BIOL 190 Lecture Notes - Lecture 18: Tay–Sachs Disease, Homologous Chromosome, Gamete
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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. |
13. The arms of a human and the wing of a bat are _________________ structures, composed of the same bones that have been modified for different functions.
a. | analogous |
b. | vestigial |
c. | homologous |
d. | convergent |
14. Xeroderma pigmentosum is an autosomal recessive genetic disorder. People who are homozygous for the disease-causing allele have skin that is damaged by exposure to ultraviolet radiation; this can lead to skin cancer at an early age. The mutation that causes this disorder is in a gene that functions:
a. | to repair DNA by excising (removing) nucleotides damaged by UV light. |
b. | in lysosomes, to break down lipids that otherwise accumulate in the nervous system. |
c. | to produce the UV blocking pigment melanin in the skin cells |
d. | in red blood cells to carry oxygen to the skin. |
15. The Amish are a religious sect descended from a small group of colonists who came to the United States over 200 years ago. Their religious beliefs have kept them isolated from society. The Amish have a much higher than average incidence of both polydactyly (extra fingers and toes) and dwarfism in their communities. This is most likely explained by:
a. | inheritance of acquired characters. |
b. | the founder effect. |
c. | disruptive selection. |
d. | natural selection. |
16. In the structure of DNA that Watson and Crick proposed, the sides of the "ladder" of the DNA molecule are always the same distance apart, making the molecule a constant width. This occurs because when the bases hydrogen bond to form the rungs of the "ladder", a:
a. | purine always pairs with a pyrimidine. |
b. | purine always pairs with a purine. |
c. | pyrimidine always pairs with a pyrmidine. |
d. | The structure of the double helix is not determined by how the bases pair. |
17. The RNA transcript of DNA that travels to the cytoplasm, carrying the instructions to make a protein, is called:
a. | rRNA. |
b. | tRNA. |
c. | mRNA. |
d. | RNA polymerase. |
18. When DNA is replicated, the error rate is approximately one error for every 10,000 nucleotides copied. However, that error rate is reduced to only 1 error for every 1 billion nucleotides. The DNA sequence is "corrected" by:
a. | repeating S phase to see if the error rate is lower the second time around. |
b. | enzymes that proofread the DNA and repair errors. |
c. | messenger RNA during the process of transcription. |
d. | Any errors made during DNA replication cannot be corrected. If errors are detected after S phase, the cell is destroyed. |
19. Mendel's principle of segregation says that:
a. | when gametes are formed, each gamete receives only one allele for a particular gene. |
b. | some genes are dominant to others. |
c. | a testcross must be used to determine the genotype of an organism with a dominant phenotype. |
d. | all of the above |
20. Tay-Sachs disease is lethal before reproductive age, but the allele persists in Louisiana French Canadians because:
a. | it is a dominant allele. |
b. | new mutations causing this disease are common in that population. |
c. | it is not expressed in the phenotype of heterozygous individuals. |
d. | the disease is contagious and can be transmitted by nonheritable means. |
21. Physical features that are similar in organisms which are not closely related to each other are most likely a result of ____________. A good example of this is the similarities seen between some marsupial and placental mammals.
a. | natural selection. |
b. | adaptation to similar environments |
c. | convergent evolution |
d. | All of the above phrases can be used to correctly fill this blank. |
22. In humans, which of the following sex chromosome compliments could be found in males?
a. | XY |
b. | XX |
c. | Y |
23. The proteins that are associated with eukaryotic chromosomes:
a. | help to package the DNA within the nucleus. |
b. | are involved in gene expression, through binding with the DNA. |
c. | may be replicating or transcribing the DNA. |
d. | All of these are true of proteins that are associated with eukaryotic chromosomes. |
24. A sequence of DNA nucleotides that contains the information to produce a single protein is a(n):
a. | codon. |
b. | gene. |
c. | polypeptide. |
d. | anticodon. |