Please enable JavaScript.
Coggle requires JavaScript to display documents.
DNA, RNA and ATP Nucleic-Acid - Coggle Diagram
DNA, RNA and ATP
Nucleic Acids
They are made of C, H, O, N and P atoms.
The nucleic acids are polymers specialized for the storage, transmission and use of information.
There are two types of nucleic acids:
- DNA (deoxyribonucleic acid) DNA molecules are giant polymers that encode hereditary information and pass it through generations.
- RNA (ribonucleic acid). Through using RNA, the information coded in DNA is used to specify the amino acid sequence of proteins.
Nucleic acids are composed of monomers called nucleotides, each of which consists of a pentose sugar, a phosphate group and a nitrogenous base which is either a pyrimidine or purine.
- Purines have two fused rings
- The smaller pyrimidines have a single ring.
Molecules consisting of a pentose sugar and a nitrogenous base, without a phosphate group are called
nucleosides.
A sugar-phosphate backbone is formed by covalent bonding between the phosphate of one nucleotide and the sugar of the next nucleotide.
Nitrogenous bases extend from the sugar-phosphate backbone.
DNA
In DNA, pentose sugar is deoxyribose, which differs from the pentose found in RNA called
ribose.
The nitrogenous bases of DNA are adenine (A), guanine (G), cytosine (C) and thymine (T).
-
DNA has two polynucleotide strands held together by hydrogen bonding between their nitrogenous bases.
The nucleotides are joined by phosphodiester linkages between the sugar of one nucleotide and the phosphate of the next nucleotide. The bond between the deoxyribose and the nitrogenous base is called glycosidic bond.
Adenine and thymine always pair (A-T), and cytosine and guanine always pair (C-G). Adenine pairs thymine and makes 2 hydrogen bonds. Also, guanine pairs cytosine and makes 3 hydrogen bonds. The pairing of a large purine with a small pyrimidine provides a stable and consistent double stranded molecule of DNA.
In a cell, DNA is primarily found in nucleus, chloroplast and mitochondria of eukaryotic cells.
In prokaryotes, DNA is found in the cytoplasm.
- Prokaryotic DNA is circular whereas Eukaryotic DNA is linear.
- In Eukaryotes, DNA in the nucleus is linear, but in chloroplasts and mitochondria, the DNA is circular like in prokaryotes.
Functions of DNA are storing genetic material, storing information for protein synthesis and inheriting genetic information to offspring.
Before cell division, the cell duplicates its DNA, this reaction is called as DNA replication.
This reaction is also enzymatic and the name of the enzyme is called as DNA polymerase.
-
RNA
RNA consists of one polynucleotide chain. RNA are also made up of four different monomers, but their nucleotides differ from those of DNA.
In RNA, nucleotides are named as ribonucleotides.
-
Instead of base thymine, RNA uses the base uracil(U). And the other three bases are the same as in DNA.
-
-
All RNA are synthesized according to the genetic code on the DNA. This reaction is called as transcription.
-
In prokaryotes, RNA is found in cytoplasm and ribosomes.
In Eukaryotes, RNA is found in nucleus, cytoplasm, ribosome, mitochondria and chloroplasts.
ATP
-
It has adenine nucleotide, ribose sugar and three phosphate groups in its structure.
ATP is made of C, H, O, N and P atoms.
It is similar to nucleic acids, especially adenine ribonucleotide.
All living cells use ATP for energy requiring processes. Energy is stored in high energy phosphate bonds.
ATP cannot be stored in cells, it is built up and broken down continuously. ATP is synthesized during respiration via aerobic or anaerobic respiration.
The hydrolysis of ATP that means the breakdown of high energy phosphate bond yields ADP (adenosine-di-phosphate) and energy. ADP can be further broken down into AMP (adenosine-mono-phosphate) with energy.
The dehydration synthesis of ATP or ADP is also called phosphorylation, as there is an addition of phosphate group. The hydrolysis of ATP or ADP is also called dephosphorylation, as there is removal of phosphate group.
ATP Cycle: ATP is used for endergonic (anabolic) reactions such as synthesis reactions, active transport across the cell membrane, movement and contraction of muscles, nerve impulse transmission...etc. A TP is produced from exergonic (catabolic) reactions such as aerobic and anaerobic respiration. Therefore, ATP is used and produced in a cell as a cycle.