2.3- nucleic acids Flashcards
What is a double helix
The shape of a DNA molecule, due to the coiling of the two sugar-phosphate backbone strands into a right-handed spiral configuration
What is a monomer
A molecule that when repeated, makes up a polymer- nucleotides are the monomer of nucleic acids
What is a nucleotide
A molecule consisting of a 5 carbon sugar, a phosphate group, and a nitrogenous base
What is a polynucleotide
a large molecule containing many nucleotides
Describe nucleotides
- Biological molecules that participate in nearly all biological processes
Describe the general structure of nucleotides
- Phosphate esters of pentose sugars- where a nitrogenous base is linked to the C1 of the sugar residue
- a phosphate group is linked to either the C3 or the C5 of the sugar residue, by covalent bonds formed by condensation reactions
What do nucleotides form
- The monomers of nucleic acids- DNA and RNA
What is the pentose sugar in DNA and RNA
- DNA= Deoxyribose
- RNA= Ribose
What do nucleotides become when they contain more than one phosphate group- give 3 named examples
- Phosphorylated nucleotides
- Adenosine- ribose and adenine
- Adenosine monophosphate- ribose, adenine and 1 phosphate (AMP)
- Adenosine diphosphate- ribose, adenine and 2 phosphates (ADP)
- Adenosine triphosphate- ribose, adenine and 3 phosphates (ATP)
What is ATP
An energy-rich end-product of most energy-releasing biochemical pathways- used to drive most energy-requiring metabolic processes in cells
What do nucleotides help regulate
-Many metabolic pathways, for example by ATP, ADP, and AMP
What coenzymes are adenine nucleotides part of, and what are these involved in
NADP- nicotinamide adenine dinucleotide phosphate- used in photosynthesis
NAD- nicotinamide adenine dinucleotide- used in respiration
FAD- flavine adenine dinucleotide and coenzyme A- both used in respiration
List 4 general functions of nucleotides
- Form monomers of nucleic acids
- become phosphorylated nucleotides when they contain more than one phosphate group
- help regulate many metabolic pathways
- May be components of co-enzymes
What is a nucleoside
Consist of a sugar and base- no phosphate group
Where is DNA found
In the nuclei of all eukaryotic cells, within the cytoplasm of prokaryotic cells and in some types of viruses
What is DNA
- the hereditary material and carries coded instructions used in the development and functioning of all living organisms
What is DNA an example of, and what are the others
- Macromolecules (large numbers of atoms) that make up the structure of living organisms
- proteins
- carbohydrates
- lipids
What type of structure is DNA and why
- a polymer
- it is made up of many repeating monomeric units- nucleotides
What does a molecule of DNA consist of
Two polynucleotide strands running in opposite directions- antiparallel
What does each DNA nucleotide consist of
- phosphate group
- 5-carbon sugar- deoxyribose
- one of 4 nitrogenous bases- adenine, guanine, thymine or cytosine
What does DNA stand for
Deoxyribonucleic acid
Name and explain the covalent bonds in nucleotides
- between sugar residue and phosphate group is phosphodiester
- between sugar and base is glycosidic
- broken when polynucleotides break down, formed when synthesised
Describe the length of DNA molecules and what this means
-long- can carry a lot of encoded genetic information
What type of reaction is used to form a nucleotide- describe it
Condensation- 2 x OH from deoxyribose, 1x H (from OH) from phosphate, and 1x H from base forms 2 water molecules