Biology 9 Study Guide
Chromosomes and Cell Division
Reading:
• Goodenough et al., “Biology of Humans”, Chapter 19 and Chapter 20, pages 443 to 445
Key Terms:
cell cycle
chromosomal inheritance
apoptosis
chromatin
histones
chromosomes
sister chromatids
centromere
centrosome, centrioles
spindle fibers
karyotype
interkinesis
G1, G2, S, and M stages
cytokinesis
mitosis
nuclear division
interphase
prophase
metaphase
anaphase
telophase
diploid (2n), haploid (n)
homologous chromosomes
meiosis I and II
synapsis
crossing-over
independent alignment
gametogenesis
spermatogenesis
oogenesis
polar body
autosome
syndrome
mutation
amniocentesis
chorionic villi sampling
nondisjunction
Down syndrome (trisomy 21)
Turner syndrome (XO)
Klinefelter syndrome (XXY)
deletion
duplication
translocation
inversion
Study Objectives:
• Draw a diagram describing the human life cycle. What are the functions of mitosis and meiosis in the life cycle
of humans?
• Describe the interplay of cell division and apoptosis in humans.
• Describe the structural organization of chromosomes using the terms DNA, histones, and chromatin.
• Define karyotype. How many chromosomes are present in the normal somatic cell? Define homologous
chromosomes, diploid, and haploid.
• What are the stages of the cell cycle and the major events that occur in each stage?
• Describe how DNA is replicated before cell division. What is the point of attachment for two sister chromatids
called?
• Name the four phases of mitosis and describe what is happening to the chromosomes during each phase. What is
the function of the mitotic spindle?
• Name the phases of meiosis I and II and describe what is happening to the chromosomes during each phase.
• How do the terms diploid (2n) and haploid (n) pertain to meiosis? What is the significance of meiosis?
• Describe crossing-over (prophase I) and independent alignment (metaphase I). What is the significance of these
processes? Do they occur during mitosis?
• Contrast meiosis I with meiosis II.
• Compare and contrast meiosis and mitosis.
• How does spermatogenesis in males compare with oogenesis in females?
• What two processes are said to regulate the cell cycle? Be able to give examples of cells that continually divide
through adulthood, those that do not generally divide but can be stimulated to do so, and those believed not to
divide.
• Describe what is meant by selective gene expression and why it is important to how a cell functions.
• When and how is karyotyping of fetal cells done? Describe the two most common procedures used in the US.
• What is nondisjunction and how does it occur? What is the result?
• Describe Down syndrome (trisomy 21), the most common autosomal chromosome abnormality in humans.
• Recognize syndromes caused by changes in sex chromosome number including Turner syndrome (XO) and
Klinefelter syndrome (XXY).
• Define mutation and describe four changes that can occur in chromosome structure.