nucleic acids 2
TRANSCRIPT
NUCLEIC ACIDS
Topic Outline:
Structure and Function Types of Nucleic Acids
1. DNA2. RNA
Central Dogma of Life
Nucleic acids- comprise the fourth major group of biomolecules in living cells.
- play extremely important roles in the cell.
- also called as biopolymersCommon nucleic acids:
1. DNA- deoxyribonucleic acid- the hereditary molecule
2. RNA- Ribonucleic acid- participate in the conversion
of the genetic code into proteins and other gene products.
Nucleotides- are building blocks of the nucleic acid polymers.
- are complex monomers than amino acids.
Structural Components of the Nucleotides:a. Nitrogen-containing base
- nitrogenous baseb. A five-carbon sugar- pentosec. A phosphate group
Types of Nucleic acids:1. DNA- deoxyribonucleic acid
- DNA nucleotides- found in the nucleus with
small amount of mitochondria and chloroplast
Component:a. Nitrogenous baseb. Deoxyribosec. Phosphate group-genetic instructions used in
the development and functioning of all known living organisms.
- The DNA segments that carry this genetic information are called genes,
2. RNA- Ribonucleic acid- RNA Nucleotides- found throughout the cell
Component:a. Nitrogenous base b. Ribosec. Phosphate group
- plays several important roles in the processes of transcribing genetic information from deoxyribonucleic acid (DNA) into proteins.
PHOSPATE SUGAR
Ribose or Deoxyribose
NUCLEOTIDE
BASEPURINES PYRIMIDINES
Adenine (A)Guanine(G)
Cytocine (C)Thymine (T)Uracil (U)
Difference between the pentose sugar of DNA and RNA
RIBOSE DEOXYRIBOSE
CH2OH
H
OH
C
C
OH OH
C
O
H HH
C
CH2OH
H
OH
C
C
OH H
C
O
H HH
C
THE SUGAR-PHOSPHATE BACKBONE
The nucleotides are all orientated in the same direction
P
P
P
P
P
P
ADDING IN THE BASES
The bases are attached to the 1st Carbon
Their order is important It determines the genetic information of the molecule
P
P
P
P
P
P
G
C
C
A
T
T
DNA IS MADE OF TWO STRANDS OF POLYNUCLEOTIDE
P
P
P
P
P
P
C
G
G
T
A
A
P
P
P
P
P
P
G
C
C
A
T
T
Hydrogen bonds
DNA IS MADE OF TWO STRANDS OF POLYNUCLEOTIDE
The sister strands of the DNA molecule run in opposite directions (antiparallel)
They are joined by the bases Each base is paired with a specific partner:
A is always paired with T G is always paired with C“Purine with Pyrimidine”
The sister strands are complementary but not identical
The bases are joined by hydrogen bonds, individually weak but collectively strong
There are 10 base pairs per turn
Difference between Pyrimidine and Purine Bases
Major difference between DNA and RNA
*DNA is double stranded, whereas RNA is single stranded
*DNA contains deoxyribose, whereas RNA contains ribose
* DNA contains thymine, whereas RNA contains uracil.
CENTRAL DOGMA
It was Francis Crick who in 1957, proposed what referred to as the central dogma.
DNA mRNA PROTEIN
Cellular Processes
DNA
RNA (mRNA)
Proteins
replication
transcription
translation
Replication
- 0ccurs by the separation of the DNA strands and the building of complementary strands by the addition of the correct DNA nucleotides.
Replication-formation of two new double-DNA strands
from a parent strand
Transcription-the information in one gene of a DNA molecule is used to produce mRNA molecule.
Events:1. one strand of DNA unwinds
temporarily exposing the bases.2. Attraction of the bases of RNA
nucleotides and a MRNA molecule begins to built alongside of one of the strand.
Initiating codon:AUG
Stop codon:UAAUAGUGA
Translation- information of one mRNA molecule is used to produce protein
- The base sequence of the mRNA molecule to interpreted in the group of three bases are called codons.- this will be used for the determination of amino acid .
GENETIC CODE in mRNA
Alanine- Ala Glycine- Gly Methionine- Met Tyrosine-Tyr
Arginine- Arg Histidine-His Phenylalanine- Phe Valine- Val
Asparagine- Asn Isoleucine- Ile Proline- Pro
Aspartic Acid-Asp Leucine- Leu Serine- Ser
Cysteine- Cys Lysine- Lys Threonine- Thr
Glutamic Acid- Glu Glutamine-Gln Tryptophan- Trp
GENERAL ILLUSTRATION ON THE FLOW OF GENETIC
INFORMATION
Solve:
Using the genetic code, identify the amino acid sequence:
5’- C G C G A A T T C G C G –3’ 3’- G C G C T T A A G C G C –5’