Punnett Squares Instruction, Practice, & Assignment 50 pts
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by Kathy Egbert
| 217 Questions
Watch the video about how to make Punnett Squares and use the ppts attached to the Google Classroom Assignment to practice and see how Punnett Squares are used to determine the probablity of certain alleles (genes) and their expression. After you feel confident about the ppts, complete this practice worksheet.

Don't get overwhelmed by the amount of answers. There is a lot because you have to enter the mother and father alleles in each punnett square as well as the alleles for the offspring and then give the ratios and results for genotype and phenotype.

Questions through 50 are practice. The remaining questions are for probabilities between Wizards and Muggles from the Harry Potter Series.
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
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25
26
27
28
29
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35
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37
1
1
Last Name First Name
2
1
A A1
B A2
C A4
D A5
E A6
F A7
G A 8
3
1
Date:
4
1
This is a cross between two homozygous dominant alleles.
A B
B b
5
1
A B
B b
6
1
A B
B b

7
1
A B
B b
8
1
A BB
B Bb
C bb
9
1
A BB
B Bb
C bb
10
1
A BB
B Bb
C bb
11
1
A BB
B Bb
C bb
12
1
the gene alleles
A 100% BB
B 50% Bb and 50% BB
C 100% bb
13
1
the expression of the trait - physically looks like
A 100% dominant trait expression
B 50% dominant and 50% recessive trait expression
C 100% recessive trait expression
14
1
A 100% black fur
B 50% black and 50% white fur
C 100% white fur
15
1
this is a cross between two homozygous recessive alleles
A 100% black fur
B 50% black and 50% white fur
C 100% white fur
16
1
this is a cross between a homozygous dominant and a homozygous ressessive alleles
A B
B b
17
1
A B
B b
18
1
A B
B b
19
1
A B
B b
20
1
A BB
B Bb
C bb
21
1
The same alleles as #20.
True
False
22
1
The same alleles as #20.
True
False
23
1
The same alleles as #20.
True
False
24
1
A 100% BB
B 100% Bb
C 100% bb
D 50% BB and 50% bb
25
1
A 4:0 (four dominant to 0 recessive alleles)
B 0:4 (0 dominant to 4 recessive alleles)
C 1:1 (50% dominant to 50% recessive alleles)
26
1
all offspring are heterozygous, dominant allele is expressed
A 100% black fur color
B 100% white fur color
C 50% black and 50% white fur color
27
1
A B
B b
28
1
A B
B b
29
1
A B
B b
30
1
A B
B b
31
1
A BB
B Bb
C bb
32
1
A BB
B Bb
C bb
33
1
A BB
B Bb
C bb
34
1
A BB
B Bb
C bb
35
1
A 2:2 or reduced to 1:1 BB to Bb
B 4:0 (4 BB and 0 Bb)
C 0: 4 (0 BB and 4 Bb)
D 2:2 or reduced to 1:1 BB to bb
36
1
A 4:0 (4 homozygous dominant to 0 recessive)
B 4:0 (2 homozygous dominant & 2 heterozygous dominant to 0 recessive)
C 1:1 ( 1/2 homozygous dominant to 1/2 homozygous recessive)
D 0:4 (0 homozygous dominant to 4 recessive)
37
1
A 100% black fur
B 50% black fur and 50% white fur
C 100% white fur
38
39
40
41
42
43
44
45
46
47
48
38
1
cross between two heterosygous alleles
A B
B b
39
1
A B
B b
40
1
A B
B b
41
1
A B
B b
42
1
A BB
B Bb
C bb
43
1
A BB
B Bb
C bb
44
1
A BB
B Bb
C bb
45
1
A BB
B Bb
C bb
46
1
A 4:1 (BB to Bb)
B 2:2 (BB to bb)
C 1:2:1 (BB to Bb to bb)
D 3:1 (BB to bb)
47
1
A 4:1 (dominant to recessive)
B 2:2: (dominant to recessive)
C 1:2:1 (dominant to hetero to recessive)
D 3:1 (dominant to recessive)
48
1
A 100% black fur
B 75% black fur and 25% white fur
C 50% black fur and 50% white fur
D 25% black fur and 75% white fur
49
5
Try the backcross shown on the ppt slides with Google Classroom assignment. A backcross is used to identify an unknown genotype of an organism expressing a dominant trait. The cross is made with a homozygous recessive pair or alleles. If the unknown genotype is homozygous for the dominant allele then all the offspring will express the dominant allele. However, if the unknown genotype is heterozygous for the dominant allele then 1/2 of the offspring will express the dominant allele and 1/2 will express the recessive allele. Complete the punnett squares to show these results.
