Download unit 5 study guide (ch 13-15)

Chapter 13-15 Study Guide / Review
Vocabulary Terms
Chapter 13 - Meiosis
Gene
Locus
Asexual vs. sexual reproduction
Somatic cell
Karyotype
Homologous chromosomes
Sex chromosomes vs. autosomes
Haploid vs. diploid
Fertilization
Zygote
Meiosis (I and II)
Synapsis
Tetrad
Chiasmata
Crossing over
Ch 15 – Chromosomes & Genetics
Sex determination
Barr bodies
Pedigrees
Nondisjunction
Down syndrome
Chapter 14 – Mendelian Genetics
Trait
True-breeding
Monohybrid vs. dihybrid cross
P, F1, F2 generations
Alleles
Dominant vs. recessive
Law of segregation
Homozygous vs. heterozygous
Genotype vs. phenotype
Testcross
Law of independent assortment
Incomplete dominance
Codominance
Multiple alleles
pleiotropy
Epistasis
Polygenic inheritance
Pedigree
Cystic fibrosis
Tay-Sachs disease
Sickle-cell disease
Huntington’s disease
Amniocentesis
Chorionic villus sampling
Ultrasound
ABO blood groups
Sex-linked inheritance
Linked genes / linkage maps
Duchenne muscular dystrophy
Aneuploidy
X and Y chromosomes
Recombinant frequencies
Hemophilia
Monosomic / trisomic / polyploidy
Review / Short Answer
1 a) If 2n = 18, how many chromosomes will be present in somatic cells?
b) If 2n = 18, how many chromosomes will be found in the gametes?
c) If n = 18, how many chromosomes will be found in diploid somatic cells?
d) If n = 18, how many pairs of homologous chromosomes will be found in gametes?
e) If 2n = 32, how many different combinations of maternal and paternal chromosomes are possible?
2) In the spaces provided below, draw and label a cell with a diploid number of 6 (2n = 6) in prophase I of meiosis
before and after crossing over has occurred. Use colored pencils and color the maternal chromosomes one color
and the paternal chromosomes a different color. After crossing over, use the appropriate colors to show the “new”
locations of the exchanged chromosomal sections. Then draw prophase II of meiosis.
PROPHASE I OF
MEIOSIS
(before/during
crossing over)
PROPHASE I OF
MEIOSIS
(after crossing over)
PROPHASE II OF
MEIOSIS
3) Two true-breeding varieties of a newly discovered plant species are crossed. One parent has red, axial flowers,
and the other had white, terminal flowers. All F1 individuals had red, terminal flowers. If 100 F2 offspring were
counted, how many of the offspring would you expect to have red, axial flowers?
4) What are two advantages to using chorionic villus sampling (CVS) over amniocentesis? (see Fig. 14.19 on p.
281)
5) Flower position, stem length, and seed shape were three characters that Mendel studied. Each is controlled by
an independently assorting gene and has dominant and recessive expression as follows:
Character
flower position
stem length
seed shape
Dominant
axial (A)
tall (T)
round (R)
Recessive
terminal (a)
dwarf (t)
wrinkled (r)
If a pea plant that is heterozygous for all three characteristics were allowed to self-fertilize, what proportion of
the offspring would be expected to be as follows: (Note: use the rules of probability instead of a huge Punnett
square).
A) homozygous for the three dominant traits:
B) homozygous for the three recessive traits:
C) heterozygous:
D) homozygous for axial and tall, heterozygous for seed shape:
6) Consider the pedigree below for the trait albinism (lack of skin pigmentation) in three generations of a family.
(Solid symbols represent individuals who are albinos). From your knowledge of Mendelian inheritance, answer the
questions that follow.
A) Is this trait caused by a dominant or
recessive allele? How can you tell?
B) Determine the genotypes of the
parents in the first generation.
(Let AA and Aa represent normal
pigmentation and aa be the albino
genotype.)
C) Determine the probable genotypes of the
every individual in the second generation.
D) Can you determine the genotype of son 3
in the second generation? Why or why not?
7) The height of spike weed is a result of polygenic inheritance involving three genes, each of which can contribute
an additional 5 cm to the base height of the plant. The base height of the week is 10 cm, and the tallest plant can
reach 40 cm.
For example, with a genotype of aabbcc, a plant would be the shortest height, 10 cm. Each time you add a
dominant allele to the genotype, it adds 5 cm to the base height. So, a genotype of Aabbcc, would have an
additional 5 cm over the base height, or a phenotype of 15 cm.
A) If a tall plant (AABBCC) is crossed with a base-height plant (aabbcc), what is the height of the the F1 plants?
B) How many phenotypic classes will there be in the F2 generation? (list them)
8) Examine this karyotype. Identify whether this
individual is male or female, and if there are any
chromosomal abnormalities.
9) What are the three events (specific to sexually reproducing organisms) which can contribute to genetic variation
in offspring? WHEN does each occur?
●
●
●
10) The following recombination frequencies were found between genes A, B, C, D, and E. Determine the order of
these genes on the chromosome and sketch a linkage map of this chromosome with the map units labeled.
A, C: 10%
B, C: 4%
C, D: 20%
A, D: 30%
B, D: 16%
A, E: 6%
B, E: 20%
11) In guinea pigs, black (B) is dominant to brown (b), and solid color (S) is dominant to spotted (s). A
heterozygous black, solid-colored pig is mated with a brown, spotted pig. The total offspring for several litters are:
black solid = 16; black spotted = 5; brown solid = 5; brown spotted = 14. Are these genes linked or nonlinked? If
they are linked, how many map units are they apart?
12) Complete the table below for genetic disorders.
Disorder
Sickle Cell Anemia
Cause
Symptoms
Huntington’s Disease
Achondroplasia
Cystic Fibrosis
Duchenne muscular dystrophy
Hemophilia
Down syndrome
Klinefelter syndrome
Turner syndrome
cri du chat
Chronic myelogenous leukemia
(CML)
13) Two normal-sighted individuals produce the following children and grandchildren. Fill in the probable genotype
of each individual (next to each circle or each square) in the pedigree. Squares are males, circles are females, and
solid symbols represent individuals with colorblindness. You must show the sex chromosome complement for each
individual and put the genes for this trait on the X chromosome. (example: X C Xc)
14) CHI-SQUARE PROBLEM: A genetics engineer was attempting to cross a tiger and a cheetah. She predicted
a phenotypic outcome of the traits she was observing to be in the following ratio: 4 stripes only: 3 spots only: 9 both
stripes and spots. When the cross was performed and she counted the individuals she found 50 with stripes only,
41 with spots only and 85 with both. According to the Chi-square test, are these results within an acceptable
statistical range for the engineer to accept her original prediction (null hypothesis)?