Ch 6 - Pt 1 - Tour of the Cell Flashcards
Techniques in light microscopy to increase visibility of structures
1) Bright field light microscopy (stained and unstained specimens) 2) Phase-contrast light microscopy 3) Differential-interference contrast light microscopy
4) Fluorescence light microscopy
5) Confocal light microscopy
6) Fluorescence light microscopy
Light microscope
Can magnify effectively to about 1,000x the size of the actual specimen, but most subcellular structures are too small to be seen with a light microscope.
Scanning electron microscopes (SEM)
Focus a beam if electrons onto the surface of a specimen and collect emitted electrons to provide images that look 3D
Transmission electron microscopes (TEMs)
Focus as beam of electrons on a specimen and collect electrons that pass through the specimen. Mainly used to study the internal structure if cells and magnify up 1 million times the size of the actual specimen.
Cell theory
All living things are composed if cells and all cells have the same basic features
Basic features of a cell
1) Semiautonomous, reproduce
2) Carry a genetic program in the form of DNA
3) Enclosed by a plasma membrane
4) Semifluid internal substance called cytoplasm
5) Contain ribosomes (make proteins)
Prokaryotic cell characteristics
1) Simple and have existed for ~3.5 billion years.
2) Do not contain organelles; cellular processes occur diffusely within the cell.
3) Genetic material is in the firm of a single large, naked DNA molecule.
Eukaryotic cell characteristics
1) More complex than prokaryotic cells and have existed for ~2.5 billion years
2) Has a distinct, membrane bound nucleus containing the cell’s DNA
3) Has separate organelles
Organelles
Specialized structures that perform specific functions
Who was the first person to observe and describes cells?
Robert Hooke was the first man to observe and describe cells in plant tissues. Published “Micrographia”
What limits cell size?
The ratio between surface area and volume limits cell size because as surface area increases, volume increases massively more.
Why is it important for a cell to have a higher surface area to volume ratio?
Cells with a higher surface area to volume ratio have a greater ability to exchange materials with its environment.
Plasma membrane
A selective barrier comprised primarily if a phospholipid bilayers that enclosed the interior of the cell, the cytoplasm; maintains the difference between internal and external environments.
Cell wall
Protects and supports plant cells
Nucleus
Contains the cell’s genetic material; pores in the membrane of the nucleus allow molecules to move between the nucleus and the cytoplasm.
