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Genes and the Genetic basis of metabolism (Analysis of genes and…
Genes and the Genetic basis of metabolism
Storing genetic information
The genetic code
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Start codon
AUG
Stop codon
UAA, UAG and UGA
20 types of amino acids are used in synthesizing proteins, but only 4 different nucleotides are present in DNA
Genetic codes are almost perfectly universal, only in mitochondria several codons are changed
The structure of genes
Double helix structure
Functions are, replication, encoding information, mutation and gene expression
Genes are composed of structural region that actually codes for amino acid sequence
Protecting the genes
Most DNA is stored in the nucleus, protected from the cytoplasm by the nuclear envelope
Histone protein hold most nuclear DNA in an inert, resistant form.
DNA does not participate directly in protein synthesis. Instead, DNA produce a messenger molecule.
Transcription of genes
First step of DNA based gene expression
Particular segment of DNA is copied into RNA by the enzyme RNA polymerase
Initiation, elongation and termination are the three steps of transcription
Protein synthesis
tRNA
It decode a specific codon of mRNA using anticodon
It reads the message of nucleic acid or nucleotides, and translate it into proteins, or amino acids.
mRNA Translation
Carries the genetic information copied from DNA in the form of series of three-base code
Translation is the whole process by which the base sequence of an mRNA is used to order an to join the amino acids in a protein
Ribosomes
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Catalyze the assembly of amino acids into protein chains
Also binds tRNAs and various accessory molecules
Control of protein level
Many enzymes and structural proteins are found inactive in cells.
Example: Tubulin, which became active in specific time
Genes expression is also controlled by short RNA molecules called micro-RNA.
Analysis of genes and recombinant DNA Techniques
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DNA cloning
Molecular biology technique that makes many identical copies of a piece of DNA
Restriction Endonucleases
A restriction endonuclease is an enzyme that cuts the DNA molecule at, or near to, a specific nucleotide sequence to produce discrete DNA fragments that can be separated by gel electrophoresis. From: Medical Microbiology (Eighteenth Edition), 2012.
DNA sequencing
DNA sequencing is the process of determining the nucleic acid sequence
Nucleic acid hybridization
A technique in which single-stranded nucleic acids (DNA or RNA) are allowed to interact so that complexes called hybrids are formed
Sequencing entire genome
Entire genome cannot be sequenced
It should break down into small pieces, sequence the pieces and reassemble them in proper order
Genetic engineering of plants
Examples-: plants with resistance to some insects, plants that can tolerate herbicides, and crops with modified oil content.
Genetic engineering provides a quicker and more precise way to achieve the same goal
Involves adding a specific stretch of DNA into the plant's genome, giving it new or different characteristics.
Genetic engineering and evolution
Herbert Boyer invented genetic engineering
In plants, genetic engineering has been applied to improve the resilience, nutritional value and growth rate of crops such as potatoes, tomatoes and rice.
steps of genetic engineering
Step 2 : Gene Cloning. ...
Step 3 : Gene Design. ...
Step 4 : Transformation. ...
Step 5 : Backcross Breeding.
Step 1: DNA Extraction
