Semester 2 Genetics Review Name: ______
1. Selective breeding produces ______
2. The crossing of buffalo and cattle to produce beefalo is an example of ______
3. What is the ultimate source of genetic variability? ______
4. Breeders maintain the desired traits of an organism by______
5. Polyploidy instantly produces new plant species because it______
6. Genetic engineering involves ______
7. What has been an advantage of producing transgenic plants? ______
8. Scientists produced oil-eating bacteria by______
9. One function of gel electrophoresis is to ______
10. What is the approximate probability that a human offspring will be female? ______
11. How many chromosomes are shown in a normal human karyotype? ______
12. To produce a fruit that has some characteristics of an orange and some of a grapefruit, you would use the selective breeding technique of ______.
13. The mutations that breeders induce in organisms are passed on to the organisms’ ______.
14. The sequence of a DNA fragment can be determined by observing the order of the ______fluorescent bands on an electrophoresis gel.
15. A(An) ______is a diagram that follows the inheritance of a single gene through several generations of a family.
16. ______is the technique of selective breeding that has led to deformities in certain dog breeds.
17. For a plant transformation to be successful, the recombinant DNA is integrated into one of the ______of the cell
18. Scientists use radiation and chemicals to induce ______.
19. A(An) ______can be used to determine whether a person has inherited the normal number of chromosomes.
Short Answer In complete sentences, write the answers to the questions on the lines provided.
1. How are the selective breeding techniques of hybridization and inbreeding opposites?
In hybridization, organisms with dissimilar traits are crossed. In inbreeding, organisms with similar traits are crossed.
2. Why would breeders want to increase a population’s mutation rate?
Increasing the mutation rate in a population increases the population’s genetic variation. This increases the chance that an individual will have the desired trait.
3. Explain the advantage and disadvantage of inbreeding. Give an example of each.
One advantage of inbreeding is that it maintains the desired traits within the breed. A disadvantage is that is can lead to genetic defects within a breed, such as blindness in german shepherds.
4. In what ways are transgenic organisms useful to people?
Transgenic bacteria make human proteins cheaply and in large amounts. Transgenic animlas are used to study human genes and to improve animal foods. Transgenic plants help increase crop yields and may be healthier for people to eat.
5. Give two reasons why it is almost impossible to associate many human traits with single genes.
Most human traits cannot be associated with single genes because many traits are polygenic, or controlled by many genes, and the environment influences many traits.
6. Why are viruses used in gene therapy?
Viruses are used in gene therapy because of their ability to enter a cell’s DNA.
7. Why are all x-linked alleles expressed in males, even if they are recessive?
Males have only one X chromosome so all the x-linked alleles are expressed.