A2.2 Cell Structure Flashcards
functions of life
Metabolism,
reproduction,
homeostasis,
movement,
growth,
response to stimuli,
excretion (removal of metabolic waste),
nutrition
Cell theory
Living organisms are composed of cells
Cells are the smallest unit of life
Cells come from pre-existing cell
Magnification
the ability to enlarge an object’s image
Resolution
the ability to differentiate two separate objects
Light Microscopes
Use lenses to bend light and magnify images by a factor of roughly 100-fold
Electron microscopes
Use electromagnets to focus electrons resulting in significantly _greater magnifications and resolutions__
Transmission electron microscopes (TEM) pass electrons through specimen to generate a cross-section
Scanning electron microscopes (SEM) scatter electrons over a surface to differentiate depth and map in 3D
Light Microscope advantages
Can observe living specimen
Cheap to use
Portable
Easy to used
Can observed colored specimen
light microscope disadvantages
Low Resolution
Only produced a two- dimensional image
electron microscope advantages
Can view finer details (Higher resolution)
electron disadvantages
Expensive
Difficult to prepare specimen
Not portable
May produce artifacts (structure that is not present in specimen) due to heavy metal staining
Cannot observed colored specimen. (The ‘color’ observed are ‘false-color scanning)
structures of prokaryotic cell
Capsule (Glycocalyx)
Cell wall
Cell membrane
Cytoplasm
Pili
Flagella
Nucleoid region
Plasmid
70S ribosome
capsule (glycocalyx)
Protect the cell from external environment
cell wall (prokaryotic)
Act as a structural support, made up of peptidoglycan
Cell membrane
Control substances going in and out of the cell
cytoplasm
Contain enzymes, site for metabolic reactions
pili
Responsible for exchange of plasmid between bacteria (horizontal gene transfer/sexual reproduction)
Flagella
Responsible for locomotion of the bacterium
Nucleoid region
Contain genetic material of the bacterium
Plasmid
Circular DNA in the cytoplasm
70S ribosome
Site for protein synthesis