Exam 2 Flashcards
eukaryotic cells
cells with a nucleus
plasma membrane
controls what goes into and out of the cell
Ribosomes
site of protein synthesis
DNA in nucleus
contains instructions for making proteins
What do only plant cells have?
cell walls
Chloroplasts covert ___ energy to ___ energy
light, chemical
Mitochondria break down molecules, generating ___
ATP
light microscope (LM)
visible light is passed through a specimen and then through glass lenses
Magnification
the ratio of an object’s image
Resolution
the measure of the clarity of the image, or the minimum distance of two distinguishable points
Contrast
visible differences in brightness between parts of the sample
organelles
the membrane-enclosed structures in eukaryotic cells
Light microscopes can magnify effectively to about ___ times the size of the actual specimen
1000
Scanning electron microscopes (SEMs)
focus a beam of electrons onto the surface of a specimen, providing images that look 3-D
Transmission electron microscopes (TEMs)
- focus a beam of electrons through a specimen
- used mainly to study the internal structure of cells
electron microscopes (EMs)
used to study subcellular structures
Cryo-electron microscopy (cryo-EM)
allows preservation of specimens at very low temperatures
- allows visualization of structures in their cellular environment, with no need for preservatives
cytology
the study of cell structure
Cell fractionation
takes cells apart and separates the major organelles from one another
- enables scientists to determine the functions of organelles
Only organisms of the domains Bacteria and Archaea consist of ___ cells
prokaryotic
Protists, fungi, animals, and plants all consist of ___ cells
eukaryotic
Basic features of all cells
–Plasma membrane
–Semifluid substance called cytosol
–Chromosomes (carry genes)
–Ribosomes (make proteins)
Prokaryotic cells are characterized by having
–No nucleus
–DNA in an unbound region called the nucleoid
–No membrane-bound organelles
–Cytoplasm bound by the plasma membrane
Eukaryotic cells are characterized by having
–DNA in a nucleus that is bounded by a double membrane
–Membrane-bound organelles
–Cytoplasm (the region between the plasma membrane and nucleus)
–larger