Meiosis & Modern Genetics
Name: ________________________________________ Date: ______ Period: _____
I. Meiosis (Chap 8, Sec 3)
A. Meiosis is the process of making ________________ _______________ (gametes) which contain __________ the
normal number of genetic material = haploid cells(n)
B. What is the difference between diploid and haploid numbers of chromosomes?
C. In your body which types of cells are diploid and which are haploid?
D. Match the terms with their definition.
_____ allele
_____ gene
_____ homologous chromosomes
_____ autosomes
_____ sex chromosomes
_____ gametes
A.
B.
C.
D.
Sex cells of the body like sperm and egg
Different forms of a gene (ex: black vs. blonde hair)
Chromosomes with genes in the same order but with different alleles
A hereditary unit consisting of a sequence of DNA that occupies a
specific location on a chromosome and determines a particular
characteristic in an organism.
E. Chromosomes that determine an organisms sex (XX in ♀ and XY in ♂)
F. Chromosomes NOT involved in sex determination
E. Diagram the stages of meiosis I with 1 chromosome. Use dots for the paternal chromosome and shaded
for the maternal chromosome.
Prophase I
MetaphaseI
Anaphase I
Telophase I
Cytokinesis
-each
homologous
chromosome
moves to an
opposite pole of
the dividing cells
-**random
separation of
homologous
chromosomes
-chromosomes
reach opposite
ends of the cell
-nucleus reforms
around
chromosomes of
new cells
–spindle fibers
disassemble
-cell is still 2n
-cytoplasm
divides between
two cells
Description
Diagram
Interphase
-chromosomes
replicate
-two genetically
identical
chromatids
-DNA coils
-spindle
fibers/centrioles
appear
-nucleus
disassembles
-homologous
chromosomes
pair up &
exchange genes*
-tetrads line up
randomly along
midline of cell
-spindle fibers
from the
opposite pole
attach to
chromosomes
F. *The pairing of homologous chromosomes during prophase I is called synapsis. Diagram a pair of
homologous chromosomes undergoing synapsis and then crossing over. Label the tetrad & crossing
over (pg 161-162)
Define crossing over:
Define genetic recombination:
G. **Independent assortment of homologous chromosomes occurs during Anaphase I. What is
independent assortment?
H. Diagram the stages of meiosis II with 1 chromosome. Use chromosomes from meiosis I.
Description
Diagram
Prophase II
Metaphase II
Anaphase II
Telophase II
Cytokinesis II
-chromosomes
reach opposite
ends of the cell
-nucleus reforms
–spindle fibers
disassemble
-each of the four
cells is 1n
-cytoplasm
divides
-result is four
new cells each
with half the
original cells # of
chromosomes
Meiosis II occurs
in each cell
formed during
meiosis I. DNA is
NOT copied
before meiosis II.
-DNA coils into
chromosomes
-spindle
fibers/centrioles
appear
-nucleus
disassembles
-chromosomes
line up in the
midline of cell
-spindle fibers
from the
opposite pole
attach to
chromosomes
-chromosomes
separate and
move to
opposite poles
of the dividing
cells
II. Gamete formation & sexual reproduction (Chap 8, Sec 3)
A. Compare and contrast spermatogenesis and oogenesis. Where do each occur?
B. Are the gametes produced during meiosis the same genetically? Explain.
C. Compare the development of the sperm and the egg in sexual reproduction. Specify which cells are
diploid and which are haploid.
Spermatogenesis
Oogenesis
Process:
Process:
D. What occurs during fertilization?
E. Is the resulting zygote/embryo haploid or diploid. Explain.
F. Which parent contributes more mitochondria to the new embryo explain your reasoning?
G. Describe the differences between mitosis and meiosis? What is the end result of each process?
H. What is nondisjunction? (pg 239)
I.
What is amniocentesis? (pg 245)
J.
What is chorionic villi sampling? (pg 246)
III. Genetic Engineering (Chap 13, pg 266 -270)
A. What is gene therapy? Gene therapy works best on what type of disorders? Give an example.
B. Describe cloning by nuclear transfer.
C. What is a genetically modified crop? (pg 269)