aCross Development

a crossword puzzle study guide to Gilbert's Developmental Biology, 5th edition

© Kathryn Tosney
Professor of Biology
The University of Michigan

ktosney@umich.edu


Puzzle 2A


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    1 transformation of one differentiated cell type into another, as in newt lens regeneration

    8 somatic cells from Rana pipiens ___ their ability to direct complete development as they become determined and differentiated, showing a progressive restriction of nuclear potency

    11 insert an O for milk, then add ARD to run away

    12 anagram for a conjunction

    13 when Morgan removed cytoplasm from a _ _ _ _ophore egg, the embryos were defective, suggesting to him that cytoplasm carried the important developmental information

    15 because iris cells can form lens cells in the newt, they have not ___ any lens genes during their initial formation

    17 a nucleus that is ____potent would be able to generate all the cell types of the body; the nucleus of the fertilized egg is ___potent


    18 malformations in the fruit fly ___ (a structure) result from genes affecting the developmental primordia

    20 the early history of developmental biology sounds rather like a w_ _ (conflict) between embryologists and geneticists, as each side became partisan over which compartment of the fertilized egg controls inheritence

    22 sea urchin eggs fertilized by ___ (number) sperm divide abnormally, so that daughter cells have different types of chromosomes; those with different chromosomes have different defects, thus showing individual differences in
    chromosomes
    23 refers to what cell types a cell can develop to form

    25 a _ _ _ism (estrangement) separated early geneticists and embryologists
    26 male pronoun

    27 each nucleus contains _ _st if not all of the same genes; the operon_ _del gave us one way of understanding how gene expression could be regulated

    28 the Brachyury mutation affects the development of the ___ (posterior) of the embryo

    32 progressive restriction of nuclear potency during development appears to be the general view; developmental events _ _ _ (prohibit) expression of every gene in every cell

    34 end in AY to wait, ETE to remove, UDE to lie, VE to dig

    35 genomic ____ is the concept that all cells that are the mitotic descendent of a fertilized egg retain all the genes present in the egg

    37 a question that bedeviled early embryologists was, if chromosomes are the s_ _ _ (identical) in every cell, how can they direct development of different cell phenotypes?

    39 the concept that developmental information lies in the cytoplasm is _e_able (justifiable) because removing cytoplasm from certain kinds of eggs is sufficient to cause deformed development

    40 for the most part, all the cells of the body have the _ _me (identical) genes and chromosomes

    41 to enucleate a frog _g_, prick the egg to induce changes that mimic fertilization and then puncture it where the meiotic spindle has pushed pigment granules away; the chromosomes and meiotic spindle will then flow out of the cell

    42 one _ _ctic (plan) to reintegrate genetics and embryology was to look for mutations that alter early development

    44 diety

    45 regeneration of the ___ in salamanders showed that even differentiated adult cells retain the potential to produce other cell types

    47 very important person, abbrev

    49 _ _o_; to find, pinpoint

    51 the operon model forms one b_ _ _s (fundamental principle) of our understanding of developmental mechanisms

    54 In 1938, Glueksohn-Schoenheimer reflected that a _ _ _ _ _ _ _mental geneticist couldn't change a structure and evaluate the consequences, but had to examine the results of the gene's experiment

    57 metaplasia is also termed ___-differentiation, a change from one differentiated cell into another

    59 long playing record, abbrev

    61 when Morgan removed cytoplasm from fertilized comb jelly eggs, the embryos developed with _ _fects, showing that the cytoplasm is essential for development and leading him to propose that the nucleus does not contain differentiating power.