50
51
52
53
54
55
56
57
58
59
60
61
62
63
50
1
Since everyone in this cross has wizarding capabilities and the allele has to be recessive homozygous for the individual to have these capabilities, all of the answers 50 through 59 have to be the alleles, m m.
True
False
51
1
Complete the punnett square by putting in the appropriate recessive alleles in all of the locations.
enter the alleles without a space between the letters
52
1
53
1
54
1
55
1
56
1
57
1
58
1
59
1
60
1
A 4:0
B 2:2
C 0:4
61
1
A 4:0
B 2:2
C 0:4
62
1
A all are wizards/witches
B all homozygous muggles
C all heterozygous muggles
63
1
Remember, whatever Harry was considered it would be the same for his possible siblings
A pure bloods
B muggle born
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
64
1
Since everyone in this cross has wizarding capabilities, the alleles have to be recessive homozygous for the individual to have these capabilities, and it is known that they are all pure bloods, all of the answers 64 through 73 have to be the alleles, mm.
True
False
65
1
Fill in all of the punnett square with the homozygous recessive alleles.
do not put a space between the two letters
66
1
67
1
68
1
69
1
70
1
71
1
72
1
73
1
74
1
A 4:0
B 2:2
C 0:4
75
1
A 4:0
B 2:2
C 0:4
76
1
A 100% all wizards/witches
B 100% homozygous muggles
C 100% heterozygous muggles
77
1
A MM
B Mm
C mm
78
1
A MM
B Mm
C mm
79
1
format dictates that dominant alleles are listed first
A M
B m
80
1
A M
B m
81
1
A M
B m
82
1
A M
B m
83
1
A MM
B Mm
C mm
84
1
This is the same alleles as Question #83 above.
True
False
85
1
A MM
B Mm
C mm
86
1
The alleles for this square are the same as those in Question #85 above.
True
False
87
1
A 4:0
B 3:1
C 2:2 or reduced to 1:1
88
1
A 4:0
B 3:1
C 2:2 or reduced to 1:1
89
1
A all are wizards/witches, 100%
B all are muggles, 100%
C 50% are muggles & 50% are wizards/witches
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
90
1
Since everyone in this cross has wizarding capabilities and the alleles have to be recessive homozygous for the individual to have these capabilities, all of the answers 90 through 99 have to be the alleles, mm.
True
False
91
1
Type in the correct homozygous recessive alleles for wizarding for the Punnett Square.
92
1
93
1
94
1
95
1
96
1
97
1
98
1
99
1
100
1
A 4:0
B 3:1
C 0:4
101
1
A 4:0
B 3:1
C 0.4
102
1
A 100% wizards/witches
B 100% muggles
103
1
refer to the Background Information if needed for the definition of purebloods
A Yes
B No
104
1
A MM
B Mm
C mm
105
1
A MM
B Mm
C mm
106
1
Formatting rules state dominant alleles are placed first in the punnett squares
A M
B m
107
1
parents have to be heterozygous if they have a child that is a witch
A M
B m
108
1
A M
B m
109
1
A M
B m
110
1
A MM
B Mm
C mm
111
1
A MM
B Mm
C mm
112
1
A MM
B Mm
C mm
113
1
A MM
B Mm
C mm
114
1
A 4:0
B 1:2:1
C 3:1
115
1
A 0:4
B 1:3
C 3:1
116
1
A 100% all wizards/witches
B 75% muggles and 25% wizards/witches
C 100% muggles
117
1
A There is a 75% chance that her siblings could be muggles.
B There is a 25% chance that her siblings could have wizarding capabilities. If they did, then they would also be considered muggle born.
C All of her siblings would have to be wizards/witches and they would be called muggle born as well.
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
118
1
Since everyone in this cross has wizarding capabilities and the alleles have to be recessive homozygous for the individual to have these capabilities, all of the answers 118 through 127 have to be the alleles, mm.
True
False
119
1
Complete the punnett square with the recessive wizarding alleles.
120
1
121
1
122
1
123
1
124
1
125
1
126
1
127
1
128
1
A 4:0
B 0:4
129
1
A 4:0
B 0:4
130
1
A 100% muggles
B 100% wizarding capabilities
131
1
A pure bloods
B muggle born
132
1
A MM
B Mm
C mm
133
1
A MM
B Mm
C mm
134
1
A M
B m
135
1
A M
B m
136
1
formatting rules state that dominant alleles are written first
A M
B m
137
1
A M
B m
138
1
A MM
B Mm
C mm
139
1
A MM
B Mm
C mm
140
1
A MM
B Mm
C mm
141
1
A MM
B Mm
C mm
142
1
A 4:0
B 2:2
C 0:4
143
1
A 4:0
B 2:2
C 0:4
144
1
A 100% muggles
B 100% wizards/witches
C 50% muggles and 50% wizards/witches
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
145
1
Since everyone in this cross has wizarding capabilities and the alleles have to be recessive homozygous for the individual to have these capabilities, all of the answers 145 through 154 have to be the alleles, mm.
