CBSE Board Exam: Revision Terminology Part 19

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  • Wheat from India -> Australia

  • Chakraborty’s super bug – Small population added to oil polluted water maker it pollution free

  • To degrade pollutants

    1. OCT ( octane, Hexane, decane)

    2. XYL (Xylene, toluene)

    3. CAM (Camphor)

    4. NAH (naphthalene degraded)

  • Somoclonal variation – wheat – rust resistance & high temperature tolerance.

    • Rice – resist tungro virus & leafhopper.

    • Potato – high protein & resist late blight

    • Sugarcane – short harvest duration

    • Tomato – increment shelf life.

  • Cloning – preserves genotype, replace original one, product HGH genes in E. coli

  • Deficiency of aspartic acid leads to diabetes.

  • Arabidiopsis thaliana -> polyhydroxybutrate (PHB) = biodegradable plastic

  • Disease free plants by meristem culture.

  • Third generation pesticide = insect hormone analogues.

  • Quarantine regulation – prevent entry of diseased plant in a country

  • Howard & pelc – cell cycle

    1. G1 – synthesis of r RNA, mRNA, ribosomes, structural & functional proteins

    2. S – Replication of DNA, histone proteins & chromosome with 2 chromatid.

    3. G2 – Cellular synthesis – division of mitochondria & chloroplast -> Kinase Activated (Cause phosphorylation of protein of nuclear brine leading to breakdown to of nuclear envelope).

    4. M – karyokinesis (Shortest).

  • Cells like neurons, RBC etc. do not divide (Skeletal) Epithelial cells divide rapidly.

  • Point & no return (restriction point or R point occurs) in late G1

  • G0 state – when the cells have being arrested in the G1 phase (late) – undergo differentiation & enter G0 phase

  • Cell need to accumulate a level of protein (U – protein) to pass through R point.

  • Amitosis – (Robert Remak) – in eukaryotic nucleus becomes dumb belled Shaped.

  • Amitosis – prokaryote, protozoan, yeast, fetal cells, Cartilage cells, degenerating diseased cells & old tissues.

  • Mitosis = Indirect division – in cell haploid & polyploidy – educational division

  • Mitosis most preferred – root tip

  1. Prophase – plectonemic coiling viscous, refractive, mitotic spindle (bipolar fibrous structure of microtubules) (1) mitotic center, refractive, astral/ amphiastral (Animal). (2) Plant – not centriole mitosis (no asters). Shortening of chromosomes

    • Mitotic center associated with centrioles – when of animal cell destroyed by laser then too Spindle formation takes place – it ensures the pushing of daughter cells to opposite Poles & equal distribution among themself

    • By late G1 or early S – centrioles duplicate.

  2. Late prophase – nuclear envelope break by kinase, kinetochores develop on either surface of centromere, spindle fibers formed by gelation of cytoplasmic & nuclear proteins

  3. Metaphase – Across equator – best time to observe chromosome morphology.

  4. Anaphase – inter-zonal fiber appear & movement to poles, angular, divergence decreased

  5. Telophase – reversal of prophase, nucleolus reappear, chromosome uncoil

  • Karyokinesis is not always follow by cytokinesis – e.g. Fungi, algae, endosperm of tissues

  • Mitosis – maintains genetic stability

    1. (positive) Kinetin (6 furfurylaminopurine) – in low conc.

    2. (negative) Oxidation (Cyanide, azide)

    3. (negative) Oxidative phosphorgation (2, 4 dinitrophenol)

  • Cytogenetic = Muller

  • Colchicine act on metaphase & inhibit it – if affect formation of spindle fibers to cause difference degree of blockage of chromosome Division at metaphase & anaphase (2 chromatid not separate & remain united = SKI CONFIGURATION)

  • Dinomitosis – in dinoflogellates, intra nuclear division.

  • Karyochorisis (moore) – intra-nuclear division but spindle formed either by centrioles or small spindle polar bodies (SPB’s) in fungi.

  • Cancer cells – Continues division, no contact inhibition, divide indefinitely (not show hay flick limit).

  • Hayflick limit – normal somatic cells do not live forever, after undergoing number of divisions they die.

  • Meiosis – in diploids & polyimides. (nucleus divides twice but chromosome once)

  • Meiosis best part to study = anthers.

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