Competitive Exams: Revision Terminology Part 20

  • 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 = lengthoflongchromosomelengthofshortchromosome (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