1. health and fitness
2. disease

Chapter 5: Genetics – Study Guide
1.
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For Evaluation
Only.
Name:___________________
Date:______
If a black-furred male gerbil and a white-furred female gerbil mated. All their offspring were black-furred.
Why is this?
The black fur allele is dominant over the white fur gene.
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2. How is anaphase II in meiosis similar to anaphase in mitosis?
In both of these steps the chromosomes are pulled apart
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Gg
________________
3.
In pea plants, the gene for green seeds (G) is dominant over the gene for yellow seeds (g).
How is the genotype for the heterozygous condition written?
4.
78
If a dog’s sex cells have 39 chromosomes, how many chromosomes do its body cells have? __________________
5.
46
How many chromosomes does a human body cell have? _____________
6.
23
How many chromosomes does a human gamete have? _____________
7.
If two heterozygous purple Fast Plants were crossed, what are the chances that the offspring would have green
stems and leaves? (Purple stems are the dominant trait.)
To solve this you will need to complete a punnett square between the two parents.
Bb and Bb
If you do this correctly you should get the answer: 25%
8.
A homozygous purple Fast Plant was crossed with a green Fast Plant. What percentage of the offspring would have
purple stems? (Purple stems are the dominant trait.)
To solve this you will need to complete a punnett square between the two parents.
BB and bb
You should see that the only possibility is Bb and therfore 100% of the offspring will
have purple stems.
9. List two benefits of asexual reproduction
It is quick, easy, and requires only one "parent".
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10. Although Janele’s blood is normal, her brother Randy has sickle-cell disease. Janele is worried about having a child
with the disease. Janele just found out that her husband Terence has one allele for sickle-cell disease. As their
genetic counselor, determine Janele and Terences chances of having a child with sickle-cell disease. How would
you explain the results of your analysis to the couple?
between 0 - 25%
Percent chance their child will have sickle-cell disease: __________________
Explanation to the parents: __________________________________________________________________
If
Janele is a carrier then her child will have a 25% chance of getting Sickle Cell.
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If
Janele is not a carrier then her child will have a 0% chance of getting Sickle Cell.
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Copyright(C) by Foxit Corporation,2005-2010
For Evaluation Only.
The genotypes of two cats are shown below:
Dominant Alleles: solid color fur (F), short fur (L), short ears (E), and short tail (T)
Recessive Alleles: patches on fur (f), long fur (l), long ears (e), and long tail (t)
Genotype
Phenotype
Genotype
Phenotype
Fur pattern
Ff
solid
Ff
solid fur
Fur length
ll
long fur
Ll
short fur
Ear length
ee
long ears
ee
long ears
Tail length
TT
Short tail
Tt
short tail
11. Complete the Punnett squares and predict the expected ratios of phenotypes in the offspring for each trait.
F
f
F
FF
Ff
f
Ff
ff
e
e
e
ee
ee
e
ee
ee
Fur Pattern
Ratio of solid to
patches
1
3 : ___
___
Ear length
Ratio of short to
long
4
0 : ___
___
l
l
L
Ll
Ll
l
ll
ll
Fur length
Ratio of short to
long
2
2
___ : ___
T
t
T
TT
Tt
T
TT
Tt
Tail length
Ratio of long to
short
0
4
___
: ___
Consider if these two cats mate: circle any traits would be impossible for the offspring to get.
Fur Pattern
Fur Length
Ear length
Tail length
Solid
Long
Long
Long
Patches
Short
Short
Short
12. Green (G) is the dominant color for pods in pea plants. Yellow (g) is recessive. Is it possible to have a
heterozygous yellow pod? Explain.
Gg
will produce a geen pea pod. It can never be yellow because the allele for green
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is dominant.
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13. Explain how you could determine whether the seeds in a packet of round pea seeds have the genotype RR or Rr, in
which R represents round seeds and r represents wrinkled seeds.
This
will not be on the test.
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14. Why can’t a male be a carrier of color blindness?
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Copyright(C) by Foxit Corporation,2005-2010
For Evaluation Only.
Males
only have one X chromosome so they only have one opportunity to get the correct
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gene
so they either have the trait or they do not.
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15. Predict how Mendel’s results would have differed if he had not controlled the breeding of plants in his experiments.
Mendel
would not have been able to tell the difference between GG homozygous and
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Gg heterozygous.
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16. When gametes join to form a new organism how does that zygote return to the diploid number
Have
of the chromosomes come from mom and the other half from dad.
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When
they are added together the zygote then has the full set.
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In humans: 23 + 23 = 46
46 is a full set.
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17. Describe the relationship between genes and chromosomes.
Chromosomes are made from many genes put together in the same way a bracelet
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can be made of many beads put together.
18. Mammals, including humans, reproduce sexually. Explain the genetic benefits of sexual reproduction.
Include the term genetic variation in your response.
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19. Why do sexually reproducing organisms always have an even number of chromosomes in their body cells?
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20. Two students are discussing the studying of heredity: Decide which of the two students you agree with and explain why.
Kate says that Heredity has shown us that the traits expressed in the offspring are exactly half from the mother
and half from the father.
Brett disagrees with Kate and states that only half of each parent’s chromosomes are passed on to the offspring.
Brett
is correct. We get an equal number of chromosomes and genes from each of our parents
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However, we don't necessarily get an equal number of traits from our parents.
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This would be easier for me to show with a picture.
21. Luther Burbank, a California plant breeder, grafted branches from many kinds of fruit - pears, plums, peaches, and
different varieties of apples - onto one apple tree. If seeds produced by one of the apple blossoms germinated and
grew into a tree, how many kinds of fruit would you expect to find on the new tree and why?
The seed from the apple would only produce an apple tree. That tree would not have any
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of the other fruits because the DNA in the apple seed was not changed.
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22. Protein synthesis