biological theories + technology

Question 1

cell theory

Answer 1

• 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

Question 2

RNA world hypothesis

Answer 2

• self replicating RNA molecules were precursors to life
• RNA stores genetic information like DNA
• RNA can catalyze chemical reactions like enzymes

Question 3

central dogma of biology

Answer 3

DNA&raquo_space; RNA&raquo_space; Protein

Question 4

light microscope

Answer 4

use visible light to view a thin sample

Question 5

scanning electron microscope

Answer 5

used to view surface of 3D objects with high resolution

Question 6

Transmission Electron Microscope (TEM)

Answer 6

used to view thin cross sections and internal structures within samples at very high magnification

Question 7

confocal laser scanning microscope/fluorescence

Answer 7

can observe specific parts of a cell using fluorescent tagging antibodies
- used to view chromosomes during mitosis

Question 8

polymerase chain reaction (PCR)

Answer 8

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

Question 9

reverse transcriptase

Answer 9

• 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

Question 10

centrifugation

Answer 10

• 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&raquo_space; mitochondria/chloroplast&raquo_space; ribosomes

Question 11

DNA sequencing

Answer 11

• 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

Question 12

blotting techniques

Answer 12

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

Question 13

southern blot

Answer 13

DNA

Question 14

northern blot

Answer 14

RNA

Question 15

western blot

Answer 15

protein

Question 16

gel electrophoresis

Answer 16

• 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

Question 17

in gel electrophoresis, does a smaller molecule travel further or shorter down the gel

Answer 17

farther

Question 18

microarray assays

Answer 18

used to monitor the expression of large groups of genes across a genome

Question 19

recombinant DNA & gene libraries

Answer 19

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

Question 20

examples of vectors

Answer 20

plasmids + bacteriophages

Question 21

recombinant DNA in bacterial cloning

Answer 21

1. restriction enzyme is applied to both the bacterial plasmid and the foreign DNA to create the same sticky ends
2. DNA ligase attaches the fragments to create plasmid with new DNA
3. plasmid is introduced into bacteria using transformation
4. 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

Question 22

recombinant DNA vital for…

Answer 22

creating gene libraries = collections of DNA pieces from a genome