Section 1
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Animation: Somatic Mutations in Cancer
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Cards (111)
Section 1
(50 cards)
Animation: Somatic Mutations in Cancer
5/5
Mutations arise in which order in the colon cancer example shown in the animation?
APC, Ras, p53
In normal meiosis, when do homologous chromosomes separate from each other?
in the first meiotic division
What effect does each successive mutation have on the colon cells in the example?
It causes them to divide more rapidly than normal cells.
The failure of a pair of chromosomes to separate during anaphase is referred to as:
nondisjunction.
According to Figure 14.2, the average number of new mutations that occur across an entire human genome in one generation is approximately _____ times higher than in nematodes.
100
In this partial image of anaphase I of meiosis, most of a chromosome is shaded dark, whereas a portion of what is in the circle is shaded light. Which of the following statements best explains the meaning of this shading?
The light part came from the homolog by crossing over.
_____ mutations are important to the evolutionary process; most cancers result from _____ mutations.
Germ-line, somatic
Homologous chromosomes separate from each other in:
meiosis I
Animation: Nondisjunction
5/5
Huntington's disease is a devastating neurological disorder. If a child of an affected parent receives one copy of the Huntington allele, he or she will develop Huntington's disease. Thus, Huntington's disease is considered _____ trait.
a dominant
In the figure above, which box contains only single gene copies from one of the parents?
box a
Pre-Class Review Questions T part I
6/6
Which of the following is NOT a characteristic of meiotic cell division?
Daughter cells are genetically identical.
An organism that has two different alleles of a given gene has a _____ genotype.
heterozygous
If nondisjunction occurs in the first meiotic division, how many of the four possible gametes produced from meiosis will have the wrong number of chromosomes?
four
Animation
8/8
In a homozygous genotype:
both alleles for a given trait are the same.
In genetic crosses, the symbol Aa refers to a:
genotype.
Which of the following is true?
Errors in chromosome segregation can occur in either the first or second meiotic division.
During meiosis, crossing over that results in recombination between paternal and maternal DNA takes place between:
non-sister chromatids.
Prophase of meiosis I has some important differences from prophase of mitosis. These differences include: ___________BLANK pair, and _________BLANK occurs.
homologous chromosomes; crossing over
When p53 becomes mutant in cells already mutant for APC and Ras, what occurs?
These cells survive despite DNA damage and divide extremely rapidly.
Which of the following is NOT true about gametes?
Which of the following is NOT true about gametes?
In the image above, let the light shade indicate maternally derived chromosomal material and the dark shade indicate paternally derived material. Which circle is likely to contain both paternal and maternal gene variants (alleles)?
circle b
When do sister chromatids separate in meiosis?
anaphase II
In the figure above, which box contains some gene variants (alleles) from one parent and some from the other, but not variant alleles from the same gene?
box d
How do most cancers arise?
from a series of mutations that arise in the descendants of a single somatic cell
Pre-class review questions R pt II
4/4
Which of the following genotypes would result in a true-breeding stock?
AA or aa, but not Aa
In the figure above, which box encloses two copies of the same gene variants (alleles) from only one of the parents?
box c
The genotype of an organism constitutes its observable characteristics.
false
In which type of nondisjunction could the two copies of a chromosome in a gamete be heterozygous?
Nondisjunction in the first meiotic division.
How do mutations arise?
Mutations arise randomly and independent of other mutations in the cell.
In the figure above, which box encloses gene variants (alleles) of the same genes from both parents?
box b
What is an allele?
one of several different forms of a gene
Sites in the genome that are more susceptible to mutations than others are called:
hotspots
Harmful mutations are always quickly weeded out of a population.
false
Consider a normal human cell in which one chromosome undergoes nondisjunction in mitosis. What chromosome numbers would be found in the daughter cells?
45 and 47
First division nondisjunction will only yield gametes with an extra chromosome, whereas second division nondisjunction will only yield gametes missing a chromosome.
false
Pre-class Review Questions R part III
6/6
What is nondisjunction?
failure of chromosomal separation
A phenotype always refers to something that you can see with your eyes, such as hair color or eye color.
false
What is one reason a woman with the genotype XXX are not phenotypically different from an XX female?
Only one X is active in each cell, regardless of how many X chromosomes there are in a cell.
Which of the following statements concerning cancer and mutations is CORRECT?
Usually, multiple mutations are required in different genes to cause cancer.
The number of new mutations in organisms following a round of genome replication:
generally increases with larger genomes.
Which one of the following BEST describes genotype-by-environment interactions?
Genetic and environmental factors combine to influence phenotype.
The definition of mutation is "any heritable change in the genetic material." The qualifier "heritable" is necessary because:
most changes in the genetic material are repaired soon after they occur.
Pre-class Review Questions R part I
5/5
Pre-class Review Questions T Part II
4/4
Section 2
(50 cards)
Which of the following is TRUE of incomplete penetrance?
Gene interactions have been shown to result in incomplete penetrance in some cases.
