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Nucleic acids, when nitrogen base is purine, N in 9th combines with OH on…

- - - - glycosidic, hydrogen - nitrogen bases - and ester - holds nucleotide bonds togetherbonds
  - - - its tucked inside hydrophobic
  - - - 20 angstrom
  - - - distance travelled by one complete turn of the double helix
  - - - 3.4 angstrom
        
        distance present between any 2 adjecent nucleotides
  - - - deep gropove
        
        22 angstrom
        
        histones are in deep grooves
      - shallow
        
        12 angstroms
  - - - 5'3'
    - - template for transcription
        
        non coding dna
        
        so when
  - - - strength of dna depepnds on weakest link - hydrogen bonds
        
        makes it easy to remove
        
        h bonds break
        
        strands unzip and move apart
        
        denaturing
  - - - 5 - phosphate group
        
        3 end - free oh group
- - - - carbon 2 has OH - so ribose
      - deoxy
        
        in 2nd carbon, there is no O in H
  - - - purine bases
        
        very complex
        
        fused ring system
        
        9 membered ring system
        
        9 corners
        
        imidazole ring fused with pyrimidine
        
        adenine
        
        nh2 - amine group
        
        guanine
        
        ketone group and amine C=O
        
        what, how many corners, why fused,
        
        bases are of two tyop
      - pyrimidine bases
        
        compared to purines are simpler, since there is only one ring
        
        6 corners
        
        nitrogen is in same positions - 1 and 3
        
        2 types
        
        thymine - T
        
        dna
        
        cytosine - C
        
        dna
        
        uracil
        
        instead of C and T in rna its U
        
        bonds with A
  - - - has 3 acidic groups - oxy with single bond
    - - acid - cooh, alcohol - oh -
        
        form coo
    - - forming phosphomonoester
      - sugar is a polyhydroxy alcohol
- - - - information about - construction of cells, behaviour, how to multiply and divide
        
        has to regulate factors for every cell in a multicellular organism
  - - - must have the ability to express itself
        
        by formation of important biological molecules like protein which regulates the activities of cell
        
        cell signalling
  - - - by undergoing mutation or recombination
        
        must be able to undergo a change
  - - - a genetic material must be able to form EXACT copies of itself
        
        must keep these and also transfer to the daughter cells in karyokinesis and cytokinesis
- - - - lagging strand - in many parts (okazaki fragments) 5 3 direction with 5 3 template
  - - - lag needs no one for each fragment
  - - - molecular glue
        
        for lag needs several - for each fragment
  - - - lag - 53 - 53
  - - - lag is slow
- - - - could exert regulatory activity
  - - - dna
      - rna
    - - in nucleus, cytoplasm - semi autonomous mitochondria, etc
    - - giant macromolecules having a very complex molecular structure, high molecular weight, linear polymers formed by polymerisation of basic building blocks called nucleotides
- - - - add a phosphate group to a nucleoside and you get a nucleotide
  - - - the name of the base and the phosphate together
        
        sometimes adenosine monophosphate/ adenylic acid
        
        guanosine monophosphate/ deoxy guanylic acid
        
        nucleoside + phosphate
  - - - glycosidic and ester bonds present in the whole nucleoside
- - - - process of adding phosphate group to a nucleoside - phosphorylation
        
        forming bonds and attaching it
    - - for the 2nd and 3rd phosphate group removed - 30.5kJ/mol released
        
        releases /breakdown of inner groups releases more energy
        
        this is why atp holds more energy - it has 3 phosphate groups
  - - - +phosphate
        
        adenosine diphosphate - adp - can interchangebaly become atp or adp
        
        +phosphate (Pi)
        
        adenosine triphosphate
        
        energy currency of the cell
        
        releases 30.5kJ/mol
        
        1 more item...
        
        phosphorylation and de-phosphorylation
        
        easy to make and break down
        
        for energy currency, must be
        
        must be small
        
        highly soluble in water
        
        rich reserve of energy
        
        small and highly water soluble
        
        as soon as atp present, makes adp, when no atp, makes adp?
        
