GCD 3033. Chapter 1
Detection - answerability to perceive the presence of an object
Resolution - answer Ability to discriminate between two objects that are close together,
limited by the wavelength of light.
Contrast - answer to detect an object, it must contrast with its surroundings
Bright-field - answer low contrast images in living cells, often fiz and stain cells to add
contrast. Image of live cell, see nucleus and a few large organelles.
Phase contrast & differential interference contrast: - answer look at structures that
refract light
Fluorescence microscopy - answer Stain specific structures of cell with fluorescent
dyes. Improves detection but not resolution, WHY?
Process:
-Excite specimen with light of one wavelenth.
-Fluorescent dye ements light of a different wavelength
-Fixed cells (dead): stain cell components with specific antibodies or dyes
-Live cells: label cell componenets by genetic engineering
Confocal fluorescence microscopy - answerOptical sectioning of thicker samples with
laser beam
Central Dogma - answerDNA to RNA to Proteins
Fix and Stain cells - answerRedy dye stains positively charged molecules (proteins)
Purple dye stains negatively charged molecules (DNA,RNA)
Light microscopy - answerUsed to observe som sub-cellular structures or organelles
(nucleus), but need stronger magnification to see smaller structures-most organelles are
not visible by light microscopy.
Electron microscopy - answerAllows higher magnification of fixed cells (dead cells)
Transmission electron microscopy (TEM) - answerUsed to look at very thing sections of
cells. Allows detection of MORE sub-cellular organelles.
Scanning Electron Microscopy)SEM) - answerUsed to look at the surface details of
cells.
, Mitochondria - answer-present in nearly all eukaryotic cells, variable in size, shape, and
number
- double membrane structures
- contain their own DNA and reproduce by division
- DNA sequence related to bacterial DNA sequences
- Mitochondria (and chloroplasts) evolved from symbiotic bacteria engulfed by ancestral
cell (Figure 1-18)
- perform cellular respiration
- generate chemical energy (ATP) from food and O2, release CO2 and H2O
Endoplasmic Reticulum - answer(ER): network from nuclear envelope throughout
cytoplasm, Fig. 1-21
- rough ER has bound ribosomes, and is the site of synthesis of transmembrane
proteins
- smooth ER does not have bound ribosomes; it is the site of steroid hormone synthesis
and Ca2+ uptake
Golgi apparatus - answer-usually a stack of flattened membranes near the nucleus,
Figure 1-22
- receives and modifies and redistributes proteins made in the ER
- packages them for delivery to other locations or to the plasma membrane for secretion
-Located near nucleus in cell center
-Moevement of vesicles from ER to cis face of golgi
-Movement from trans face of golgi to other parts of the cell
Cytoskeleton - answer-filamentous proteins that provide structural framework for cell,
Figure 1-26
- three filament systems
(1) actin-based: used for contraction and transport. flexible strands with tensil strength,
support plasma membrane
(2) intermediate filament based: used for mechanical stabilization, rope-like strands
(3) microtubule-based: used for support and transport. hollow tubes serve as rigid
struts.
Yeast (S. cerevisae) - answerbrewers and baker's yeast
finish
Scizosaccarmoyces pombe - answer
C. elegans - answernematode worm
Advantages
- slightly smaller and simpler than Drosophila, 97 million bp, 19,000 genes
- detailed knowledge of cell fate from fertilized egg to 959 cells of adult worm
- worm counterparts exist for ~70% of human genes
- good model for animal development, programmed cell death
Detection - answerability to perceive the presence of an object
Resolution - answer Ability to discriminate between two objects that are close together,
limited by the wavelength of light.
Contrast - answer to detect an object, it must contrast with its surroundings
Bright-field - answer low contrast images in living cells, often fiz and stain cells to add
contrast. Image of live cell, see nucleus and a few large organelles.
Phase contrast & differential interference contrast: - answer look at structures that
refract light
Fluorescence microscopy - answer Stain specific structures of cell with fluorescent
dyes. Improves detection but not resolution, WHY?
Process:
-Excite specimen with light of one wavelenth.
-Fluorescent dye ements light of a different wavelength
-Fixed cells (dead): stain cell components with specific antibodies or dyes
-Live cells: label cell componenets by genetic engineering
Confocal fluorescence microscopy - answerOptical sectioning of thicker samples with
laser beam
Central Dogma - answerDNA to RNA to Proteins
Fix and Stain cells - answerRedy dye stains positively charged molecules (proteins)
Purple dye stains negatively charged molecules (DNA,RNA)
Light microscopy - answerUsed to observe som sub-cellular structures or organelles
(nucleus), but need stronger magnification to see smaller structures-most organelles are
not visible by light microscopy.
Electron microscopy - answerAllows higher magnification of fixed cells (dead cells)
Transmission electron microscopy (TEM) - answerUsed to look at very thing sections of
cells. Allows detection of MORE sub-cellular organelles.
Scanning Electron Microscopy)SEM) - answerUsed to look at the surface details of
cells.
, Mitochondria - answer-present in nearly all eukaryotic cells, variable in size, shape, and
number
- double membrane structures
- contain their own DNA and reproduce by division
- DNA sequence related to bacterial DNA sequences
- Mitochondria (and chloroplasts) evolved from symbiotic bacteria engulfed by ancestral
cell (Figure 1-18)
- perform cellular respiration
- generate chemical energy (ATP) from food and O2, release CO2 and H2O
Endoplasmic Reticulum - answer(ER): network from nuclear envelope throughout
cytoplasm, Fig. 1-21
- rough ER has bound ribosomes, and is the site of synthesis of transmembrane
proteins
- smooth ER does not have bound ribosomes; it is the site of steroid hormone synthesis
and Ca2+ uptake
Golgi apparatus - answer-usually a stack of flattened membranes near the nucleus,
Figure 1-22
- receives and modifies and redistributes proteins made in the ER
- packages them for delivery to other locations or to the plasma membrane for secretion
-Located near nucleus in cell center
-Moevement of vesicles from ER to cis face of golgi
-Movement from trans face of golgi to other parts of the cell
Cytoskeleton - answer-filamentous proteins that provide structural framework for cell,
Figure 1-26
- three filament systems
(1) actin-based: used for contraction and transport. flexible strands with tensil strength,
support plasma membrane
(2) intermediate filament based: used for mechanical stabilization, rope-like strands
(3) microtubule-based: used for support and transport. hollow tubes serve as rigid
struts.
Yeast (S. cerevisae) - answerbrewers and baker's yeast
finish
Scizosaccarmoyces pombe - answer
C. elegans - answernematode worm
Advantages
- slightly smaller and simpler than Drosophila, 97 million bp, 19,000 genes
- detailed knowledge of cell fate from fertilized egg to 959 cells of adult worm
- worm counterparts exist for ~70% of human genes
- good model for animal development, programmed cell death
