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Genes and the Genetic Basis of Metabolism and Development (Control of…
Genes and the Genetic Basis of Metabolism and Development
Concepts
Plants - many cells
distinct metabolism
respiration
amino acid synthesis
proteins
microtubules
membrane proteins
enzymes
Cell differ in shapes too
trachied/vessels - same enzymes/metabolism
secondary wall deposition
pattern varies
Division
differential activation of genes
underlying development process
protein synthesis
amino acids
structure
other properties of protein
DNA
hold info for protein
linear, polymer
4 monomers - A,T,G,C
Gene
Storing Genetic Information
Protecting the Genes :red_flag:
many ways
Most stored in nucleus
protected by nuclear envelope
formed during interphase
keep cytoplasmic components out
Histone proteins hold most nuclear DNA
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#
inert, resistant form
in all organisms that have nuclei
no participation directly in synthesis
mRNA
carry to site of synthesis
enzymes, substrates. activators, controlling factors
if damaged, can be replaced
Nucleosome
spherical structure
formed by histones
chromatin
DNA/protein structure
The Genetic Code
20 amino acids synthesize protein
1 nucleotide :forbidden: specify 1 amino acid
groups of 3
64 possible triplets
codons
most AA have 2 or more codons
using 4 nucleotides
UAA, UAG, UGA
stop codon
AUG
start codon
Structure of Genes
most genes
quiescent most of the time
activated when needed only
composed of
structural region
TATA Box
6 - 8 base pairs
rich in A, T
promoter
controlling region
regulate synthesis of mRNA
Exons
Introns
Transcription of Genes
creates RNA
performed by RNA polymerase
link nucleotides to form an RNA strand
hnRNA
both introns + exons
modified by nuclear enzymes
Protein Synthesis
Ribosomes : :red_flag:
read the genetic message in mRNA
construct proteins
rRNA
3 types
80S
large and dense
eukaryotes
70s
smaller, lighter
plastids, mitochondira, prokaryotes
tRNA :red_flag:
carries AA to ribosomes
important :warning:
codon cannot interact directly with AA
anitcodon
complementary to codons
a lot of them
mRNA translation : :red_flag:
Initiation of Translation
begins
start codon: AUG
eukaryotic initiation factors
bind to smallest subunit
important to align ribosomes on mRNA
Frameshift error
wrong sets of three
synthesis of a protein molecule
Elongation of the Protein Chain
extending outward from mRNA strand
AA brought by tRNA to ribosomes
Termination of Translation
polypeptide is released
stop codon enters A site
recognized by release factors
fit into P site
Control of Protein Levels
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unique enzymes
gene physically available for transcription
transcription factors
bind to promoter or enhancer
trans-acting factors
nature of the promoter region
processing if hnRNA into mRNA
transport of mRNA
binding of mRNA to subunits
rate of translation
processing of protein
activation/inactivation of the protein
many present in its inactive form
Analysis of Genes and Recombinant DNA Techniques
Nucleic Acid Hybridization :red_flag:
break hydrogen bonds
heat it
DNA melting and DNA denaturation
if cooled down
complementary sequences form hydrogen bonds
reformation of double stranded DNA by cooling
DNA hybridization
Restricting Endonucleases :red_flag:
Genetic Engineering of Plants
recombinant DNA
identify, isolate, and study gene structure and activity
insert genes
to plants that originally did not have it
ex. cotton plant got genes from
Bacillus thuringiensis
GMOs
genetically modified organisms
not welcomed by people
Golden rice
Virus
Virus Structure :red_flag:
small particles
usually contains protein and nucleic acid only
have no protoplasm, organelles, membranes
cannot carry out metabolic functions
first seen with electron microscope
Plant viruses
long or short rods or even round particles
retrooviruses
contain single-stranded RNA
greatest number
source of reverse transcriptase
Split genome viruses
not all of nucleic acid is packed as one particle
Virus Metabolism :red_flag:
plants, fungi, animals, protozoans, algae, prokaryotes
all are attacked by viruses
bacteriophages
virus that attack bacteria
Formation of New Virus Particle
some self assemble
tertiary structure
bind to viral DNA
attract/adhere to more viral protein
Plant Diseases Caused by Viruses
at least thousand
detection can be difficult
do not try to cure the entire plant
infect through wounds
then divert plant's nucleic acid
to synthesize more virus molecules
self-assemble into complete virus particle
