Download genetic study guide/quiz

Study Guide for Genetics Test (Ch.10.1 and Ch.12)
*Be sure to study your human disorders chart and your notes. Your reading essentials is also a
good review.
1. The father of genetics was _________ ____________.
2. He used ______ plants to study heredity. Garden pea plants reproduce sexually, which means
they use the process of _________ to produce haploid ____________, also called male and
female sex cells. The male gamete in peas forms in the ________ and the female gamete forms
in the female reproductive organ. The fusing of a pollen grain with a female gamete is called
____________ and produces a diploid __________.
3. If an organism has 78 chromosomes in a somatic cell, it has _______ in each new cell after
mitosis and __________ in each new cell after meiosis. After fertilization occurs, fusing two
gametes, the zygote will have _______ chromosomes.
4. An allele is __________________________________.
5. A dominant allele __________ a recessive allele. You represent a dominant allele with
____________________________.
6. A recessive allele is ___________ by a dominant allele. You represent a recessive allele with a
____________________________.
7. A genotype is ________________________________________.
There are 3 possible genotypes for an individual:
a) _________________________________ represented by BB
b) _________________________________ represented by bb
c) _________________________________ represented by Bb
8. The only way to express a recessive trait is to have a _______________________ genotype.
9. A phenotype is _______________________________________. To name the phenotype, use
the __________ from your punnett square.
10. Carrier means _______________________ genotype.
11. In sheep, black wool is dominant to white wool. If several matings between a black sheep and a
white sheep produce 7 white and 5 black offspring, what are the parents’ genotypes?
12. A carrier of cystic fibrosis and a normal person marry. What are the children’s possible
genotypes and phenotypes?
13. A person with abnormally shaped red blood cells marries a person homozygous dominant for the
trait. What percentage of their children have this disorder?
What is the name of
the disorder?
14. Huntington’s is inherited on ________________ chromosomes and is characterized as a
__________ disorder, the only one of this type.
15. A woman heterozygous for Huntington’s marries a normal man. What percentage of their
children have the disorder?
16. Hemophilia and colorblindness are ________________________ disorders, meaning they are
inherited on the ________________________ (the sex chromosome rather than an autosomal
chromosome.) Who is more likely to express a sex-linked disorder – males or females?
17. Who determines the gender of a child? Mom or dad? Why?
18. If a couple has three daughters, what is the chance their next child will be a girl?
19. A man with hemophilia marries a carrier of hemophilia. What is the probability their daughters
will inherit the disorder?
Their sons?
20. Blood types are inherited by ______________ ___________, meaning more than 2 alleles
control the trait. Types ______ and ________ are dominant and _________ is recessive.
21. A woman heterozygous for type A and a man homozygous for type B have a child. What are the
possible phenotypes of the child?
22. When more than one gene controls a trait, this is called _____________ inheritance. Examples
of this include _________ color, _________, and eye color in humans.
23. The environment influences gene expression (which is ____________). Examples of external
influences are: _______________________________________________________________
______________________________________________________________________________.
Examples of internal influences include an organisms’ hormones, especially sex hormones, as well
as age.
24. Define codominance and give two examples:
25. In chickens, feather color follows codominant inheritance. Show a cross between a black
feathered chicken (B) and a white-feathered chicken (W). What is the phenotype of their
offspring?
26. Define incomplete dominance and give two examples:
27. In snapdragon flowers, petal color follows incomplete dominance inheritance. Show a cross
between a red (R’) flower and a white (R) flower. Next show a cross for the F2 generation.
What are the resulting phenotypic ratios?
28. Work out a punnett square from the following illustration: