Chapter 1 acid nucleic 2015813

CHAPTER 3

NUCLEIC ACID


CONTENT
Nucleoside, nucleotide, oligonucleotide
DNA, RNA
Physical & chemical properties
Modification mechanism
Biosynthesis of nucleotide
Application of molecular biology in Food
technology
Restriction enzymes
Genetic engineering
GMO (Genetically modified organism)
GMF (Genetically modified food)
Human genome


NUCLEIC ACID - HISTORY

 Isolated nuclein
(from nuclei of white blood cells)
nucleic acid
Nucleic acids: polynucleotides

Friedrich Miescher (1844-1895)
Swiss physician and biologist

NUCLEOTIDE STRUCTURE

PHOSPHATE
GROUP (PO4)

NITROGEN BASE (C-N ring)

SUGAR (5C)
Ribose (RNA)
Deoxyribose (DNA)

PURINES
Adenine (A)
Guanine(G)

NUCLEOTIDE

PYRIMIDINES
Thymine (T); Uracil (U)
Cytocine (C)


NUCLEOTIDE STRUCTURE - SUBUNITS


NUCLEOTIDE STRUCTURE - BONDS


NUCLEOTIDE STRUCTURE - PENTOSE

POLYNUCLEOTIDE-BACKBONE
 THE SUGAR-PHOSPHATE BACKBONE
 Sugar-phosphate joined by phosphodiester bonds
 Sugar-phosphate in poly nucleotide orientated in the same
direction
 3’-OH group of the sugar in one nucleotide forms an ester bond to
the phosphate group on the 5’-carbon of the sugar of the next
nucleotide


POLYNUCLEOTIDE-BACKBONE


NUCLEOTIDE STRUCTURE-BASE
Bases

 Attached to the 1st Carbon
of sugar


NUCLEOSIDE & NUCLEOTIDE
• Nucleoside

– consists of a nitrogen base linked to C1’ of a ribose or
deoxyribose (glycosidic bond)
– Named
• for purines: changing the nitrogen base ending: -ine to osine : adenine  adenosine
• for pyrimidines: changing the nitrogen base ending (osine to
– idine: cytosine  cytidine

NUCLEOSIDE & NUCLEOTIDE
• Nucleotide

– nucleoside forms a phosphate ester with the C5’-OH group of
ribose or deoxyribose
– Named: using the name of the nucleoside followed by 5’monophosphate: adenosine 5’-monophosphate

• Oligonucleotide: short nucleotide (<100 nt) (primers for DNA
replication)


NAMES OF NUCLEOSIDES AND NUCLEOTIDES


ATP - MAJOR ENERGY SOURCE FOR CELLULAR ACTIVITY
 ATP: adenosine triphosphate
 All cells need chemical energy carried out by ATP
 Molecules in food store chemical energy in their bonds

Starch molecule

Glucose molecule


HOW DOES ATP STORE ENERGY?

 Energy is stored in the last high energy phosphate
bond (it can store more energy than other types of

bonds)
 The cell stores energy by bonding a phosphate to
ADP (Adenosine Diphosphate)


ATP-CHEMICAL STRUCTURE
+

+


HOW DOES CELL GET ENERGY FROM ATP?: HYDROLYSIS

H2O

By breaking the high- energy bonds
between the last two
phosphates in ATP


THE ADP-ATP CYCLE

ATP-ase

ATP
Synthetase


ATP & CHEMICAL ENERGY
Organisms break down carbon-based molecules to produce

ATP
 Carbohydrates: the most commonly broken down to
make ATP
– not stored in large amounts
– up to 36-38 ATP from one glucose molecule
 Fats store the most energy: 80 percent of energy in
the body
– about 146 ATP produced from a triglyceride
 Proteins: the least likely to be broken down to make
ATP
– amino acids not usually needed for energy


WHEN IS ATP MADE?

 During Cellular Respiration
•
•
•

Includes pathways that require oxygen
Glucose is oxidized and O2 is reduced
Glucose breakdown  one molecule of glucose  3638 ATP molecules