• The human life cycle involves two types of cell divisions: mitosis and meiosis.

1. The human life cycle involves what two types of cell divisions?
   Answer

Essential Study Partner

• Mitosis and Meiosis

• Mitosis, nuclear division in which the chromosomal number remains constant, is involved in growth and repair.
  
  
• Cytokinesis divides the cytoplasm and organelles between the daughter cells.

1. Is the number of chromosomes the same for all organisms? How many chromosomes are found in human cells?
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2. Following mitosis, how does the chromosome number of the daughter cells compare to the chromosome number of the parental cell?
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3. What are the stages of mitosis?
   Answer
   
   
4. How is the cytoplasm divided between the daughter cells following mitosis?
   Answer

Animation Activity

• Mitosis

Art Labeling Activity

• Mitosis Overview I (34.0K)
• Mitosis Overview II (45.0K)

• Meiosis, nuclear division in which the chromosomal number is reduced by one-half, is involved in gamete production.

1. What is the function of meiosis?
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2. How does the chromosome number of the parental cell before meiosis differ from the chromosome number of the daughter cells?
   Answer
   
   
3. How does meiosis ensure genetic recombination in the daughter cells?
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4. What are the stages of meiosis?
   Answer

Essential Study Partner

• Meiosis

Animation Activity

• Meiosis

Art Labeling Activity

• Meiosis I (29.0K)

• Normally, humans inherit 22 pairs of autosomes and one pair of sex chromosomes for a total of 46 chromosomes.
  
  
• Normally, males have the sex chromosomes XY and females have the sex chromosomes XX.
  
  
• Abnormalities arise when humans inherit abnormal chromosomes or an abnormal number of chromosomes.

1. What process usually causes an individual to have an abnormal number of chromosomes?
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2. What is the specific chromosome abnormality of a person with Down syndrome?
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3. What are some other syndromes that result from inheritance of an abnormal chromosome number?
   Answer

Essential Study Partner

• Abnormal Chromosomes

Exploration

• Exploring Meiosis-Down syndrome

Chapter Summary

• Review Quiz