Unit 1

• 7 Characteristics of Living Things

  • Cells
  • Metabolism
  • Homeostasis
  • Heredity
  • Reproduction
  • Growth and Development
  • Response to Stimuli
• Cells


  Building blocks of all living things, have organelles which are specialized structures that carry out specific functions within the cell
• Hierarchical organization


  From the smallest level (organelle) to the largest level (organism), ensures each level contributes to the overall functioning of the organism
• Metabolism


  Chemical reactions in an organism, includes cellular respiration and photosynthesis

  
• Cellular respiration


  Converts food into energy to carry out activities and maintain life functions
• Photosynthesis


  Process through which plants convert sunlight, water, and carbon dioxide into glucose and oxygen

  
• Homeostasis


  Ability of organisms to maintain a stable internal environment despite changes in the external environment
• Heredity


  All living things possess DNA which carries genetic information and determines traits and characteristics
• Reproduction


  • Asexual
  • Sexual
• Asexual reproduction


  Production of genetically identical offspring from a single parent
• Sexual reproduction


  Fusion of male (sperm cell) and female (egg cell) reproduction cells (gametes), resulting in offspring with genetic variation
• Growth and development


  All living things exhibit growth throughout their life cycles, increase in size and complexity, includes embryonic development
• Response to stimuli


  Living things can respond to internal or external factors that trigger a response, examples include movement, changes in heart rate, or adapting to environmental conditions
• Microscopes are essential tools for studying cells and other microscopic organisms, they allow observation and analysis of structures too small to see with the eye
• Using a microscope


  Turn on light, start at lowest magnification, adjust coarse and fine adjust knobs to bring specimen into focus, switch to higher magnification only using fine adjustment
• Total magnification


  Magnification of eyepiece (ocular lens) multiplied by magnification of objective lens
• Calculating specimen size


  Measure field of view diameter using grid slide, convert to micrometers, estimate how many specimens fit across diameter, use formula: FOV (micrometer) / Est. # of specimens fit across diameter

  
• Preparing wet mount slide


  Place specimen on slide, add drop of water, cover gently with coverslip to avoid air bubbles, prevents specimen from drying out

  
• Staining


  Used to enhance visibility of certain structures within the specimen, examples include methylene blue or iodine
• Organelles


  • Nucleus
  • Cell membrane
  • Cytoplasm
  • Mitochondria
  • Ribosomes
  • Cell wall
  • Chloroplasts
  • Vacuole
• Levels of organization


  • Organism
  • Tissue
  • Organ
  • Cell
  • Organelle
• Photosynthesis


  Occurs in chloroplasts, converts sunlight, water, and carbon dioxide into glucose and oxygen

  
• Cellular respiration


  Occurs in mitochondria, converts oxygen and glucose into energy (ATP) and expels carbon dioxide as waste
• Products of photosynthesis


  • Glucose
  • Oxygen

  
• Products of cellular respiration

  • Carbon dioxide
  • Water
• Heredity


  Passing of genetic material from parent to offspring, ensuring continuity of species
• DNA


  Carries genetic information that determines traits and characteristics
• Sexual reproduction


  Fusion of male and female gametes, resulting in offspring with genetic variation
• Advantages of asexual reproduction

  • Faster
  • More efficient
• Disadvantages of asexual reproduction

  • Lack of genetic variation
  • Susceptibility to disease
• Advantages of sexual reproduction

  • Genetic variation
  • Adaptability
• Disadvantages of sexual reproduction

  • Slower
  • More complex
• The cells have identical genetic instructions, but different parts of these instructions are being expressed in each cell
• Growth and development


  Increase in size and complexity of living organisms, guided by DNA instructions, results in specialized cells

  
• Example of a specialized cell in the human body: muscle cell
• Parts of a microscope

  • Eyepiece
  • Body tube
  • Objective lens
  • Stage
  • Diaphragm
  • Nosepiece
  • Coarse adjust knob
  • Fine adjust knob
  • Light source
  • Base
  • Arm
  • Clip
• Measuring field of view (FOV) and calculating specimen size

  Measure FOV diameter using grid slide, convert to micrometers, estimate number of specimens that fit across diameter, use formula: FOV (micrometer) / Est. # of specimens fit across diameter
• The laboratory technique shown is preparing a wet mount slide
• The stain used to stain cheek cells was methylene blue
• The cover slip should be lowered at an angle to avoid air bubbles