Answers to the review!!

1. A Punnett square shows you all the ways in which ____ can combine. ALLELES

 2. Blood type in humans is controlled by ____ alleles.  How many? 3-A, B, O

 3. Mendel called plants that received different alleles for a trait from each parent ____. HYBRIDS OR HETERZYGOUS

 4. Give an example of a recessive genetic disorder. CYSTIC FIBROSIS

5. In a Punnett square, a capital letter stands for a ____ allele.DOMINANT

6. What are the 4 blood phenotypes? A, AB, B, O

7. Give example of homozygous recessive genotype, homozygous dominant genotype, heterozygous.  Use the letter A.

 aa, AA, Aa

8. A yellow pea plant (Yy) and a green pea plant (yy) could produce ________2____________ green offspring.

 9. Through genetic engineering, scientists are experimenting with methods to change the arrangement of ___DNA________ in a gene.

 10. A human baby has two X chromosomes. Its sex is __female__________________.

 11. A(n) _pedigree___________________ is a visual tool for following a trait through generations of a family.

 12. A useful segment of DNA is inserted into a bacterium to make __recombinant DNA__________________.

 13. Every sex cell has _one______ allele(s) for each trait.

 14. The father of genetics is an Austrian monk named ___Gregor Mendel_________________.

 15. Purebred dogs often show variations in coat color. This is an example of ___incomplete____ dominance in genetics.

 16. organisms with two different alleles for a trait-heterozygous

 17. when an intermediate form is expressed in offspring-incomplete dominance

 18. when more than two alleles control a trait-multiple alleles

 19. physical appearance of an organism-phenotype

 20. helps determine the chance that something will occur-probability

 21. when a group of gene pairs act together-polygenic inheritance

 22. genetic makeup of an organism-genotype

 23. tool for tracing a trait through a family-pedigree

 24. a genetics tool that uses letters to represent dominant and recessive alleles-punnett square

 25. a factor that seems to disappear-recessive

 26. when there are two alleles that are exactly the same-homozygous

 27. a factor that covers up another factor-dominant

 28. the different forms a gene has for a trait-alleles

 29. passing on of traits from parents to offspring-heredity

 30. study of heredity-genetics


           31.   Write a pedigree for a family (parents and four children) in which one girl and one boy are color-blind while one boy and one girl are not…will go over in class

   32.   If two people are heterozygous for cystic fibrosis, what are the chances that their children will have the disease?                 25%

           33.   Suppose you crossed a heterozygous yellow pea plant (Yy) with a homozygous green pea plant (yy). What are the possible genotypes and phenotypes of the offspring? Use the Punnett square in Figure 13-1 to compute your answers.

Genotypes-Yy, yy

Phenotypes-yellow, green

          34.   The pedigree shown in Figure 13-2 shows the inheritance pattern in one family for color-blindness. How is this disease inherited?  It is inherited on the X chromosome.

 Short Answer

          35.   A family has four children, two girls and two boys. One girl and one boy are color-blind. Are their parents color-blind? The father is colorblind the mother is a carrier

          36.   Is it more common for girls or boys to be color-blind?

                  Boys-colorblindness is linked to the X chromosome and boys only have one x chromosome.

           37.   Why would it be important some day for scientists to be able to correct damaged genes in babies before they are born? To cure genetic disorders

           38.   Parents of children with cystic fibrosis often spend time pounding them on their backs as part of their therapy. Why do they do this?  To break up the mucus in their lungs so they can breathe more easily.

           39.   Offspring with homozygous alleles received how many alleles from each parent?

                   One from mom and one from dad.

           40.   What possible genotypes will the offspring have if the parents’ blood types are O and AB?

                  AO or BO genotypes

           41.   Describe the advantage of genetically engineered tomatoes.

They can be picked green and transported great distances before they ripen completely, so that they are ripe when at the market for purchase.

           42.   Name one disease that is already being treated by use of recombinant DNA, a method of genetic engineering.


           43.   Name at least three traits that are a result of polygenic inheritance.

human height, human eye color, human skin color, human hair color, grain color in wheat, milk production in cows, egg production in chickens

           44.   How can a Punnett square predict results of crossbreeding in peas?

The Punnett square shows all the possible ways in which alleles for a particular trait can be combined.

           45.   You are looking at four tall pea plants. What are their phenotypes and genotypes?

The phenotypes are tall. You cannot tell the genotype by looking alone; it could be Tt or TT.

           46.   How many crosses of red and white four-o’clock flowers would you need to find out all of the possible phenotypes for color of flowers?

You would need two. The first cross would be red with white. The second would be to cross pink with pink offspring. This would give you red, white, and pink phenotypes.

           47.   What is selective breeding?

                  Selecting plants or animals with the most desired traits to breed for the next generation

           48.   What did Mendel do that made his predictions so accurate?

Mendel worked with large numbers of plants, concentrated on one trait at a time, and kept a record of the results until a pattern began to emerge (the 3:1 ratio).

          49.   What is gene therapy?

              A normal allele is placed into a virus, which delivers it when it infects its target cell.


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