NUCLEIC ACID PART 1

REPLICATION

PROCESS : DNA molecules produce exact duplicates of themselves 

• Old strands act as templates for the synthesis of new strands 

DNA POLYMERASE 

checks the correct base pairing and catalyzes the formation of phosphodiester linkages 

• This enzyme can ONLY FUNCTION in the 5’-TO-3’ DIRECTION

leading strand

top

• grows continuously in the direction of unwinding

 lagging strand

• Okazaki fragments

grows in segments

• called that segment

NICK

Okazaki fragments

• gap called

15% by mass DNA and 85% by mass protein.

 A chromosome is about

• % by mass DNA

• % by mass protein.

tranSCRIPTION

PROCESS: DNA directs the synthesis of mRNA molecules

tranSLATION

PROCESS: mRNA is deciphered to synthesize a protein molecule

HAIRPIN LOOP

• produced when single-stranded RNA doubles back on itself and complementary base pairing occurs

HETEROgeneous nuclear RNA (hnRNA)

Formed directly by DNA transcription. 

• Post-transcription processing converts the hnRNA to mRNA

Messenger RNA(mRNA)

Carries instructions for protein synthesis (genetic information) fromDNA 

• The molecular mass of mRNA varies with the length of the protein

SMALL NUCLEAR RNA (snRNA)

Facilitates the conversion of hnRNA to mRNA.

• Contains from 100 to 200 nucleotides

Ribosomal RNA (rRNA):

Combines with specific proteins to form ribosomes 

• the physical site for protein synthesis Ribosomes have molecular masses on the order of 3 million

Transfer RNA (tRNA)

Delivers amino acids to the sites for protein synthesis 

• tRNAs are the smallest (75–90 nucleotide units)

GENE

A segment of a DNA base sequence responsible for the production of a specific hnRNA/mRNA molecule

GENOME

All of the genetic material (the total DNA) contained in the chromosomes of an organism

20,000–25,000

Human genome is about —- genes

HELICase

what ENZYME?

• Unwinding

• unzipping

TOPO ISOMERASE

what ENZYME?

• keep the DNA for SUPERCOILING

DNA POLYMERASE

what ENZYME?

• builder

PRIMASE

what ENZYME?

• Inializer

• 5 to 3

LIGASE

what ENZYME?

• GLUE to okazaki fragment

MOLECULES

• responsible for such information are nucleic acids

DNA:  Deoxyribonucleic Acid

Storage and transfer of genetic information

• FOUND:  within cell nucleus 

• PASSED: one cell to other during cell division

RNA:  Ribonucleic Acid

Occurs in all parts of cell 

• PRIMARY FUNCTION: synthesize the proteins

NUCLEOTIDE

NUCLEIC ACID

Polymers in which REPEATING UNIT IS

• Pentose Sugar: Monosaccharide

• Phosphate Group (PO4 3- ) 

• Heterocyclic Base

A NUCLEOTIDE has THREE COMPONENTS:

RIBOSE 

present in RNA 

•  a —OH group present on carbon 2’ in ribose

2-DEOXYRIBOSE

present in DNA 

• a —H atom in 2-deoxyribose

• Thymine (T)

• Cytosine (C)

• Uracil (U) 

 THREE PYRIMIDINE DERIVATIVES 

• Adenine (A) 

• Guanine (G) 

TWO PURINE DERIVATIVES

URACIL (U)

found only in RNA 

THYMINE (T) 

found only in DNA

PHOSPHORIC ACID (H3PO4 )

PHOSPHATE

• is derived from

• SUGAR-PHOSPHATE GROUPS

are referred to as nucleic acid backbone 

• Found in all nucleic acids 

Phosphate-Sugar

Backbone:

• Nucleic acids 

Peptide bonds

Backbone:

• Proteins

Phosphodiester

• bond at 3’ and 5’ position 

• Thymine

• Adenine

MAJOR GROOVE

• 2 hydrogen bond

• Guanine

• Cytosine

MINOR GROOVE

• 3 hydrogen bond

Backbone

• Phospho Di Ester

SUGAR PHOSPHATE

• LOCATION

• BOND

Center

• Hydrogen bond

Nitrogenous BASE

• LOCATION

• BOND

• JAMES WATSON

• FRANCIS CRICK

WHO DISCOVER

•  DNA DOUBLE HELIX

5 methyl 2 4 di oxo Pyridine derivatives

• THYMINE

4 amino 2 oxo Pyridine derivatives

• CYTOSINE

2 4 di oxo Pyridine derivatives

• URACIL

6 amino Purine derivatives

• ADENINE

2 amino 6 oxo Purine derivatives

• GUANINE

RIBOSE

DEOXYRIBOSE