AP Biology : Systems Physiology

Study concepts, example questions & explanations for AP Biology

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Example Questions

Example Question #1230 : Ap Biology

During which of the following stages of embryonic development does the process of invagination occur?

Possible Answers:

Fertilization

Gastrulation

Blastula development

Implantation

Correct answer:

Gastrulation

Explanation:

Invagination is the infolding of the epiblast cell layer to form the endoderm germ layer. This process takes place during gastrulation.

Example Question #1231 : Ap Biology

Which of the following structures is referred to as the “blastocoel”?

Possible Answers:

The glycoprotein layer around the blastocyst

The fluid-filled cavity of the blastocyst

The area of cellular invasion during implantation

Outer layers of cells in the blastocyst

Correct answer:

The fluid-filled cavity of the blastocyst

Explanation:

The “blastocoel” is a fluid-filled cavity in the blastocyst. It is enclosed by trophoblast cells.

Example Question #1232 : Ap Biology

During what stage of embryonic development do cells differentiate into primary germ layers?

Possible Answers:

Fertilization

Gastrulation

Implantation

Blastula development

Correct answer:

Gastrulation

Explanation:

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 #31 : Understanding Embryogenesis And Development

Which of the following does not develop from the mesoderm?

Possible Answers:

Muscle cells

Red blood cells

Kidney cells

Pigment cells

Correct answer:

Pigment cells

Explanation:

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 : Understanding Embryogenesis And Development

During which of the following stages of embryogenesis is the developing embryo called a “zygote”?

Possible Answers:

During the entirety of cleavage

During gastrulation

Only after implantation

After fertilization

Correct answer:

After fertilization

Explanation:

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 #32 : Understanding Embryogenesis And Development

Which of the following sets of terms best describes the names of the two poles present in developing embryos?

Possible Answers:

Animal and blastomeric poles

Animal and vegetal poles

Chorionic and vegetal poles

Animal and chorionic poles

Correct answer:

Animal and vegetal poles

Explanation:

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 #33 : Understanding Embryogenesis And Development

Which of the following is true about holoblastic cleavage?

Possible Answers:

It takes place when the developing embryo has a high concentration of yolk

It takes place when the developing embryo has little yolk

It is partial cleavage

One patterning example of holoblastic cleavage is superficial cleavage

Correct answer:

It takes place when the developing embryo has little yolk

Explanation:

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 #34 : Understanding Embryogenesis And Development

Which of the following is not a true characteristic about meroblastic cleavage?

Possible Answers:

Cleavage planes extend all the way across the zygote

It is partial cleavage

It is found in developing embryos with a high concentration of yolk

It is found in insects

Correct answer:

Cleavage planes extend all the way across the zygote

Explanation:

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 #1238 : Ap Biology

In which of the following groups of organisms does indeterminate cleavage take place?

Possible Answers:

Deuterostomes

Protostomes

Placental mammals 

Chordates

Correct answer:

Deuterostomes

Explanation:

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 #265 : Systems Physiology

Which of the following terms best describes the type of cleavage that occurs in developing mammalian embryos?

Possible Answers:

Radial

Bilateral

Rotational

Spiral

Correct answer:

Rotational

Explanation:

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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