What is recombinant DNA ?

Seedless guava Calorie free sugar

DNA structure

#1. DNA Structure (an overview)

• DNA has three main components

– 1. deoxyribose (a pentose sugar)

– 2. base (there are four different ones)

– 3. phosphate

#2. The Bases

 They are divided into two groups

 Pyrimidines and purines

 Pyrimidines (made of one 6 member ring)

 Thymine

 Cytosine

 Purines (made of a 6 member ring, fused to a 5 member ring)

Adenine

Guanine

 The rings are not only made of carbon (specific formulas and structures are not required for IB)

#3. Nucleotide Structure

• Nucleotides are formed by the condensation of a pentose sugar, phosphate and one of the

4 bases

• The following illustration represents one nucleotide

• Nucleotides are linked together by covalent bonds called phosphodiester linkage

#3. Nucleotide Structure

#4. DNA Double Helix and Hydrogen Bonding

• Made of two strands of nucleotides that are joined together by hydrogen bonding

• Hydrogen bonding occurs as a result of complimentary base pairing

– Adenine and thymine pair up

– Cytosine and guanine pair up

– Each pair is connected through hydrogen bonding

– Hydrogen bonding always occurs between one pyrimidine and one purine

• Complimentary base pairing of pyrimidines and purines

#4. DNA Double Helix and Hydrogen Bonding

#4. DNA Double Helix and Hydrogen Bonding

#1. DNA Structure (an overview)

• DNA has three main components

– 1. deoxyribose (a pentose sugar)

– 2. base (there are four different ones)

– 3. phosphate

#2. The Bases

 They are divided into two groups

 Pyrimidines and purines

 Pyrimidines (made of one 6 member ring)

 Thymine

 Cytosine

 Purines (made of a 6 member ring, fused to a 5 member ring)

Adenine

Guanine

 The rings are not only made of carbon (specific formulas and structures are not required for IB)

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ÖZET:

Dünya gıda katkı maddeleri pazarının % 25’ini oluşturan aroma maddeleri yıllık 7 milyar dolar civarında bir pazar  payına sahiptir. Aroma maddeleri önceden beri bitkilerden elde edilmiş, ancak bitkilerde düşük miktarlarda bulundukları için  saflaştırılmaları  zor  ve  pahalı  olmuştur.  Kimyasal  yolla  sentezlenen  sentetik  aroma  maddelerinin  üretimi  ucuzdur,  ancak  sağlık açısından zararlı etkileri ve tüketicilerde doğal ürünlere olan talebin artması nedeniyle tercih edilmemektedirler. Bu  nedenle,  son  dönemlerde  alternatif  olarak  biyoteknolojik  yöntemler  üzerinde  durulmaktad›r.  Bu  derlemede,  aroma  maddelerinin üretiminde kullanılan fermantasyon ve biyodönüşüm yöntemleri ile bu yöntemlerle vanilin, benzaldehit, lakton  ve ester aromalarının üretimi ele alınmıştır.

Anahtar kelimeler:  Biyoteknoloji, fermantasyon, biyodönüşüm, doğal aroma maddeleri

ABSTRACT:

Flavour compounds represent 25 % of the total additives market on the world and have an annual value of  about 7 billion US dollars. For a long time, plants were the sole source of flavour compounds. However, they are often  present at low concentrations and thus their isolation is difficult and expensive. Even though, production of synthetic flavours   is  cheap,  they  do  not  prefered  because  of  harmful  effects  to  the  health  and  increasing  demand  to  natural  products  by  consumers. Therefore, in recent years an alternative route is the utilisation of biotechnological processes on the production  of flavour compounds. In this review, production of flavour compounds via fermentation and bioconversion techniques and   the production of vanillin, benzaldehyde, lactons and esters by these techniques were discussed.

Keywords :  Biotechnology, fermentation, bioconversion, natural flavour compounds

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