Download Chromosomes Notes - Milton

Chromosomes
(Chapter 11, Pages 323-329 and Chapter 14, Pages 391-401)
Learning Targets:
-State the number of chromosomes in a typical human being.
-Name the two sex chromosomes in a human female.
-Name the two sex chromosomes in a human male.
-Define “nondisjunction.”
A. Review
1. Human cells are ___________, meaning there are
____ pairs of chromosomes for a total of ______.
2. Human sex cells are __________. Each sex cell
(gamete) has ___ chromosomes and only one copy of
every _______.
Sperm (23)
+
Egg (23)
=
A new human (46) !
3. ________ are located on chromosomes. The location
where they are found on that chromosome is called a
__________ (pl. loci) (Diagram, Page 393)
*Chromosome theory of heredity: Genes are located
on the chromosomes and each gene occupies a specific
place on a chromosome. A gene may exist in several
forms called __________, and each chromosome
contains ______ allele for each gene.
1
4. Genes are _____________ between homologous
chromosomes during ______________of meiosis
when chromosomes are paired as __________. This
process is called ___________ over.
B. Sex Determination
1. Autosomes :
2. Sex chromosomes :
a. Females are _____
b. Males are ______
3. Genes that are found on sex chromosomes are
____________________.
C. Chromosome mutations:
1. inversion: a section of a chromosome is _________ in
order
2. translocation: non-homologous chromosomes _______
regions
3. deletion: part of a chromosome is ______________
4. duplication: region of a chromosome is ___________
2
5. nondisjunction: chromosome pairs do not _________
during meiosis
*Many genetic disorders result from
____________________
during meiosis. (Diagram, Page 401)
D. Chromosome mutations can be observed using a
______________
1. Karyotype: the arrangement of ________________
pairs of chromosomes
2. Common chromosomal defects
a. Down Syndrome (Trisomy ___)
b. Edwards Syndrome (Trisomy ___)
c. Patau Syndrome (Trisomy ___)
d. ___________ Syndrome (X)
e. _________________ Syndrome (XXY)
Word Bank
13
18
21
23
23
46
Haploid
Diploid
Gene
Genes
Swap
Swapped
One
Locus
Prophase I
XX
XY
Sex-linked
Crossing
Alleles
3
Removed
Reversed
Doubled
Tetrads
Separate
Homologous
Nondisjunction
Karyotype
Klinefelter
Turner