Download Genetics, DNA, and Heredity

Genetics, DNA, and Heredity
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1. Given an example of selective breeding?
2. In pea plants, round peas (R) are dominant to wrinkled peas (r). Show five possible crosses for round and wrinkled
peas. Combinations of Crosses for Round and Wrinkled Peas
Two pea plants produce an offspring with a genotype of Rr. Complete the Punnett Square for this cross.
3.The following Punnett square, in which (Y) are yellow flowers and (y) are purple flowers, is incomplete.
Which genotype should replace the question mark?
4. Genes determine whether you have dimples, what color eyes you have, even if you can roll your tongue. What
statement best describes the role of a gene in inheritance?
5. What does the notation TT mean to geneticists?
6. A clone is an organism that is ______________________________________.
7. The sex cells produced by meiosis have _____ (the) number of chromosomes as the parent cells.
8. What is the probability of producing a tall pea plant from a genetic cross between two hybrid tall pea plants?
9. An example of genetic variation in an organism would be __________________________________.
10. A heterozygous organism has ___________________________________
11. Scientists call an organism that has two different alleles for a trait _______________________.
12. A black guinea pig has the genotype (BB) for fur color. A white guinea pig has the genotype (bb) for fur color.
What is the probability that these two Guinea pigs will produce a guinea pig with white fur?
13. In pea plants, green pod color is controlled by a dominant allele. Yellow is controlled by a recessive allele. Explain
why a plant with yellow pods can never be a hybrid.
14. When a purebred plant with red flowers is crossed with a purebred plant that has white flowers, what will be the
expected result, assuming that flower color in this plant is a co-dominant trait?
15. Identical twins Jenna and Joanna are separated at birth. Jenna is raised by a family whose diet includes a variety of
foods, including many fresh fruits and vegetables. Joanna’s family has a diet that lacks variety; it includes very
few vegetables and many kinds of junk food. When the twins are reunited 25 years later, what physical difference
may be present in the twins?
16.
A couple has three brown-eyed children the parents are brown-eyed (Bb) The allele for brown eyes is dominant
over the allele for blue eyes. They believe the fourth child they have will be blue-eyed. Explain what actually will
happen.
17.An organism’s physical appearance is its _____________________________.
18.In humans, earlobes can be considered attached or unattached. The following list describes earlobe type:
·
Attached earlobe: bottom portion of earlobe is attached directly to head
·
Unattached earlobe: bottom portion of earlobe slopes upward before attaching to head
Unattached earlobes (E) are dominant to attached earlobes (e). The following family pedigree shows which
individuals have unattached or attached earlobes.
Family members 4 and 5 in Generation II are expecting identical twins.
Summarize the gender and earlobe appearance of these two offspring.
19. Alleles are ________________________________________________.
Use this information given below to answer the following questions.
A dog breeder has begun to raise Labrador retrievers. So far, she hasn’t been able to predict the color of
the puppies that she breeds. She does not know the dark fur (D) is dominant over yellow fur (d).
When the breeder crossed a yellow female Lab with a male that had dark fur, she expected half of the
puppies to be yellow and half he puppies to be dark. However, in a litter of 8 puppies, all had dark fur. The
breeder next crossed the same yellow female with a different dark male. This time half of the puppies were yellow
and half were dark.
20. Which letters represent the most probable genotype of the second male?
21. How can the woman breed a litter of all yellow puppies?
22. The breeder is going to cross two dark Labradors. One is homozygous and the other is heterozygous for the trait.
Predict what percentage of the puppies will be yellow.
23. Use the diagram to answer the following question
Which individuals have the trait that is being traced by the pedigree?
Use the diagram to answer the following questions
The Punnett square below shows a cross between two pea plants, each with green seed pods. Use the square to
answer these questions.
G
G
G
GG
g
Gg
Gg
24. The missing genotype in the empty square is correctly written as _______________________________.
25. What is the genotype for each of the parents? Tell whether they are homozygous or heterozygous.
26. What percentage of the offspring of this cross will produce green seed pods?
27. Jeremiah has been studying the experiments performed by Gregor Mendel in his study of inheritance patterns.
Jeremiah decides that he would like to test the inheritance patterns of tall and short pea plants. What statement
would likely be his hypothesis?
Use the information below to answer the following questions
The Sickle Cell Mutation and Malaria
Sickle cell anemia is a hereditary disorder caused by a mutation in the shape of red blood cells. Red blood cells are
normally disk-shaped. Sickle red blood cells are shaped like a crescent moon, or sickle. The sickle-shaped cells
cannot travel easily through the blood vessels of the circulatory system. Therefore, people with sickle cell anemia
have problems with oxygen circulation.
Malaria is a disease caused by a parasite. The parasite is transmitted to humans through mosquito bites. Malaria
is common in the warm, wet, tropical and subtropical regions shown in the following map.
Distribution of Malaria
Doctors found that patients with sickle cell anemia seemed to be immune to malaria. Research found that the
sickle cell mutation disabled the effects of the parasite. People with one sickle cell gene did not develop sickle cell
anemia and often survived exposure to malaria. People with two sickle cell genes had very high rates of surviving
malaria, but these people developed sickle cell anemia.
28. In the early 1900s, scientists concluded that a mutated sickle cell gene was harmful and presented no benefits.
What is a logical justification why this conclusion needs revision?
29. Some scientists concluded that the sickle cell mutation is beneficial to some people. What is logical evidence that
supports this conclusion?
30. The following cross shows two people who are not affected by sickle cell anemia but who carry one mutated gene
for the disorder. In this cross, R is the gene for a normal red blood cell, while r is the sickle cell mutated gene.
R
r
R
RR
Rr
r
Rr
rr
What is the chance that an offspring from this cross will be affected with sickle cell anemia?