True
False
146
1
Complete the punnett square with the appropriate recessive wizarding alleles.
147
1
148
1
149
1
150
1
151
1
152
1
153
1
154
1
155
1
A 4:0
B 0:4
156
1
A 4:0
B 0:4
157
1
A 100% wizards/witches
B 100% muggles
158
1
Remember Harry's maternal grandparents were muggles
A muggle born
B pure bloods
159
1
For muggles to have wizarding children they must be heterozygous
A MM
B Mm
C mm
160
1
A MM
B Mm
C mm
161
1
Formatting rules dictate that dominant alleles are listed first
A M
B m
162
1
A M
B m
163
1
A M
B m
164
1
A M
B m
165
1
A MM
B Mm
C mm
166
1
A MM
B Mm
C mm
167
1
A MM
B Mm
C mm
168
1
A MM
B Mm
C mm
169
1
A 4:0
B 3:1
C 1:2:1
170
1
A 4:0
B 3:1
C 0:4
171
1
A 100% muggles
B 75% muggles and 25% wizards/witches
C 100% wizarding characteristics
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
172
1
A MM
B Mm
C mm
173
1
A MM
B Mm
C mm
174
1
Formatting rules dictate that the dominant allele is listed first
A M
B m
175
1
A M
B m
176
1
A M
B m
177
1
A M
B m
178
1
A MM
B Mm
C mm
179
1
A MM
B Mm
C mm
180
1
A MM
B Mm
C mm
181
1
A MM
B Mm
C mm
182
1
A 4:0
B 1:2:1
C 0:4
183
1
A 4:0
B 3:1
C 0:4
184
1
A 100% muggles
B 75% muggles and 25% wizards/witches
C 50% muggles and 50% wizards/witches
185
1
A MM
B MM or Mm
C mm
186
1
A Yes. She wants to have a child with wizarding capabilities.
B No. She doesn't want anything to do with the wizarding community.
187
1
A MM
B Mm
C mm
188
1
A MM
B Mm
C mm
189
1
A M
B m
190
1
A M
B m
191
1
Formatting rules dictate that dominant alleles are written first
A M
B m
192
1
A M
B m
193
1
A MM
B Mm
C mm
194
1
A MM
B Mm
C mm
195
1
A MM
B Mm
C mm
196
1
A MM
B Mm
C mm
197
1
A 4:0
B 2:2
C 0:4
198
1
A 4:0
B 1:2:1
C 2:2
D 0:4
199
1
A 100% wizards/witches
B 100% muggles
C 50% muggles and 50% wizards/witches
200
1
A MM
B MM or Mm
C mm
201
1
A Yes. None of her children would have wizarding capabilities.
B No. There is still a 25% chance that she could have a child with wizarding capabilities.
202
1
From the #11 cross you just completed, is there a chance that she, Mrs. Dursley, could someday have a grandchild or greatgrandchild that had wizarding capabilities
A No, because all of her potential children would be homozygous dominant, MM, for muggles, so only M dominant alleles would be passed on in gametes.
B Yes, because 50% of her children could be heterozygous muggles, Mm. This means that the recessive m allele would appear in 50% of gametes and could be fertilized by another heterozygous muggle's recessive allele.
C Yes, because 25% of her children could be heterozygous muggles, Mm. This means that the recessive m allele would appear in 25% of gametes and could be fertilized by a heterozygous muggle's recessive allele.
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
203
1
Since everyone in this cross is homozygous muggles, all of the answers 203 through 212 have to be the dominant alleles, MM.
True
False
204
1
Enter the correct dominant alleles to complete the punnett squares.
205
1
206
1
207
1
208
1
209
1
210
1
211
1
212
1
213
1
A 4:0
B 0:4
214
1
A 4:0
B 0:4
215
1
A 100% muggles
B 100% wizards/witches
216
1
A MM
B Mm
C mm
217
1
A No. There is still a chance a recessive allele could show up in future generations due to a single gene mutation.
B Yes. Although there is a slight chance of a single allele mutation that could cause a recessive allele to show up in future generations.
C Yes. Very happy! There aren't any recessive alleles that can be passed on to future generations.