biological theories + technology Flashcards
cell theory
- all living organisms are composed of 1 or more cells
- cell is basic unit of structure, function, and organization
- all cells come from preexisting, living cells
- cells carry hereditary information
RNA world hypothesis
- self replicating RNA molecules were precursors to life
- RNA stores genetic information like DNA
- RNA can catalyze chemical reactions like enzymes
central dogma of biology
DNA»_space; RNA»_space; Protein
light microscope
use visible light to view a thin sample
scanning electron microscope
used to view surface of 3D objects with high resolution
Transmission Electron Microscope (TEM)
used to view thin cross sections and internal structures within samples at very high magnification
confocal laser scanning microscope/fluorescence
can observe specific parts of a cell using fluorescent tagging antibodies
- used to view chromosomes during mitosis
polymerase chain reaction (PCR)
creates large amount of DNA by amplifying a DNA sample through 3 steps:
1. denaturation - high heat separates double stranded DNA
2. annealing - sample is cooled so primers attach to separated strands
3. elongation - polymerase synthesizes new strands
reverse transcriptase
- used to synthesize DNA from an RNA template
- used to create complementary DNA (cDNA) off an mRNA temple
cDNA lacks introns - naturally used by viruses
centrifugation
- technique to separate a liquified sample into its different components by spinning it rapidly
- largest/most dense separate first forming a pellet at bottom of sample
- cell fractionation (largest to smallest) : nuclei»_space; mitochondria/chloroplast»_space; ribosomes
DNA sequencing
- used to determine the sequence of base pairs in a DNA or RNA molecule
- dideoxy chain terminations based on principle that during DNA synthesis the addition of a nucleotide requires a free OH group on the 3’ carbon of the sugar of the last nucleotide of growing DNA strand
blotting techniques
used for identifying specific fragments of DNA, RNA, protein
1. electrophoresis used to separate sample
2. sample is transferred to nitrocellulose gel
3. probe is added to hybridize and mark target fragment
southern blot
DNA
northern blot
RNA
western blot
protein
gel electrophoresis
- used to separate DNA molecules by size and charge
- after separating the DNA sample, it can be sequenced or probed to find location of specific sequence
in gel electrophoresis, does a smaller molecule travel further or shorter down the gel
farther
microarray assays
used to monitor the expression of large groups of genes across a genome
recombinant DNA & gene libraries
recombinant DNA contains segments from multiple sources
1. uses restriction enzymes to cut specific segments of DNA called restriction sites. these enzymes create sticky ends which allow new DNA pieces to bind
2. DNA ligase connects the different fragments together
3. vector can then be used to transfer foreign DNA into another cell
examples of vectors
plasmids + bacteriophages
recombinant DNA in bacterial cloning
- restriction enzyme is applied to both the bacterial plasmid and the foreign DNA to create the same sticky ends
- DNA ligase attaches the fragments to create plasmid with new DNA
- plasmid is introduced into bacteria using transformation
- bacteria can be grown to produce a product or form a colony. to ensure that the bacteria has included the plasmid, a gene for antiobiotic resistance is added to the plasmid. bacteria without the plasmid will perish
recombinant DNA vital for…
creating gene libraries = collections of DNA pieces from a genome
