Biology
Dr. Swanchara
Name ______________________
Date _______________
Test Review - Genetics
1. Gregor Mendel used pea plants to study inheritance traits in peas
2. Offspring that result from crosses between true-breeding parents with different traits hybird
3. The chemical factors that determine traits are called genes
4. The principle of dominance states that if a dominant allele is present, then it will be seen in the
phenotype
5. When you flip a coin, what is the probability that it will come up tails? ½ What is the
probability that it will come up heads three times in a row? ½ x ½ x ½ = 1/8
6. Organisms that have two identical alleles for a particular trait are said to be homozygous
7. Situations in which one allele for a gene is not completely dominant over another allele for that
gene (blending of traits) are called? Incomplete dominance
8. A cross of a red cow (RR) with a white bull (WW) produces all roan offspring (RW). This type
of inheritance is known as codominance
9. Variation in human skin color is a result of many genes = polygenic traits
10. If an organism’s diploid number is 36, its haploid number is 18
11. Gametes are produced by the process of meiosis
12. meiosis results in? 4 different haploid cells
13. How many chromosomes are shown in a normal human karyotype? 46 or 23 pairs
14. What are the sex chromosomes for males? XY
15. In a pedigree, what does a shaded circle represent? Female with the trait expressed
16. What are all the chromosomes EXCEPT the sex chromosomes called? autosomal
17. The different forms of a gene are what? Alleles
18. If you flip a coin five times and it comes up heads each time, the probability that it will be heads the
next time is? 1/2
19. An organism must inherit ___both______ recessive alleles for a trait in order to show that trait.
2
20. The “matching” chromosomes from each parent in a human karyotype are _homologous
chromosomes.
21. During meiosis, what happens to the chromosome number? Reduced by half
22. The physical appearance of an organism is its _phenotype__.
23. . gametes are haploid / diploid
definitions:
24. heterozygous different alleles
25. probability - chance of something occuring
26. codominance - both traits are expressed
27. hybridization - cross between tow homozygous or similar individuals
28. polyploid - 3n, 4n, etc
29. recombinant DNA
30. clone
31. pedigree
- DNA put into another organism
- exact genetic copy (usually does not include mitochondrial DNA)
- family tree used to follow traits
32. recessive trait – will not be expressed unless there are no dominant alleles present
33. If red four o’clock flowers (RR) and ivory-flowered four o’clock flowers (WW) are crossed, pink four
o’clock flowers are produced. If two pink-flowered four o’clock flowers are crossed, what percent will
be white? 25%
34. On a gene map of a fruit fly’s chromosome which two genes will cross-over occur most frequently?
gene A is at 12 gene B is at 24
gene C is at 36
gene D is at 95 - A and D
35. Understand how to read a Dihybrid Punnett square such as RRYy x RrYY
36. In a pedigree, what symbol would represent a male with a disease? Shaded in square
37. In a pedigree of a sex-linked trait, what symbol would represent a female(s) that is a carrier? circle
38. How is sex-linked trait inherited? Usually by the X chromosome and by one parent
39. Know the steps of meiosis. – NOT ON THE TEST