ICSE/ISC Board Exam: Revision Terminology Part 20

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  • Meiosis I = educational or heterotypic
  • If Diplotene is long lasted = Dictotene (in lamp brush chromosome, human female – end of 3rd mouth of prenatal life to 12 year arrested
  • Separation of homologous chromosome = Disjunction (Anaphase I)
  • Meiosis II – necessary as due to crossing over, chromatids are not identical & natural be separated spindles in meiosis II at right angle to that of meiosis I
  • Meiosis II haploid no of chromosome present, crossing over during prophase – I, radon distribution of char in anaphase – I
  • Meiosis ⇾ cytological basis of Mendel՚s law of inheritance
  • Anaphase II – Centromere divides.
  • Chromosome are carrier of Mendel՚s factor.
  • Each pair of factor – carried by homologous chromosome
  • Each chromosome must carry factors.
  • DNA duplication ⇾ euchromatin
  • In case translocation present in one of 2 sets of chromosome = translocation heterozygote – normal pairing into bivalents is not possible
  • Hammerling – chromosome of individuals are controlled by nucleus
  • Carmine stains nucleus.
  • Hematoxylin stains chromosome
  • Eukaryotes = DNA + histone (true chromosome) – protamine present
  • A is linear ds DNA – Circular & joined at ends by polynucleotide ligase
  • DNA molecule in tertiary helix & Supercoiled & them fit into vires.
  • Bacterial chromosome = single ds DNA – Folded genomes – basic proteins, not histones – maintain stability in absence of member name.
  • Even polyploidy = fertile
  • Odd polyploidy = sterile
  • Polyploidy disc by lutz – induced by colchicine ⇾ gigantism octaploids usually die higher polyploidy
  • Euploidy = exact multiple of haploid number.
  • Aneuploidy = chromosome no which is not exact multiple of chromosome number.
  • Monosomics isolated from diploids like tomato & maize.
  • 21 monosomics isolated for hexaploid wheat.
  • 21 nullisomics isolated for wheat
  • (haploids of polyploidy = golyhaploids)
  • Autopolyploids – some basic set of chromosome multiplied (autotriploid – sudleos watermelon, sugar beet, tomato, banana) .
  • Polyploidy cell in otherwise diploid org = endopolyploidy.
  • Size of chromosome – mitotic metaphase.
  • Shape of chromosome – Anaphase
  • Monocots contain larger chromosome than dicots
  • Centromere – chromosome Movement during cell division
  • Kinetochores – actual site of attachment of the spindle (in zea mays nulture)
  • Metacentric – V – trillium & Tradescentia
  • Sub metacentric – L
  • Acrocentric – J
  • Telocentric – I
  • Arm ratio = (highest in acrocentric)
  • Second constrictions are distinguish from primary as chromosome bends only in primary.
  • Telomeres – Exhibit polarity & prevent union of chromosome ends with one another.
  • Second Constriction involved in organization of nucleolus = nucleolus organizer region
  • Histones (H2A, H2B (lysine) , H3 & H4 (arginine) ) hold by H1 lysine rich linker.
  • DNA content in pictograms.
  • Most abundant form of chromatin in interphase nucleus.
  • Ideogram – represent haploid set of organism in a series.
  • Asymmetric Karyotype is an advanced feature over symmetric karyotype.
  • Heterochromatin – Condensed, more deep stain, late replicating
  • Euchromatin – expanded, less deep stain, early replicating or diffuse regions

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