Download GENETIC PROBLEMS

Name ____________KEY________________________Date __________ Pd ________
TEST REVIEW - GENETIC PROBLEMS
1. When an organism inherits 2 genes for a trait that are the same, this is termed
____homozygous_________.
2. The physical appearance of an organism is called the ___phenotype___.
3. Which of Mendel’s laws states that gene pairs separate when gametes are formed? __law__ of
__segregation______.
4. Segments of DNA that control a trait are called ____genes___.
5. The genetic makeup of an organism is called its __genotype_________.
6. When an organism inherits one dominant gene & one recessive gene for a trait, this is termed
____heterozygous__________.
7. A trait controlled by 3 or more alleles is called _multiple allele____________.
8. Another word for heterozygous is hybrid____.
9. The study of heredity is called genetics
10. Give an example of a trait in humans that is determined by multiple alleles: ____hair color___
11. Fill in the blanks in the table below, specifying which antigen and which antibodies are present with
each blood type.
BLOOD TYPE
A
B
AB
O
ANTIGEN
A
B
A,B
NONE
ANTIBODY
B
A
NONE
A,B
12. Fill in the blanks in the table below on transfusions.
BLOOD TYPE
A
B
AB
O
CAN RECEIVE
A,O
B,O
A,B,AB,O
O
13. What determines blood type? ANTIGEN
14. Which blood type is the universal donor? _O___
CAN BE GIVEN TO
A
B
AB
A,B,AB,O
15. Which type is the universal recipient? ___AB_____
16. The genotypes for a person with blood type A are __iAiA__ & iAi
17. The genotype for a person with blood type O is __ii_____; the genotype for a person with blood type
AB is __ iAiB________.
18. The genotypes for a person with blood type B are __ iBiB ____________ & ____ iBi ___________.
19. A man who is homozygous for blood type A marries a woman with blood type O. What blood types are
possible in this couple’s children?
______ iAiA x ii_______________________________
(Equation)
iAi
gr _________DO NOT DO__________________________________
A
i i
iAi
pr __________100% A type blood__________________________________
iAi
20. A man with blood type B, whose mother was blood type O, marries a woman with blood type AB. What
blood types are possible in this couple’s children?
_____iBi x iAiB________________________
(Equation)
B
i
i
iA
iB
iAiB
iAi
iB iB
iB i
gr ____________Do not do
pr ________50% B, 25% AB, 25% A_____________________________
Polygenic Traits
21. The inheritance pattern of a trait controlled by many (2 or more genes) with a wide range of possible traits
in the offspring is __polygenic_______________.
22. List 3 traits in humans that are controlled by polygenic inheritance: height, hair color, eye color
23. In Dinosaurs, height is controlled by more than one pair of genes. We can symbolize the genes as A, B, C,
D, & E. Brachiosaurus is homozygous dominant for every gene and was 17 meters tall. The smallest dinosaur
was 2 meters tall. Answer the following questions.
a. How many meters does each dominant allele add to the height of a dinosaur?
17-2=15/10=1.5 meters for every dominant allele
b. How tall are each of the following dinosaurs:
T-rex: AABBCCDdEe- 14 meters
Triceratops: AABbccddee- 6.5 meters
24. In plants, height is controlled by more than one pair of genes. We can symbolize the genes as
L, M, & N. A plant of intermediate height (10 cm) would have 3 dominant & 3 recessive alleles, and may be
written as LlMmNn, llMMNn or any combination thereof. Each extra dominant allele adds 2 cm to the total
height of the plant.
a. Write the genotype of a plant that is 14 cm tall.
LLMMNn
b. Write the genotype of a plant that is 6 cm tall
Llmmnn
Sex-linked
25. Traits that are determined by genes on the sex chromosomes are called ___X-linked or sex linked____
traits. The chromosome that the genes are usually found on is the ___X chromosome_________.
26. The 23rd pair of chromosomes that differ in males & females are called ____sex chromosomes_______.
27. The sex chromosomes for a male are __XY_;The sex chromosomes for a female are __XX___.
28. Why are more males born with hemophilia or any sex-linked trait?
They only have one X chromosome so only need one recessive allele to have the trait.
29. Since color-blindness is carried on the X chromosome, a mother who is a carrier can pass the gene to:
a. All of her daughters
b. 50 % of her daughters
c. All of her sons
d. 50 % of her sons
e. Both b & d
30. A color-blind father cannot pass the color-blind gene to:
a. his daughters
b. his sons
c. any of his children
31. What are the genotypes of the following:
Man with hemophilia: _XhY_____
Carrier Female: __XHXh______
Normal Male: _XHY____
Normal Female: __XHXH___
Female with hemophilia: ___XhXh_____
32. Hemophilia is a blood disorder that prevents clotting. It is a recessive, sex-linked trait. If the mother is a
completely healthy for the disease and the father is a hemophiliac, complete the following questions:
a. Cross them and show their punnett square.
______ XHXH x XhY ______________
(Equation)
H
X
gr ______Do not do_____________
XH
Xh
XHXh
XHXh
XHY
XHY
pr _____do not do____________________
Y
b. What is the probability that the child will NOT have hemophilia? 100%_
c. What is the probability that a child will be affected? 0%_
33. One form of colorblindness in humans is caused by a sex-linked recessive gene. A woman with normal
color vision and whose father was color blind marries a man of normal vision whose father was also color blind.
____ XHXh x XHY_____________________
(Equation)
XH
XH
Xh
XHXH
XHXh
gr ___Do not do____________
Y
XHY
XhY
pr __Do not do________________________
a. What proportion of their offspring will be color blind? (give your answer separately for males and
females) ____Females- 0%, Males- 50%_______________________________
Pedigrees
34. Fill out the Chart
Symbol
Meaning
Normal female
Normal male
Affected female
Affected male
Normal female
Normal male
Married couple
Answer the following questions about the sex-linked pedigree. The sex-linked trait is Hemophilia.
35. Is this trait dominant or recessive? ___recessive_____
36. How many males have the trait? _3_
37. How many females have the trait? _2__
38. List the genotypes of each individual in the pedigree.
Remember this trait is sex-linked!
Individual
Genotype
I-1
I-2
II-1
II-2
II-3
III-1
XHY
XhXh
XHXh
XHXh
XHY
XHY
III-2
III-3
III-4
IV-1
IV-2
IV-3
XHX?
XhY
XHXh
XhY
XHXh
XhY
IV-4
IV-5
IV-6
IV-7
XhXh
XHY
XHY
XHXh
39. Is the trait dominant or recessive? ___Recessive__
Individual Genotype
I-1
XnXn
XNX?
I-2
II-1
XNXn
II-2
XNXn
II-3
XNXn
II-4
XNX?
III-1
XNXn
III-2
XNXn
III-3
XNX?
IV-1
XnXn
IV-2
XNX?
IV-3
XnXn
IV-4
XNX?
40. Write the genotype for each individual (use a letter of your choice)
41. How is individual II-3(male) related to the individual IV-1(female)?
Father and daughter