Nucleic Acids and ATP Flashcards
nucleic acids, ATP and DNA replication
functions of DNA
replicate to produce an exact copy before cell division
carry code for protein synthesis
types of RNA
mRNA = messenger RNA
tRNA = transfer RNA
rRNA = ribosomal RNA
which RNA is functional RNA?
tRNA and rRNA
monomer and polymer of nucleic acids
monomer = nucleotide
polymer = polynucleotide
what bond joins nucleotides in a polynucleotide chain?
phosphodiester bond
where is DNA found?
nucleus of cell
where is RNA found?
nucleus and cytoplasm of cell
describe the structure of a general nucleotide
a pentose sugar, with a nitrogenous base and one or more phosphate groups attached
three types of nucleotides
DNA, RNA and ATP
differences between DNA and RNA structure
- DNA has deoxuribose sugar, while RNA has ribose
- DNA has nitrogenous bases ATCG while RNA has bases AUCG, with uracil instead or thymine
- DNA has 2 polynucleotid strands while RNA has 1
purine bases
adenine and guanine
feature of purine bases
double ring
pyrimidine bases
thymine, cytosie and uracil
feature of pyrimidine bases
single ring
why does DNA have a 1:1 ratio of purine:pyrimidine bases
purine always base pairs with pyrimidine
ensures 2 sugar-phosphate backbones completely parallel to each other, always 3 rings apart
what are the complementary base pairs and the number of H- bonds between them?
adenine-thymine (2 bonds)
cytosine-guanine (3 bonds)
function of DNA having a coiled structure
this protects the H-bonds between strands therefore reducing corruption of the genetic code
function of a strong sugar-phosphate backbone
gives strength to the DNA molecule
function of DNA being a long molecule
DNA can store a lot of genetic information (genes)
function of the many weak H-bonds in DNA
makes DNA a stable molecule
function of weak H-bonds holding polynucleotide strands together
strands can be separated for transcription and replication
function of seuencing of bases in DNA
allows information to be stored
describe the structure of a DNA molecule
a DNA molecule is a double helix structure made up of two polynucleotide strands each with a strong sugar-phosphate backbone made up of nucleotides joined by phosphodiester bonds. these strands are joined by weak hydrogen bonds which form between complementary base pairs (A-T and C-G)
structure of an ATP nucleotide
an ATP molecule contains a ribose sugar with a nitrogenouse base adenine and three phosphate groups (a triphosphate).
ATP
adenosine triphophate
4 features of ATP hydrolysis
- forms ADP and Pi
- is an exergonic reaction
- releases energy by breaking bond between 2nd and 3rd phosphate groups
- is catalysed by ATP hydrolase
4 features of ATP synthesis
- uses ADP and Pi
- is an endergonic reaction
- stores energy in high energy bond between 2nd and 3rd phosphate groups
- is catalysed by ATP synthase
roles of ATP
- energy donor molecule
- immediate source of energy
- universal energy molecule
ATP as a universal energy molecule
all reactions, all cells, all organisms use ATP
6 advantages of ATP over glucose
- only requires 1 enzyme for hydrolysis
- releases energy in usable quantities
- easily transported across organelle membranes
- water soluble
- doesn’t need to be stored
- easy recycling between ATP and ADP + Pi
why is it an advantge that ATP releases energy in usable quantities?
hydrolysis of glucose would result in a surplus
why is it an advantage that ATP doest need to be stored?
glucose must be stored as glycogen or starch
energy needed, energy released, coupled, Pi, synthesis
5 steps of ATP recycling
- when energy needed by cell, ATP hydrolysed into ADP + Pi (catalysed by ATP hydrolase)
- hydrolysis of phosphate bond rleases energy
- ATP hydrolysis coupled to other energy-requiring reactions in cell so energy released is used directly, not lost as heat
- released Pi can be added to another compound in phosphorylation, often making compound more reactive
- ATP can be resynthesised in a condensation reactionbetween ADP + Pi, during PS and RS, catalysed by ATP synthesis
