Cells as a basis of life Flashcards
What is a cell?
The building blocks of life. They make up everything. All cells are similar but differ in some way.
What are the 6 kingdoms?
Archaea
Eubacteria
Protista
Fungi
Plantae
Animalia
What are the three domains?
Archaea
Bacteria
Eukarya (Eukaryotes)
What are the types of Bacteria?
Cyanobacteria- Nostoc
Stromatolites- Green Algae
Nitrogen fixing bacteria- Bacillus
What are characteristics of Eukaryotic cells?
- Have membrane-bound organelles
- DNA contained within a nucleus
- Range from 10-100um
What is the ‘Cell Theory’?
- Cells are the smallest units of life
- All living things are made up of cells
- All cells come from preexisting cells
What are prokaryotes?
Organisms that are made up of a single cell (unicellular)
What are the types of Archaea?
Methanogens- Methanosarcina Barkeri
Halophiles- Halobacterium
Thermophiles- Alicyclobacillus
WHat are some characteristics of Prokaryotes?
- Surrounded by cell wall
- Does not have membrane bound organelles
- No nucleus so DNA moves freely within Cytoplasm
- Ranges in size from 0.1 - 10um
What are the two types of prokaryotes and where are they found?
Archaea and Bacteria
Found in most environments and inside our bodies
Can be extremophiles (lives in harsh environemnts)
What can Eukaryotes be classified into?
Plant, Animal, Fungi, Protist
What are examples of plant eukaryotes
Algae
Moss
Ferns
Conifers
Flowering Plants
What are examples of animal eukaryotes?
Invertabrates- worms, insects
Vertebrates- fish, amphibians, reptiles, birds, mammals
What are examples of fungi eukaryotes?
Mushrooms
Yeast
What are examples of Protist eukaryotes?
Amoeba
Paramecium
Euglena
What is the equation for scale?
Scale= Actual length of cell/ the length of the drawing
What is a microscope?
A tool that uses lenses to enlarge or magnify objects to make them easier to observe
What is a compound microscope?
A microscope that uses two sets of lenses to enlarge the image
What specimens can you see with a light microscope?
Thin sections or whole organism (dead or alive)
What is the treatment for a light microscope?
Stains can be applied to highligth different components of the cell
What image can you see with a light microscope and at what magnification?
Can view inside a cell or the whole cell at up to 1500x magnification dependieng on lense
What are the advantages of a ligth microscope?
- Live Specimens can be viewed
- Easy to prepare specimens slides
- Stains can easily be applied to highlight aspects of the cell
What are the disadvantages of a light microscope?
Lower magnification and resolution so less detail can be seen.
What are the types of electron microscopes?
Transmission Electron Microscope
Scanning Electron Microscope
What specimen can be viewed with an Transmission ELectron Microscope?
Ultra thin section or whole microscopic dead organism
What is the treatment on an Transmission ELectron Microscope?
Stained, dehydrated or fixed specimens embedded in resin and sectioned.
What image can you see with an Transmission ELectron Microscope?
Can view inside a cell or the whole organism, with multiple images to create 3D view. The electrons are transmitted through the specimen.
What is the treatment for a Scanning Electron Microscope?
Stained, dehydrated, fixed specimens, coated in thin layer of metal atoms.
What specimens can be viewed with a Scanning Electron Microscope?
Thin Section or whole organism (dead or alive)
How is the imaged processed and what image do we see from a Scanning Electron Microscope?
Electrons bombard specimen and rebound pattern. We get see a 3D surface view.
What are the advantages of electon microscopes?
- Specimens can be viwed with greater detail due to higher magnification and resolution
What is the FOV diameter for x1000 magnification?
150um
What are the disadvantages of using an electron microscope?
- Preparation of specimens is time consuming, difficult and expensive
- Cannot view live specimens with Transmission Microscope
- Harsh treatment of specimens can distort the true nature of the structure os cells being viewed.
Why are microscopes important?
- it allowed scientists to view microscopic organisms
- Cells can be examined inmore detail and organelles identified
- Enabled scientists to identify the nucleus and DNA
- Genes that caused diseases could be identified
How do you calculate magnification?
Multiply the power of ocular lens by power of objective lens
E.g. x10 x x4 = x40 magnification.
What is the formula for estimating cell size?
Cell Size= Diameter of field of view / No. of cells across field of view
What is the FOV diameter for x100 magnification?
1.5mm
What is the FOV diameter for x40 magnification?
4.5mm
How do you convert from mm to um?
mm x 1000
4mm= 4000um
What is the FOV diameter for x400 magnification?
450um
What are the two microscopy techniques and thier purpose?
Wet mounts- improves a sample’s appearance and enhances visible detail.
Stains- highlights specific features, mostly used on dead specimens.
What is a model?
Physical, conceptual or mathematical representation of a real phenomenon that is difficult to observe directly.
What are the advantages of using scientific models?
- provides information when the object or process can’t be observed directly.
- use to notice patterns and revise representations
- Can break down a concept into similar terms with a visual component.
- Helps visualise ideas or abstract concepts
- Models save time, money and lives.
- Can be used to make and test predictions
- Can be changed as theories change or update.
What are the disadvantages of a scientific model?
- Usually simplified versions have missing information and details
- Accuracy can be lost
- Models do not behave exactly like the thing they represent.