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Genes: Metabolism and Development - Coggle Diagram
Genes: Metabolism and Development
Storing Genetic Information
DNA
Deoxyribonucleic acid
linear
A,C,T, G
Gene
DNA sequence analysis
genetic engineering
Protecting the Genes
Critically important
methods
messenger RNA (mRNA)
if damaged, can be replaced
multiple copies
small piece of DNA
stored in nucleus
protected from cytoplasm
nuclear envelope
Histone proteins
nuclear DNA
Resistant form
H1, H2A, H2B, H3, H4
nucleosome
chromatin
DNases
Genetic Code
20 amino acids used in synthesizing proteins
only 4 nucleotides are present in DNA and mRNA
codons
64 possible triplets
mRNA not DNA
degenerate
mutations
stop codons
UAA, UAG, UGA
signal ribosomes
start codon
AUG
signal ribosome to start
universal for all organism's
except mitochondria
Structure of Genes
90% of the time quiescent
structural region
promoter
regulates mRNA synthesis
codes amino acid sequence
exons and introns
exons=expressed
introns=intervene between exons
TATA box
6-8 base pairs long
if damaged
RNA polymerase II does not bind well
Enhancer elements
eukaryotic genes
several hundred base pairs away from structural region
hormone alters cell metabolism
promoter region
Transcription
creation of RNA
2 strands of DNA seperate
free ribonucleotides
form H bonds
forms covalent bond
produces RNA
process proceeds rapidly
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heterogenous nuclear RNA (hnRNA)
rapidly modified
by nuclear enzymes
introns are cut out
exons spliced together
poly (A) tail
Alternative Splicing
1 or more exons removed with introns
1 gene can produce 2 or more mRNA
both transcribed into DNA
Protein Synthesis
Ribosomes
small particles
"read" mRNA genetic message
Ribosomal RNA (rRNA)
80s ribosomes
large and dense
70s ribosomes
smaller and lighter
tRNA
Transfer RNA
carry amino acids during protein synthesis
can only be read by anticodon
amino acid attachment site
amino acid activation
after process gives up its amino acid and shuttles back to cytosol
mRNA Translation
Initiation
synthesis of protein
start codon AUG
methionine
tRNA
initiator tRNA binds to small ribosome subunit
eukaryotic initiation factors (eIFs)
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Elongation
mRNA lies between 2 ribosomes subunits
initiator tRNA in P channel
adjacent A channel
empty, numerous molecules enter at random
most diffuse out
correct codons and anticodons
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amino acid
p= protein
Termination
stop codon in A channel elongation cannot occur
no anticodon equivalent
H2O released
Control of Protein Levels
We know very little about control of transcription in eukaryotes
transcription factors
proteins that bind to the promoter
trans-acting factors
promoters, enhancers, and TATA boxes
cis-acting factors
micro-RNAs
large number
ends in -RNA
Genes and Recombinant DNA Techniques
Nucleic Acid Hybridization
heat can break double helix
DNA Melting
DNA Denaturation
slowly cooled and bonded back together
DNA Hybridization and reannealing
used to determine relatedness of DNA
Restriction Endonculeases
Natural DNA is long
fragments are more manageable
impossible before 70's
restriction endonucleases discovered
cuts and cleaves DNA
DNA ligase
repair enzyme
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Identifying DNA Fragments
Evolutionary Studies
fragments are used to study DNA evolution
restriction map
fragment # reveals # of PstI sites
plastid DNA
restriction fragment length polymorphism (RFLP)
mutation adds extra base pairs
Physiological Studies
reverse transcriptase
virus enzyme that synthesizes DNA using RNA
Complementary DNA (cDNA)
hydrogen bonds with gene fragments
if amino acids are known
can reasonably guess code
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DNA Cloning
copy of important fragments
mixed with plasmids or virus DNA
plasmid
short, circular piece of DNA
acts like tiny bacterial chromosome
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Polymerase Chain Reaction
(PCR)
powerful DNA cloning technique
uses enzymes only
heated to separate
cools both sides
adds two types of primer DNA
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DNA Sequencing
chain termination method
first cloned to obtain large sample
divided into four batches
enzymes and free nucleotides are added to batches
dideoxyadenosine added to 1 tube
Pyrosequencing method
DNA is added to solution with enzymes
enzymes release light
sequencers sequences DNA strands
Open-reading frame (ORF)
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Sequencing Entire Genomes
Genetic Engineering of Plants
recombinant DNA allows botanists to do a lot
identify, isolate, study the structure of genes
can insert genes
genes can protect plant and prevent damage
GMO's
not accepted by everyone
golden Rice could help people who rely on rice
ti plasmid
insertion vector
inserting into nuclear DNA is hard
CRISP-Cas9
new tool for precisely editing DNA
guide RNA binds
CRISP cuts both strands of DNA
new tech can add DNA also
binds to natural and artificial RNA
new modifications are coming
almost limitless potential
Genetic Engineering and Evolution
herbicide-resistant crops
glyphosphate
blocks synthesis of important amino acids
in plants
kills all plants
Roundup
not harmful to animals nor pollutes water
bacterial CP4 gene
immune to Roundup
added to soybean plants
Genetically Modified [GM]
leads to mutated weeds
potentially dangerous for future growth
Are GMOs Bad?
science doesn't have an answer
can identify consequences through scientific method
Great possible outcomes
also very bad possible outcomes
Emergent Properties
the sum is greater than its parts
emergent property
exists in number of units not in just one unit
central to biology
our carbon doesn't have traces of our consciousness
water is an example
Evolutionary Modifications of One Feature May Affect Other Features
ancestral cacti were small and wooded
modern cacti are succulents
cells must divide to replicate its DNA
can't be completely exact
leads to evolution of species'
called apical domincance
