Skip to main content
Pearson+ LogoPearson+ Logo
Ch. 8 The Cellular Basis of Reproduction and Inheritance
Taylor - Campbell Biology: Concepts & Connections 10th Edition
Taylor, Simon, Dickey, Hogan10th EditionCampbell Biology: Concepts & ConnectionsISBN: 9780136538783Not the one you use?Change textbook
All textbooksTaylor, Simon, Dickey, Hogan 10th EditionCh. 8 The Cellular Basis of Reproduction and InheritanceProblem 20
Chapter 8, Problem 20

Red blood cells, which carry oxygen to body tissues, live for only about 120 days. Replacement cells are produced by cell division in bone marrow.
How many cell divisions must occur each second in your bone marrow just to replace red blood cells? Here is some information to use in calculating your answer: There are about 5 million red blood cells per cubic millimeter (mm³) of blood. An average adult has about 5 L (5,000 cm³) of blood. (Hint: What is the total number of red blood cells in the body?
What fraction of them must be replaced each day if all are replaced in 120 days?

Verified step by step guidance
1
Calculate the total number of red blood cells in the body by multiplying the concentration of red blood cells (5 million cells per mm³) by the total blood volume in mm³. Convert the blood volume from liters (5 L) to mm³ using the conversion factors: 1 L = 1,000 cm³ and 1 cm³ = 1,000 mm³.
Determine the number of red blood cells that need to be replaced each day by dividing the total number of red blood cells by 120 (since red blood cells live for 120 days).
Calculate the number of red blood cells that must be replaced each second by dividing the daily replacement number by the number of seconds in a day (24 hours × 60 minutes × 60 seconds).
Recognize that each cell division produces two daughter cells. Therefore, determine the number of cell divisions required per second by dividing the number of red blood cells replaced per second by 2.
Summarize the process: The total number of red blood cells is calculated, the daily replacement rate is determined, the replacement rate per second is found, and the number of cell divisions per second is calculated by accounting for the fact that each division produces two cells.

Verified video answer for a similar problem:

This video solution was recommended by our tutors as helpful for the problem above.
Video duration:
1m
Was this helpful?

Key Concepts

Here are the essential concepts you must grasp in order to answer the question correctly.

Red Blood Cell Lifespan

Red blood cells (RBCs) have a lifespan of approximately 120 days in the human body. After this period, they are removed from circulation and must be replaced. Understanding this lifespan is crucial for calculating the rate of RBC production needed to maintain adequate oxygen transport in the body.
Recommended video:
Guided course
07:01
Blood Sugar Homeostasis

Bone Marrow Function

Bone marrow is the primary site of hematopoiesis, the process of blood cell formation, including red blood cells. It produces new RBCs through cell division, ensuring that the body maintains a sufficient supply to replace those that are lost. This concept is essential for understanding how the body compensates for the continuous turnover of blood cells.
Recommended video:
Guided course
06:04
Functional Groups

Cell Division Rate Calculation

To determine how many cell divisions occur each second in the bone marrow, one must calculate the total number of RBCs in the body and the daily replacement rate. Given that an average adult has about 5 liters of blood containing approximately 5 million RBCs per cubic millimeter, this calculation involves understanding volume, concentration, and time to find the necessary production rate.
Recommended video:
Guided course
03:19
Importance of Cell Division
Related Practice
Textbook Question

Sketch a cell with three pairs of chromosomes undergoing meiosis, and show how non-disjunction can result in the production of gametes with extra or missing chromosomes.

2241
views
Textbook Question

Suppose you read in the newspaper that a genetic engineering laboratory has developed a procedure for fusing two gametes from the same person (two eggs or two sperm) to form a zygote. The article mentions that an early step in the procedure prevents crossing over from occurring during the formation of the gametes in the donor's body. The researchers are in the process of determining the genetic makeup of one of their new zygotes. Which of the following predictions do you think they would make? Justify your choice, and explain why you rejected each of the other choices.

a. The zygote would have 46 chromosomes, all of which came from the gamete donor (its one parent), so the zygote would be genetically identical to the gamete donor.

b. The zygote could be genetically identical to the gamete donor, but it is much more likely that it would have an unpredictable mixture of chromosomes from the gamete donor's parents.

c. The zygote would not be genetically identical to the gamete donor, but it would be genetically identical to one of the donor's parents.

d. The zygote would not be genetically identical to the gamete donor, but it would be genetically identical to one of the donor's grandparents.

1053
views
Textbook Question

Bacteria are able to divide on a faster schedule than eukaryotic cells. Some bacteria can divide every 20 minutes, while the minimum time required by eukaryotic cells in a rapidly developing embryo is about once per hour, and most cells divide much less often than that. State at least two testable hypotheses explaining why bacteria can divide at a faster rate than eukaryotic cells.

2491
views
Textbook Question
A mule is the offspring of a horse and a donkey. A donkey sperm contains 31 chromosomes and a horse egg cell contains 32 chromosomes, so the zygote contains a total of 63 chromosomes. The zygote develops normally. The combined set of chromosomes is not a problem in mitosis, and the mule combines some of the best characteristics of horses and donkeys. However, a mule is sterile; meiosis cannot occur normally in its testes (or ovaries). Explain why mitosis is normal in cells containing both horse and donkey chromosomes but the mixed set of chromosomes interferes with meiosis.
3730
views
Textbook Question

What you think of as 'a banana' is a Cavendish, one variety of the species Musa acuminate. It is a triploid organism (3n) with three sets of chromosomes in every somatic cell. The Cavendish cannot be naturally bred; it can only be reproduced by cloning. Explain how its triploid state accounts for its inability to form normal gametes. Discuss how the lack of sexual reproduction might make the species particularly vulnerable to a new pest.

1590
views