Question 1

In humans,germ line cells originate in the

Accepted Answer

Germ line cells, which give rise to gametes (sperm and eggs), originate in the yolk sac during early embryonic development in humans.

Question 2

Human females probably evolved the ability to live beyond their reproductive years because

Accepted Answer

The contribution of grandmothers to child rearing increases the survival rate of children. Studies have shown that in many traditional societies, grandmothers play an important role in caring for their grandchildren, which in turn increases the survival rate of children. This may have led to the evolution of longer post-reproductive lifespans in human females.

Question 3

Which of the following would NOT be exchanged between a mother and her fetus through the umbilical cord?

Accepted Answer

Enzymes are not typically exchanged through the umbilical cord. The other choices (carbon dioxide, nutrients, and oxygen) are substances that are commonly exchanged between a mother and her fetus through the umbilical cord.

Question 4

Humans complete their development in a protected environment inside their mothers' bodies,in the

Accepted Answer

The uterus is the organ where the fetus grows and develops during pregnancy. It provides a protected environment for the developing fetus and is where labor and delivery occur. The cervix and vagina are parts of the female reproductive tract but are not involved in fetal development. The oviduct, also known as the fallopian tube, is where fertilization typically occurs but is not where the fetus develops.

Question 5

The Pill does NOT prevent

Accepted Answer

The Pill, or oral contraceptives, primarily works by preventing ovulation and can also alter the uterine lining to prevent implantation, but it does not protect against sexually transmitted diseases (STDs). Protection against STDs requires the use of barrier methods such as condoms.

Question 6

The human embryo develops in a fluid-filled sac called the

Accepted Answer

The amnion is a fluid-filled sac that surrounds and protects the developing embryo/fetus during pregnancy. It contains amniotic fluid, which helps cushion and protect the fetus from external pressure and temperature changes.

Question 7

The graph below shows the rate of cell division in a developing frog embryo.

Why does the rate of growth decrease dramatically after the point indicated by the arrow?

Accepted Answer

The rate of growth decreases dramatically after the point indicated by the arrow because development switches from rapid cell growth to cell differentiation and migration. This is a more deliberate process that requires the cells to take on specific functions and move to specific locations within the developing embryo.

Question 8

Why does an embryo undergo the process of gastrulation?

Accepted Answer

Gastrulation is the process by which cells in the blastocyst differentiate to form embryonic tissues, but these cells are not originally located in the right place. Gastrulation moves these cells to the proper position in the embryo, which is essential for proper development and differentiation of different tissues and organs.

Question 9

Disruptions to the development of a zygote can occur at any time during pregnancy.Among the time periods mentioned below the most vulnerable period of development for a zygote/fetus/embryo would be the ________ week.

Accepted Answer

During the first week of development, the zygote undergoes rapid cell division and differentiation, and any disruptions during this time can have significant consequences on the development of the fetus. This is the most vulnerable period of development for a zygote/fetus/embryo.

Question 10

By the end of a normal first trimester,the zygote has

Accepted Answer

By the end of the first trimester, the zygote has developed into an embryo and then a fetus, with recognizable human features such as limbs and facial structures. The other options are incorrect: the embryo develops three tissue layers (ectoderm, mesoderm, and endoderm), not just the mesoderm; it is far from its birth length; and organ systems have begun to form, though they are not fully developed.

Question 11

During development,the process by which unspecialized cells acquire specific identities is called

Accepted Answer

Differentiation is the process by which unspecialized cells acquire specific identities, either as different cell types during embryonic development or as mature, specialized cells during tissue repair and homeostasis in adult organisms. Gametogenesis is the process by which specialized cells, called gametes, are produced for sexual reproduction. Fertilization is the fusion of two gametes to form a zygote, which then undergoes cell division and differentiation to form an embryo. Gastrulation is a key stage in embryonic development in which the embryo folds in on itself to form three germ layers, which will give rise to all of the body's tissues and organs.

Question 12

Which of the following structures are commonly manipulated for sterilization?

Accepted Answer

The answer of Which of the following structures are commonly...

Question 13

In the last few weeks of pregnancy,the level of estrogen in a woman's blood rises.This causes

Accepted Answer

The rise in estrogen levels during the last few weeks of pregnancy causes the muscles of the uterus to become more sensitive to the hormone oxytocin. This makes the contractions of the uterus stronger and more coordinated, helping to initiate and progress labor.

Question 14

In mammals,the blastocyst consists of the trophoblast and the

Accepted Answer

The inner cell mass is the part of the blastocyst that will eventually develop into the embryo itself, while the trophoblast will give rise to the placenta. Therefore, the correct answer is B) inner cell mass.

Question 15

A woman with high blood pressure and a history of breast cancer asks her doctor to recommend a birth control method.Based on the woman's medical history,the doctor is LEAST likely to recommend

Accepted Answer

Oral contraceptives, especially those containing estrogen, are generally not recommended for women with a history of breast cancer due to the potential for hormone-sensitive cancer cells to grow. Additionally, high blood pressure can be exacerbated by the estrogen in combined oral contraceptives, making them a less suitable option for this patient.

Question 16

In humans,the exchanges of materials between the embryo and its mother occur through the

Accepted Answer

The umbilical cord connects the developing embryo to the placenta, which is attached to the mother's uterus. The placenta allows for the exchange of nutrients, oxygen, and waste products between the mother's blood and the embryo's blood through a network of blood vessels in the umbilical cord. The amnion is a fluid-filled sac that surrounds the embryo, providing protection and cushioning. The yolk sac is a structure that produces blood cells and germ cells in early development. The endometrium is the lining of the uterus that builds up and sheds during the menstrual cycle.

Question 17

In mammals,the trophoblast layer in a blastocyst will become part of the

Accepted Answer

The trophoblast layer is responsible for the formation of the placenta in mammalian embryos, therefore the correct choice is D. This layer differentiates into two layers: the cytotrophoblast and syncytiotrophoblast, which are responsible for implantation and nutrient exchange between the mother and fetus. Choices A, B, and C are not correct because they are not associated with embryonic development or the trophoblast layer.

Question 18

Examine this close-up of the placenta (on the left of the figure below).

Why do the chorionic villi have the shape of a tree?

Accepted Answer

The branches of the chorionic villi create a large amount of surface area for the exchange of nutrients and gases between maternal and fetal blood. This is necessary for the developing fetus to obtain the necessary nutrients and oxygen from the mother's bloodstream.

Question 19

During the rapid cell division that occurs after fertilization,cells increase rapidly in number,but the embryo stays the same size.The cells of this very early embryo must

Accepted Answer

During rapid cell division, there is little time for cell growth, so the interphase (growth phase) of the cell cycle is very short. Therefore, the cells of the early embryo must have a very short interphase to be able to divide rapidly without increasing in size. Choice A (undergo gastrulation) and D (contain a large yolk sac) are not relevant to the question, and choice B (undergo meiosis) is incorrect because meiosis is a type of cell division that reduces the number of chromosomes, and is not relevant to the early stages of embryonic development.

Question 20

The quality of human eggs declines as people age.One possible reason for this is

Accepted Answer

As a woman ages, the number of harmful mutations in her eggs increases. This can lead to chromosomal abnormalities in the developing embryo, which can result in miscarriage or birth defects. Research suggests that the accumulation of these mutations is the primary reason for the decline in quality of human eggs with age.

Quiz 33: Reproduction and Development