Nucleic acids, ATP, Water and inorganic ions Flashcards
(9 cards)
how does the structure of DNA relate to its function
-helical so compact
-sugar phosphate backbone so provides strength
-large molecule so can store lots of information
-base sequence codes for amino acids
-double stranded so strands can act as templates
-complementary bass pairing (A-T , G-C) so accurate replication
-weak hydrogen bonds for so strands easily separated
-many weak hydrogen bonds so stable/strong molecule
describe the structure of dna
polymer of nucleotides
each nucleotide formed from deoxyribose, a phosphate group and a nitrogenous base
phosphodiester bonds (between adjacent nucleotides)
2 strands held by hydrogen bonds
hydrogen bonds between adenine , thymine, and cytosine, guanine (the complementary base pairings
Describe semi conservative replication of DNA
DNA helicase breaks H bonds between the strands
Each strand acts as a template
Free DNA nucleotides attach by complementary base pairing (thymine and adenine or guanine and cytosine) with template by H bonds reforming
DNA polymerase joins up free adjacent nucleotides with phosphodiester bonds in a condensation reaction
New DNA molecule contains one old strand and one new strand
Describe the reaction to hydrolyse ATP and the products of this reaction
hydrolysis of ATP to adenosine diphosphate (ADP) and inorganic phosphate group (Pi) catalysed by ATP hydrolyse
describe the two uses of ATP
hydrolysis of ATP provides energy for active transport/ protein synthesis/ DNA replication
hydrolysis of ATP provides and inorganic phosphate to phosphorylate a substance to make them more reactive
compare and contrast DNA in prokaryotic cells (or dna in mitochondria/chloroplasts) and DNA in eukaryote cells
comparisons
both have nucleotides that have identical structures(dna structure: deoxyribose, phosphate,nitrogenous base)
both have nucleotides joined by phosphodiester bonds
DNA in mitochondria/ chloroplasts same as DNA in prokaryotes
Contrasts
eukaryotic nuclear DNA is longer than prokaryotic DNA
eukaryotic nuclear DNA contains introns, whereas prokaryotic does not(both contain exons)
eukaryotic nuclear DNA is linear whereas prokaryotic DNA is circular
eukaryotic nuclear DNA is associated with histones whereas prokaryotic DNA is not
describe why ATP is useful in biological processes
releases energy in small amounts
break single bond down in one step to release energy
phosphorylates substances to make them more reactive (add phosphate)
can easily be reformed in one step
describe the reaction to synthesise an ATP molecule from its component parts
condensation of ADP AND Pi catalysed by ATP synthase during respiration/ photosynthesis
this molecule contains adenine ribose and three phosphate
explain the properties that make water important for organisms
a metabolite in condensation/ hydrolysis reactions
a solvent so allows transport of substances
high specific heat capacity so buffers change in temperature
high latent heat of vaporisation so provides cooling effect
cohesion (H Bonding) so supports columns of water
cohesion (H bonding) so produces surface tension supporting small organisms
