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Edexcel GCSE Combined Science

GCSE · EdexcelCombined Science71 篇笔记 个文件夹，366 KB

cookie 制作的复习笔记，共 71 篇，分为 3 个章节，按照课程主题编排。

Notes for Edexcel GCSE Combined Science (1SC0), in folders for biology, chemistry and physics, each split into the topics of the specification in order, with the core practicals in the topics they belong to. Higher-tier content is marked where it sits. Delete any folder or note your tier does not need once the notes are yours.

添加后，这些笔记的副本会放入你的笔记中，存放在一个单独的文件夹里，并保留下面的文件夹结构，你可以修改它们并转换成抽认卡或题目组。下载会生成一个包含 Markdown 文件的 zip 压缩包，可用任何笔记应用打开。

内容

  • Biology
    • Key concepts in biology
      • Cells and specialised cells4 KB
      • Microscopy, size and scale5 KB
      • Enzymes6 KB
      • Transport in and out of cells5 KB
    • Cells and control
      • Mitosis and cancer3 KB
      • Growth, differentiation and stem cells4 KB
      • The nervous system and reflexes5 KB
    • Genetics
      • Meiosis, DNA and the genome4 KB
      • Inheritance6 KB
      • Variation, mutation and the Human Genome Project5 KB
    • Natural selection and genetic modification
      • Evolution by natural selection4 KB
      • Human evolution and classification4 KB
      • Selective breeding and genetic engineering5 KB
    • Health, disease and the development of medicines
      • Health and communicable disease5 KB
      • Defences, immunity and vaccination4 KB
      • Antibiotics and new medicines5 KB
      • Non-communicable disease and lifestyle5 KB
    • Plant structures and their functions
      • Photosynthesis6 KB
      • Transport in plants6 KB
    • Animal coordination, control and homeostasis
      • Hormones, adrenalin and thyroxine4 KB
      • Blood glucose and diabetes4 KB
      • Menstrual cycle, contraception and fertility6 KB
    • Exchange and transport in animals
      • Exchange surfaces and alveoli4 KB
      • Blood, blood vessels and the heart6 KB
      • Respiration5 KB
    • Ecosystems and material cycles
      • Communities and fieldwork5 KB
      • Human impact and biodiversity5 KB
      • Material cycles5 KB
  • Chemistry
    • Formulae, equations and hazards
      • Formulae, equations and hazard symbols5 KB
    • Atomic structure and the periodic table
      • Atoms, isotopes and relative atomic mass5 KB
      • The periodic table and electronic configuration4 KB
    • Bonding and structure
      • Ionic bonding and ionic compounds5 KB
      • Covalent bonding and simple molecules4 KB
      • Giant structures, metals and types of substance6 KB
    • Quantitative chemistry
      • Formula mass, empirical formulae and conservation of mass6 KB
      • Reacting masses, concentration and the mole5 KB
    • States of matter and mixtures
      • States of matter4 KB
      • Separating mixtures, chromatography and water7 KB
    • Chemical change
      • Acids, alkalis and reactions of acids6 KB
      • Making salts and titration6 KB
      • Electrolysis6 KB
    • Extracting metals and equilibria
      • Reactivity series, extraction and recycling of metals7 KB
      • Reversible reactions, equilibrium and the Haber process5 KB
    • Groups in the periodic table
      • The alkali metals, the halogens and the noble gases8 KB
    • Rates of reaction and energy changes
      • Rates of reaction6 KB
      • Energy changes in reactions5 KB
    • Fuels and Earth science
      • Crude oil, hydrocarbons and cracking5 KB
      • Combustion of fuels and pollution5 KB
      • The atmosphere and climate change6 KB
  • Physics
    • Motion and forces
      • Units, scalars, vectors and speed4 KB
      • Acceleration and velocity-time graphs4 KB
      • Newton's laws, weight and circular motion6 KB
      • Momentum4 KB
      • Stopping distances and reaction times5 KB
    • Energy
      • Energy stores, transfers and efficiency6 KB
      • Work, power and energy calculations4 KB
      • Energy resources5 KB
    • Waves and the electromagnetic spectrum
      • Wave properties and refraction8 KB
      • The electromagnetic spectrum6 KB
    • Radioactivity
      • Atoms and types of radiation6 KB
      • Nuclear equations, half-life and safety7 KB
    • Forces and their effects
      • Interacting forces and resolving forces6 KB
      • Springs and elasticity4 KB
    • Electricity and circuits
      • Circuits, current, potential difference and resistance6 KB
      • Components and current-potential difference graphs5 KB
      • Energy and power in circuits4 KB
      • Mains electricity4 KB
    • Magnetism and electromagnetic induction
      • Magnets, electromagnets and the motor effect7 KB
      • Induction, transformers and the national grid5 KB
    • Particle model
      • Density and states of matter4 KB
      • Thermal energy, latent heat and gases7 KB

