Download genome, chromosomes, chromatin, sister chromatids, and centromere

Bio 111 Study Guide
Chapter 13 – Meiosis and Life Cycles
BEFORE CLASS:
Reading:
 Read the whole chapter from p. 252-265. Pay special attention to Figure 13.8, as it is such a good
depiction of meiosis.
 Figure 13.10 is a comparison of mitosis and meiosis. Don’t let it confuse you; it may be really helpful to
clarify some similarities and differences between the two processes.
Definitions:
gametes –
asexual reproduction –
sexual reproduction –
karyotype –
homologous chromosomes/homologs –
sex chromosomes –
autosomes –
diploid cell –
haploid cell –
fertilization –
zygote –
meiosis –
chiasmata –
synapsis –
crossing over –
Questions/Problems:
For questions 1-5, fill in the blanks with the words provided. Some words may be used more than once.
asexual
crossing over
diploid
fertilization
gametes
haploid
sexual
synapsis
zygote
1. Meiosis begins with a __________________ (haploid/diploid) cell in the reproductive organs of an
organism. It is the process that makes _______________, which are _______________ (haploid/diploid) cells.
2. When homologous chromosomes pair up in Prophase I, this is called _________________. Also,
________________________ occurs between nonsister chromatids of the pairs when they exchange
corresponding segments of DNA.
3. ______________ reproduction is when one parent produces offspring that are genetically identical to itself.
4. When two parents give rise to offspring that have genetic variation and unique combinations of genes, it is
called ________________ reproduction.
5. The process of ______________________ is when a sperm and egg unite. It results in the formation a
______________ (haploid/diploid) cell called a _________________.
6. Recall learning in Chapter 12 how bacteria reproduce by simple cell division called binary fission. Sexual
reproduction is far more complicated and difficult, and success is not guaranteed. After reading this chapter,
what do you think is the main advantage of sexual reproduction? Why is it an advantage?
DURING CLASS:
Types of Reproduction
Basics
Human Life Cycle
Meiosis
Purpose:
Prophase I –
Metaphase I –
Anaphase I –
Telophase I / Cytokinesis –
Prophase II –
Metaphase II –
Anaphase II –
Telophase II / Cytokinesis –
End Result –
Bioflix Animation – Meiosis
Genetic Variability
Independent assortment of chromosomes –
Crossing over –
Random fertilization –
Evolutionary Significance
Compare and contrast mitosis and meiosis in a Venn diagram.
**Take Away Concept**
Meiosis is an amazing cellular process that, along with sexual reproduction, has the potential to give great
evolutionary advantages to living organisms.
AFTER CLASS:
Questions/Problems:
1. Label the following parts in the figure below: homologous chromosomes (homologs), sister chromatids,
nonsister chromatids of a homologous pair, centromere, kinetochore, and chiasmata/crossing over.
2. Looking again at the above figure, in which phase of meiosis is the cell?
3. Meiosis II is similar to mitosis because
a. sister chromatids separate.
b. homologous chromosomes separate.
c. DNA replication occurs during the division.
d. they both take place in the same cells.
e. haploid cells are almost always produced.
4. Which of the following is least likely to be a source of genetic variation in sexually reproducing organisms?
a. crossing over
b. replication of DNA during S phase before meiosis I
c. independent assortment of chromosomes
d. random fertilization of gametes
e. All of the above contribute equally to genetic variation.
5. My cat Freckles has 38 chromosomes in his somatic cells. How many chromosomes
did he inherit from each of his parents?
How many chromosomes are in each of his gametes?
If he sired kittens, how many chromosomes will be in each somatic cell of each
of them?
6. Draw the chromosomes and other significant cell structures for a cell that is 2n = 4 as it goes through
meiosis. Also, list any important information about each phase.
Prophase I
Metaphase I
Telophase
I/Cytokinesis
Metaphase II
Anaphase I
Prophase II
Anaphase II
Telophase II/Cytokinesis