Simulation: Pedigree
8/8
A Punnett square can be used to interpret the results of a testcross.
true
In genetics, the dash symbol (-) is a "wild card" that stands for either the dominant allele or the recessive allele; for example, W- means the individual has either the genotype WW or Ww. In summer squash, genotypes W- G- and W- gg are white, ww G- are yellow, and ww gg are green. W and G show independent assortment. What is the ratio of white : yellow : green among progeny of the cross Ww Gg × Ww Gg?
12:3:1
For an individual who is heterozygous for two genes, Aa and Bb, what does independent assortment predict?
Offspring inheriting the dominant (A) allele of the first gene are equally likely to inherit either the dominant (B) or the recessive (b) allele of the second gene.
The principle of independent assortment holds that:
the pattern of inheritance of one trait does not influence the pattern of inheritance of another trait.
Using the following settings, press "Generate Pedigree" three to six times, and notice the frequency of affected sons and daughters in the F1 to F4 progeny. Settings: Mode of inheritance - Recessive Parental generation - Male - Homozygous mutant Female - Homozygous mutant Matings between relatives - disallow Progeny in first generation - 4 Show carriers - turn off Why are all the offspring in the F1 generation affected?
All gametes produced that combine to make up the F1 generation have the mutant allele. It is impossible to have a carrier in the F1 generation.
In his cross, what did Mendel do?
He studied traits controlled by a single gene.
Using the following settings, press "Generate Pedigree" three to six times, and notice the frequency of affected sons and daughters in the F1 to F4 progeny. Settings: Mode of inheritance - Recessive Parental generation - Male - Homozygous mutant Female - Homozygous nonmutant Matings between relatives - disallow Progeny in first generation - 4 Show carriers - turn off Why aren't there any affected individuals in the F1 generation?
Two recessive alleles are required to express the phenotype, and F1 individuals always receive one nonmutant allele from the unaffected parent.
While doing a pedigree analysis of a European royal family, you notice a disease in a female child of two healthy parents. There are also some cousins with the same genetic disease. If this disease is controlled by a single gene, then the MOST likely explanation for these observations is that the disease is:
recessive and only seen in homozygous recessive individuals such as the daughter.
In Mendel's crosses:
the plants he started with had two alleles of each gene.
When Mendel crossed yellow peas with green peas, the next generation was all yellow. How is this explained?
The parental plants pass one of their two alleles on to the offspring which is heterozygous, and the A allele is dominant to the a allele.
Pre-class Review Questions R part VI
4/4
Animation: Independent Assortment
5/5
In the pedigree above, what can you say about the likely genotypes of individuals A and B?
both are Aa
Pre-class Review Questions R part IV
5/5
Consider a gene with four alleles A1, A2, A3, and A4. In the cross A1A2 × A3A3, how many offspring genotypes are possible?
2
If you crossed two heterozygous yellow-seed pea plants (genotypes Aa), the relative frequency of:
All of these choices are correct.
Using the following settings, press "Generate Pedigree" three to six times, and notice the frequency of affected sons and daughters in the F1 to F4 progeny. Settings: Mode of inheritance - Recessive Parental generation - Male - Heterozygous Female - Homozygous mutant Matings between relatives - disallow Progeny in first generation - 4 Show carriers - turn on Why is there a higher number of carriers than affected individuals?
Since both parents have disease alleles, all the offspring will inherit at least one mutant allele.
In genetics, the dash symbol (-) is a "wild card" that stands for either the dominant allele or the recessive allele; for example, A- means the individual has either the genotype AA or Aa. Two genes that undergo independent assortment affect flower color in sweet peas. Each gene as two alleles, one of which is dominant for flower color. Genotypes of the form A- B- have purple flowers, whereas those of the form A- bb, aa B-, and aa bb have white flowers. What ratio of purple : white is expected from the cross Aa Bb × Aa Bb?
9:7
When the F1 plants are allowed to self fertilize, they produced both yellow and green peas in the next generation. How is this explained?
In the F1 heterozygotes, the alleles segregate from each other when gametes form and then combine to make homozygotes and heterozygotes offspring.
.You are given two populations of true-breeding tomato plants with two simple dominant/recessive traits that sort independently. Using the multiplication rule, how many different phenotypic combinations would you expect to see in the F2 generation? In what phenotypic ratio?
four, 9:3:3:1
Using the following settings, press "Generate Pedigree" three to six times, and notice the frequency of affected sons and daughters in the F1 to F4 progeny. Settings: Mode of inheritance - X-linked dominant Parental generation - Male - Mutant Female - Heterozygous Matings between relatives - disallow Progeny in first generation - 4 Show carriers - turn off Why are all daughters, but only some sons, affected in the F1 generation?
Fathers pass on their X chromosome to their daughters, so all daughters in the F1 will have the disease.
Assuming that the trait represented by the filled symbols below is a rare inherited trait with complete penetrance due to a single gene with alleles A and a, what mode of inheritance does the pedigree suggest?
recessive
Genes on different chromosomes _____ during meiosis. Genes that are very close together on the same chromosome are _____.
assort independently; linked
Pre-class Review Questions R part V
3/3
According to Figure 14.2, the average number of new mutations that occur across an entire human genome in one generation is approximately _____ times higher than in nematodes.
