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Some organs in the human body are represented in the diagram below.
A sudden change in the DNA of cells developing in which organ could be passed to future generations?*
Base your answers to questions 2 on the diagram below and on your knowledge of biology. The diagram represents the human female reproductive system.
Structure A usually produces*
The diagram below represents one stage during the human reproductive process.
A function of structure A is to*
Human reproduction usually involves*
The diagram below represents a stage in the development of a fetus.
A major function of structure X is to*
The diagram below represents structures found in the female reproductive system.
If the areas labeled A were completely blocked on both sides, the most likely result would be that*
Which statement best describes an important process carried out by structure X?
*
The major function of the placenta is to*
Occasionally, during pregnancy, the placenta can separate from the uterus. This causes a disruption in development and sometimes death of the fetus. Harm to the developing fetus might occur because the placenta*
The human female reproductive system is represented below.
Which structure produces chemicals that regulate the reproductive cycle?*
In humans, the placenta is essential to the embryo for*
Base your answer to question 12-15 on the information below and on your knowledge of biology.
Artificial Placenta
It is estimated that every year more than 15 million babies are born too early. The lungs of these premature infants are often immature and easily damaged. Premature births happen for a variety of reasons—some known and some unknown. Those that are known include infections and conditions such as diabetes and high blood pressure. Scientists are researching what causes premature births, in an attempt to develop solutions to prevent them.
Scientists are also working on the development of an artificial placenta. At the University of Michigan, five premature lambs were placed in artificial placentas and kept alive for weeks. During this time, each lamb’s blood was circulated through its artificial placenta.
Discuss how the development of an artificial placenta is an important step in the study of premature births. In your answer, be sure to:
• explain why it would be harmful for a human mother’s blood to pass across the placenta and into the
fetus [1]
• state how an artificial placenta would be of benefit to the lungs of premature infants [1]
• explain why the lambs’ blood must be filtered as it circulates through the artificial placenta [1]
• state one reason why premature lambs were likely used as model organisms in this study rather than
mice [1]*
Base your answer to question 16-18 on the information below and on your knowledge of biology.
The Critical Role of the Placenta
The proper functioning of the placenta is critical to the growth and development of a healthy fetus. For example, the placenta appears to act as a nutrient sensor. It regulates the amounts and types of nutrients that are transported from the mother to the fetus.
Improper functioning of the placenta can alter the structure and function of specific cells and organ systems in the developing fetus, putting it at risk for health problems as an adult. For example, in some pregnancies, the placenta develops a resistance to blood flow. This resistance appears to force the heart of the fetus to work harder. This could result in an increased chance of the individual developing heart disease as an adult. A group of hormones known as glucocorticoids affects the development of all the tissues and organ systems. One of the things this group of hormones does is to alter cell function by changing the structure of cell membrane receptors.
Discuss the importance of the placenta in the development of a healthy fetus. In your answer, be sure to:
• identify two factors that could influence the nutrients that can pass from the mother to the fetus [1]
• identify the group of hormones that alter cell membrane receptors and explain how this alteration can affect cell function [1]
• state the role of the uterus in the development of the fetus and the placenta [1]*
Estrogen is one of the hormones produced by human females. Identify one organ that produces estrogen and state one specific function of estrogen in a human female. [1]
Organ:
Function:*
Base your answers to questions 20 on the information below and on your knowledge of biology.
Mitochondrial Replacement Therapy
Mutations in mitochondrial DNA (mtDNA) are associated with some severe human diseases and are inherited through the cytoplasm in the egg cell. These diseases vary, but often affect organs and tissues with the highest energy requirements, including the brain, heart, muscle, pancreas, and kidney.
Scientists have successfully used mitochondrial replacement therapy with monkeys. Scientists are considering using this technique to reduce the incidence of mitochondrial disease in children. The proposed treatment would involve removing the nucleus from an egg donated by a healthy woman and replacing it with an egg nucleus from a patient (mother) with mitochondrial disease. This would place the patient’s egg nucleus into the cytoplasm of the donor’s egg containing healthy mitochondria. The egg is then fertilized with the father’s sperm externally using in vitro fertilization (IVF) to produce a zygote. The zygote is cultured for a few days to produce an embryo.
Explain what must be done with the embryo after in vitro fertilization (IVF) has been completed so the embryo can complete development. [1]*
