human biology

• Random error


  An error in an experiment due to limits to the precision of the measurements
• Human error


  Error due to limitation of human ability
• Experiment groups


  Those being tested to see if there is an effect
• Control group


  There to ensure the validity of the experiment (if there is an effect on the control group then the experiment is valid)
• Types of graphs


  • Discrete data (continuous): separate types of measurements, counting ect., e.g number of cars = colour + bar graph
  • Continuous data: incremental, e.g age, temperature, growth rate = line graph
• Discussion


  • Evaluation of investigation
  • Supports/does not support hypothesis
  • Trends in data
  • Results explained
  • Limitations /errors
  • Improvements
• Conclusion


  • Concise
  • Related to aim
  • Statement if supported/not supported hypothesis
• The structure and function of the human body results from the activity of cells
• Cell theory


  • All living organisms are made up of cells
  • Cells are the basic structural and functional units of life
  • All cells are made from other cells
• Cell membrane


  • Separates cells from other cells and from the outside environment
  • Very thin
• Cytoplasm


  Thick fluid inside cell membrane and all structures within the cell (excluding nucleus)
• Cytosol


  Liquid part of the cytoplasm
• Cytoskeleton


  • Framework of protein fibres
  • Gives cells their shape
  • Move materials around the cell
• Microtubules


  • Hollow rods that keep organelles in place or move them around the cell
• Microfilaments


  • Move materials around the cell or move the whole cell
• Centrioles


  • Two cylindrical structures usually located near the nucleus
  • Involved in cell division
• Nucleus


  • Contains DNA
  • Separated from the cytoplasm by nuclear membrane
  • Double membrane with nuclear pores
• Ribosomes


  • Site of protein synthesis
  • Can be free or attached to endoplasmic reticulum
• Endoplasmic reticulum


  • Membranes throughout cytoplasm
  • Connect nuclear membrane to cell membrane
  • Provides a surface for chemical reactions (e.g. protein synthesis)
  • The channels between the paired membranes are used for storage or transport of materials
  • Smooth/agranular
  • Rough/granular -> rigid = ribosomes attached
• Golgi body


  • Flattened membranes
  • Often located near the nucleus
  • Modifies and packages proteins for secretion from the cell
• Lysosomes


  • Contains digestive enzymes able to break down proteins, lipids, nucleic acids and some carbohydrates
  • Includes materials that are taken into the cell or breakdown worn out organelles
• Mitochondria

  • Has a double membranes
  • Release energy for the cell through the process of cellular respiration
• Cilia & Flagella


  • Fine projections that beat back and forth to move the whole cell or substances over the surface of the cell
  • Cilia: short and numerous e.g. lining the tracheas
  • Flagella: longer and one/two e.g. sperm cell
• Vesicle


  • A membrane bound sac that transports materials into, out and within cell
  • Pinched off golgi body membrane
• Nucleolus


  • Found within the nucleus
  • Composed of mainly RNA
  • DNA & nucleons suspended in jelly like nucleoplasm
• Inclusions


  • Substances not part of cell structure but found in cytoplasm
• Levels of biological organisation


  • Cells
  • Tissue
  • Organ
  • System
  • Body
• Cell


  Smallest unit of stuff and function in an organism (living thing)
• Cell


  • Red blood cell
  • White blood cell
• Tissue


  A group of similar cells working together to perform a specific function
• Organ


  A group of similar tissues working together to perform a specific function
• Organ


  • Heart
  • Lungs
  • Skin
• Organ system


  A group of similar organs working together to perform specific functions
• Organ system


  • Circulatory system
  • Nervous system
• Cell membrane function


  • Separates the cell contents from the external environment
  • Represents a barrier between the cell and its surroundings
  • Determines which substances get into or out of the cell
• Cell membrane


  Contains cholesterol and proteins, provides stability of membrane
• Functions of cell membrane


  • Physical barrier: separates internal and external cellular environment allowing them to be different
  • Regulation of passage of materials: controls movement of substances into and out of cell
  • Sensitivity: receptors detects changes to external environment
  • Support: attached to cytoskeleton supporting the whole cell
• Cell membrane


  • Peripheral proteins - attracts to surface of newer and at different times
  • Integral proteins - permanently imbedded within cell membrane (e.g. channel or carrier protein)
• Structure of cell membrane

  Fluid mosaic model
• Selectively permeable


  Allows some materials to pass through but not others, based on size, polarity and charge