2: Cells, Viruses & Reproduction

• Give the order of organisation from cells to organisms in multicellular organisms?


  Cells, tissues, organs, organ systems, organisms
• Define magnification?

  How much bigger a sample appears under a microscope than it actually is
• What is total manification equal to with regards to the two lenses?

  Objective magnification multiplies by eyepiece magnification
• Define resolution?

  The smallest possible distance between two points that can still be seen as two points in a microscope
• How do you convert from mm to um?

  Multiply by 1000
• How do you convert from um to nm?

  Multiply by 1000
• How do you convert from nm to um?

  Divide by 1000
• How do you convert from um to mm?

  Divide by 1000
• How does a scanning electron microscope work?

  An image is produces through scanning of the object surface with a focussed beam of electrons
• How does a transmission electron microscope work?

  An image is produced by passing a high energy beam of electrons through the object (has to be thin)
• Do electron or light microscopes have a higher resolution and why?

  Electron because electrons have a smaller wavelength than light
• What is an artefact?

  Something you may see under a microscope which isn't actually part of the specimin
• What are dust, air bubble, fignerprints ona microscope slide all examples of?

  Artefacts
• What is the field of view?

  The area you can see under a microscope
• How is magnfication calucated with regard to actual size and image size?

  Image size divided by actual size
• Explain how you could calibrate and use an eyepiece graticule to find the actual length of an object using a microscope?

  Calibrate the eyepiece graticule using the stage micrometer. One the eyepiece graticule has been calibrated it can be used to measure the length
• Give the main difference between a eukaryotic and prokaryotic cell?

  Eukaryotic has a nucleus
• Explain the function of the nucleus?

  Contains genetic information and controls what the cell does
• What type of cells have a nucleus?

  Eukaryotic
• What is the function of the nucleolus?

  Where ribosomes are made
• What does the nucleolus look like?

  A darker circular region inside the nucleus
• What type of cells have a nucleolus?

  Eukaryotic
• Where are ribosomes made?

  Nucleolus
• What is the function of ribosomes?

  The site of protein synthesis
• What size are eukaryotic ribosomes?

  80s
• What size are prokaryotic ribosomes?

  70s
• What types of cells have ribosomes?

  Animal, plant & bacteria
• What is the function of mitochondria?

  Site of aerobic respiration
• What cells have mitochondria?

  Eukaryotic
• What is the name for the region of space in a mitochondria?

  Matrix
• What is the name for the folds of the inner membrane in a mitochondria?

  Cristae
• What is the function of a cell membrane?

  Controls what enters and exits the cell
• What is the ctructure of a cell membrane?

  Phospohlipid bilayer
• What types of cells have cell membranes?

  Animals, plants & bacteria
• What types of cells have a cell wall?

  Plants & bacteria
• What is the cell wall in plants made of?

  Cellulose
• What is the cell wall in bacteria made of?

  Peptidoglycan
• What is the function of the cell wall?

  Provides support and structure
• What makes an endoplasmic reticulum rough?

  Ribosomes
• What is the function of the rough endoplasmic reticulum (RER)?

  Develops the tertiary and quaternary structure of proteins