Category: ZOOLOGY(I Year VIDEO)

Nucleic acids are genetic material. DNA and RNA are two important nucleic acids. Deoxyrbose sugar is present in DNA while in RNA sugar is ribose. Nitrogenous bases A, G, C, T are present in DNA while in RNA U is present instead of T

It belongs to phylum Arthropoda. It is a cursorial animal. Its body is divided into head, thorax and abdomen. Chitinous skeleton is present in cockroach. Tripodial movement is present in cockroach.

Species of Riccia are found in the tropical and subtropical regions of the world. Riccia fluitans is an aquatic species. The thallus of Riccia is flat , prostrate, dark green coloured and dichotomously branched. On the ventral surface of the thallus are found rhizoids and scales. Rhizoids are of two types. (a) Smooth walled rhizoids and (b) tuberculate rhizoids. The scales are pink in colour due to the presence of Anthocyanin pigment. The internal structure of the thallus is differentiated into photosynthetic region and storage region. The vegetative reproduction occurs by means of progressive death and decay of the thallus, by means of tubers and by rhizoids. The sexual reproduction occurs my means of specialized sex organs antheridia and archegonia.

This video is about structure of sperm. Sperm is divided into three parts- head, middle part and tail. Shape of head is different in different organisms.

Fusion of male and female gamete is known as fertilization. Complete fusion of both gametes is referred as syngamy. It can be of two type- Isogamy and . Fertilization can be of two types- External and Internal.

This video lecture is about the clover leaf model of tRNA which is a secondary configuration of single stranded nucleotide tRNA proposed by Holley . It has five asrms with stems and loops formed due to complementary base pairing on itself. It ha amino acid acceptor arm, DHU Arm, Anticodon Arm, Ribosome biding arm and variable arm. tRNA carries raw material amino acid to the Ribosome for Protein Synthesis.

DNA replication is semi conservative type it means in newly formed DNA one strand is new and another is old. Helicase enzyme opens both strand of DNA. Topoisomerase stop torsion. RNA primer starts adding nucleotides in 5 to 3 direction. Continuous strand is known as leading strand and discontinuous is lagging strand. Gaps are filled by DNA ligase enzyme. RNA polymerase enzyme stops replication process.