nucleic acid

UNIT 4. NUCLEIC ACIDS
I.BASIC CONCEPTS
II.CLASSES
III.CHEMICAL NATURE
IV.FUNCTION

I.BASIC CONCEPTS
NUCLEIC ACIDS polymeric macromolecules, or large biological molecules, essential for all known forms of life are made from monomers known as nucleotides Each nucleotide has three components: a 5-carbon sugar, a phosphate group, and a nitrogenous base If the sugar is deoxyribose, the polymer is DNA. If the sugar is ribose, the polymer is RNA.
Together with proteins, nucleic acids are the most important biological macromolecules
The two nucleic acids used in repair, reproduction and protein synthesis are deoxyribonucleic acid (DNA) and ribonucleic acid (RNA).
RNA maybe found throughout the cell

II.CLASSES
DEOXYRIBONUCLEIC ACID (DNA) nucleic acid containing the genetic instructions used in the development and functioning of all known living organisms
DNA is usually found in the nucleus of the cell
A DNA molecule is a double helix made up of two strands of polymers that are complementary to each other, but not identical plays a vital role in heredity because it is the chief material in chromosomes contains phosphate, a sugar called deoxyribose and compounds called bases there are four different bases in DNA, adenine, guanine, thymine and cytosine
The DNA segments carrying this genetic information are called genes
DNA REPLICATION
The process of producing two identical replicas from one original DNA molecule. This biological process occurs in all living organisms and is the basis for biological inheritance.
Cell division is essential for an organism to grow, but, when a cell divides, it must replicate the DNA in its genome so that the two daughter cells have the same genetic information as their parent. The double-stranded structure of DNA provides a simple mechanism for DNA replication.
RIBONUCLEIC ACID (RNA)
There are four different bases, adenine, guanine, cytosine, and uracil
RNA carries the materials used in making protein
Unlike double-stranded DNA, RNA is a single-stranded molecule in many of its biological roles and has a much shorter chain of nucleotides
The main job of RNA is to transfer the genetic code need for the creation of proteins from the nucleus to the ribosomes.
The three universal types of RNA include transfer RNA (tRNA), messenger RNA (mRNA), and ribosomal RNA (rRNA).
THREE UNIVERSAL TYPES OF RNA Messenger RNA acts to carry genetic sequence information between DNA and ribosomes, directing protein synthesis Ribosomal RNA is a major component of the ribosome, and catalyzes peptide bond formation
Transfer RNA serves as the carrier molecule for amino acids to be used in protein synthesis, and is responsible for decoding the mRNA.
III.CHEMICAL NATURE
Nucleic acid structure refers to the structure of nucleic acids such as DNA and RNA. Chemically speaking, DNA and RNA are very similar. Nucleic acid structure is often divided into four different levels primary, secondary, tertiary and quaternary.
PRIMARY STRUCTURE
Primary structure consists of a linear sequence of nucleotides that are linked together by phosphodiester bonds. It is this linear sequence of nucleotides that make up the primary structure of DNA or RNA. Nucleotides consist of 3 components:
1. Nitrogenous base
1. Adenine
2. Guanine
3. Cytosine
4. Thymine(present in DNA only)
5. Uracil (present in RNA only)
2. 5-carbon sugar which is called deoxyribose (found in DNA) and ribose (found in RNA).
3. One or more phosphate groups.
SECONDARY STRUCTURE
Secondary structure is the set of interactions between bases, i.e., parts of which is strands are bound to each other. In DNA double helix, the two strands of DNA are held together by hydrogen bonds. The nucleotides on one strand base pairs with the nucleotide on the other strand. The secondary structure is responsible for the shape that the nucleic acid assumes. The bases in the DNA are classified as Purines and Pyrimidines. The purines are Adenine and Guanine. Purines consist of a double ring structure, a six membered and five membered ring containing nitrogen.
TERTIARY STRUCTURE
Tertiary structure is the locations of the atoms in three-dimensional space, taking into consideration geometrical and steric constraints. A higher order than the secondary structure in which large-scale folding in a linear polymer occurs and the entire chain is folded into a specific 3-dimensional shape. There are 4 areas in which the structural forms of DNA can differ.
1. Handedness - right or left
2. Length of the helix turn
3. Number of base pairs per turn
4. Difference in size between the major and minor grooves
QUATERNARY STRUCTURE
The quaternary structure of nucleic acids is similar to that of protein quaternary structure. Although some of the concepts are not exactly the same, the quaternary structure refers to a higher-level of organization of nucleic acids. Moreover, it refers to interactions of the nucleic acids with other molecules. The most commonly seen form of higher-level organization of nucleic acids is seen in the form of chromatin which leads to its interactions with the small proteins histones. Also, the quaternary structure refers to the interactions between separate RNA units in the ribosome or spliceosome.
IV.FUNCTIONS
1. Transmission of Hereditary characters
- Nucleic acids allow organisms to transfer genetic information from one generation to the next.
2. Protein synthesis
- It carries information from DNA to your cells' ribosome which are the sites for protein synthesis.
3. Regulates/Stores what types of genes are in you
- Stores information to construct proteins and other organic molecules to develop an organism
4. DNA controls the synthesis of RNA in the cell.
5. Directs the production of new protein by transmitting genetic information to the protein building structures.
-serves as carrier of genetic structures to the protein production site
6. It uses the genetic information to direct the synthesis of new protein
-data gathered from the genes helps in making and a great factor in protein synthesis
10 Interesting DNA Facts

1. Even though it codes for all the information that makes up an organism, DNA is built using only four building blocks, the nucleotides adenine, guanine, thymine, and cytosine.
2. Every human being shares 99% of their DNA with every other human.
3. If you put all the DNA molecules in your body end to end, the DNA would reach from the Earth to the Sun and back over 600 times (100 trillion times six feet divided by 92 million miles).
4. A parent and child share 99.5% of the same DNA.
5. You have 98% of your DNA in common with a chimpanzee.
6. If you could type 60 words per minute, eight hours a day, it would take approximately 50 years to type the human genome.
7. DNA is a fragile molecule. About a thousand times a day, something happens to it to cause errors. This could include errors during transcription, damage from ultraviolet light, or any of a host of other activities. There are many repair mechanisms, but some damage isn't repaired. This means you carry mutations! Some of the mutations cause no harm; a few are helpful, while others can cause diseases, such as cancer.
8. Scientists at Cambridge University believe humans have DNA in common with the mud worm and that it is the closest invertebrate genetic relative to us. In other words, you have more in common, genetically speaking, with a mud worm than you do with a spider or octopus or cockroach.
9. Humans and cabbage share about 40-50% common DNA.
10. Friedrich Miescher discovered DNA in 1869, although scientists did not understand DNA was the genetic material in cells until 1943. Prior to that time, it was widely believed that proteins stored genetic information.

Prepared by:
MR. IAN BRENT “CHOT” SERVIANO
GROUP 1