BIO 113 CH. 7 Learningcurve
What action do CDKs perform on target proteins?
They add a phosphate group to the protein.
Which of the following is a feature of interphase?
Typical cellular functions
Refer to the figure showing two sexual life cycles. (Click image to enlarge.) An example of an organism with life cycle A is _______, and an example of an organism with life cycle B is _______.
a bird; Rhizopus fungus
Chromosome number is reduced during meiosis because the process includes
a cell division in which homologous chromosomes are separated from each other.
Organisms of a species of fern have both a multicellular haploid and a multicellular diploid phase. This is an example of
a haplo-diplontic life cycle.
Having extra copies of one chromosome in a cell is an example of
aneuploidy.
Caspases play a role in the process of
apoptosis.
The offspring resulting from asexual reproduction are called _______ and are genetically _______ their parent.
clones; identical or virtually identical to
Sexual reproduction increases genetic variability through
crossing over, independent assortment, and random fertilization.
Following _______, each daughter cell contains all the components of a complete cell.
cytokinesis
As a result of fertilization, the number of chromosomes in the zygote _______ in comparison to that in each of the gametes.
doubles in plants and animals
Refer to the figure. (Click image to enlarge.) This electron micrograph was taken of a
eukaryotic germ cell in prophase I.
During mitotic anaphase, chromosomes migrate
from the equatorial plate toward the poles.
Maternal chromosome 1, paternal chromosome 2, and maternal chromosome 3 go to the same pole during meiosis. This is an example of
independent assortment.
The typical complete eukaryotic cell cycle consists of
interphase, mitosis, and cytokinesis.
A triploid watermelon plant has
is infertile and is called seedless.
efer to the figure. (Click image to enlarge.) This figure shows a
karyotype.
Pairing of homologous chromosomes occurs
meiosis I only
The number of chromosomes in a cell becomes haploid during
meiosis I.
The mitotic spindle is composed of
microtubules.
A product of asexual reproduction differs from its parent by a base pair change. This change occurred due to
mutation.
Oxygen starvation in a cell will most likely lead to
necrosis
Programmed cell death (apoptosis)
occurs when cells have reached the Hayflick limit of cell divisions.
Bacteria typically have _______, whereas eukaryotes have _______.
one chromosome that is circular; many chromosomes that are linear
In meiosis, DNA replicates _______ the nucleus divides.
one less time than
Homologous chromosomes come together and line up along their entire lengths
only in meiosis.
In a bacterial cell, DNA replication begins near the center of the cell, and as it proceeds, the _______ regions move toward _______ of the cell.
ori; opposite ends
Microtubules of the spindle fan out from the poles and attach to the kinetochores of the chromosomes. This is most likely to occur during
prometaphase.
At which stage of mitosis are chromosomes becoming condensed?
prophase
Human geneticists assume that any allele that causes an abnormal phenotype is
rare
The essence of _______ reproduction is the random selection of half of the _______ chromosome set to make a _______ gamete.
sexual; diploid; haploid
Mutations in a hypothetical gene S67 can lead to cancer when they reduce the expression of the gene. Thus, S67 likely produces a protein that is involved in
suppressing cell division.
Down syndrome is an example of _______ in humans.
trisomy
After the centromeres divide during mitosis, the chromatids, now called _______, move toward opposite poles of the spindle.
unreplicated chromosomes
A monosomic individual has 27 chromosomes. What is the haploid chromosome number?
14
The haploid number of chromosomes in a cell of a grasshopper is 18. How many chromosomes are in one of its gametes?
18
If n is the haploid number of chromosomes, a trisomic individual has _______ chromosomes.
2n + 1
The haploid chromosome number of a human cell is 23. How many chromosomes will a trisomic individual have?
47
If n = 30 for a species of beetle, then a diploid cell would have a total of _______ chromosomes.
60
Refer to the figure. (Click image to enlarge.) How many chromosomes are present in this cell? When this particular cell division is complete, how many chromosomes will each daughter cell have? Is this a diploid or haploid number?
6; 3; haploid
Suppose that in mitotic metaphase, there are 16 sister chromatids in a cell. How many centromeres are in the cell?
8
If the haploid chromosome number is 29, then triploids would have _______ chromosomes.
87
Which of the following must occur for a prokaryotic cell to divide?
A cell division signal, DNA replication, segregation of DNA, and cytokinesis
Which cellular structure consists of a pair of centrioles?
A centrosome
Which of the following is most likely to lead to aneuploidy?
Nondisjunction
Refer to the figure. (Click image to enlarge.) Which phase of cell division is shown in panel 3?
Prophase II of meiosis
In which stage of meiosis would chiasmata be visible?
Prophase of meiosis I
Which process is closest to the opposite of meiosis in terms of effects on the number of chromosomes?
Fertilization
Refer to the figure. (Click image to enlarge.) What process is being shown in the insert labeled A?
Formation of a constricting ring of proteins in a dividing bacterium
What stage in the eukaryotic cell cycle comes immediately before S?
G1
Cells that do not divide usually arrest during
G1.
Which list shows life cycles ranked from that with the greatest proportion spent in the haploid phase to that with the smallest proportion spent in the haploid phase?
Haplontic; haplo-diplontic; diplontic
What is the essential difference between necrosis and apoptosis?
In apoptosis, cell death is part of the normal developmental process; in necrosis, cell death is the result of something going wrong.
Which statement about necrosis is true?
It may occur when cells are damaged by toxins.
What structures are made up of proteins and play important roles in the movement of chromosomes in mitosis?
Kinetochores
Refer to the figure showing two sexual life cycles. (Click image to enlarge.) Which type of life cycle do you have? Is the life cycle of a fern represented by one of these diagrams, and if so, which one?
Life cycle A; no, a fern's life cycle is not represented by either diagram
Which of these processes would likely produce progeny with the greatest genetic variation?
Meiosis
In pea plants the allele R produces a red flower and is dominant to the white allele (r). When a pea plant with red flowers is test crossed, one-half of the resulting progeny have red flowers and the other half have white flowers. Therefore, the genotype of the test-crossed parent was
Rr
DNA replication occurs during
S phase.
Which statement about reproduction is true?
Some multicellular fungi reproduce sexually.
During which phase of mitosis do chromosomes become less compact?
Telophase
Refer to the figure. (Click image to enlarge.) Which phase of cell division is shown in panel 2?
Telophase I of meiosis
In animals, meiosis is
The process that results in gametes
Refer to the figure. (Click image to enlarge.) In which type of cell could this sequence of events be found?
A germ cell in its first meiotic division in a eukaryote
Refer to the figure. (Click image to enlarge.) Which phase of cell division is shown?
Anaphase I of meiosis
When does a eukaryotic cell make the commitment for another cell cycle?
At the transition between G1 and S
The initiation of the S phase and the M phase of the cell cycle each depend on pairs of molecules called _______ and _______.
CDK, cyclin
Which statement about independent assortment is true?
Chance determines which member of a homologous pair goes to each daughter cell.
If you were interested in determining the rates of recombination between homologous chromosomes during meiosis, what feature would you most likely observe and measure?
Chiasmata
What leads to recombinant chromatids?
Crossing over
Which statement about the relationship between cyclins and CDKs is true?
Cyclins activate CDKs.
In which type of cell would you expect to find a spindle beginning to form?
Eukaryotic cell in prophase