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WorksheetsUnit 4 Genetics
Total questions: 26
Worksheet time: 41mins
You’re the new manager of a plant nursery in a university town that breeds and sells popular varieties of flowers, vegetables, and decorative plants. At your old nursery, customer questions never went beyond color, growth, and propagation needs for that growing season. Here, customers have questions that go much deeper. You quickly realize that you are going to have to review your botany and genetics textbooks.
Last year, a customer purchased several red flowering plants of the same species. Those plants self-seeded and grew back this year. This year, however, both red and white flowers bloomed in the customer’s garden. You know that the red allele is dominant over the white allele in this plant species. Complete this Punnett Square, using the labels below to show what the genotypes of some of last year’s plants must have been to produce white flowers this year.
RR
Rr
rr
You’re the new manager of a plant nursery in a university town that breeds and sells popular varieties of flowers, vegetables, and decorative plants. At your old nursery, customer questions never went beyond color, growth, and propagation needs for that growing season. Here, customers have questions that go much deeper. You quickly realize that you are going to have to review your botany and genetics textbooks.
Last year, a customer purchased several red flowering plants of the same species. Those plants self-seeded and grew back this year. This year, however, both red and white flowers bloomed in the customer’s garden. You know that the red allele is dominant over the white allele in this plant species. Complete this Punnett Square, using the labels below to show what the genotypes of some of last year’s plants must have been to produce white flowers this year.
RR
Rr
rr
Another customer from a previous season comes into your store confused. A bed of pink four o’clock flowers she planted the previous season self-seeded and produced a mixture of about 1/4 red, 1/4 white, and 1/2 pink flowers this year. The customer wants to know why the pink flowers are now a mix of colors. You explain that this is possible because four o’clocks express a(n) (a) inheritance pattern in which an intermediate phenotype is expressed. This means that (b) plants will be either white or red, but (c) plants will be pink.
simple dominance
As your business grows, José joins your greenhouse staff. He is fascinated by the science behind plant husbandry. José asks, "I've noticed that certain traits in particular plants are often inherited together. But every once in a while, new combinations appear. How does this happen?" You explain that although offspring inherit chromosomes from their parents during the process of meiosis, material may be exchanged between homologous pairs of chromosomes. That process is known as crossing-over and results in genetic (a) .
Place an "X" on the section of the diagram that shows where crossing over is occurring.
José is really fascinated by what you have shown him so far. He corners you at lunch and asks: "Can crossing-over occur with any combination of genes?" You answer that there are some factors that limit the probability of a particular event. You grab your book again and turn to a gene map showing some of the genes on chromosome 2 of a fruit fly. You explain that the inheritance of some characteristics are linked to other genes, since they are located close to one another on the same chromosome. These genes are less likely to be impacted by crossing over. Using the diagram as a guide, number the following pairs of genes 1–4, from least likely to most likely to be impacted by crossing over. Write a 1 by the least likely to be impacted and a 4 by the most likely.
Star eye and Dumpy wing
Black body and Purple eye
Brown eye and Curved wing
Black body and Short legs
People involved with the raising and breeding of domesticated plants and animals have a keen interest in genetics. Understanding how various traits are inherited is essential to producing consistent and desirable breeds. Dog breeders provide an excellent example of how such knowledge is put into practice. Breeders are interested in maintaining and enhancing certain traits while avoiding the passing on of undesirable traits, such as genetic disorders.
The fur of Labrador Retrievers occurs in three distinct colors—black, chocolate, and yellow. The allele for black (B) is known to be dominant over the allele for chocolate (b) coat color. Interestingly, coat color is polygenic with the yellow coat color controlled by a different gene that can override the production of dark hair color. It is a recessive trait, so only dogs that are homozygous for the “e” gene are yellow. Breeders performed the follow two crosses of Labrador Retrievers:
Cross #1: A female BbEE × a male bbEE. The cross produced 10 puppies. Six were chocolate in color, and four were black.
Cross #2: A yellow female Bbee × a black male BbEe. The following is the Punnett square for this cross:
What is the dominant fur color?
Black fur (B) is dominant
Yellow fur (b) is dominant
Brown fur (B) is dominant
What is the recessive fur color?
Black fur (B) is recessive
Brown fur (b) is recessive
Yellow fur (b) is recessive
What were the genotypes of the puppies in Cross #1?
The puppies could only have the genotype bbEE.
The puppies could have genotypes of either BbEE or
bbEE.
The puppies could have genotypes of either bbee or
bbEE.
The puppies could only have the genotype BbEE. or
bbEE.
Interpret the Punnett square for Cross #2. Determine the predicted ratio of black, chocolate, and yellow puppies in the F1 generation.
The predicted ratio of phenotypes of the puppies in the F 1 generation is...
6 black: 2
chocolate: 8 yellow.
The predicted ratio of phenotypes of the puppies in the F 1 generation is...
8 black: 2
chocolate: 6 yellow.
The predicted ratio of phenotypes of the puppies in the F 1 generation is...
2 black: 0
chocolate: 10 yellow.
