Unit Two Review Flashcards
Which of the following is true of a diploid organism?
a. all of its gametes have two copies of every gene
b. all of its somatic cells have two copies of every gene
c. all of its somatic cells have one copy of every chromosome
b. all of its somatic cells have two copies of every gene
Which of the following best describes the relationship between DNA, genes, and chromosomes?
a. Genes are pieces of DNA, chromosomes are genes held together by centromeres
b. A chromosome is a single molecule of DNA. A gene is a specific region of DNA on a chromosome
c. Genes are made of DNA and chromosomes
d. Chromosomes are made of DNA. multiple chromosomes are found in a single gene.
b. A chromosome is a single molecule of DNA. A gene is a specific region of DNA on a chromosome
Which of the following best describes a pair of homologous chromosomes?
a. a pair of chromosomes that have the same genes, but arranged in a different order, and with potentially different alleles of some of the genes.
b. a pair of chromosomes that have the same alleles of the same genes arranged in the same order
c. a pair of chromosomes that have different alleles of the same genes arranged in different order
d. a pair of chromosomes that have the same genes in the same order but possibly with different alleles of some of the genes.
d. a pair of chromosomes that have the same genes in the same order but possibly with different alleles of some of the genes.
Which of the following correctly describes a homologous pair of chromosomes in prophase of meiosis-1?
a. four replicated chromosomes, each of which is one double-stranded DNA molecule
b. four replicated chromosomes, each of which is two double-stranded DNA molecules
c. Two replicated chromosomes, each of which is one double-stranded DNA molecule
d. Two replicated chromosomes, each of which is two double-stranded DNA molecules
d. Two replicated chromosomes, each of which is two double-stranded DNA molecules
During which phases of the cell cycle are different alleles of the same gene separated?
a. meiosis 1
b. meiosis 2
c. meiosis 1 and mitosis
d. meiosis 2 and mitosis
e. meiosis 1, meiosis 2, and mitosis
a. meiosis 1
During which phases of the cell cycle are homologous chromosomes separated?
a. meiosis 1
b. meiosis 2
c. meiosis 1 and mitosis
d. meiosis 2 and mitosis
e. meiosis 1, meiosis 2, and mitosis
a. meiosis 1
During which phases of the cell cycle are sister chromatids separated?
a. meiosis 1
b. meiosis 2
c. meiosis 1 and mitosis
d. meiosis 2 and mitosis
e. meiosis 1, meiosis 2, and mitosis
d. meiosis 2 and mitosis
During which phases of the cell cycle does a diploid cell becomes haploid?
a. meiosis 1
b. meiosis 2
c. meiosis 1 and mitosis
d. meiosis 2 and mitosis
e. meiosis 1, meiosis 2, and mitosis
a. meiosis 1
How many copies of each gene are present in somatic cells of a diploid organism following s phase when the DNA of the chromosomes was replicated in preparation for cell division?
a. 1
b. 2
c. 4
d. 8
c. 4
How many copies of each chromosome are present in the somatic cells of a diploid organism following s phase when the DNA of the chromosomes was replicated in preparation for cell division?
a. 1
b. 2
c. 4
d. 8
c. 4
How many copies of each gene are present in the gametes of a diploid organism at the end of meiosis 1?
a. 1
b. 2
c. 4
d. 8
b. 2
How many copies of each gene are present in the gametes of a diploid organism at the end of meiosis 2?
a. 1
b.2
c. 4
d. 8
a. 1
Which of the following is the ultimate origin of genetic variation?
a. recombination
b. mutation
c. genetic drift
d. descent with modification
e. natural selection
b. mutation
endangered species with very small populations are especially at risk of loss of genetic diversity due to which of the following?
a. mutation
b. natural selection
c. nonrandom mating
d. gene flow
e. genetic drift
e. genetic drift
Which of the following is not a condition that must be met for Hardy-Weinberg equilibrium?
a. individuals with different genotypes are equally likely to survive and reproduce
b. there is no migration of individuals in or out of population
c. there is no sexual selection .mating is random
d. new alleles arise by mutation.
d. new alleles arise by mutation.
If a plant with red flower color is crossed with a plant that produces all white flowers, what is the probability that the offspring will include plants that have white flowers?
a. 0%
b. 25%
c. 50%
d. 75%
e. there is not enough information to say
e. there is not enough information to say
As the industrial revolution progressed in nineteenth century england, the color of the pepper moth shifted from light to dark. this is an example of which of the following?
a. stabilizing selection
b. disruptive selection
c. directional selection
c. directional selection
Robins typically lay four eggs. Larger clutches with more eggs result in malnourished chicks, while smaller clutches often result in no viable offspring. the number of eggs in a typical clutch of robins’ eggs is an example of which of the following?
a. stabilizing selection
b. disruptive selection
c. directional selection
a. stabilizing selection
selection that favors the survival of individuals that vary in both directions from the average
a. directional selection
b. disruptive selection
c. stabilizing selection
b. disruptive selection
Characters that are similar because of descent from a common ancestor are ____; characters that are similar due to convergent evolution are ___.
a. homologous; analogous
b. analogous; homologous
c. similar; analogous
d. analogous; similar
a. homologous; analogous
Which of the following is true of population bottlenecks?
a. they tend to increase genetic variation of a population
b. they rarely result in a change in allele frequencies
c. they arise from severe reduction in population size
d. they come about when individuals from one population migrate and join another population
c. they arise from severe reduction in population size
Which of the following is true about mistakes that occur during the replication of DNA?
a. they occur when an organism requires then
b. they are always repaired by DNA polymerase
c. they provide genetic variation
d. they are most often beneficial to the organism
e. they are almost always deleterious to an organism
c. they provide genetic variation
Gene flow is best described as an exchange of genetic information between
a. individuals
b. populations
c. males and females
d. chromosomes
b. populations
When we say that an individual organism has a greater fitness than another individual, we specifically mean that the organism:
a. lives longer than others of its species
b. mates more frequently than others of its species
c. leaves more viable offspring than others of its species
d. utilizes resources more efficiently than other species occupying the same niches, or habitats
e. competes more successfully for resources than others of its species
c. leaves more viable offspring than others of its species
