Question

Use a Punnett square to help answer the question. Use a Punnett square. In rabbits, black fur is dominant over white fur. What percentage of offspring will be white if a heterozygous male and homozygous dominant female have offspring? Question 1 options: 50% 100% 25% 0% Question 2 (3 points) Question 2 Unsaved Use a Punnett square to help answer the question. In humans, free ear lobes are dominant over attached ear lobes. Two parents who are heterozygous are expecting a child. What is the percentage that the child will have free ear lobes? Question 2 options: 75% 100% 50% 0% Question 3 (3 points) Question 3 Unsaved Use a Punnett square to help answer the question. In humans, free ear lobes are dominant over attached ear lobes. Two parents who are heterozygous are expecting a child. What is the percentage that the child be homozygous dominant? Question 3 options: 75% 25% 0% 50% Question 4 (3 points) Question 4 Unsaved Use a Punnett square to answer the question. In peas, wrinkled seeds are recessive to smooth seeds. If a homozyous recessive and a heterozygous plant have offspring what will percentage will have smooth seeds? Question 4 options: 50% 75% 0% 25% Question 5 (3 points) Question 5 Unsaved Use a Punnett square to answer the question. In peas, wrinkled seeds are recessive to smooth seeds. If a homozyous recessive and a heterozygous plant have offspring what will percentage will be homozygous dominant? punn Question 5 options: 25% 50% 100% 0% Question 6 (3 points) Question 6 Unsaved Given the nucleotide sequences below, what type of mutation has occurred? Before: A C C G T A T G T C A T After: A C C G T A A G T C A T Question 6 options: mixer deletion insertion substitution Question 7 (3 points) Question 7 Unsaved What genetic variation has occurred in the picture below where a black bunny and a white bunny have an offspring that shows both black and white fur? Question 7 options: Incomplete dominance Codominance Mixed dominance Co-allele Question 8 (3 points) Question 8 Unsaved Which answer below, would be a possible new strand if there was a insertion mutation in the sequence below? T T C G A A T C G T A T G A C Question 8 options: T T C G A A T C T G T A T G A C T T G A A T C G T A T G A C T T C G A A T C C T A T G A C T T C G A T T C G T A T G A C Question 9 (3 points) Question 9 Unsaved Environmental influences and genetics can determine a person's phenotype. Question 9 options: True False Question 10 (3 points) Question 10 Unsaved Humans have been choosing desired traits of livestock and pets for centuries by breeding organisms that they choose with the traits they desire. This process is called Question 10 options: breed choosing selective breeding pick selelction selective webbing Question 11 (3 points) Question 11 Unsaved Karyotypes are done by matching up _____________________________ so that they are paired up. Question 11 options: homologous chromosomes sister chromatids sister chromosomes homologous chromatids

Answer 1

When using a Punnett square, you first need to identify the genotype of each parent.  We use capital and lower case letters to express dominant and recessive traits where capital letters are dominant and lower case letters are recessive.

In the case of your first question Black fur is dominant over white. Let Black (B) and white (b). The male is heterozygous so its genotype is both Black and white thus, it is expressed as such: Bb. The female is homozygous dominant meaning its genotype is both the dominant black color BB. 

With this we can put it into our punnett square:
     B      b
B  BB  Bb        Because the dominant trait is always expressed, whether or
                       not it is paired with a recessive trait, the chances of a white 
B  BB  Bb        off-spring is 0%


For numbers 2 to 5, we will apply the same principles:

2. Let: F - free earlobes    and f - attached earlobes
Parent genotype: Both heterozygous 
Question: Probability of a child with free earlobes
     F      f
F  FF   Ff      The dominant trait is expressed in 3 out of 4 squares, thus the
                     probability of the child having free earlobes is 75%
f   Ff     ff

3. Using the same given, the question asks for the probability of having a homozygous dominant. This means the offspring should have an FF genotype. Using the same Punnett square, you can see that only 1 out of the 4 squares have a genotype of FF, so the probability is 25%.

4. Let: S - wrinkled seeds    and    s - smooth seeds
Parent genotypes: Homozygous recessive = ss
                              Heterozygous    = Ss
Question: Probability of yielding off spring with smooth seeds: ss  
         s        s
S    Ss       Ss        Because 2 out of 4 squares have the genotype ss, we 
                              can say that there is a 50% probability. 
s     ss        ss

5. This question uses the same Punnet square because it assigns the same genotype for the parents and the dominant and recessive traits are the same. It asks the probability for a homozygous dominant offspring, which means its genotype has to be SS. Looking at the Punnet square, there is no square that has a genotype of SS, so the probability is 0%.

6. There are 3 possible genetic mutations that can occur:
Substitution, Insertion or Deletion. 
You can easily determine the type just by looking at the resulting DNA sequence. If it is longer than the original, insertion occurred. If it is shorter then deletion occurred. If it did not get longer nor shorter, substitution occurred. So in the case of your problem, it is SUBSTITUTION, specifically missense substitution because only 1 amino acid changed. 

7. The genetic variation that occurred in the scenario given where a black rabbit and a white rabbit have an off spring that is both white and black is called Codominance. This occurs when both traits of the parents are expressed in the offspring. 

8. When an insertion mutation occurs, one of the noticeable changes is that there is an extra amino acid in the chain. If you look at the first option, T T C G A A T C T G T A T G A C, there is one amino acid inserted in the original sequence. In the other selections, you will see that the sequence is in complete disarray where some were substituted and at the same time, there were insertions in between.

9. Environmental influences can affect genetic expression. Light and temperature for example can affect the genetic expression of certain organisms. Chemical exposure can also have a direct impact on development. 

10. The process of breeding certain livestock to yield certain traits in their off spring is called selective breeding.  The process is also sometimes called artificial selection. 

11. Karyotypes are done by matching up homologous chromosomes. Homologous chromosomes should be of the same size and the same structure.