Paper 1

Subdecks (3)

Cards (413)

  • Light microscope
    Can see cells and maybe the nucleus, but not subcellular structures
  • Electron microscope
    Can see much finer details and subcellular structures, has better resolving power and higher resolution
  • Calculating cell size
    1. Measure image size
    2. Divide by magnification
  • Cell types
    • Eukaryotic cells
    • Prokaryotic cells
  • Eukaryotic cells
    • Have a nucleus where DNA is found
  • Prokaryotic cells
    • Don't have a nucleus, DNA is in a ring called a plasmid
  • Subcellular structures
    • Cell membrane
    • Cell wall
    • Cytoplasm
    • Mitochondria
    • Ribosomes
    • Chloroplasts
    • Vacuole
  • Bacterial binary fission
    1. Number doubles every 10 minutes
    2. After 1 hour, 64 bacteria
    3. After 6 hours, 6.87 x 10^10 bacteria
  • Practical: Bacterial culture on agar
    1. Use aseptic technique
    2. Lift lid towards flame
    3. Use sterilized equipment
    4. Incubate at 25°C
  • Measuring bacterial culture
    1. Calculate size from initial drop or area where bacteria did not grow
    2. Use πr^2 or πD^2/4 to calculate area
  • Human cells
    • Have 23 pairs of chromosomes (diploid)
    Gametes have 23 chromosomes (haploid)
  • Cell division by mitosis
    1. Genetic material duplicated
    2. Ribosomes and mitochondria doubled
    3. Nucleus breaks down
    4. Chromosomes pulled to opposite sides
    5. New nuclei form
  • Specialised cell types
    • Nerve cells
    • Muscle cells
    • Root hair cells
    • Xylem cells
    • Phloem cells
    • Stem cells
  • Stem cells
    Unspecialised cells that can differentiate into various cell types
  • Diffusion
    Movement of molecules/particles from high to low concentration, down concentration gradient, passive process
  • Osmosis
    Diffusion of water across a semi-permeable membrane
  • Practical: Osmosis in potato cylinders
    1. Cut equal size cylinders
    2. Weigh and place in sugar solutions
    3. Reweigh after a day
    4. Calculate percentage change in mass
    5. Plot against sugar concentration
  • Active transport
    Using energy to move substances against a concentration gradient
  • Tissues
    • Heart tissue
    • Digestive tissue
  • Organs
    • Heart
    • Liver
    • Gallbladder
  • Organ systems
    • Circulatory system
    • Digestive system
  • Enzymes
    Biological catalysts that break down larger molecules into smaller ones
    Work on a lock and key principle with specific substrates
  • Practical: Investigating enzyme activity
    1. Mix amylase and starch at different temperatures or pH
    2. Test for starch presence with iodine every 10 seconds
    3. Plot time taken for starch breakdown against temperature or pH
  • Food tests
    Iodine for starch
    Benedict's solution for sugars
    Biuret's reagent for proteins
    Ethanol for lipids
  • Breathing and gas exchange
    Air moves down trachea, bronchi, bronchioles to alveoli
    Oxygen diffuses into blood, carbon dioxide diffuses out
  • Parts of the circulatory system
    • Right atrium
    • Right ventricle
    • Pulmonary artery
    • Pulmonary vein
    • Left atrium
    • Left ventricle
    • Aorta
  • Coronary artery
    Supplies blood to the heart muscle
  • Stents
    Tubes inserted into blood vessels to keep them open
  • Statins
    Drugs that reduce cholesterol and fatty deposits
  • Types of disease
    • Non-communicable diseases (e.g. cardiovascular disease, cancer)
    Communicable diseases (e.g. infections)
  • Coronary artery
    Delivers blood to the heart muscle to supply oxygen
  • Coronary heart disease (CHD)
    Occurs when coronary arteries are blocked by fatty deposits, causing a heart attack
  • Stent
    A small tube inserted into blood vessels to keep them open and allow blood flow
  • Faulty heart valves
    Result in backflow, can be replaced with artificial ones
  • Cardiovascular (CV) disease
    An example of a non-communicable disease, caused by factors within the body
  • Examples of non-communicable diseases
    • Cardiovascular disease
    • Autoimmune conditions
    • Cancer
  • Communicable disease
    Caused by a pathogen that enters the body, resulting in viral, bacterial or fungal infection
  • Carcinogen
    Anything that increases the risk of cancer, e.g. ionizing radiation
  • Benign cancer
    Doesn't spread through the body and is relatively easy to treat
  • Malignant cancer
    Cancerous cells spread through the body, much worse