aCross Development

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

© Kathryn Tosney
Professor of Biology
The University of Michigan

Puzzle 5A

Blank puzzle 5A




    1 the _ _ _rease in cytoplasm volume relative to nuclear volume may help trigger the first gene transcription

    2 central cavity inside a blastula

    9 cells of the tunicate Styela partita that receive _ _llow cytoplasm become mesoderm

    10 the _ _imal pole is the yolk-poor pole of the egg, zygote and cleaving embryo

    11 in _ _i_ _ _ cleavage, cells cleave at oblique angles and form a stereoblastula, as in annelids, flatworms and many molluscs

    15 ___ pressure may help expand the sea urchin blastocoel during later stages

    18 embryonic portion of the placenta, enables the embryo to get oxygen and nutrients from mom, and secretes hormones to assure embryo retention

    21 in _e_olecithal eggs, a dense yolk lies to one side, as in reptiles, fish and birds

    22 yolk distribution will affect the _ _mmetry of cleavage

    24 anagram for synonym of sinistral

    26 an ass_ _ is a test

    27 copy to, abbrev

    29 in _ _ _i_l holoblastic cleavage, the cleavage furrows are oriented parallel to and perpendicular to the animal-vegetal axis of the egg

    30 small spot

    32 vertebrate embryos containing 16-64 cells, after the Latin word for the "mulberry" that they are said to resemble

    33 is, plural form

    35 _acr_meres are large blastomeres formed by unequal cleavages in the vegetal pole of sea urchins

    36 the b_ _ _ _ocyst is produced by cavitation in the morula, as fluid secreted by trophoblast cells accumulates

    37 the hya_ _ne layer is a non-cellular layer necessary for blastocoel expansion in sea urchins

    38 hit, as in cartoons

    41 old, used cloth

    42 enzyme secreted by the trophoblast during mammalian implantation that helps digest the extracellular matrix of the uterine wall

    45 in the meridi_ _al cleavage pattern, the cleavage furrow passes through animal and vegetal poles, like a meridian on a globe

    46 a fr_ _ _ _ is a disorderly fight

    47 in _ _roblastic cleavage, the cleavage furrow fails to penetrate the yolky cytoplasm

    48 relative size of blastomeres formed during early radial holoblastic cleavage

    51 the _ro_hect_derm is the outer layer of cells formed during mammalian cleavage

    52 the ___ cell mass will form the entire mammalian embryo, the yolk sac, allantois and amnion

    54 bilate_ _ _ holoblastic cleavage is typical of ascidians

    55 the direction of coiling in snail shells is determined by this individual's genome

    56 if mRNA for EP-cadherin is destroyed, the blastula will lo_ _ its blastocoel

    57 mammalian eggs may contain ___ numbers of cells because the divisions are asynchronous

    58 in the _ _ _ _blastic cleavage pattern, the cleavage furrow extends through the entire egg

    60 a ste_ _ _blastula is formed by spiral cleavage and lacks a blastocoel

    62 a characteristic of mammalian eggs that has made them difficult to study

    63 in spiral cleavage, the blastomeres are packed in the most thermodynamically stable orientation, like ___ bubbles


    1 type of meroblastic (incomplete) cleavage typical of eggs in which the yolk lies to one side (telolecithal eggs), as in birds

    3 the b_ _stula is a hollow sphere of single cells produced by early cleavage, cell movements and changes in cell adhesion

    4 signal for help

    5 material in the egg _ _ _ _plasm will dictate the cleavage pattern that is important to the direction of shell coiling in snail eggs

    6 three vowels

    7 during membrane po_ _rization in mammalian cleavage, cell surface molecules rearrange to specific positions on cells

    8 unlike almost all other animals, in mammals the genome is activated during ___ cleavage

    12 hydrogen ion concentration, logrithmic scale

    13 during cleavage in mammals, cleavage planes can ___ relative to each other

    14 ci_ _a are motile structures that develop on the outer surface of blastula cells

    15 the positi_ _n of a cell determines whether it will form trophoblast or embryonic structures

    16 the inner cell _ _ _s is composed of cells that develop within the trophoblast during mammalian cleavage

    17 series of mitotic divisions that divides the egg cytoplasm into numerous smaller, nucleated cells

    19 the y_l_ lies toward one side in mesolecithal eggs

    20 cell during the cleavage stage

    23 an evolutionary adaptation that lets an embryo develop without an external food source

    24 the _ _ophoblast will produce chorion and the embryonic part of the placenta, but no cells of the mammalian embryo

    25 _lui_ is secreted by the trophoblast during blastocyst formation

    27 process unique to mammalian cleavage; after the third cleavage, blastomeres become closely packed; exterior cells develop tight junctions while internal cells develop gap junctions

    28 mi_ _ _meres are small blastomeres formed by unequal cleavages in the vegetal pole of sea urchins

    31 in the equat_ _ _al cleavage pattern, the mitotic spindles of each blastomere are positioned parallel to the animal-vegetal axis

    34 superfic_ _ _ cleavage is the type of meroblastic cleavage that is typical of eggs where the yolk lies centrally, as in insects

    36 the b_ _ _tocoel in amphibians helps prevent cells from interacting prematurely

    38 when intact, the ___ pellucida prevents implantation by preventing adhesion

    39 _ _ _sminogen activator is an enzyme secreted by trophoblast during mammalian implantation that helps digest the extracellular matrix of the uterine wall

    40 _ _ _ _lecithal eggs have little yolk

    41 the ___ of cytoplasmic to nuclear volume decreases as cleavage progresses

    42 was able to

    43 junctions that allow communication between blastomeres during spiral cleavage

    44 in the _ _ _ _ _lastic cleavage pattern, the cleavage furrow fails to penetrate the yolky cytoplasm

    47 _ _ _ _meres are blastomeres of equal volume formed in the animal pole of sea urchins

    49 a _u_ _ is an area partially or entirely enclosed by walls or buildings; common on college campuses

    50 _ef_ is a synonym for sinistral, as in snail shell coiling

    53 little of this is made until late in cleavage, anagram

    58 greeting

    59 strome_ _sin is an enzyme secreted by trophoblast during mammalian implantation that helps digest the extracellular matrix of the uterine wall

    61 the trophoblast is an external layer of _ _ithelial cells connected by tight junctions that is formed during mammalian cleavage