Name: _______________________ Date: __________
Period #: ____
Study Guide for Genetics Test
1. Where do the alleles of the offspring come from?
Hint: 1 from __________ and 1 from _______________
2. How would you write a dominant allele? What does dominant mean?
3. How would you write a recessive allele? What does recessive mean?
4. If a person has 1 allele for dimples and 1 for no dimples, what trait will show up?
5. Write the 2 alleles for homozygous dominant. For heterozygous. For homozygous recessive. (Use
whatever letter you would like)
6.
Can a person with no dimples ever be heterozygous? Why or why not? (Remember…dimples is
dominant and no dimples is recessive)
Define:
7. Phenotype –
8. Genotype –
9. Homozygous –
10. Heterozygous –
11. Codominance –
12. When you flip a coin, and you got a heads the first time, does that mean that you have less of a chance
of getting a heads they second time? Why or why not?
13. Give an example of a phenotype and a genotype.
14. T = CAN taste PTC
t = CAN’T taste PTC
Tt x
a.
b.
c.
d.
e.
Tt
What is the probability of TT?
What is the probability of Tt?
What is the probability of tt?
What is the probability you can taste PTC?
What is the probability you can’t taste PTC?
15. Cross an AB blood type mother with a homozygous B blood type father:
AB x B
A.
B.
C.
D.
E.
What blood type(s) do the offspring have?
Are the offspring heterozygous or homozygous?
Are the parents homozygous or heterozygous?
What is the codominance?
Which blood type shows codominance?
16. Make a punnett square for dimples crossing DD x dd
D = Dimples
d = no dimples
What is the probability of a person having dimples?
What is the probability of a person having no dimples?
What is the probability of a person being DD?
What is the probability of a person being Dd?
What is the probability of a person being dd?
18. How many chromosomes do humans have in each body cell?
19. How many pairs of chromosomes do humans have in each body cell?
20. How many chromosomes are in human sex cells? (I.E. Sperm and Egg cells)
21. Write the symbols for the chromosomes that these people have: Men:
`
Women:
22. Which chromosome is smaller, X or Y?
23. All eggs carry a __________ chromosome.
24. ½ the sperm carry a __________ chromosome and the other ½ carry a ________.
25. Explain the difference between identical and fraternal twins. Use a diagram if helpful.
26. List 3 characteristics that are inherited.
27. List 3 characteristics that are acquired.
28. Explain the difference between acquired and inherited traits.