Developmental Biology Trivia Quiz

Answer: Sertoli Cells

Sertoli cells maintain the developing sperm cells' environment to ensure that they receive enough nourishment during their journey from a single diploid spermatagonium to four haploid spermatozoa. The sertoli cells also ensure that the cells' development and eventual release into the lumen of the seminiferous tubule are properly synchronized.

Answer: Cytostatic Factor (CSF)

The typical oocyte goes through two arrests during its journey to become a fertilizable egg. The first arrest occurs in prophase I of meiosis, due to a lack of mitosis promoting factor, (MPF). This block is lifted by the presence of the hormone progesterone, which initiates a cascade that activates the catalytic subunit of MPF.

The oocyte continues to divide until it reaches metaphase II where it is arrested until fertilization. This arrest is caused by cytostatic factor, (CSF), a compound that contains byproducts from the activation of MPF.

The breakdown of CSF is calcium dependent and therefore is only broken down after the Ca 2+ influx subsequent to fertilization.

Answer: Autopodium

Tetrapod limb development is one of the most complex aspects of developmental biology. You have to develop two identical limbs on the same region on each side of the flank. There are numerous factors that go into the development of the tetrapod limb including fibroblast growth factor, wnt, and sonic hedgehog.

The typical tetrapod limb consists of a proximal stylopod, a middle zeugopod and a distal most autopod.

Answer: Bone morphogenic protein (BMP)

Chordin, follistatin, and noggin are all dorsalizing factors secreted by the Spemann organizing center. This establishes mesodermal dorso/ventral polarity. Areas high in BMP will be ventral mesoderm, the area in the middle where dorsalizing factors compete with ventralizing factors becomes intermediate mesoderm, and those areas high in dorsalizing factors will become dorsal mesoderm.

Answer: One, two, and five

As a result of evolution we take the time and effort to develop six aortic arches; however by the end of cardiac development arches one, two and five are long gone. The remaining arches, arches three, four and six become the carotid artery, aortic arteries, and pulmonary arteries respectively.

Answer: It, along with the primitive ventricle, forms the ventricles

The tube heart is formed by the fusion of lateral plate mesoderm from two distinct cardiac fields. The four bulges are, going from posterior to anterior, the sinus venosus, the primitive atrium, the primitive ventricle, and the bulbus cordis. Factors cause the heart to loop; this causes the more posterior structures to move to the anterior side and vice versa.

The bulbus cordis along with the primitive ventricle become the ventricles of the adult heart, the primitive atrium becomes the two atria, and the sinus venosis becomes incorporated into the wall of the right atrium.

Answer: You would not develop aortal cells and therefore arteries

Angioblasts that are destined to become arteries stimulate the notch signaling pathway, which up-regulates gridlock expression; the cells with up-regulated gridlock express ephrin-B2 and become arteries. The opposite is true for veins; there is low notch signaling, so gridlock is not expressed and the angioblast express eph-B4 and becomes a vein.

Answer: Motor neurons

The gradient of BMP4 and Shh influences cells of the roof and floor plate to differentiate into different neuron types. This type of gradient is viewed as a dorso/ventral patterning, because the dorsal most roof plate will give rise to sensory neurons and the ventral most floor plate will give rise to motor neurons.

This is why neurons for sensation and pain are located in the dorsal horn of the spinal cord and motor neurons are located in the ventral horn.

Answer: Yolk Syncytial Layer

The yolk synscytial layer is a layer of cells at the bottom of the blastoderm that has fused with the underlying yolk cells. The YSL helps direct the movement of cells during gastrulation.

Answer: See

The diencpehalon is the second bulge of the primitive brain. The optic vesicle originates from this region, which will eventually form the retina. If I were to knock out your diencephalon you would not be able to see.

Answer: False

A person who is genetically XY, the male genotype, who is suffering from androgen insensitivity, will have all the phenotypic characteristics of a female, except the sex organs responsible for reproduction. People suffering from this disease are also referred to as sex reversed males.

These patients do have testes that produce testosterone; however they lack testosterone receptors and are therefore insensitive to it. The hormone testosterone degrades the Mullerian ducts, the ducts that will eventually become the ovaries, oviduct, and uterus in the adult female; so these patients are therefore infertile.

Answer: Rotational Cleavage

Mammalian embryos have a unique form of cleavage when compared to other species. The first division is a typical meridional; however in the second division one blastomere divides meridionally while the other divides equatorially. This is known as rotational cleavage.

Answer: Spermatheca

The sperm storage area in C. elegans is known as the spermatheca. It is located between the oviduct and the uterus. An unfertilized egg passes into the spermatheca and becomes fertilized; the embryo then moves into the uterus and passed through the vulva.

Answer: Christmas

Believe it or not Easter, sptatzle, and snake are all factors that interact in a chain of events that allow for the activation of the dorsal protein that enters the nucleus of cell and ventralizies it. It may seem confusing that the dorsal protein actually ventralizes cells; however scientists oftentimes discover what certain proteins do by knocking them out or removing them from cells.

When the dorsal protein was removed from a cell; the cell was completely dorsalized; hence the name dorsal

Answer: One has the same genes as the ovum, two have different ones

During oogenesis, the original primary oocyte divides twice during meiosis. The first time, the chromosomes are split between the daughter cells, each receiving one half of the set, while the second split (of each of the cells) does not further change genetic makeup. One of the four resulting cells becomes the ovum while the other three are the polar bodies, but only the one resulting from the second split of the later ovum has chromosomes identical to it.

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