BCH 203 Nucleic acids Flashcards
What are nucleic acids?
Nucleic acids are macromolecules present in all living cells. They are concerned with the storage and transfer of genetic information
Nucleic acids are polymers of nucleotides (which is why they are referred to as polynucleotides) held together by what bond?
Phosphodiester bond
Types of nucleic acids
Deoxyribonucleic acid or DNA
Ribonucleic acid or RNA.
Where are DNA and RNA present and in what amount?
DNA is present in nuclei (70%) and small amounts are also present in mitochondria (30%) , whereas 90% of the RNA is present in cell cytoplasm and 10% in the nucleolus.
What are nucleotides composed of?
- A nitrogenous base
- A pentose sugar
- A phosphate group
Classes of nitrogenous bases
Purines
i. Adenine (A)
ii. Guanine (G)
Pyrimidines
i. Cytosine (C)
ii. Uracil (U)
iii. Thymine (T).
Which pentose sugars are in DNA and RNA?
DNA contains D-2-deoxyribose
RNA contains D-ribose
What is a nucleoside?
structures containing only sugar and
nitrogen base
A pentose sugar (D-ribose or D-2 deoxyribose) is linked to a nitrogenous base via which bond?
covalent N-glycosidic bond
Nucleosides of AGCTU
Adenosine, guanosine, cytidine, thymidine and uridine
What bond joins phosphate groups together?
Squiggle bond
What is ATP?
ATP as the universal energy currency is formed during oxidative processes by trapping the released energy into high energy phosphate bond
ATP serves as the main biological source of energy in the cell. ATP is required as a source of energy in several metabolic pathways, e.g. fatty acid synthesis, glycolysis, cholesterol synthesis, protein synthesis, gluconeogenesis,
etc. and in physiologic functions such as muscle contraction, nerve impulse transmission, etc
What is AMP?
AMP is the component of many coenzymes such as NAD+, NADP+, FAD, coenzyme A, etc. These coenzymes are essential for the metabolism of carbohydrate, lipid and protein
Where is DNA found in plants?
Chloroplasts
Functions of Nucleotides
- Nucleotides are the building block of DNA and RNA. They contain genetic information
- Nucleotides act as coenzymes, which are required to catalyse many biochemical reactions by enzymes
- Energy is stored in our body as ATP. When there is a need for energy, they convert to ADP or AMP. ATP also acts as a coenzyme
- NAD, NADP has an essential role to play in many redox reactions, they act as an electron carrier
- cAMP helps in transporting chemical signals and metabolic regulation
