UNIT 1 AOS 1

• Independent variable


  The factor that is manipulated (changed) in an experiment
• Dependent variable


  The factor measured in the experiment that changes when the independent variable is manipulated
• Controlled variable

  A factor that is kept constant throughout the experiment, also known as the constant variable
• Surface area to volume ratio (SA:V)

  A comparison of the amount of surface area per unit of volume
• SA:V in biology

  Influences temperature regulation and a high SA:V leads to more effective transport into and out of the cell
• Effect of size on SA:V

  Smaller objects have a larger surface area to volume ratios
• Effect of size on SA:V

  Having less skin compared to body volume is an advantage to animals in colder climates
• Effect of shape on SA:V

  Flat objects have a greater SA:V than other objects of the same volume with a less flattened shape
• Big mammals in hot environments

  Often have elongated or large flattened shapes (ears)
• Influence of SA:V on cells


  The small size of structures and their greatly elongated membranes make cells more efficient
• Surface Area

  The sum of the area of all exposed sides of a 3D shape
• Volume


  The amount of space inside an object
• Types of errors

  • Personal
  • Systematic
  • Random
• Personal errors

  Mistakes or miscalculations made by the experimenter, e.g., counting incorrectly, labelling samples incorrectly
• Systematic errors


  Errors that cause results to differ from the true value, usually due to faulty equipment or calibration
• Random errors


  Errors caused by unpredictable variations in the measurement process, resulting in a spread of readings
• Random errors

  Reduce precision
• Hypothesis


  A statement that describes how experimenters expect the dependent variable to change as the independent variable changes, a prediction
• Organelle

  Structures that are enclosed within one or two membranes
• Plant and Animal Cell Differences

  Prokaryotes have no nucleus and a circular loop of DNA, while eukaryotes have a nucleus and linear strands of DNA
• Nucleus

  A large organelle surrounded by a membrane that protects and contains the genetic information (DNA) of a cell
• Nucleolus


  Not a membrane-bound organelle, a region of the cell's DNA on which ribosomes are being made, a dark staining patch
• Protists are eukaryotic
• Eukaryotic organisms


  • Animals
  • Plants
  • Fungi
  • Protists
• Cell Theory
• Nucleus

  Large organelle surrounded by a membrane that protects and contains the genetic information (DNA) of a cell
• Nucleolus

  Not a membrane-bound organelle. Region of the cell's DNA where ribosomes are being made. Dark staining patch inside the nucleus
• Ribosomes


  Small RNA-protein structures, site of protein synthesis. Read genetic code from mRNA (enzyme) which is a copy strand of DNA found within the nucleus
• Mitochondria


  Contain their own DNA and ribosomes. Site of aerobic cellular respiration, releasing energy from glucose in the form of ATP required to power cellular processes
• Lysosomes


  Membrane-bound vesicles containing digestive enzymes. Responsible for breaking down cell waste and toxins, acting like a garbage disposal
• Golgi Apparatus (Golgi Body)


  Stack of flattened membrane-bound sacs. Function is to modify and package proteins for export from the cells
• Centrioles

  Animal cells contain 2. During mitosis and meiosis division, the centrioles move apart to opposite sides of the cell
• Cilia and Flagella


  Protuberances from the cell membrane. Flagella are longer than cilia but have a similar structure. Responsible for cell locomotion or moving fluids across cell surfaces in multicellular organisms
• Chloroplasts (plant cells only)

  Double membrane-bound organelle containing flattened, fluid-filled sacs that are the site of photosynthesis. Also contain their own DNA and ribosomes
• Large Vacuole

  Plant cells contain a large vacuole, a membrane-bound sac used for water and solute storage, maintaining cell structure
• Cytoplasm

  Includes everything in the cell between the nuclear envelope and plasma membrane
• Cytosol


  The fluid in which organelles of cytoplasm are suspended
• Rough Endoplasmic Reticulum


  Network of membrane channels within a cell, transporting materials throughout the cytoplasm, synthesizing and modifying proteins. Dotted with ribosomes
• Smooth Endoplasmic Reticulum

  A membranous chain of connected and flattened sacs not coated with ribosomes. Responsible for lipid production in a cell
• Membrane-bound organelle


  Structure within a cell enclosed by a phospholipid bilayer