Partial diploids

Pectinolytic enzymes secreted by the diploid K. marxianus have been partially purified and characterized [eg 2] but the results obtained were very variable, partially contradictory and paid little attention to the physiological aspects of PG secretion [3]. Commercial use and production of PG from K. marxianus has attracted considerable interest [4]. 

Sexuality Zygote partially diploid (merozygotic) Zygote diploid... 

The most informative genetic studies were performed on cells containing two copies of the lac operon with point mutations in different genes. Partial diploids (merodiploids) of this sort are constructed by mating experiments in which a second copy of the lac region is incorporated into the test cell by mating. For this purpose the F factor plasmid is a... 

Cells that carry a single copy of each gene are referred to as haploids. Cells that carry two copies of each gene are referred to as diploids. Bacteria are haploid cells because they carry a single chromosome with a unique representation for each gene. Bacterial cells that are partial diploids (merodiploids) may occur naturally, or they may be selected for by genetic techniques. 

Figures 14.11 and 14.12 show the presence of two partially overlapping cell populations Pp the normal population (diploid), and P2, the tumour population (aneuploid). The results given in Table 14.7 show that the efficacy of...

Recombination occurs primarily in germ cells of eukaryotes and during cell division in partially diploid prokaryotes. In general, recombination does not occur in mitosis of eukaryotic cells. However, recombination is an integral part of meiosis in which recombinant sperm and ova provide new genotypes and phenotypes in each generation which may be favored by natural selection. 

Partial chromosome transfer from a male cell transforms the F cell into a partial diploid (merozy-gote) containing double the usual number of some of the genes. Within this partial diploid genetic recombination between the two chromosomes takes place (Fig. 

For each of the follovAng, predict whether active enzymes Z, Y, and A will or will not be produced. For partially diploid cells, assume semidominance that is, the enzyme activity in a diploid cell will be twice that found in a haploid cell. Use the following answer code ... 

Analysis by haploidization has been facilitated by the use of />-fluoro-phenylalanine. At suitable concentration this analog partially inhibits growth of the diploids, but haploids, formed during the stunted growth, produce vigorous sectors which can usually be tested without further purification (Morpurgo, 1961). 

Campbell, A. 1965. The steric effect in lysogenization by bacteriophage lambda. I. Lysogenization of a partially diploid strain of Escherichia coli K12. Virology, 27 329-339. 

Fertilization is twofold. One of the two sperm cells fuses with the diploid, secondary embryo sac nucleus to form the triploid endosperm nucleus. The endosperm nucleus divides to form many nuclei each of which combines with cytoplasm to form a cell. In this way the multicellular endosperm emerges. Subsequently it can be enriched with reserve materials, vitamins, phytohormones, and other factors that are necessary for development before and, in part, also after germination. In some cases such as the coconut and pumpkin plants the endosperm is wholly or partially fluid. 

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