        when amp, breaks down coz some energy is released, but has to go a longer route to get converted to atp, so not ideal
        
        so gets a longer route to get atp
        
        when lots of energy present, amp - converted to adp - converted to atp
        
        no energy around - atp de-phosphorylated
- - - - linear chain of hundred polynucleotides
        
        must show presence of nitrogen base, pentose sugar and phosphate group
  - - - not single polynucleotide strand - there are 2
        
        spirally coiled around one an other
        
        simplest way of describing - a spiral staircase, or ladder
        
        railing - sugar and phosphate, steps - bases
        
        sugar and phosphate alternate to form a stable backbone
        
        deoxy ribose sugar
      - railings - sugar and phosphate, steps - purine and pyrmidian bases
- - - - would've gotten tangled
        
        but dna never gets tangled - splits into 2 strands
    - - beads - histones
        
        string - polynucleotide chain
      - 4 types of histone proteins - h2A, h2b, h3, h4, h1 (additional)
        
        whole thing is made of 8 parts - two of each histone
        
        long strand of dna with 147 nucleotides, form 1 1/2 circles around a core - the 8 histone proteins
        
        called octamer (the dna strand that holds it together)
        
        then attached to h1 proteins - the linker dna (octamers) - the short strand of dna with the h1 on it - it attaches
      - each nucleosome is 1 octamer + linker
        
        strong electrostatic force of attraction
        
        phosphate group so negative
        
        histone proteins - argenine and lyseine - basic proteins, so charge is +
        
        dna is wound round by means of strong forces of attraction between phosphate group and basic proteins
    - - with histones and dna
    - - histones (forming the nucleosome)
        
        solenoid
        
        chromatin fibre
        
        chromatin thread
        
        chromosomes
- - - - formation of complex polymer
    - - important enzyme
        
        dnap - III
        
        dna polymerase
        
        catalyses joining of free nucleotides to pre existing adjecent nucleotides
        
        extension of dna strsads
        
        co factor magnesium or manganese dioxide
  - - - continuous process as long as dna unwinds
        
        once starts, keeping in pace of unwinding
        
        replication fork
        
        helicases makes it unwind
        
        where it splits
- - - - thousands of nucleotides
        
        phosphate sugar
        
        ester bond and glycosidic
    - - polynucleotide - like polypeptide
        
        attached by 2 bonds - called 3,5 phospho di ester bonds
  - - - from th5 5' end to the 3' en d
        
        it exhibits polarity
        
        added only to 3' end
        
        diagonally downwards
    - - so it can add on to only one end - lengthens from that end
- - - - proposed salient features of dna
        
        observations
        
        structure
        
        appears like a spiral staircase
        
        2 polynucleotide strands, wound together -
        
        diameter
        
        long and thin - 20 angstrom
        
        distance
        
        distance covered by single turn of dna double helix - like a wavelength
        
        34 angstrom - helical pitch
        
        nucleotides
        
        in between pitch - 10 nucleotides
        
        so distance between 2 nucleotides is 3.4 angstrom
- - - - dna must divide forst, and identical, onyl then cell divides
        
        otherwise they daughter cells won't get the same genes
  - - - dna splits/ untwists
        
        new strand is a hybrid
        
        one strand is the original, other is a new polynucleotide strans
        
        semi conservative - one conserved, other synthesised
        
        dna replication happens in s phase - interphase
- - - - multifunctional
        
        herediatry material and
        
        protein synthesis
    - - head - g cap
        
        untranslated region
        
        start codon
        
        stop codon
        
        tail at 3 end
    - - lifespan
        
        relatively short lifespan
      - high turnover raate
        
        no of times it can be used to make one
        
        produce many copies of same protein
        
        then lifespan decreases
        
        becauses it exists as logn as the protein exists/ is required - longer lifespan
      - length
        
        varies depnding of length of polypeptide chain
      - highly specific
        
        each mrna only codes for a specific protein - polypeptide chain
        
        primary structure - only sequence
      - hnrna
        
        heterogenous nuclear rna
        
        varied fm one an other, sizes, length
        
        one mrna differnt fm each other by size, length, and sequence
        
        because the protein it's coding for is different
- - - - transcription means copying
        
        sequence of nitrogenous bases
        
        fm the template strand 3'to 5'
        
