biotechnology Flashcards
DNA sequencing
determining order of nucleotides
robotic sequencing
- Tag nucleotides with colors
- Shoot DNA pieces by a camera
- Order of colors reveals order of nucleotides
DNA cloning: restriction enzymes
Their function is to cut apart viral DNA to prevent infection, but we can use them for our purposes.
restriction enzymes cut DNA at
a specific sequence of nucleotides
HINDIII cuts at:
AAGCTT (cuts anywhere this sequence is found, making many pieces of DNA)
restriction enzymes usually cut unevenly, creating
sticky ends (ends want to stick to matching sequence)
recombinant DNA
DNA created from multiple sources
how does recombinant DNA work?
Cut DNA from each source with the same restriction enzyme (matching sticky ends)
Mix DNA from both sources
Sticky ends from different sources attach
DNA ligase enzyme bonds sources together
plasmids
small circular pieces of DNA (not chromosomes) that have NON ESSENTIAL genes on them
bacteria pass ___ to each other
plasmids
DNA cloning uses ____ to…
bacteria to make copies of DNA pieces
how do you find the bacteria that has the plasmid?
the environment contains an antibiotic, plasmids contain defense against this antibiotic. The bacteria WITHOUT plasmids DIE.
how do you find plasmid with foreign DNA in it?
plasmids withOUT DNA have an intact lacZ gene that turns the colony blue. plasmids WITH the DNA have disrupted lacZ gene and produce white colonies.
polymerase chain reaction (PCR) is a fast way of
duplicating DNA (minutes or hours)
what does PCR use?
NOT bacteria, instead enzymes from bacteria in hot springs
PCR process is driven by
temperature changes
PCR process: 1. denaturing
-95 C
-separates DNA strands (no helices)
PCR process: annealing
-68 C
-add/mix in primer sticks to target DNA sequence
PCR process: elongation
-72 C
-DNA polymerase adds nucleotides
-from species that live in hot environments to avoid denaturing
each PCR cycle step
doubles the number of target sequences
identical twins have identical
DNA
how do twins arise?
1 fertilized egg splits in half
artificial splint
reproductive cloning
somatic cell nuclear transfer
take DNA out of somatic cell, take DNA out of an egg, put DNA from somatic cell into egg. Egg does not need to be fertilized because it has 2 copies of DNA.
*DNA instructs egg to grow into genetic copy of first individual
to clone, cells must be tricked..
into going back into the embryonic state
* Turns on all instructions again
* Very difficult
DOLLy the sheep
the sheep was the first cloned sheep in 1977
why do cloned animals have health problems?
Adult cell telomeres are already used up leading to health issues
* Premature aging
how can restriction enzymes be used to tell people apart?
- Individuals have different numbers of restriction sites
- Size of pieces will be different
DNA electrophoresis separates pieces by
size
single nucleotide polymorphism (SNP)
o A DNA sequence variation that occurs when a single nucleotide (adenine, thymine, cytosine, or guanine) in the genome sequence is altered
o We know of 4.5 million SNPs
o There are many more we have not found
DNA tests look for
o From cells in spit
o Search for common SNPs
genetic engineering: intentionally change a __ to make something new
genome
transgenic organism
Has genes from more than 1 species
typical modified microorganisms:
Usually use bacteria (prokaryote) and yeast (fungi, eukaryote) are small and easy to grow
transgenic bacteria used to make
insulin
GMO crops attempt to avoid
environmental problems while having a high yield
GMO crop advantages
More resistant to diseases and pests (reduces pesticide use)
-more resistant to herbicides
Increase nutrients
biggest GMO concern
- Transgenic genes appearing in wild plants: moderate concern
o Weed could get new genes, and you cannot get the genes back.
gene therapy is treatment for
genetic disorders
problem with gene therapy on children with no immune system?
o Gene enters at random spot on chromosome: can be bad if they disable cell cycle control genes
o Can cause cancer
o Risk for treatment was not worth it
genomes are all ____ in an organisms DNA
genes
number of ___ does not have to do with complexity
genes
genomic size:
o Number of bases is not directly related to complexity
o Number of genes not directly related to complexity
helpful comparisons related to genome size
Number of base pairs (measured in haploid cells like gametes)
Number of genes
Density: genes per million bases
number of base pairs in humans (in haploid cells)
3 billion
number of genes in humans
21,000
density in humans
7
eukaryotes have a lot of
noncoding DNA (prokaryotes have NONE)
short tandem repeats
Repeating series of the same sequence of 2-5 bases
Useful for distinguishing individuals
transposable elements can move from …
one location in DNA to another
transposable elements make up a large % of
noncoding DNA (20-50% in mammals, 80% in corn )
