BRAINCAKEGenetics
Revision notes for Genetics in Edexcel Combined Science (1SC0). Every lesson in BrainCake comes with R.E.C.I.P.E. recall steps, a quick check and spaced reviews.
- Meiosis and gametesMeiosis is a type of cell division that happens only in the reproductive organs, where it makes gametes (sex cells).
- The structure of DNADNA is a polymer, which means it is a very long molecule made of many small repeating units joined in a chain.
- Genome and genesThe genome of an organism is the entire DNA of that organism.
- Extracting DNA from fruitDNA can be extracted from fruit such as strawberries or kiwi fruit using simple equipment.
- Alleles and differences in inherited characteristicsA gene can come in different versions.
- Genetics key termsGenetics has a set of key terms.
- Monohybrid inheritance, Punnett squares and pedigreesIn a monohybrid cross we follow the inheritance of one gene that has two alleles.
- How the sex of offspring is determinedHuman body cells have 23 pairs of chromosomes.
- Calculating outcomes from crosses and pedigreesThe results of a monohybrid cross can be given as a probability, a ratio or a percentage.
- Multiple genes and phenotypeSome features are controlled by a single gene.
- Causes of genetic variationDifferences between individuals of the same species are called variation.
- The Human Genome ProjectThe Human Genome Project was an international research project, completed in 2003.
- Genetic variation and mutationsLook at any population of one species, such as the sparrows in a park or the daffodils on a verge, and you will see that the individuals are not…
- Effects of mutations on the phenotypeMutations happen all the time, but they do not all matter equally.
- Acids and alkalis as sources of ionsThe properties of acidic and alkaline solutions come from the ions they contain.
- The pH scaleThe pH scale tells you how acidic or alkaline a solution is.
- Dilute and concentrated solutionsWhen a substance dissolves in water it forms a solution.
- Strong and weak acidsWhen an acid dissolves in water, its molecules can dissociate, which means they split up to release hydrogen ions, H+.
- Bases and the reactions of bases with acidsA base is any substance that reacts with an acid to form a salt and water only.
- Alkalis as soluble basesAn alkali is a base that is soluble in water.
- Reactions of acids with metals, oxides, hydroxides and carbonatesAcids react in four general ways to produce salts.
- Core practical: Preparing pure, dry hydrated copper sulfate crystalsCopper sulfate is made from copper oxide and sulfuric acid: CuO + H2SO4 gives CuSO4 + H2O.
- Acid-alkali titration to prepare a pure, dry saltA titration finds exactly how much acid reacts with a given volume of alkali.
- Movement of ions during electrolysisAn electrolyte is an ionic compound that is molten or dissolved in water.
- Electrolysis of copper chloride and sodium chloride solutionsA solution contains two sets of ions: the ions from the dissolved compound, and H+ and OH- ions from the water.
- Electrolysis of molten binary ionic compoundsA binary compound contains just two elements.
- Half equations at the electrodesA half equation shows what happens to one ion at one electrode.
- Oxidation and reduction as loss or gain of electronsIn terms of electrons, oxidation is the loss of electrons and reduction is the gain of electrons.
- Reduction at the cathode and oxidation at the anodeDuring electrolysis the cathode is the negative electrode and the anode is the positive electrode.
- Electrolysis of copper sulfate with copper electrodes and purifying copperWhen copper sulfate solution is electrolysed with copper electrodes, the electrodes take part in the reaction.
- Core Practical: Electrolysis of copper sulfate solutionIn this practical you pass a direct current through blue copper sulfate solution and compare two kinds of electrode.