work W (energy moved by a force, like a moving piston). First law: ΔQ = ΔU + ΔW. Heat given to a gas partly raises its internal energy and partly lets it do work. Work by a gas at constant pressure is PΔV. For an ideal gas Cp − Cv = R.
Pressure in Fluids and Pascal's Law – A fluid (liquid or gas) pushes on every surface it touches. Pressure is this normal force per area, P = F/A. Because of gravity, the fluid above a point has weight, so pressure grows with depth: P = P₀ + ρgh. Points at the same depth in a still liquid have the same pressure, whatever the vessel's shape. Pascal's law says an extra pressure applied to an enclosed fluid reaches every point equally. The hydraulic lift and brakes use this: a small force on a small piston becomes a big force on a big piston, F = f × A/a.

11. Lab sciences: Project

Research or industry project

Project Management – A project is a one-time piece of work with a clear goal, a start and an end. Project management means planning and controlling it so it meets its scope on time and within cost. The life cycle runs initiate, plan, execute, monitor and close. Planners break the work into tasks (WBS), place them on a Gantt chart, find the critical path, manage risks and review lessons learned at the end.