AP Biology : Systems Physiology
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Example Questions
Example Question #261 : Systems Physiology
During which of the following stages of embryonic development does the process of invagination occur?
Blastula development
Implantation
Gastrulation
Fertilization
Gastrulation
Invagination is the infolding of the epiblast cell layer to form the endoderm germ layer. This process takes place during gastrulation.
Example Question #262 : Systems Physiology
Which of the following structures is referred to as the “blastocoel”?
The glycoprotein layer around the blastocyst
Outer layers of cells in the blastocyst
The fluid-filled cavity of the blastocyst
The area of cellular invasion during implantation
The fluid-filled cavity of the blastocyst
The “blastocoel” is a fluid-filled cavity in the blastocyst. It is enclosed by trophoblast cells.
Example Question #263 : Systems Physiology
During what stage of embryonic development do cells differentiate into primary germ layers?
Blastula development
Gastrulation
Implantation
Fertilization
Gastrulation
Germ layers are primary layers of cells that form during embryogenesis. In mammals, they are the endoderm, ectoderm, and mesoderm. In embryo development, the germ layers differentiate during gastrulation.
Example Question #264 : Systems Physiology
Which of the following does not develop from the mesoderm?
Pigment cells
Muscle cells
Kidney cells
Red blood cells
Pigment cells
The mesoderm is a primary germ layer that forms during gastrulation. The mesoderm develops into most of the organ systems of the human body, including the muscular system, circulatory system, and excretory system.
Example Question #31 : Reproductive Physiology
During which of the following stages of embryogenesis is the developing embryo called a “zygote”?
During gastrulation
Only after implantation
After fertilization
During the entirety of cleavage
After fertilization
The term “zygote” is sued to describe a fertilized egg. The zygote is diploid and formed by the fusion of the sperm and egg gametes. The developing organism is called the zygote until it is composed of 16 cells during cleavage, when it is called the “morula.”
Example Question #261 : Systems Physiology
Which of the following sets of terms best describes the names of the two poles present in developing embryos?
Animal and chorionic poles
Animal and vegetal poles
Chorionic and vegetal poles
Animal and blastomeric poles
Animal and vegetal poles
Developing embryos exhibit an asymmetry; the zygote can be described as having two hemispheres. These two poles are called the animal and vegetal poles. The vegetal pole contains more yolk and will become the endoderm. The animal pole contains less yolk and will become the ectoderm and mesoderm.
Example Question #261 : Systems Physiology
Which of the following is true about holoblastic cleavage?
It takes place when the developing embryo has little yolk
It is partial cleavage
One patterning example of holoblastic cleavage is superficial cleavage
It takes place when the developing embryo has a high concentration of yolk
It takes place when the developing embryo has little yolk
Holoblastic cleavage is the type of cleavage found in developing embryos with a low yolk concentration. This allows for the complete cleavage that forms planes that extend through the entirety of the zygote. Different cleavage patterns in holoblastic cleavage include bilateral, radial, rotational, and spiral. Animals whose zygotes undergo holoblastic cleavage include placental mammals, amphibians, and annelids.
Example Question #262 : Systems Physiology
Which of the following is not a true characteristic about meroblastic cleavage?
It is found in developing embryos with a high concentration of yolk
It is partial cleavage
It is found in insects
Cleavage planes extend all the way across the zygote
Cleavage planes extend all the way across the zygote
Meroblastic cleavage is partial cleavage in zygotes with a high concentration of yolk. In developing embryos that undergo this process, cell divisions do not penetrate the yolk. Two types of meroblastic cleavage are discoidal and superficial cleavage. This process occurs in insects, some fish, and some types of birds.
Example Question #269 : Systems Physiology
In which of the following groups of organisms does indeterminate cleavage take place?
Protostomes
Deuterostomes
Placental mammals
Chordates
Deuterostomes
Indeterminate cleavage takes place in most deuterostomes. It is a type of cleavage in which embryonic cells can be separated and successfully develop into different organisms.
Example Question #263 : Systems Physiology
Which of the following terms best describes the type of cleavage that occurs in developing mammalian embryos?
Spiral
Radial
Bilateral
Rotational
Rotational
Developing mammalian embryos exhibit rotational cleavage. In this type of cleavage, the first cell division occurs on meridionally. The next cell division in the two resulting daughter cells occurs meridionally in one and equatorially in the other.
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