2.3- DNA-deoxyribose nucleic acid Flashcards
What does double helix mean?
Shape of DNA molecule, due to coiling of the two sugar- phosphate backbone strands into a right handed spiral configuration.sugar-
What does monomer mean?
Molecule that when repeated makes up a polymer. Amino acids are the monomers of proteins. Nucleotides are the monomers of nucleic acids.
What does nucleotide mean?
Molecule consisting of a five carbon sugar, a phosphate group and a nitrogenous base.
What does polynucleotide mean?
Large molecule containing many nucleotides
What are nucleotides?
Nucleotides are biological molecules that participate in nearly all biochemical processes. They are phosphate esters of pentose sugar, where a nitrogenous base is linked to C1 of the sugar residue and a phosphate group is linked to either C5 or C3 of the sugar residue by covalent bonds formed by condensation reactions..
What do nucleotides form?
-Form the monomers of nucleic acids, DNA and RNA In RNA, the nucleotide pentose sugar is ribose. In DNA, the nucleotide pentose sugar is deoxyribose.
What do nucleotides become?
Become phosphorylated nucleotides when they contain more than one phosphate group : for example, ADP ( adenosine diphosphate) and ATP (adenosine triphosphate). They are used to store and transport energy in cells. ATP is an energy rich end product of most energy releasing biochemical pathways and it is used to drive most energy requiring metabolic processes in cells.
What does nucleotide help regulate?
Helps regulate many metabolic pathways, fro example by ATP
What might nucleotide be a component of?
May be a component of many coenzymes. Adenine nucleotides are components of the coenzymes NADP- which is used in photosynthesis .
Where is DNA found?
DNA is found in the nuclei of all eukaryotic cells, within the cytoplasm of prokaryotic cells and is also inside some typed of viruses.
What does DNA carry?
It is the hereditary material and carriers coded instructions used in the development and functioning of all known living organisms.
What is DNA most important of?
DNA is one of the important macromolecules that make up the structure of living organisms, the others being protein, carbohydrates and lipids.
What is the structure of DNA?
- DNA is a polymer as it is made up of many repeating monomeric units called nucleotides.
- A molecule of DNA consists of two polynucleotide strands.
- The two strands run in opposite directions so they are described as antiparallel.
- Each DNA nucleotide consists of a phosphate group, a five- carbon sugar called deoxyribose and one of four nitrogenous bases: adenine guanine, thymine or cytosine.
- The covalent bond between the sugar residue and the phosphate group in a nucleotide is also called a phospodiester bond. These bonds are broken when polynucleotides break down and are formed when polynucleotides are synthesised.
- DNA molecules are long and so they can carry a lot of encoded genetic information.
What are purine and pyrimidines?
DNA consists of just four types of nucleotides. In each nucleotide the phosphate and sugar groups are the same BUT the organic (nitrogenous) base differs.
- Purine- Adenine or Guanine (2 rings)
- Pyrimidines- Thymine or cytosine (1 ring)
What is the importance of hydrogen bonds?
The two antiparallel DNA strands are joined to each other by hydrogen bonds between the nitrogenous bases.
- Adenine always pairs with thymine, by means of tow hydrogen bonds.
- Guanine always pairs with cytosine by means of three hydrogen bonds.
- A purine always pairs with a pyrimidine giving equal sized rungs on the DNA ladder. These can then twist, like twisting a rope ladder around an imaginary axis into the double helix. This gives the molecule stability
- Hydrogen bonds allow the molecule to unzip for transcription and replication.