第一篇笔记

Biology / Key concepts in biology / Cells and specialised cells

Eukaryotic and prokaryotic cells

Animals and plants are made of eukaryotic cells, which keep their genetic material in a nucleus surrounded by a membrane. Bacteria are prokaryotic: they have no nucleus, and their DNA lies loose in the cytoplasm. Prokaryotic cells are also much smaller, usually a few micrometres long, while typical animal and plant cells are tens of micrometres across.

Each part inside a cell, called a sub-cellular structure, has a job, and a cell works because those jobs fit together.

Animal cells
StructureWhat it does
NucleusContains the chromosomes, which carry the genes, so it controls the activities of the cell
Cell membraneA thin, partly permeable layer that controls which substances enter and leave
CytoplasmA watery gel where most chemical reactions take place
MitochondriaWhere aerobic respiration releases energy for the cell; cells that use a lot of energy have many
RibosomesWhere amino acids are joined in the order set by the genes to make proteins
Plant cells

A plant cell has all of the structures above and three more.

StructureWhat it does
Cell wallMade mainly of cellulose, it is rigid and strengthens the cell and gives the plant support
ChloroplastsContain the green pigment chlorophyll, which absorbs light for photosynthesis
Permanent vacuoleA space filled with cell sap, a solution of sugars and salts; it keeps the cell firm when full of water

Chloroplasts are found in the cells of leaves and green stems but not in root cells, which sit in the dark and have no light to absorb.

Bacterial cells

A bacterium has a cell wall (not made of cellulose), a cell membrane, cytoplasm and ribosomes, and its genetic material is arranged differently from ours.

  • Chromosomal DNA is a single loop that floats in the cytoplasm, since there is no nucleus to hold it.
  • Plasmid DNA is one or more small extra rings of DNA, separate from the chromosome, which often carry genes such as those for antibiotic resistance. Plasmids can be passed from one bacterium to another.
  • A flagellum (plural flagella) is a long whip-like tail that rotates and moves the cell through liquid. Not all bacteria have one.

Specialised cells

In a many-celled organism, cells become specialised: their structure is adapted to a particular function. Each adaptation can be explained by what the cell has to do.

Sperm cells

A sperm cell has to reach an egg and get its genetic material inside.

  • The tail moves the sperm through fluid towards the egg.
  • Many mitochondria in the middle section release the energy the tail needs to keep moving.
  • The acrosome at the head holds digestive enzymes, which break down the outer layers of the egg so that the sperm nucleus can enter.
  • The nucleus is haploid, meaning it holds one copy of each chromosome (23 in a human sperm), so that fertilisation restores the full set of 46.
Egg cells

An egg cell is much larger than a sperm, because it has to support the first stage of a new organism.

  • The cytoplasm holds a store of nutrients, which feed the embryo until it can obtain food in other ways.
  • The nucleus is haploid, carrying the mother's half of the chromosomes.
  • After one sperm has entered, the cell membrane changes so that no other sperm can get in. If a second sperm fused with the egg the embryo would have too many chromosomes and would not develop properly.
Ciliated epithelial cells

Ciliated epithelial cells line the airways, including the trachea and bronchi. Their surface is covered with cilia, tiny hair-like projections that beat together in a wave. Mucus made by other cells in the lining traps dust and bacteria, and the cilia sweep this mucus up towards the throat, where it is swallowed or coughed out. This keeps the lungs clear and cuts the risk of infection. Smoking damages cilia, which is one reason smokers cough more.

Ciliated cells are found in other tubes too, such as the oviduct, where the cilia help move the egg cell along.

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