The predicted ratio of phenotypes of the puppies in the F 1 generation is...
0 black: 12
chocolate: 0 yellow.
Dogs, like all species, carry many different genes on each of their chromosomes. The chromosomes that are inherited by the puppies do not always carry the same set of alleles for these genes as the original matching chromosomes of their parents. This is a result of...
dominant alleles influencing recessive alleles.
crossing over during meiosis.
the independent assortment of homologous pairs of chromosomes during meiosis.
the parent's cells are diploid, but their gametes are haploid.
When Arthur Kornberg was researching DNA replication in 1956 and discovered polymerase, he was building on work done by many other scientists. Frederick Griffith began the process in 1928, when he discovered the presence of a “transforming factor” that could be passed from one bacterial cell to another. Hershey and Chase identified DNA as that transforming factor. Edwin Chargaff, Rosalind Franklin, James Watson, and Francis Crick all contributed still more pieces to the understanding of DNA’s structure. Like many scientific discoveries, this process has been an incremental effort over many years.
Who contributed to the understanding of DNA's structure?
Gregor Mendel
Marie Curie
Rosalind Franklin
Isaac Newton
The discovery of DNA's structure was an incremental effort over many years involving multiple scientists. Who is credited with the discovery of DNA's structure?
Watson + Crick
Chargaff
Mendel
Marie Curie
Who discovered polymerase while researching DNA replication in 1956?
James Watson
Francis Crick
Arthur Kornberg
Rosalind Franklin
This Punnett square shows flower color inheritance in snapdragons in the F1 generation.
What is the expected ratio of red flowers to pink flowers to white flowers in the F2 generation?
[USE THE OFFSPRING TO MAKE A NEW PUNNETT SQUARE]
1 red: 2 pink: 1 white
9 red: 3 pink: 1 white
4 red: 1 white
all pink
In chickens, the allele for black feathers is co-dominant with the allele for white feathers. Black-feathered and white-feathered birds are (a) for either the black (B) allele or the white (W) allele. The genotype of an offspring of a black rooster and a white hen is (b) and has a (c) of (BW).
Tag ALL the gametes. [Sperm and Egg alleles]
Tag ALL the parent genotypes.
Tag the offspring genotype.
Tag the Rabbit that has at least one dominant allele.
Red blood cells carry antigens, molecules that can trigger an immune reaction, on their surfaces. Human blood type A carries an A antigen, type B has a B antigen, type AB has both antigens, and type O carries neither antigen. The gene for these antigens has three alleles: A, B, and O.
For a blood transfusion to succeed, it must not introduce a new antigen into the body of the recipient. So, a person with type A blood may receive type O, but not vice versa.
Tag the universal donor.
Red blood cells carry antigens, molecules that can trigger an immune reaction, on their surfaces. Human blood type A carries an A antigen, type B has a B antigen, type AB has both antigens, and type O carries neither antigen. The gene for these antigens has three alleles: A, B, and O.
For a blood transfusion to succeed, it must not introduce a new antigen into the body of the recipient. So, a person with type A blood may receive type O, but not vice versa.
Tag the universal recipient.
What is amino acid from the codon AUC?
(a)
What is amino acid from the codon AUG?
(a)
What is amino acid from the codon UUU?
(a)
If the change in template DNA occurred one base pair over so that instead of CTC → CAC the change was CTC → CTT, what would the effect be on the amino acid sequence?
It would have no effect
It would change from glutamic acid to leucine.
It would change from glutamic acid to valine.
It would change from glutamic acid to alanine.
Cystic fibrosis is a recessive hereditary disease. The parents of children who
have cystic fibrosis each carry one normal CFTR gene and one mutated CFTR gene.
Choose the numbers to finish the sentence.
If both parents each carry one mutated CFTR gene, (a) of their children will probably have cystic fibrosis, (b) of their children will probably be carriers, and (c) of their children will probably not have cystic fibrosis or carry the mutated gene.
What type of mutation is the sickle cell mutation?
Inversion
Deletion
Insertion
Substitution
Explain how a mutation in DNA translates to a change in the function of the
hemoglobin protein.
(a) is (b) and produces (c) of the mutated beta-globin gene. The mutated
beta-globin mRNA travels out of the (d) to the (e) where it is translated. The
mutation causes one of the amino acids to be translated into valine instead of glutamic
acid. This changes the protein function affecting the cell’s phenotype.
Explain how a mutation in DNA translates to a change in the function of the
hemoglobin protein.
(a) is (b) and produces (c) of the mutated beta-globin gene. The mutated
beta-globin mRNA travels out of the (d) to the (e) where it is translated. The
mutation causes one of the amino acids to be translated into valine instead of glutamic
acid. This changes the protein function affecting the cell’s phenotype.
Explain how a mutation in DNA translates to a change in the function of the
hemoglobin protein.
DNA is transcribed and produces mRNA of the mutated beta-globin gene. The mutated
beta-globin mRNA travels out of the nucleus to the ribosome where it is translated. The
(a) causes one of the (b) to be (c) into valine instead of glutamic
acid. This changes the (d) function affecting the cell’s (e) .
