Nucleic Acids
how many base pairs per full turn of helix how long
10 base pairs 3.4 nm
Double helix
2 strands of polynucleotides coiled into a helix
how wide is double helix
2.0 nm
How much energy is released overall from one molecule?
30.6 kJ mol^-1
What is the name of the reaction that joins nucleotides
A condensation reaction
How do nucleotides link together?
A condensation reaction. The phosphate group at 5' of one nucleotide bonds covalently with the hydroxyl group at 3' of the adjacent nucleotide. This releases a water molecule and forms the sugar-phosphate backbone.
Phosphodiester bond
A covalent bond formed between the phosphate group (at 5') of one nucleotide and the hydroxyl group (at 3') of another.
Nucleic acid
A large polymer formed from nucleotides, containing the elements carbon, hydrogen, oxygen, phosphorus and nitrogen
Polymer
A long-chain molecule composed of bonded multiple monomers in a repeating pattern
Nucleotide
A monomer used to form nucleic acids, made up of a pentose monosaccharide, a phosphate group and a nitrogenous base
Polynucleotide
A polymer made up of nucleotides linked by condensation reactions
Why does this reaction release energy? in terms of bonding
A small amount of energy is needed to break relatively weak bond holding the last phosphate group in ATP A large amount of energy is released when the liberated phosphate undergoes other reactions involving bond formation
What is the reaction that shows how energy is released from ATP to provide energy for cellular activities
ATP + H2O --> ADP + Pi + energy
Which bases are purine?
Adenine and guanine
Complementary base pairing rules
Adenine and thymine Cytosine and guanine
Define Monomer
An individual molecule that makes up a polymer
Similarities between DNA and RNA
Both contain a phosphate group Adenine, cytosine and guanine bases present, phosphodiester bonds, pentose sugar, sugar-phosphate backbone
Add protease enzyme
Breaks down proteins associated with the DNA in the nuclei
what is the significance of the sequence of bases in a strand for its function?
Carries genetic information of an organism in the form of a code order of bases codes for the order of amino acids needed to make different proteins
What is the role of cellular respiration in this process?
Cellular respiration creates ATP
Similarities between ATP DNA and RNA nucleotides
Contain at least 1 phosphate group Contain a pentose sugar Contain a base
Similarities between ATP DNA and RNA
Contain at least one phosphate group Contain a pentose sugar Contain a base
What are the two main types of nucleic acid?
DNA RNA
What evidence did they find?
DNA crystals were symmetrical- strands must run antiparallel Picture of DNA B- x shaped, bases are stacked (3.4nm apart), 10 layers in every twist of helix, diameter=2nm Genes in pairs 2 phosphate-sugar backbones - on outside to attract water Placement of hydrogen (new) meant C goes with G and T goes with A so strands join in parallel
what is the result>
DNA will be seen as white strands forming between layer of sample and layer of alcohol can be picked up by spooling onto glass rod
What does the base pairing allow?
Dna to be copied and transcribed necessary for molecule of hereditary
How is energy needed/released in bonding?
Energy is needed to break bonds and released when bonds are formed
Isolation and purification of DNA by precipitation
Grind Mix with detergent Add salt Add protease enzyme Add alcohol (ethanol)
What is the reaction that breaks phosphodiester bonds?
Hydrolysis
why are the reactions of hydrolysis and energy-requiring reactions said to be 'coupled'?
Hydrolysis does not happen in isolation, only in association with energy-requiring reactions
Differences between ATP DNA and RNA nucleotides
In ATP the base is always adenine, in DNA and RNA it can be 5 bases In ATP there are 3 phosphate groups, in DNA and RNA there is only one
What is Pi?
Inorganic phosphate
WHat is the significance of double stranded, complementary base paired nature of DNA for its function?
It allows DNA to be copied and transcribed this is required for gene transcription in hereditary
Why do cells not store large amounts of ATP?
It is unstable
Components of ATP
Nitrogenous base---- adenine ALWAYS Pentose sugar---- ribose 3 phosphate groups
Strand
One chain of nucleotides Each has a phosphate group (5') and a hydroxyl group (3') at each end
What are the 3 components of a nucleotide?
Pentose monosaccharide Phosphate group (acidic and negatively charged) Nitrogenous base (containing one or two carbon rings and nitrogen)
example of transport
Pumping molecules or ions across cell membranes by active transport
2 types of nitrogenous bases
Pyrimidines Purines
Define complementary base pairing (DNA)
Specific hydrogen bonding between nucleic acid bases. Adenine binds to thymine or uracil or cytosine binds to guanine
Differences between DNA and RNA
Sugar in RNA is ribose whereas it is deoxyribose in DNA Thymine base in DNA is replaced with uracil in RNA, DNA forms double helix
Antiparallel
THe 2 parallel strands in DNA are arranged so they run in opposite directions
Sugar-phosphate backbone
The structure of many nucleotides joined together by phosphodiester bonds, with a base attached to each sugar, forming a strong chain.
Which bases are pyrimidine?
Thymine and Cytosine and Uracil
What are the 5 possible bases in nucleic acids?
Thymine, Adenine, Cytosine, Guanine and Uracil
Structure of ADP
Two phosphate groups Ribose sugar Adenine base
WHo discovered the structure of DNA
Watson and Crick
Where is the energy released in the interconversion of ATP and ADP?
When the Pi is removed from ATP
Structure and full name of ATP
adenosine triphosphate
Mix with detergent
breaks down cell membrane releases cell contents into solution
Grind sample importance
breaks down cell walls
Add salt
breaks the hydrogen bonds between DNA and the water molecules
How is ATP formed rapidly?
by phosphorylation of ADP
Easily regenerated
can be recharged with energy
Add layer of alcohol
causes DNA to precipitate out of the solution
Water-soluble
energy-requiring processes happen in aqueous environments
Adenine and thymine
form 2 H bonds
Cytosine and guanine
form 3 H bonds
Bonds between phosphates
have intermediate energy large enough to be useful for cellular reactions but not so large that energy is wasted as heat
What are the names of the reactions involved in the interconversion of ATP and ADP?
hydrolysis (ATP to ADP and Pi) condensation (ADP and inorganic phosphate to ATP)
What type of reaction is this?
hydrolysis because water is used in the removal of the phosphate group
Purine
larger bases double carbon ring structure
What is the effect of pyrimidines always bonding to purines
maintains a constant distance between the DNA backbones so the polynucleotide chains are parallel
example of synthesis
making large molecules like proteins
Small
moves easily into, out of, and within cells
Structure of deoxyribose
one fewer oxygen atom
WHy do they not need to store large amounts of it?
phosphorylation is happening constantly in all living cells
example of movement
protein fibres in muscle cells that cause muscle contraction
Releases energy in small quantities
quantities are suitable to most cellular needs, so that energy is not wasted as heat
WHy is ATP ideally suited to its function as an energy storage molecule? 5
small (moves into/out of/ within cells) water-soluble (most cellular reactions happen in aqueous environments) contains bonds between phosphates with intermediate energy (large enough to be useful but not so large to be wasted as heat) releases energy in small quantities (suitable for most cellular needs but not wasted as heat) easily regenerated (can be recharged with energy)
Pyrimidine
smaller bases single carbon ring structure
What is the structure of DNA
sugar-phosphate backbone pairs of bases (AT or CG)
What are the 3 main types of activity for which cells require energy
synthesis transport movement
Define Phosphorylation
the addition of a phosphate group to a molecule
DNA molecule
the double helix composed of 2 antiparallel strands each strand is one chain of nucleotides (a polynucleotide)
what is special about the amounts of G and C, and T and A
they are the same