GENETICS PROBLEMS
PLEASE help me with these questions! I've provided the answers I just need to see the WORK, detailed work so I can understand. Thank you sooo much.
21. In some genetically engineered corn plants the dominant gene (BT) produces a protein that is lethal to certain flying insect pests that eat the corn plants. It was also found that the pollen could cause death in some flying insects. If the corn plant is heterozygous for BT, what proportion of the pollen would carry the dominant gene?
Answer: 1/2
25. Sickle cell anemia is a recessive trait in humans. In a cross between a father who has sickle cell anemia and a mother who is heterozygous for the gene, what is the probability that their first three children will have the normal phenotype?
Answer: 1/8
26. The dominant trait, Huntington disease causes severe neural/brain damage at approximately age 40. A female whose mother has Huntington disease marries a male whose parents are normal. It is not known if the female has the disease. What is the probability that their firstborn will inherit the gene that causes Huntington disease?
Answer: 25%
GENETICS PROBLEMS
PLEASE help me with these questions! I've provided the answers I just need to see the WORK, detailed work so I can understand. Thank you sooo much.
21. In some genetically engineered corn plants the dominant gene (BT) produces a protein that is lethal to certain flying insect pests that eat the corn plants. It was also found that the pollen could cause death in some flying insects. If the corn plant is heterozygous for BT, what proportion of the pollen would carry the dominant gene?
Answer: 1/2
25. Sickle cell anemia is a recessive trait in humans. In a cross between a father who has sickle cell anemia and a mother who is heterozygous for the gene, what is the probability that their first three children will have the normal phenotype?
Answer: 1/8
26. The dominant trait, Huntington disease causes severe neural/brain damage at approximately age 40. A female whose mother has Huntington disease marries a male whose parents are normal. It is not known if the female has the disease. What is the probability that their firstborn will inherit the gene that causes Huntington disease?
Answer: 25%
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Related textbook solutions
Related questions
If an organismâs diploid chromosome number is 18, how many different possible combinations of homologous chromosomes lining up during meiosis exist for the eggs or sperm produced by that organism?
| A. | 512 | |
| B. | 9 | |
| C. | 18 | |
| D. | 128 | |
| E. | 36 |
At the end of metaphase I, _______________ separate.
| A. | sister chromatids | |
| B. | germ cells | |
| C. | homologous chromosomes | |
| D. | haploid chromatids | |
| E. | centrioles |
Mendel observed that dominant traits
| A. | are seen in all of the F1 hybrid pea plants in his experiments. | |
| B. | are expressed in all plants. | |
| C. | were absent in the F1 generation of pea plants that he used in his experiments. | |
| D. | were the only traits seen in the F2 generation of pea plants in his experiments. | |
| E. | are only expressed in hybrids. |
Cytokinesis in plant cells differs from cytokinesis in animal cells because
| A. | there is no difference. | |
| B. | in plant cells, the cell plate must also divide into two parts. | |
| C. | the contractile protein, actin, is important only in plant cells. | |
| D. | plant cells have a rigid cell wall. | |
| E. | a contractile ring forms only in plant cells. |
Sickle cell anemia is an example of what type of inheritance?
| A. | complete dominance | |
| B. | incomplete dominance | |
| C. | codominance | |
| D. | multiple alleles | |
| E. | recessive dominance |
Which of the following statements is true:
| A. | The dominant allele is masked in homozygous dominant individuals. | |
| B. | With recessive genetic disorders, if both parents are carriers, the offspring will all be affected. | |
| C. | In carriers, the recessive allele causes an intermediate phenotype. | |
| D. | In recessive genetic disorders, the mother and/or father of an affected individual must also be affected. | |
| E. | With dominant genetic disorders, the mother and/or father of an affected individual must also be affected. |
Skin cancers typically develop in the
| A. | upper layers of the epidermis. | |
| B. | lower layers of the dermis. | |
| C. | subcutaneous layer. | |
| D. | lower layers of the epidermis. | |
| E. | upper layers of the dermis. |
Duchenne muscular dystrophy (MD) is inherited from an X-linked recessive allele. What is the probability that a son with Duchenne MD inherited this disease from his biological father?
| A. | 1/2 | |
| B. | 0 | |
| C. | 1/16 | |
| D. | 1/4 | |
| E. | 1/8 |
The genetic makeup of a particular trait in an individual is its
| A. | genotype. | |
| B. | heterozygosity. | |
| C. | phenotype. | |
| D. | filial. | |
| E. | dominance. |
What structure holds the sister chromatids to the spindle fibers?
