BIOLOGY ZNOTES

Revised Printed Notes Molecular Basis of Inheritance (PDF Printed note)  Download

Revised Printed Notes Principles of Inheritance & Variation (PDF Printed note)  Download

Sex chromosomes together with Autosomes Most of the diploid organisms are amongst dissever sexes. The organisms producing sperms are called males and those producing eggs (ova) are called females.  Chromosome is the major ingredient to decide the sexual practice of an organism.  The chromosomes that are involved inwards sexual practice conclusion are called  sex chromosomes (allosomes).  They include  X & Y chromosomes.  Autosomes are chromosomes other than sexual practice chromosomes. Number of autosomes is same inwards males together with females. Henking (1891) studied spermatogenesis inwards simply about insects together with observed that fifty % of sperm received a nuclear construction later spermatogenesis, whereas other fifty % sperm did non have it. Henking called this construction every bit the X body. Later it is called every bit X-chromosome. Mechanism of sexual practice conclusion XX-XO mechanism: Here, manly individual...

Comparison betwixt DNA, mRNA, rRNA too tRNA Name DNA mRNA rRNA tRNA Number of strands Double stranded Single stranded Single stranded Single stranded Location Mainly inwards nucleus, too inwards mitochondria too chloroplasts In nucleus too cytoplasm (mainly ribosomes) Only inwards ribosomes In the cytoplasm Functions Acts equally shop of coded instructions for the synthesis of proteins required yesteryear the cell. It is made on the deoxyribonucleic acid template. It carries coded instructions (codons) from nucleus to ribosomes for the synthesis of proteins. Forms utilisation of ribosome structure. Helps inwards locating mRNA correctly on ribosome surface. Acts equally amino acid carriers during translation (protein synthesis)

Comparison of dissimilar types of DNA  (Differences betwixt A, B, C, D too Z DNA) Features A-DNA B-DNA C-DNA D-DNA Z-DNA Handedness of double helix Right handed Right handed Right handed Right handed Left handed Base couplet per amount plow of the helix 11 10 9.33 8 12 Diameter of helix 23 Å 19 Å 19 Å - 18 Å Tilt of nitrogen base of operations pairs ( g ) 20.2 O 6.3 O -7.8 O -16.7 O 7 O Axial ascension (h) 2.56 Å 3.37 Å 3.32 Å 3.03 Å 3.7 Å

Self pollination in addition to Cross pollination:  Major differences Self pollination Cross pollination 1.         Pollen grains are transferred to stigma of same or genetically like flower. Pollen grains are transferred to stigma of genetically dissimilar flower 2.         Anthers in addition to stigma mature simultaneously They mature at dissimilar fourth dimension i.e, protandry in addition to protogyny 3.         It occurs inwards opened upward equally good equally unopen flower It occurs exclusively inwards opened upward flower 4.         It is real economical for plants It is non economical equally the constitute has to create large pose out of pollen grains, nectar, smell in addition to colouration 5...