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BIO 140 Human Biology I - Questions and Solutions

Erythrocytes - Solutions

Review Questions

1. Which of the following statements about mature, circulating erythrocytes is true?
  1. They have no nucleus.
  2. They are packed with mitochondria.
  3. They survive for an average of 4 days.
  4. All of the above

2. A molecule of hemoglobin ________.

  1. is shaped like a biconcave disk packed almost entirely with iron
  2. contains four glycoprotein units studded with oxygen
  3. consists of four globin proteins, each bound to a molecule of heme
  4. can carry up to 120 molecules of oxygen

3. The production of healthy erythrocytes depends upon the availability of ________.

  1. copper
  2. zinc
  3. vitamin B12
  4. copper, zinc, and vitamin B12

4. Aging and damaged erythrocytes are removed from the circulation by ________.

  1. myeoblasts
  2. monocytes
  3. macrophages
  4. mast cells

5. A patient has been suffering for 2 months with a chronic, watery diarrhea. A blood test is likely to reveal ________.

  1. a hematocrit below 30 percent
  2. hypoxemia
  3. anemia
  4. polycythemia

 

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Critical Thinking Questions

1. A young woman has been experiencing unusually heavy menstrual bleeding for several years. She follows a strict vegan diet (no animal foods). She is at risk for what disorder, and why?

Solution: She is at risk for anemia, because her unusually heavy menstrual bleeding results in excessive loss of erythrocytes each month. At the same time, her vegan diet means that she does not have dietary sources of heme iron. The non-heme iron she consumes in plant foods is not as well absorbed as heme iron.

2. A patient has thalassemia, a genetic disorder characterized by abnormal synthesis of globin proteins and excessive destruction of erythrocytes. This patient is jaundiced and is found to have an excessive level of bilirubin in his blood. Explain the connection.

Solution: Bilirubin is a breakdown product of the non-iron component of heme, which is cleaved from globin when erythrocytes are degraded. Excessive erythrocyte destruction would deposit excessive bilirubin in the blood. Bilirubin is a yellowish pigment, and high blood levels can manifest as yellowed skin.

 

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OpenStax, Erythrocytes. OpenStax CNX. Feb 6, 2017 http://cnx.org/contents/f52adcc4-7ee4-477a-b9ee-a23c765587c9@5. © Feb 6, 2017 OpenStax. Textbook content produced by OpenStax is licensed under a Creative Commons Attribution License 4.0 license.