2. nucleic acids Flashcards
what are the bases for DNA and RNA
ATCG (adenin, guanin, cytosine, thymine)
AUCG (uracil)
What bond holds nucleotides together
phosphodiester bond
how is DNA adapted to its function (5)
-very stable, no change between generations
-hydrogen bonds can be broken for replication
-VERY long chain, LOTS of information stored
-deoxyribose backbone protects molecule from chemical and physical forces
-base pairing allows for mRNA to be made
describe semi conservative replication (3)
-DNA helicase ‘unzips’ DNA by braking hydrogen bonds
-Free nucleotides bind to there complementary bases
-Adjacent nucleotides are joint by DNA polymerase
what enzyme catalyses the synthesis of ATP
ATP synthase
when does ATP synthesis take place
during photosynthesis (PHOTOphosphorylation)
respiration (OXIDATIVE phosphorylation)
when a phosphate group is ‘donated’ (SUBSTRATE-LEVEL phosphorylation)
Give the five uses of ATP
Metabolic processes - building of macromolecules
Movement - muscle contraction
Active transport - change shape of carrier protein, allows molecule to be moved against gradient.
Secretion - formation of lysosomes
Activation - phosphorylation, lowing compounds activation energy
What makes H2O so important
dipolar molecule;
high number of H bonds, high SHC + LH
high cohesion and adhesion, surface tension
condensation reactions
Give three differences between RNA and DNA
- RNA is shorter in length
- RNA is single chain
- ATCG, AUCG
Explain how watson and Crick verified their semi-conservative hypothesis.
Grey bacteria on medium with 14N and 15N (15N heavier than 14N)
Moved bacteria grown in 15N into 14N medium, let grow for one generation.
after centrifuging and weighing DNA, 1st generation showed a 50/50 mix of heaving and light strands.
evidence that half of the new strand was part of parent.
What else can an inorganic phosphate be used for?
phosphorylation of molecules
Why is DNA stable?
Phosphodiester backbone protects the reactive bases.
C-G has three h-bonds, more of them = stable
What enzyme catalyses the condensation of ADP + Pi?
ATP synthase
When is water a metabolite?
condensation/hydrolysis, photosynthesis
Describe waters use a solvent…
Dissolves;
- 02/CO2
- wastes, ammonia/urea
- inorganic ions, amino acids, monosaccharides and ATP
