4.1-4.9 Flashcards
(68 cards)
What are the two important factors in microscopy?
Magnification and resolution.
How do light microscopes work?
Light passes through the organism, and lenses bend it to be magnified. Max about 1000X times. Detail up to 0.2 micrometers (smallest bacteria)
Classic example of resolution?
One star becoming two stars w/ higher resolution.
Define cell theory
1665-1900s, development of our understanding of the cell using light microscopes.
What is an electron microscope?
EM, 1950s. Beams electrons through specimens. Detail up to two nanometers (100X better than LM).
What are the two types of electron microscopes?
Scanning (SEM) and Transmission (TEM). Both use lenses to bend the paths of electrons.
SEM?
Used for detail in cell surface. Electron beam touches surface covered in gold foil (excites electrons). 3D, topographical images.
TEM?
Used for details of internal cell structure. Electron beam on thin slice of specimen, which also has heavy metals in it, attracting certain organelles.
What are the downsides of EM?
Kill the cell.
Other microscopy techniques?
Differential interference contrast, fluorescent stains.
Type of microscope used for: human hair, the surface details of white blood cells, organelle in the liver
LM, SEM, TEM
What must cells be large enough to hold?
DNA, protein and structures to survive and reproduce.
Why do cells need so much surface area?
fluid membrane, allows for the most access (see blocks example, pg. 54).
In 4.2, there is a review of phospholipid bilayer.
Two types of cells?
prokaryotes and eukaryotes.
Kingdoms that are prokaryotes?
Archaea and Bacteria
Eukaryotic kingdoms?
Fungi, animalia, protista, plantae
Diff. btw eukaryotes and prokaryotes?
Membrane-bound nucleus and organelles.
Things shared between eukaryotes and prokaryotes?
Interior of cells filled with cytosol, have chromosomes, have ribosomes, inside of the cell is cytoplasm.
Define cytosol
Thick, jellylike fluid inside a cell.
Define chromosome
Made up of genes, which are made up of DNA.
Ribosome function?
tiny structures that make proteins based on instruction from DNA.
Define cytoplasm
Everything and anything within a cell. (*Eukaryotes: only between nucleus and plasma membrane)
What are different things found in prokaryotic cells?
Fimbriae (sometimes- small things on the surface that can attach to others), ribosomes (diff. from eukaryotic ribosomes), nucleoid (where DNA is found-NO nucleus), plasma membrane, cell wall (!!), capsule (jelly-like outer coating), flagella (tails that move the cell).