Biology Unit 2 - Edexcel GCSE Additional Science

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  • Biology Unit 2 - Edexcel Additional Science
    • Topic 3 - Common Systems
      • Fossils and Evolution
        • Fossils help to show us how organisms have changed over time, but there are gaps in the fossil record due to soft tissue decay
        • The biggest evidence for evolution that we have is the pentadactyl limb which indicates that all invertebrates with this shared a common ancestor
      • Growth
        • You can observe human growth through percentile charts
        • Plants grow through elongation of cells, they change and specialise according to needs, animal cells are the same.
      • Blood
        • Blood contains: White blood cells, containing antibodies to kill pathogens, Red blood cells, containing haemoglobin, plasma, making up the majority of the blood and platelets which help the blood to clot
      • The Heart
        • Pumps blood around the body, receives deoxygenated blood on the right side and oxygenated blood on the left side, the left ventricle is the biggest chamber
      • The Circulatory System
        • Made up of the heart and the blood vessels of the body, arteries, veins and capillaries, arteries take blood from the heart, veins take blood to it, one of the main organ systems
      • The Digestive System
        • Made up of: Mouth, Oesophagus, Stomach, Small Intestine, Pancreas, Large Intestine, Anus, Liver and Gall Bladder
      • Breaking Down Food
        • Amylase digests carbohydratesinto sugars and starch, Pepsin is a protease that digests protein into amino acids, Lipases digest fats into fatty acids and glycerol, bile from liver emulsifies the fats
      • Villi
        • Villi absorb the good molecules from food from the small intestine into the blood, steep concentration gradient makes the process quicker
      • Probiotics and Prebiotics
        • Probiotics contain friendly bacteria, plant stanol esters help to reduce cholesterol, prebiotics are substances the body cant digest so act as food for beneficial bacteria
    • Topic 1 - The Building Blocks of Cells
      • Plant and Animal Cells
        • Features in Common - Cell Membrane, Cytoplasm, Nucleus, Mitochondria
        • Plant Cell Features - Cell Wall, Vacuole, Chloroplasts
      • Inside Bacteria
        • Microscopes - Light magnifies up to 1500x, Electron magnifies up to 2,000,000x
        • Bacteria Cells - Chromosomal DNA, Plasmid DNA, Cell Membrane, Cell Wall, Flagella (sometimes)
      • DNA
        • Makes up genes, codes for amino acids in proteins, contains bases, hydrogen bonds, phosphate and dioxyribose sugar, A with T, C with G
      • DNA Discovery
        • Discovered by James Watson, Francis Crick, Rosalind Franklin and Maurice Wilkins, Franklin discovered the double helix shape of DNA
        • Human Genome Project: between 18 countries to find out the base sequence, took 13 years, now helps genetic disorders
      • Genetic Engineering
        • Take a human chromosome, cut out gene with enzyme, use enzyme to stick into bacterial plasmid and produce gene
        • Used to create human insulin, beta carotene rice and herbicide resistant plants
      • Mitosis and Meiosis
        • Mitosis: Copy chromosome pairs, nucleus pulls to either end of cell, cell divides, asexual reproduction
        • Meiosis: Copy chromosome pairs, nucleus pulls to either side of cell, cell divides into 4, genetically different, gamete formation
      • Clones
        • Take enucleated egg, add nucleus of body cell, stimulate to start mitosis, implant into a surrogate, get a genetically identical clone
      • Stem Cells
        • Cells that are not yet differentiated, best ones are embryonic, embryo has to be destroyed after, not ethical
      • Protein Manufacture
        • Transcription: DNA unzips and creates a strand of mRNA, no thymine, uracil instead, single stranded
        • Translation: mRNA taken to ribosome in the cytoplasm, ribosome decodes codons into amino acids which are attached to tRNA, amino acids are joined by polypeptide bonds and made into proteins
      • Mutations
        • A change in the bases sequence of the genetic code, therefore different amino acids are produced, some are harmful, some are helpful
      • Enzymes
        • Catalysts for chemical reactions in the body, used in DNA replication and digestion
      • Enzyme Action
        • Enzymes work on substrate molecules, increase rate of reactions, specialised, only work in certain conditions and only do specific jobs, lock-and-key hypothesis
    • Topic 2 - Organisms and Energy
      • Aerobic Respiration
        • Reaction between glucose and oxygen that creates carbon dioxide  and water
        • Glucose and  oxygen are delivered to cells by diffusion down a concentration gradient
        • In the lungs, oxygen enters blood by diffusion from alveoli, carbon dioxide moves the other way, this is called gas exchange
      • Anaerobic Respiration
        • During anaerobic respiration, cardiac output increases due to the increased need for oxygen, heart rate and stroke volume also increase
        • When there is n't sufficient oxygen, the glucose burns to form lactic acid, this needs to be broken down, so the heart rate remains high to break it down into carbon dioxide and water
      • Photosynthesis
        • Starch is made of thousands of glucose molecules, the bi product of this, happens in chloroplasts and chlorophyll transfers the light energy
        • Leaf: Waxy Coating, Upper Epidermis, Air spaces with large surface area for gas exchange, Lower Epidermis containing stomata
      • Limiting Factors
        • Could be light intensity, energy, pH, temperature, humidity or water
      • Water Transport
        • Osmosis in root hair cells: water moves across a partially permeable membrane with a concentration gradient, active transport is against a concentration gradient
        • In plants xylem transports water and salts, phloem transports glucose in the form of sucrose, transpiration moves water against gravity for glucose.
      • Organisms and their environment
        • Sampling is used to find out the biodiversity of plants, uses things like pooters, sweep nets, pitfall traps and quadrats
  • Topic 2 - Organisms and Energy
    • Aerobic Respiration
      • Reaction between glucose and oxygen that creates carbon dioxide  and water
      • Glucose and  oxygen are delivered to cells by diffusion down a concentration gradient
      • In the lungs, oxygen enters blood by diffusion from alveoli, carbon dioxide moves the other way, this is called gas exchange
    • Anaerobic Respiration
      • During anaerobic respiration, cardiac output increases due to the increased need for oxygen, heart rate and stroke volume also increase
      • When there is n't sufficient oxygen, the glucose burns to form lactic acid, this needs to be broken down, so the heart rate remains high to break it down into carbon dioxide and water
    • Photosynthesis
      • Starch is made of thousands of glucose molecules, the bi product of this, happens in chloroplasts and chlorophyll transfers the light energy
      • Leaf: Waxy Coating, Upper Epidermis, Air spaces with large surface area for gas exchange, Lower Epidermis containing stomata
    • Limiting Factors
      • Could be light intensity, energy, pH, temperature, humidity or water
    • Water Transport
      • Osmosis in root hair cells: water moves across a partially permeable membrane with a concentration gradient, active transport is against a concentration gradient
      • In plants xylem transports water and salts, phloem transports glucose in the form of sucrose, transpiration moves water against gravity for glucose.
    • Organisms and their environment
      • Sampling is used to find out the biodiversity of plants, uses things like pooters, sweep nets, pitfall traps and quadrats

Comments

fay bower

good resource

needs seperating so when printed you can read all the writing 

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