nucleotides and nucleic acids Flashcards
how are polynucleotides formed
by a condensation reaction between the pentose sugar of the nucleotide and the phosphate group of another
what is a phosphodiester bond
the bonds between the pentose sugar of the nucleotide and the phosphate group of another
what is a sugar phosphate backbone
chain of alternating sugar and phosphate groups
where do the bases on a sugar phosphate bcakbone project
sideways
3 main types of activity for which cells require energy
synthesis- e.g of large molecules such as proteins
movement- e.g. protein fibres in muscle cells that cause muscle contraction
transport- e.g. pumping molecules or ions across cell membranes by active transport
similarities between structure of ATP, DNA and RNA nucleotides
- all contain pentose sugar
- all contain nitrogenous base
- all contain phosphodiester bond
- all have -OH group on c3
differences between ATP, DNA and RNA
- ATP nucleotides contain 3 phosphate groups, whereas DNA and RNA nucleotides only contain one
- base in ATP is always adenine
describe how ATP releases energy
- energy needed to break bonds and released when bonds formed
- a small amount of energy needed to break relatively weak bonds holding the last phosphate group in ATP to make ADP
- however a large amount of energy is released when liberated phosphate undergoes other reactions involving bond formation
4 properties of ATP and their functions
- small: moves in and out of cells easily
- soluble: energy-requiring processes occur in aqueous environments
- releases energy in small quantities: quanities suitable to most cellular needs, so energy not wasted as heat
- easily regenerated: can be recharged with energy
describe the structure of a DNA molecule
- twisted into a double helix in which two strands run antiparallel to each other
- bases pair in the centre of the molecule by H bonds
- two strands attached to one another by complementary bases
