Biology paper 1

    Cards (102)

    • Microscopes
      Normal light microscope can see cells and nucleus, electron microscope can see subcellular structures in more detail
    • Magnification
      Image size / Object size
    • Cell types
      • Eukaryotic cells (have nucleus)
      • Prokaryotic cells (no nucleus)
    • Eukaryotic cells
      • DNA is found in the nucleus
      • Examples: plant and animal cells
    • Prokaryotic cells
      • DNA is found in a ring called a plasmid
      • No nucleus
    • Cell structures
      • Cell membrane
      • Cell wall (in plant cells and bacteria)
      • Cytoplasm
      • Mitochondria
      • Ribosomes
      • Chloroplasts (in plant cells)
    • Bacterial binary fission
      1. Number of bacteria doubles every 10 minutes
      2. After 1 hour: 2^6 = 64 bacteria
      3. After 6 hours: 2^36 = 6.87 x 10^10 bacteria
    • Practical: Bacterial growth on agar
      • Use aseptic technique
      • Incubate at 25°C
      • Measure area of growth or area where bacteria were killed by antibiotics
    • Diploid cells
      Cells with 23 pairs of chromosomes (e.g. human body cells)
    • Haploid cells
      Cells with 23 single chromosomes (e.g. human gametes)
    • Mitosis
      1. Genetic material is duplicated
      2. Nucleus breaks down
      3. Chromosomes move to opposite sides
      4. New nuclei form in the two new cells
    • Cell specialisation
      • Cells specialize to perform specific functions (e.g. nerve, muscle, root hair cells)
    • Stem cells
      Unspecialized cells that can develop into different cell types
    • Diffusion
      Movement of molecules/particles from high to low concentration, no energy required
    • Osmosis
      Diffusion of water across a semi-permeable membrane
    • Practical: Osmosis in potato cylinders
      1. Cut equal size potato cylinders
      2. Weigh and place in sugar solutions
      3. Reweigh after 1 day
      4. Calculate % change in mass
      5. Plot against sugar concentration to find no-change concentration
    • Active transport
      Using energy to move substances against a concentration gradient
    • Tissues
      • Heart tissue
      • Digestive tissue
    • Organs
      • Heart
      • Liver
      • Stomach
      • Small intestine
    • Organ systems
      • Circulatory system
      • Digestive system
    • Enzymes
      Biological catalysts that break down specific molecules (e.g. amylase breaks down starch)
    • Enzyme active site
      Specific shape that allows substrate to bind
    • Enzyme activity
      Increases with temperature until denaturation, has an optimum pH
    • Practical: Investigating enzyme activity
      1. Mix amylase and starch at different temperatures or pH
      2. Test for starch presence over time
      3. Plot time to complete reaction against temperature or pH to find optimum
    • Food tests
      • Iodine for starch
      • Benedict's solution for sugars
      • Biuret's reagent for proteins
      • Ethanol for lipids
    • Respiratory system structures
      • Trachea
      • Bronchi
      • Bronchioles
      • Alveoli
    • Alveoli
      Lungs have many small alveoli to increase surface area for gas exchange
    • Blood components
      • Red blood cells (carry oxygen)
      • Plasma (carries dissolved substances)
      • White blood cells (fight infection)
      • Platelets (clot wounds)
    • Double circulatory system
      Blood enters the heart twice on each circuit around the body
    • Heart structure
      • Right side pumps deoxygenated blood to lungs, left side pumps oxygenated blood to body
      • Pacemaker regulates heart beat
    • Blood vessels
      • Arteries carry blood away from heart, veins carry blood towards heart
      • Capillaries allow gas/nutrient exchange
    • Coronary arteries
      Supply the heart muscle with oxygen and nutrients
    • Non-communicable diseases
      Diseases not caused by pathogens, e.g. cardiovascular disease, cancer
    • Communicable diseases
      Diseases caused by pathogens, e.g. infectious diseases
    • Coronary artery
      Delivers blood to the heart muscle to supply oxygen
    • Heart attack
      Occurs when coronary arteries are blocked by buildup of fatty deposits, causing coronary heart disease (CHD)
    • Stents
      Little tubes inserted into blood vessels to keep them open and allow blood flow
    • Statins
      Drugs that reduce cholesterol and fatty deposits
    • Faulty heart valves
      Result in backflow, can be replaced with artificial ones
    • Blood
      Carries plasma, red blood cells, white blood cells, and platelets
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