Topic Notes Import 2

• Tables should be organised with independent variable in first column, measurements of dependent variable, and any calculations
• Results of calculations should be recorded with lowest number of significant figures used to record measurements
• Units should be in column headings
• If independent variable is numerical, it and associated data should be recorded in sequence - lowest to highest
• Data should be recorded with a consistent number of decimal places
• Graphs


  • Title
  • Labelled axes with units
  • Plotted data points
  • Line of best fit (if appropriate)
  • Anomalous results identified

  
• Evaluating a method involves considering how to improve it, assessing precision, identifying anomalous results, and improving reliability
• Accurate results require using equipment with good resolution
• Reliable results require repeated measurements and identifying anomalous results
• Tables should include independent variable, measurements of dependent variable, and calculated averages
• Bar charts should show compound (stacked) bars for different nutrients in food

  
• Line graphs should join data points with straight lines
• Topics covered


  • Cell structures and functions
  • Similarities and differences between plant and animal cells
  • Chromosomes, genes, and DNA
  • Chemical composition of biomolecules
  • Enzyme function and regulation
  • Levels of organisation in organisms
  • Cell differentiation
  • Features of eukaryotic and prokaryotic organisms
  • Pathogens

  
• Enzyme function


  Can be affected by changes to the shape of active site
• Enzyme function


  Can be affected by changes in pH altering the active site
• Levels of organisation in organisms

  • Organelles
  • Cells
  • Tissues
  • Organs
  • Systems
• Cell differentiation


  The development of specialised cells from stem cells
• Common features of eukaryotic organisms

  • Plants
  • Animals
  • Fungi
  • Protoctists
• Common features of prokaryotic organisms

  • Bacteria
• Pathogen


  Microorganisms which cause infectious disease, including fungi, bacteria, protoctists or viruses
• A cell is the smallest possible unit of life
• Organisms can be a single cell, or they can be made of millions (or billions) of different cells
• Cell membrane


  Boundary between the cytoplasm and the cell's surroundings, controls what substances enter and leave the cell (selectively permeable)
• Cytoplasm


  Jelly-like liquid where chemical reactions occur
• Nucleus


  Controls the activity of the cell (by making proteins), contains the chromosomes - strands of DNA which carry the genes
• Mitochondria


  Carry out some reactions of aerobic respiration, producing ATP (energy carrier molecule)
• Ribosomes


  Synthesise (assemble) proteins from amino acids
• Chloroplasts


  Absorb light energy and use it to carry out the chemical reactions of photosynthesis, making biological molecules for plant cells
• Cell wall


  Made of cellulose (a carbohydrate) in plants, helps to keep plant cells in a fixed shape (and so keeps the plant upright)
• Vacuole


  Filled with a watery liquid called cell sap, stores dissolved sugars, mineral ions and other substances
• Cells and organelles are so small that we use micrometres (μm) and nanometres (nm) to measure them
• Magnification


  How many times bigger the object is that in real life
• Some living things are made of a single cell, more complex organisms are multicellular - made of millions or billions of cells
• Levels of organisation


  • Cells
  • Tissues
  • Organs
  • Organ systems
• Stem cells

  Not specialised to a particular job, able to divide over and over to make new cells
• Cell differentiation


  Stem cells develop new features to become specialised cells
• Red blood cell


  • Contains the protein haemoglobin to transport oxygen, no nucleus to have more space for haemoglobin, biconcave shaped for larger surface area
• Sperm cell


  • Flagellum (tail) to swim, many mitochondria for energy, acrosome to digest jelly layer of egg cell
• Palisade (leaf) cell


  • Many chloroplasts to trap light energy for photosynthesis, tall and thin to pack tightly together
• Biological molecules


  • Water
  • Carbohydrates
  • Proteins
  • Lipids (fats)
  • Nucleic acids (DNA and RNA)