Nuclear and DNA
Organization
DNA
Replication
Mode of replication
Dispersive
Semi conservative
two original DNA strands
Conservative
2 Mix DNA strands
Discovered by
Meselson-Stahl
Proof Reading and repair
Proof Reading
half of the new DNA double helices would be composed of completely old, or original
Damage repair mechanism
Excision
Double Strand Break repair
Direct
Undone by Enzymes of the cell
Removal and replacement
Use to repair Double Stranded breaks in DNA
Reversal of Damage
used to restore damaged DNA
Check if there is a mismatched pair
Transcription
Contain three different Genes
Gene 2
Gene 3
Gene 1
Encodes mRNA to make a polypeptide
Encodes regulatory RNA which regulates expression of other Genes
Encodes tRNA which folds like a cloverleaf and plays key role in the synthesis of protein
Promoter
DNA unwind
RNA copy the template strand
5'3'
Hydroxyl group that is attached to 3 carbon sugar group
5 Carbon chain
Tells where to start
Human
Bacteria
Contains -10 and -35 elements
TATA Box
Elongation
strands get longer due to addition of new nucleotides
Termination
Eukaryotes
Bacteria
Rho-dependent termination
Rho-independent termination
RNA hits the region rich in C and G
Binding site Rho factor ends the transcription process
Termination happens when polyadenylation appears
Ready to be used mRNA
Translation
Process the mRNA and check for introns and exons
Introns are the junk materials
Exons are the good materials that were pasted together
RNA Splicing
Alternative Splicing
Allows more than one gene to be made from the same gene
Decode mRNA to build polypeptide
Eukaryote
Initiation
tRNA carrying methionine attaches to small ribosomal
Bind to the 5'
end of the mRNA by recognizing the 5' GTP cap
tRNA attached to small ribosomal unit "walk" along the mRNA in the 3' direction, stopping when they reach the start codon
Elongaion
Codon recognition
Bacteria
Initiation
Small ribosomal unit attaches to Shine-Dalgarno sequences
Initiation starts after Shine-Dalgarno sequences
Peptide bond formation
Translocation
Process of matching codons to the correct amino acids
Dehydration synthesis process
Carboxyl group of one amino acid moves towards the amino group of another amino acid
Subsequently, one hydrogen and one oxygen atoms are lost from the carboxyl group (COOH) of the first amino acid.
chromosome breaks and a portion of it reattaches to a different chromosome
Elongaion
Codon recognition
Peptide bond formation
Translocation
chromosome breaks and a portion of it reattaches to a different chromosome
Dehydration synthesis process
Carboxyl group of one amino acid moves towards the amino group of another amino acid
Subsequently, one hydrogen and one oxygen atoms are lost from the carboxyl group (COOH) of the first amino acid.
Process of matching codons to the correct amino acids
Termination
Ends when it reaches stop codons (UAA, UAG, UGA)