    62 serial transfer of a nucleus from _ _g to _ _g can increase the number of nuclei that can develop tadpoles; the procedure of transfering a nucleus into an enucleated _ _g is called cloning

    63 mutation in mice that alters development of the posterior portion of the embryo due to defects in early induction of the dorsal axis

    67 _NI_ is a computer system

    68 division rate during cleavage; if differentiated cells divide at this rate their chromosomes can break, leading to abnormalities that may explain why so few differentiated nuclei can support normal development when transplanted into an enucleated egg

    69 Woll_ _an regeneration of the newt lens is so named for the person who discovered it

    70 before the Christian era, abbrev

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    2 _ _o_ _ is the bacterium used to establish the operon model; as with other microbes, its environment can modulate its gene expression

    3 in microbes, one genome can produce ___ (number) functionally different cytoplasmic states, depending on the presence or absence of a particular compound such as lactose

    4 _ _ctose is a substance that stimulates E. coli to synthesize beta-galactosidase

    5 _ _aptive enzymes are proteins that are not usually synthesized by a microbe, but that become synthesized when the microbe encounters a novel substrate

    6 x-linked mutations in which traits like eye color could be directly linked to presence of a particular sex chromosome proved to be a ___ (catch) in the cytoplasmic hypothesis, and converted Morgan to the chromosmal hypothesis


    7 genes ___ and react; they both alter the cytoplasm and respond to changes in the cytoplasm, as instanced by the operon model

    8 if you ___ (allow) nuclei from differentiated skin cells to restore their abilities by serial transfer through enucleated eggs, then some can direct normal development

    9 a t_ _ _c is a restorative; e.g., drink it with gin

    10 according to Morgan, the science that studies the expression of traits; a continuing dialog between genetics and ___ parallels an ongoing dialog between the nucleus and the cytoplasm in the cell

    14 genes are the same from cell to cell; globin genes are found in ____ cells, and genes for ___ enamel are found in brain neurons

    16 number of x chromosomes that determines female sex in insects studied by Morgan

    19 novel

    20 the highest point, apex, culmination

    21 an exceptionally large chromosomal puff can be physically ___ by microdissection and its products can be analyzed; this procedure showed that puffs actively make mRNA

    22 differential gene expression has ___ (number of) postulates: differentiated cells have identical DNA, unused genes retain the potential to be expressed, and only a few specific genes are expressed in each cell

    23 ring, toll, chime, knell

    24 depend or desert, vowels only

    29 energy quotient, abbrev

    30 Scott Gilbert is the _ _ _hor of your textbook; Kathryn Tosney is the _ _ _hor of these puzzles.

    31 a Balbiani ___ is a large puff on a polytene chromosome; experiments hybridizing insects carrying different ___s showed that a puff is responsible for appearance of a particular protein

    32 structural differences in polytene chromosomes that reflect differentially condensed regions; these ____ are identical in position and size from cell to cell

    33 spermine treatment of nuclei removes histones and may help to ___ (restore) the activity of nuclei, allowing them to divide at a more rapid rate when they are placed in an enucleated egg

    34 after a newt lens is plucked out, pigmented iris cells _ _-differentiate by disposing of their pigment granules and then divide and finally redifferentiate as lens cells

    36 an archaic negative

    38 slang for the maternal person

    43 fate of most Rana pipiens embryos that develop when somatic cells of tail-bud stages are injected into enucleated eggs: they ____

    46 mutations that altered axis and wing development in Drosophila showed that genes control ____ (refers to time) development as well as the final modeling of details

    47 double letter

    48 if a cell or nucleus is _ _ _ _ _potent, it can give rise to many but not all cell types

    50 _ _ _ _tene chromosomes in larval insects undergo DNA replication without mitosis, resulting in 512, 1024 or more parallel DNA double helices per cell

    52 the _ _me number of bands are seen on polytene chromosomes from different organs

    53 an _ _ _ _ _er is a molecular agent made by one cell that is responsible for influencing differentiation of another cell

    55 anagram for a type of differentiated cell in which the nucleus, if transplanted into an enucleated egg, can support normal development

    56 the _ _ _e (rate) of mitosis is much greater during cleavage than in any differentiated cell

    58 in some species, ____ is determined by the environment

    60 a _ _ _f is an expanded region of a polytene chromosome that reflects active RNA synthesis

    63 treating nuclei with spermidine and cold may help _y_ass (evade) the demand for nuclei to suddenly revert to foreign physiological conditions and to divide incessantly

    64 even some _ _ult differentiated cells can retain their potential to produce other cell types

    65 male pronoun

    66 the inadvertant presence of p_ _mordial germs cells in the gut could, in King's view, explain why some fraction of nuclei taken from gut cells support normal development; experiments using frog foot cells countered this objection


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