100
The principle of independent assortment states that:
alleles of a gene pair assort independently of other gene pairs.
The addition rule requires which of the following?
Two outcomes (such as having the genotype BB or Bb) are mutually exclusive in an organism.
The use of the multiplication rule requires which of the following?
The events being considered occur independently.
Using the following settings, press "Generate Pedigree" three to six times, and notice the frequency of affected sons and daughters in the F1 to F4 progeny. Settings: Mode of inheritance - Dominant Parental generation - Male - Heterozygous Female - Heterozygous Matings between relatives - disallow Progeny in first generation - 4 Show carriers - run simulation three times with "show carriers" on, and three times with "show carriers" off A carrier is an individual who has an allele associated with a trait but does not display the trait. They are, however, able to pass on the allele to their offspring. When setting the simulation's conditions as described above, why does it make no difference whether or not you turn on "show carriers"?
Individuals with one mutant allele express the disease phenotype and so cannot be carriers.
Among the progeny of a heterozygous round (Aa) × homozygous wrinkled (aa) testcross, three seeds are chosen at random. What is the probability that all three seeds are round?
(1/2)3
Week 1 Practice Exam Questions
22/22
True-breeding plants are typically heterozygous for most genes.
false
A true-breeding black rabbit is crossed with a true-breeding white rabbit to produce an F1 generation of 15 individuals. If the black color trait is dominant, which of the following represents the expected phenotype of an F1 generation cross?
15 black rabbits, 0 white rabbits, 0 grey rabbits
Animals that sexually reproduce are _____ and produce _____ gametes.
diploid; haploid
You are examining a human pedigree for a trait. You notice that the trait appears in every generation; is equally likely to occur in males and females; and, when one parent is affected, about half of his or her offspring are affected. The trait is MOST likely:
dominant.
Using the following settings, press "Generate Pedigree" three to six times, and notice the frequency of affected sons and daughters in the F1 to F4 progeny. Settings: Mode of inheritance - Recessive Parental generation - Male - Heterozygous Female - Heterozygous Matings between relatives - disallow Progeny in first generation - 4 Show carriers - turn on Why is there a higher number of carriers than affected individuals?
Offspring have a 50% chance of being a carrier, but only a 25% chance of being affected.
Flower color in snapdragons is due to a gene with incomplete dominance: CRCR plants have red flowers, CRCW have pink flowers, and CWCW plants have white flowers. Which cross is expected to yield progeny that all have pink flowers?
RR X WW
How did Mendel make crosses with his plants?
He grew plants from seeds and fertilized the ovules of one plant with the pollen from another.
Using the following settings, press "Generate Pedigree" three to six times, and notice the frequency of affected sons and daughters in the F1 to F4 progeny. Settings: Mode of inheritance - Y-linked Parental generation - Male - Mutant Female - Homozygous nonmutant Matings between relatives - disallow Progeny in first generation - 4 Show carriers - turn on Why aren't there any affected females in the F1 to F4 generations under these conditions?
Only males can be affected because the trait is linked to the Y chromosome.
In a cross between two individuals who are heterozygous for two traits determined by dominant and recessive alleles (Aa Bb), what is the expected ratio of phenotypes for the traits determined by both genes?
9:3:3:1
A testcross involves crossing with a(n) _____ individual and is used to determine the _____ of the tested parent.
homozygous recessive; genotype
When one gene is able to modify the effect of a second gene, the phenomenon is known as:
epistasis
When a 9:3:3:1 ratio of phenotypes is produced by a cross between two individuals, which phenotypes are present in the rarest class that is represented by only 1 of the 16 possible genotypes of offspring?
These offspring have the recessive phenotype of both traits.
Animation: Segregation
5/5
A researcher is creating pedigrees for a trait he suspects to be dominant in humans. What are some of the likely features of his pedigrees for families with this trait?
None of the answer options is correct.
A pea plant is heterozygous (Aa) for seed color and heterozygous (Bb) for seed shape. According to Mendel's principle of independent assortment: (Select all that apply.)
- a gamete that contains the dominant allele for seed color is equally likely to contain the dominant or the recessive allele for seed shape. - possible gamete genotypes are AB or ab; each is equally likely to occur.
In a cross between two individuals who are heterozygous for two traits determined by dominant and recessive alleles (Aa Bb), what is the expected ratio of offspring for the trait determined by the first gene (Aa)?
3:1
Using the following settings, press "Generate Pedigree" (NOT "Generate Random Pedigree") three to six times, and notice the frequency of affected sons and daughters in the F1 to F4 progeny. Settings: Mode of inheritance - X-linked recessive Parental generation - Male - Nonmutant Female - Heterozygous Matings between relatives - disallow Progeny in first generation - 4 Show carriers - turn on Why aren't there any affected females in the F1 generation under these conditions?
There is only one affected allele segregating in the pedigree
Section 3
(11 cards)