Nucleic Acids Structure Lecture 1 PDF

Nucleic Acids Structure Lecture 1 __ Nucleotide e É nnucleosome 1 Deoxy Ribose É 0 15 7780088 3 DNA 57 2 phosphate 3 Nitro base pub Histone FEE 5130 1481414 nigggenous to I At the end of this lecture, you need to know: • The differences between, chromosome, allele, gene, and DNA....

Nucleic Acids Structure Lecture 1 __ Nucleotide e É nnucleosome 1 Deoxy Ribose É 0 15 7780088 3 DNA 57 2 phosphate 3 Nitro base pub Histone FEE 5130 1481414 nigggenous to I At the end of this lecture, you need to know: • The differences between, chromosome, allele, gene, and DNA. • The differences between genotype and phenotype. • The structure of nucleotides. • The structure of DNA. • Chargaff rules of base pairing • The most fundamental property of all living things is the ability to reproduce. • All organisms inherit the genetic information (Genotype ) specifying their structure and function (Phenotype) from their parents. • So, all cells arise from preexisting cells that replicate and divide. IIitensinecen I each function inside cell controlled protein created from a genetic code In humans, the patterns of inheritance is determined by a pair of inherited factors, which are now called GENES . One gene copy (called an allele ) specifying each trait is inherited from each parent . The role of chromosomes as the carriers of genes has been proposed to be diploid . Sperms and ova are haploid In humans, number of chromosomes in diploid and haploid cells? D at g too Genes part of DNA so we inherit Yimatic Te x Dna part of chrome chron as a whole g 023 238 to nucleosome histone Mj my 00 Chromosome are the carrier of Genetic material DNA DNA • D eoxyribo n ucleic a cid • It is a Macromolecule • Made of Subunits - nucleo tides • IT HAS DIRECTIONALITY – dictated by the free end groups – always written 5 ’ to 3 ’ direction for each single strand g backbone of DNA n covalent bond phosphodieste 5 s 3 bond bond between middle double strands H bond DNA Chelical Shape helps in stability O g E N O • The nucleotide is the repeating structural unit of DNA and RNA • Each has three components – A phosphate group – A pentose sugar – A nitrogenous base Nucleotides J I Sugar e e e N glycosidic bond 0 o I nucleotide nucleotidation when we say It doesn't matter If its mono die tri co nucleoside o o 2 I E niggers O O 5 3 5 g 3 free OH 31 free 51 DNA is anti - parallel • Two strands run parallel to each other but with opposite alignments (directions) • They are complementary to each other. I DNA Base Pairing Rules • Adenine (A) binds to thymine (T) Two hydrogen bonds between the bases. • Guanine (G) binds to cytosine (C). Three hydrogen bonds between bases. Chargaff’s rules: A always equal to T G always equal to C A+G=C+T Purines = pyrimidines 8 AT G Ttc Example: In a DNA strand, 30% A ? T ? G ? C Does A +T equal C+G? T I30 1 30 120 i 20 NO notiontide B -form DNA, or B -DNA. The most stable structure for a random - sequence DNA molecule under physiological conditions. Right -handed coiled structure. Contains 10.5 base pairs per turn. In conditions without water A -form DNA is seen. More compacted and contains 11 base pairs per turn. Z -form DNA is left -handed coiled structure, contains 12 base pairs. There is evidence of its presence in bacteria and eukaryotic cells. mim I 12 Hydrophilic J T T Is T2 18,01 1 1 994 s noma