| A. | chromatin | |
| B. | kinetochore | |
| C. | MPF | |
| D. | centromere | |
| E. | cyclin |
If you view a cell in which the genetic material is beginning to be visible as separate bodies, and the nucleus has disappeared from view, you may surmise that the cells is in
| A. | telophase. | |
| B. | anaphase. | |
| C. | interphase. | |
| D. | metaphase. | |
| E. | prophase. |
Gregor Mendel was successful in his analysis of the genetics of pea plants because
| A. | he examined and analyzed both the F1 and F2 generations. | |
| B. | he studied the parental plants to determine their differences. | |
| C. | he decided to only look at his results in an objective manner. | |
| D. | he studied a trait that had a strange inheritance pattern. | |
| E. | pea plants have genetics different from other organisms. |
Tall corn plants (T) are dominant to dwarf plants (tt). Solid green leaves (G) are dominant to leaves with a white tip (gg). A cross between two corn plants yielded the following phenotypes: 51 tall plants with a white tip on their leaves; 43 dwarf plants with solid leaves; 48 dwarf plants with white tips on their leaves; 45 tall plants with solid leaves. What are the genotypes of the parents that produced these plants?
| A. | None of the above | |
| B. | TtGg x Ttgg | |
| C. | ttGG x TTgg | |
| D. | TtGg x TtGg | |
| E. | TtGg x ttgg |
In humans, a gene that has been identified as causing a type of skin cancer is the
| A. | superwoman echidna. | |
| B. | mutant superman. | |
| C. | sonic hedgehog. | |
| D. | mutant mole rat. | |
| E. | superhero aardvark. |
The segregation principle states that in sexually reproducing diploid organisms the two copies of each gene
| A. | segregate from each other during meiosis. | |
| B. | must always be the same allele. | |
| C. | separate from each other during mitosis. | |
| D. | will both wind up in either the sperm or egg. | |
| E. | move together as a unit during meiosis. |
In what phases is the genetic material in the cell correctly referred to as chromatids?
| A. | metaphase and telophase | |
| B. | anaphase and metaphase | |
| C. | interphase and telophase | |
| D. | interphase and prophase | |
| E. | metaphase and prophase |
Consider two traits for an organism, determined by two genes, each of which is governed by at least two alleles. In the case of a dihybrid individual, the gametes formed will be of either the parental type or the recombinant type. Recombinant type gametes are formed because of
| A. | the principle of dihybrids. | |
| B. | multiple alleles. | |
| C. | heterozygosity. | |
| D. | incomplete dominance. | |
| E. | independent assortment. |
An allele is
| A. | an alternate form of a gene. | |
| B. | always recessive. | |
| C. | the main factor determining a trait. | |
| D. | always one of a pair. | |
| E. | the dominant form of a gene. |
After the DNA is replicated, and it condenses in prophase, two identical rods of DNA are seen. These are
| A. | spindle fibers. | |
| B. | kinetochores. | |
| C. | chromatids. | |
| D. | chromatin. | |
| E. | centromeres. |
Special cells found in the gonads that give rise to gametes upon division are called
| A. | egg cells. | |
| B. | somatic cells. | |
| C. | germ cells. | |
| D. | stem cells. | |
| E. | basal cells. |
Q:
If an organismâs diploid chromosome number is 18, how many different possible combinations of homologous chromosomes lining up during meiosis exist for the eggs or sperm produced by that organism?
| A. | 512 | |
| B. | 9 | |
| C. | 18 | |
| D. | 128 | |
| E. | 36 |
At the end of metaphase I, _______________ separate.
| A. | sister chromatids | |
| B. | germ cells | |
| C. | homologous chromosomes | |
| D. | haploid chromatids | |
| E. | centrioles |
Mendel observed that dominant traits
| A. | are seen in all of the F1 hybrid pea plants in his experiments. | |
| B. | are expressed in all plants. | |
| C. | were absent in the F1 generation of pea plants that he used in his experiments. | |
| D. | were the only traits seen in the F2 generation of pea plants in his experiments. | |
| E. | are only expressed in hybrids. |
Cytokinesis in plant cells differs from cytokinesis in animal cells because
| A. | there is no difference. | |
| B. | in plant cells, the cell plate must also divide into two parts. | |
| C. | the contractile protein, actin, is important only in plant cells. | |
| D. | plant cells have a rigid cell wall. | |
| E. | a contractile ring forms only in plant cells. |
Sickle cell anemia is an example of what type of inheritance?
