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Wednesday, May 10, 2017

Biological Principles 2 -- 52.LS



Enzymes produced by the sperm’s acrosome dissolve a hole in the egg’s jelly coat.
List these embryonic events in vertebrates starting with the earliest.
·         Cleavage; Blastulation; Gastrulation; Neurulation
Gastrulation is the process that follows cleavage in mammals.
The figure provides an overview of the events of embryonic development: Fertilization; Cleavage; Gastrulation; Neurulation; Organogenesis
Which of the following are the three germ layers formed during gastrulation? Endoderm, ectoderm, mesoderm
An organ is a differentiated part of an organism, such as a wing, that performs a distinct function.
The acrosomal reaction allows the sperm to penetrate the outer layers of the egg.
Which of the following processes occur during neurulation? Segmentation of the body; Formation of the CNS
Gastrulation in frogs includes which of the following events? Appearance of the archenteron
Put the five general development events of triploblastic animals beginning with the union of the egg and sperm nuclei.
·         Fertilization; Cleavage; Gastrulation; Neurulation; Organogenesis
Blastomeres are the cells produced during the cleavage of a zygote.
The primordial germ cells are stem cells that can divide through mitosis to make copies of themselves. Some of the resulting daughter cell can later undergo meiosis and differentiate into gametes.
The following structures are formed during neurulation in vertebrate embryos. Arrange them in order, starting with the earliest form.                     Neural plate; Neural groove; Neural tube
In the early stages of vertebrate development, the process of cleavage yields successive blastomeres that become smaller and smaller.
Match the germ layer to its appropriate location in the embryo.

Endoderm: inner layer
Mesoderm: middle layer
Ectoderm: outer layer

The final, adult body plan is organized along three axes. These are: anteroposterior, dorsoventral, left-right
The developmental event in which cells and tissues form specialized structures is called: organogenesis
The cortical reaction is characterized by which of the following? Release of Ca+2 ions from the ER into the cytosol
In humans, the embryo implants in the uterus.
An animal embryo that appears as a hollow ball formed by many cells at the end of cleavage is called a blastula.
Neurulation in vertebrate embryos occurs in four major steps. Arrange them in order, starting with the earliest.

1.       Thickening and elongation
2.       Folding
3.       Convergence
4.       Fusion

Which of the following are found in the cytosol of a human egg, and secrete an enzyme to inactivate the sperm-binding proteins on the cell membrane? Cortical granules
Complete or holoblastic cleavage of the zygote is characteristic of which of the following animals? Amphibians, mammals
Incomplete cleavage of the zygote is characteristic of which of the following animals? Fish, birds
The initial cell cycles of embryos are unique because they involve repeated cell divisions without cell growth. The process by which these cell cycles occur is called cleavage
During gastrulation, sheets of surface cells fold back into the interior of the embryo. This process is called what? Involution
Following cleavage in humans, the hollow ball of cells that make up the blastocyst develops into a highly organized structure called the gastrula
Segmentation of an animal embryo begins after gastrulation during the process of Neurulation.
In mammals, fertilization and cleavage take place in which of the following structures? Oviduct
Zygote is another term for the fertilized egg that results from the union of a sperm nucleus and an egg nucleus.
During implantation in mammals, the embryo becomes embedded in the endometrium of the mother’s uterus.
The effect of convergent extension during embryonic development allows the merging of two rows of cells into  a single elongated layer.
The notochord begins to form by the end of which stage of embryonic development? Gastrulation
The invagination of cells perpendicular to the animal-vegetal axis in frog embryos begins the process of gastrulation.
An embryo is best defined as: an early stage of a multicellular organism during which the organization of the organism is largely formed.
The notochord is a flexible rod located between the digestive tract and the nerve cord in chordate embryos.
As animals develop, cells arrange themselves in coordinated ways that lead to establishment of a body plan.
In the process of cellular differentiation, different cells within a developing organism acquire specialized forms and functions, due to the expression of cell-specific genes.
In the process called implantation, the blastocyst of a placental animal is embedded into the endometrium of the uterus.
The effect of apical constriction during embryonic development causes various cells to elongate.
Cortical granules are membrane-bound vesicles in the egg’s cytosol that release enzymes to inactivate the sperm-binding proteins on the plasma membrane.
The early stages of vertebrate development produces cleavage-stage embryos which divide repeatedly without growth.
The PGCs that give rise to gametes are called primordial germ cells.
The notochord does not persist in which of the following adult animals? Mammals, birds
The blastula is the embryonic stage which consists of an outer layer of epithelial cells and an internal water-filled cavity.
Order the following steps of fertilization, starting with the earliest.

1.       Acrosomal reaction
2.       Fusion of membranes of egg and sperm
3.       Increase in inositol trisphosphate (IP3)
4.       Ca++ released into cytosol
5.       Fusion of nuclei of egg and sperm

Which of the following statements best describes the process of cleavage in animal development? The number of embryonic cells increases, but the overall size of the embryo stays the same.
The transformation of a tadpole into a frog or a caterpillar is known as metamorphosis.
The process by which different cells within a developing organism acquire specialized forms and functions, due to the expression of cell-specific genes, is termed cellular differentiation.
Which of the following are the four tissue types in animals? Epithelial, connective, nervous, muscle
Which of the following were found to be positive side effects of the drug thalidomide? Lessens nausea, sleep inducer
The notochord is a mesodermal structure that provides rigidity along the anteroposterior axis in the dorsal side of the gastrula.
The two half-size daughter cells produced by each cell division during cleavage are known as: blastomeres.
The final, adult body plan of most animals is divided along three axes.
Which of the following are triploblastic animals? Mollusks, arthropods, echinoderms
The notochord persists in the trunks and tails of which of the following animals? Amphibians, fish
Metamorphosis is a profound change in form from one stage to the next in the life of an organism, e.g. the change of a caterpillar to a butterfly.
The initial cell cycles of embryos are unique because they involve repeated cell divisions without cell growth. The process by which these cell cycles occur is called cleavage.
Hox genes are important for establishing structures along the anteroposterior axis.
Embryonic development is best described as the process by which a zygote is transformed into an organism with distinct physiological systems and body parts.
The movement of sheets of cells during embryonic development is due to convergent extension.
Most modern animals are triploblasts; that is, they develop from embryos with three germ layers.
In a developing animal, the central, fluid-filled cavity is called a blastocoel.
The blastocyst is composed of how many layers? 2
Depolarization of the egg membrane blocks other sperm from binding to egg membrane proteins and is referred to as the fast block to polyspermy.
During gastrulation in a developing frog embryo, a new cavity called the archenteron displaces the existing blastocoel.
Placental mammals are also called eutherian.
The four main responses to positional information are: cell division, cell migration, cell differentiation, and apoptosis.
Metamorphosis occurs after organogenesis and facilitates the rapid growth of young organisms into mature ones.
The outer epithelial layer of the blastocyst is called the trophectoderm, which gives rise to the placenta.

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