        so 5'3' direction of
        
        copies fm anti sense strand, identical to sense strand
      - then moves into cytoplasm
        
        can never take place without dna - dependant - rna polymerase
        
        rnap
        
        entire process of synthesis and transcription
        
        controlled by the enzyme
        
        copying fm the strand of dna
      - process by which synthesises of mrna from a dna template in the nucleus
    - - dna is very important
        
        blueprint of activity of cell and behaviour
        
        storehouse of vital informatinon across generations
        
        but dna is house arrest - can't get out of nucleus
        
        because its double stranded - can't come out of the nucleopore
        
        but no need to get out of the nucleus since it controls things from there
        
        1 more item...
    - - when does the dna divide
        
        in the synthesis phase
        
        preparation for transcription in g1 and g2 phase (before s phase)
        
        of the interphase
        
        in g2 its double, in g1 phase, its only single
    - - in 2 sites
        
        where transcription is just initated
        
        promoter region
        
        where the start codon is
        
        where it ends
        
        terminator site
    - - mrna is a form of rna
        
        when rna enters, only rna
        
        when out of the nucleoplasm - mrna coz. its been copied
      - 5 to 3 - sense/ coding
        
        3 to.5 template
      - mrna is identical to ciding, but complementary to template
      - mrna has a sequence of bases with identical to ciding dtrand
        
        but has uracil
  - - - promoter
        
        location
        
        upstream to the structural gene
        
        LOCATED AT 3 END OF TEMPLATE strand or 5 end of coding strand
        
        important because this is where rnap can bind
        
        has a functional sequence of bases, (present on the promoter region) recognised by rnap - consensus sequence
        
        enables rnap to sttach on it
        
        depending on where located - you can identify where
        
        wherever rnao attached to its always the 3 end of template
        
        doesn't attach to ciding strand
        
        to consesus sequence of protomer
        
        5' TATAAT ^3'
        
        pribnow box
        
        for prokaryots
        
        functional sequence of nitrogenous bases fm 5 to 3 which starts with TATA and goes on TATAAT
      - terminator site
        
        location
        
        downstream
        
        5 end of template and 3 of coding
        
        place where transcription ends
      - structural
        
        beteweeen terminator and promoter
        
        functional unit of inheritance
        
        sequence on nucleotides codes for
        
        represents functional nuit of dna, has a sequence o nucletoides for specicif polyppetide
        
        dna becomes fucntional when. it can code
        
        aka cistron
        
        its a gene
- - - - gave some postulates
        
        composition
        
        composition of dna obtained of same species is saem/ bases fm ornagism of
        
        same species - base composition is same
        
        diff - then composition is differenta, t, g, c - percentage is different
        
        take dna of diff tissues fm same organism is identical
        
        base composition of dna molecule is unique
        
        within the same species, it will be similar, not identical
        
        A + G = T + C
        
        sum of purines = sum of pyramidines
        
        but A + T ≠ C + G
        
        [ercentage of bases presnte
        
        A = T
        
        adenine always pairs with thymine
        
        amount of adenine is equimolar to amount of thymine
        
        1 more item...
        
        a - purine - t is pyrimidine
        
        g = c
        
        equimolar amounts
        
        1 more item...
        
        base ratio - A +T/ G+C = 1
        
        3 more items...
- - - - entire original dna gives rise to a completely new structure
    - - oarent dna breaks into small pieces
        
        new pieces of dna doublets also synthesised
        
        new dispersed within parent dna
        
        the parent pieces generate new pieces
    - - only this one works
      - change ph or temp
        
        h bonds break
        
        2 strands break
        
        template for new strand
        
        ends up being idenstical
- - - - catalyses the formation/ synehtesis generates a short strand of ribonucleotides - 10-60 nucleotides
        
        presence of uracil is rna
- - - - forms 2 strands - leading and lagging
        
        leading strand
        
        3'5' strand as template
        
        synthesised in 5'3' direction
        
        entire strand is synthesised in one stretch
        
        very fast
        
        1000 nucleotides added every second
        
        lagging strand
        
        5'3' direction with 5'3' as template
        
        synthesised using a number of small sized fragments
        
        okazaki fragments
        
        many parts so its slower