| A. | complete dominance | |
| B. | incomplete dominance | |
| C. | codominance | |
| D. | multiple alleles | |
| E. | recessive dominance |
Which of the following statements is true:
| A. | The dominant allele is masked in homozygous dominant individuals. | |
| B. | With recessive genetic disorders, if both parents are carriers, the offspring will all be affected. | |
| C. | In carriers, the recessive allele causes an intermediate phenotype. | |
| D. | In recessive genetic disorders, the mother and/or father of an affected individual must also be affected. | |
| E. | With dominant genetic disorders, the mother and/or father of an affected individual must also be affected. |
Skin cancers typically develop in the
| A. | upper layers of the epidermis. | |
| B. | lower layers of the dermis. | |
| C. | subcutaneous layer. | |
| D. | lower layers of the epidermis. | |
| E. | upper layers of the dermis. |
Duchenne muscular dystrophy (MD) is inherited from an X-linked recessive allele. What is the probability that a son with Duchenne MD inherited this disease from his biological father?
| A. | 1/2 | |
| B. | 0 | |
| C. | 1/16 | |
| D. | 1/4 | |
| E. | 1/8 |
The genetic makeup of a particular trait in an individual is its
| A. | genotype. | |
| B. | heterozygosity. | |
| C. | phenotype. | |
| D. | filial. | |
| E. | dominance. |
What structure holds the sister chromatids to the spindle fibers?
| A. | chromatin | |
| B. | kinetochore | |
| C. | MPF | |
| D. | centromere | |
| E. | cyclin |
If you view a cell in which the genetic material is beginning to be visible as separate bodies, and the nucleus has disappeared from view, you may surmise that the cells is in
| A. | telophase. | |
| B. | anaphase. | |
| C. | interphase. | |
| D. | metaphase. | |
| E. | prophase. |
Gregor Mendel was successful in his analysis of the genetics of pea plants because
| A. | he examined and analyzed both the F1 and F2 generations. | |
| B. | he studied the parental plants to determine their differences. | |
| C. | he decided to only look at his results in an objective manner. | |
| D. | he studied a trait that had a strange inheritance pattern. | |
| E. | pea plants have genetics different from other organisms. |
Tall corn plants (T) are dominant to dwarf plants (tt). Solid green leaves (G) are dominant to leaves with a white tip (gg). A cross between two corn plants yielded the following phenotypes: 51 tall plants with a white tip on their leaves; 43 dwarf plants with solid leaves; 48 dwarf plants with white tips on their leaves; 45 tall plants with solid leaves. What are the genotypes of the parents that produced these plants?
| A. | None of the above | |
| B. | TtGg x Ttgg | |
| C. | ttGG x TTgg | |
| D. | TtGg x TtGg | |
| E. | TtGg x ttgg |
In humans, a gene that has been identified as causing a type of skin cancer is the
| A. | superwoman echidna. | |
| B. | mutant superman. | |
| C. | sonic hedgehog. | |
| D. | mutant mole rat. | |
| E. | superhero aardvark. |
The segregation principle states that in sexually reproducing diploid organisms the two copies of each gene
| A. | segregate from each other during meiosis. | |
| B. | must always be the same allele. | |
| C. | separate from each other during mitosis. | |
| D. | will both wind up in either the sperm or egg. | |
| E. | move together as a unit during meiosis. |
In what phases is the genetic material in the cell correctly referred to as chromatids?
| A. | metaphase and telophase | |
| B. | anaphase and metaphase | |
| C. | interphase and telophase | |
| D. | interphase and prophase | |
| E. | metaphase and prophase |
Consider two traits for an organism, determined by two genes, each of which is governed by at least two alleles. In the case of a dihybrid individual, the gametes formed will be of either the parental type or the recombinant type. Recombinant type gametes are formed because of
| A. | the principle of dihybrids. | |
| B. | multiple alleles. | |
| C. | heterozygosity. | |
| D. | incomplete dominance. | |
| E. | independent assortment. |
An allele is
| A. | an alternate form of a gene. | |
| B. | always recessive. | |
| C. | the main factor determining a trait. | |
| D. | always one of a pair. | |
| E. | the dominant form of a gene. |
After the DNA is replicated, and it condenses in prophase, two identical rods of DNA are seen. These are
| A. | spindle fibers. | |
| B. | kinetochores. | |
| C. | chromatids. | |
| D. | chromatin. | |
| E. | centromeres. |
Special cells found in the gonads that give rise to gametes upon division are called
| A. | egg cells. | |
| B. | somatic cells. | |
| C. | germ cells. | |
| D. | stem cells. | |
| E. | basal cells. |
