Question 1

Each of the following statements concerning development is true,except that

Accepted Answer

Each blastomere does not receive exactly the same cytoplasmic composition. Asymmetric cell division during early development can result in different cytoplasmic contents in daughter cells, which can affect their developmental pathways.

Question 2

After fertilization,the first cell division is completed

Accepted Answer

E

Question 3

During early development,the Y chromosome produces a substance called "testis determining factor" (TDF)that causes the indifferent gonad to become a testis.This would be an example of

Accepted Answer

The process described involves one tissue inducing another tissue to become a specific type of tissue. This is known as induction, and option D is the only choice that accurately describes this process.

Question 4

Sperm cannot fertilize an oocyte until they

Accepted Answer

Sperm must undergo capacitation, a process where they become more motile and able to penetrate the protective layers surrounding the oocyte, in order to fertilize an oocyte. Activation, loss of the acrosome, and time spent in the vagina are not necessary for fertilization, and sustentacular cells in the vagina do not play a role in activating sperm.

Question 5

The period of gestation when organs and organ systems complete most of their development and the fetus looks distinctly human is the ________ trimester.

Accepted Answer

The second trimester is often referred to as the "honeymoon period" of pregnancy because many women experience relief from the symptoms of morning sickness, fatigue, and frequent urination that are common in the first trimester. It is also during this trimester that the fetus looks distinctly human and all major organs and organ systems complete most of their development.

Question 6

Proteolytic enzymes that digest a path through the zona pellucida include

Accepted Answer

Hyaluronidase and acrosin are proteolytic enzymes that together digest a path through the zona pellucida, allowing the sperm to fertilize the egg. Hyaluronidase breaks down the hyaluronic acid in the zona pellucida, while acrosin is a protease that can break down proteins in the zona pellucida.

Question 7

The penetration of the endometrium by the blastocyst is referred to as

Accepted Answer

Implantation is the process where the blastocyst (early-stage embryo) attaches to and penetrates into the endometrium (lining of the uterus). Cleavage is the rapid division of the zygote into multiple cells. Placentation is the formation of the placenta, an organ that connects the developing embryo to the mother's uterus for nutrient and waste exchange. Embryogenesis is the process of embryo development from fertilization to the end of the eighth week of gestation. Fertilization is the fusion of the sperm and egg to form a zygote.

Question 8

The site where fertilization normally occurs is in the

Accepted Answer

Fertilization normally occurs in the upper one-third of the uterine tube. Sperm released during ejaculation travel through the vagina, cervix, and into the uterus. From there, they make their way into the uterine tube where they may encounter and fertilize an egg if one is present.

Question 9

Polyspermy results in

Accepted Answer

Polyspermy is the fertilization of an egg by more than one sperm cell, which results in a nonfunctional zygote. This is because the excess genetic material may interfere with normal development, and the resulting embryo is unable to survive. Twins, fetuses with different fathers, haploid individuals, and chimeric adults are not the result of polyspermy.

Question 10

Contact of a sperm with the oocyte membrane causes

Accepted Answer

All of the listed processes occur as a result of the contact between a sperm and oocyte membrane. Sperm contact is the trigger for oocyte activation, completion of the second meiosis, and extrusion of the second polar body. This contact also leads to the fusion of the sperm and oocyte membranes, allowing for the entry of the sperm nucleus into the oocyte, which ultimately results in fertilization.

Question 11

The developmental period that is the period of all embryological and early fetal development is

Accepted Answer

The first trimester is the period of embryological and early fetal development, which occurs during the first 12 weeks of pregnancy. This is when the major organs and systems begin to form and the embryo/fetus is most vulnerable to teratogens.

Question 12

Which of the following is not part of oocyte activation?

Accepted Answer

The answer of Which of the following is not part...

Question 13

The process of cell division that divides the cytoplasm of the zygote among blastomeres is called

Accepted Answer

Cleavage is the process of cell division that takes place after fertilization and divides the cytoplasm of the zygote among blastomeres. This is the earliest stage of embryonic development.

Question 14

The period of gestation when the rudiments of all major organ systems are established is the ________ trimester.

Accepted Answer

During the first trimester, the formation of major organ systems, including the nervous system, cardiovascular system, and respiratory system, takes place. It is a crucial period of development, and exposure to drugs, alcohol, or other harmful agents during this time can lead to significant birth defects.

Question 15

After ovulation,the layer of follicle cells that surround the unfertilized egg is called the

Accepted Answer

The layer of follicle cells that surround the unfertilized egg after ovulation is referred to as the corona radiata. This layer of cells is located outside the zona pellucida, which is a layer of glycoproteins surrounding the oocyte. The Graafian follicle is the mature follicle that contains the oocyte prior to ovulation. The functional zone refers to the thick layer of endometrial tissue that is shed during menstruation. The tunica follicularis is a layer of connective tissue that surrounds the follicle.

Question 16

The period of gestation that is characterized by rapid fetal growth and fat deposition is the ________ trimester.

Accepted Answer

The third trimester is characterized by rapid fetal growth and fat deposition as the fetus prepares for birth. The first trimester is characterized by the formation of major organs and structures, and the second trimester is when the fetus grows and becomes more active. There is no fifth trimester. The fourth trimester is sometimes referred to as the first three months after birth, when the newborn is adjusting to life outside the womb.

Question 17

During amphimixis,

Accepted Answer

During amphimixis, the male and female pronuclei fuse, forming a zygote with a complete set of chromosomes. Capacitation of sperm occurs before fertilization, and meiosis usually occurs before the formation of gametes, not during amphimixis.

Question 18

Differentiation among blastomeres is the result of

Accepted Answer

Blastomeres are cells that form during the early stages of embryonic development, resulting from repeated mitotic divisions of the zygote. Differentiation among blastomeres occurs due to an unequal distribution of regulatory molecules in the cytoplasm of the ovum, which determines the fate of each cell as it divides. This process is known as cytoplasmic segregation and is responsible for the formation of different germ layers and ultimately, the development of different tissues and organs in the embryo. Enzymes introduced by the sperm or hormones produced by the ovum do not play a significant role in blastomere differentiation, and regulator molecules supplied by cells of the uterus are not involved in early embryonic development. Enzymes activated by the sperm may help facilitate fertilization, but they would not have a direct effect on blastomere differentiation.

Question 19

________ are nearly identical cells that are produced by early cleavages.

Accepted Answer

Blastomeres are the nearly identical cells produced by early cleavages, while morulas are solid balls of cells formed by cleavage, and gastrulas are embryos in the stage where the germ layers (endoderm, mesoderm, and ectoderm) are forming. Amnions are sacs of fluid that surround the embryo/fetus, and blastulas are hollow balls of cells formed after the morula stage.

Question 20

The gradual modification of anatomical structures during the period from conception to maturity is

Accepted Answer

Development refers to the gradual modification of anatomical structures during the period from conception to maturity. Differentiation is the process by which cells become specialized. Embryogenesis refers specifically to the development of an embryo from a fertilized egg. Capacitation is a process undergone by sperm within the female reproductive tract prior to fertilization. Therefore, the best choice is A, as it encompasses all aspects of anatomical development.

Quiz 29: Development and Inheritance