biology p1

• Cells


  The basic building blocks of life that can replicate independently
• Multicellular organisms like animals and plants contain many cells that divide to grow or replace dead cells, not to create new organisms</b>
• Bacteria are single-celled prokaryotic organisms
• Subcellular structures common to animal and plant cells

  • Cell membrane
  • Nucleus
  • Cytoplasm
  • Mitochondria
  • Ribosomes
• Plant cells


  • Have a rigid cell wall made of cellulose
  • Contain a permanent vacuole with cell sap
  • Contain chloroplasts for photosynthesis
• Bacterial cells


  • don't have mitochondria and chloroplasts
  • Have a single circular strand of DNA instead of a nucleus
  • May have additional plasmids
  • May have flagella for movement
• Photosynthesis occurs in the chloroplasts of plant cells, using chlorophyll to absorb light energy
• Aerobic respiration in mitochondria releases energy for the cell
• The nucleus is the control center of the cell, containing genetic material (DNA) that determines the characteristics of an organism.
• cell membrane controls which substances can pass in and out of the cell
• bacteria cell is a prokaryotic cell, meaning it does not have a nucleus
• animal and plant cells have a cell membrane, cytoplasm, nucleus and ribosomes
• animal and plant cells are also eukaryotes
• multicellular cells are animal and plant cells
• bacteria cells are a whole organism and reproduce asexually by binary fission
• cytoplasm is where chemical reactions take place and where the cell's organelles are found and is a jelly like substance
• mitochondria provides energy for the cell and is where aerobic respiration takes place
• ribosomes are where proteins are made
• plant cells have an extra rigged cell wall, permanent vacuole and chloroplasts
• a rigged cell wall in a plant cell can be called cellulose and its purpose is to support and structure the cell
• a permanent vacuole contains cell sap and is found in plant cells
• Flagella is found on some bacteria cells and is used for movement
• Microscopy

  The use of microscopes
• How light microscopes work

  1. Light from the room hits the mirror

  2. Light reflected upwards through the object

  3. Light passes through the objective lens

  4. Light passes through the eyepiece lens

  5. Light enters the eye
• Object

  The real object or sample that you're looking at
• Image


  The image that we see when we look down the microscope
• Magnification


  How many times larger the image is than the object
• Magnification = image size / object size
• Resolution

  The shortest distance between two points on an object that can still be distinguished as two separate entities
• Higher resolution


  More details can be seen, less blurry the image
• The images have the same magnification (100x) but different resolutions
• The object is the real sample (e.g. onion cells)
• Image is the image we see when we look down a microscope
• magnification is how many times larger the image is than the object
• Magification equation= image size divided by object size
• Light microscopes


  Microscopes that use light, small, easy to use, relatively cheap
• Resolution of light microscopes

  Limited to 0.2 micrometers, any details less than 0.2 micrometers apart will appear blurry
• What light microscopes can be used to see

  • Individual cells like onion cells
• Electron microscopes


  Really big, very expensive, hard to use, only used by scientists in laboratories
• Resolution of electron microscopes

  Maximum resolution of 0.1 nanometers, 2000 times better than light microscopes