Bio 3
Ignoring crossover, how many kinds of gametes can be produced by an organism with a diploid number of 8?
16
A cell contains 40 chromatids at the beginning of mitosis. How many chromosomes will it contain at the completion of cytokinesis?
20
The egg (ovum) of a rabbit contains 22 chromosomes. How many chromosomes are in the somatic (body) cells of a rabbit?
44
How many chromatids does a human somatic cell contain after interphase and just prior to mitosis?
92
A human bone marrow cell, in prophase of mitosis, contains 46 chromosomes. How many chromatids does it contain? A) 92 B) 46 C) 23
A) 92 Mitosis follows the duplication of the cell's DNA.
If a eukaryotic cell is in the G1 phase of the cell cycle, which statement about the cell's chromosomes must be correct? A) Each chromosome is made of a complex of DNA and associated proteins. B) Each chromosome consists of two identical chromatids. C) The chromosomes are preparing for DNA synthesis.
A) Each chromosome is made of a complex of DNA and associated proteins. ~Eukaryotic nucleus contains chromatin, a complex of DNA and associated protein molecules. The proteins maintain the structure of the chromosomes and help control gene activity.~
Cell A has half as much DNA as cells B, C, and D in a mitotically active tissue. Cell A is most likely in A) G₁ B) prophase. C) G₂ D) metaphase.
A) G₁
Cells will usually divide if they receive the proper signal at a checkpoint in which phase of the cell cycle? A) G₁ B) G₂ C) S D) cytokinesis E) M
A) G₁ In mammalian cells, this checkpoint is termed the restriction point.
During which phase of mitosis do the chromatids become chromosomes? A) anaphase B) prophase C) telophase D) metaphase
A) anaphase
In the cells of many eukaryotic species, the nuclear envelope has to disappear to permit which of the following events in the cell cycle? A) attachment of microtubules to kinetochores B) condensation of the chromosomes C) seperation of the centrosomes
A) attachment of the microtubules to kinetochores
Movement of the chromosomes during anaphase would be most affected by a drug that prevents which of the following events in mitosis and cell division? A) shortening of microtubules B) nuclear envelope breakdown C) formation of a cleavage furrow D) elongation of microtubules
A) shortening of microtubules
A clone is the product of __________.
Asexual reproduction and mitosis
In a diploid cell with 5 chromosome pairs (2n = 10), how many sister chromatids will be found in a nucleus at prophase of mitosis? A) 10 B) 20 C) 5 D) 40
B) 20
Eukaryotic chromosomes are composed of which of the following macromolecules? A) DNA and RNA B) DNA and proteins C) DNA only D) DNA and phospholipids
B) DNA and proteins
How is plant cell cytokinesis different from animal cell cytokinesis? A) The contractile filaments found in plant cells are structures composed of carbohydrates; the cleavage furrow in animal cells is composed of contractile proteins. B) Plant cells deposit vesicles containing cell wall building blocks on the metaphase plate; animal cells form a cleavage furrow. C) Plant cells divide after metaphase but before anaphase; animal cells divide after anaphase. D) The structural proteins of plant cells separate the two cells; in animal cells, a cell membrane separates the two daughter cells.
B) Plant cells deposit vesicles containing cell wall building blocks on the metaphase plate; animal cells form a cleavage furrow.
Certain cell types normally have several nuclei per cell. How could such multinucleated cells be explained? A) The cell underwent repeated cytokinesis but no mitosis. B) The cell underwent repeated mitosis, but cytokinesis did not occur. C) The cell underwent repeated mitosis with simultaneous cytokinesis. D) The cell had multiple S phases before it entered mitosis.
B) The cell underwent repeated mitosis, but cytokinesis did not occur.
Which statement provides the best description of the interphase portion of the cell cycle? A) Interphase is a brief period between mitosis and chromosome duplication. B) During interphase, a cell is metabolically active. C) Interphase is a resting stage prior to cell division.
B) during interphase, a cell is metabolically active ~Interphase accounts for about 90% of the cell cycle and includes many key events critical to the cell cycle. It is not a resting stage; the cell is metabolically active during this phase.~
The beginning of anaphase is indicated by which of the following processes? A) Loss of kinetochores from the chromatids. B) Enzymatic cleavage of cohesin. C) Attachment of sister chromatids to each other by cohesin. D) Disappearance of the nuclear membrane.
B) enzymatic cleavage of cohesin
The M phase checkpoint ensures that all chromosomes are attached to the mitotic spindle. If this does not happen, cells would most likely be arrested in ________. A) telophase B) metaphase C) prophase D) G₂
B) metaphase
If a cell at metaphase of mitosis contains 20 sister chromatids, how many chromosomes will be present in a G1 cell? A) 20 B) 5 C) 10 D) 40
C) 10
Density-dependent inhibition is explained by which of the following processes? A) As cells become more numerous, the protein kinases they produce begin to compete with each other, such that the proteins produced by one cell essentially cancel those produced by its neighbor. B) As cells become more numerous, the level of waste products increases, which slows metabolism and inhibits growth. C) As cells become more numerous, the cell surface proteins of one cell contact the adjoining cells, and they signal each other to stop dividing. D) As cells become more numerous, they begin to squeeze against each other, restricting their size.
C) As cells become more numerous, the cell surface proteins of one cell contact the adjoining cells, and they signal each other to stop dividing.
A cleavage furrow is _____. A) the space that is created between two chromatids during anaphase B) a ring of vesicles forming a cell plate C) a groove in the plasma membrane between daughter nuclei D) the separation of divided prokaryotes
C) a groove in the plasma membrane between daughter nuclei
What is the name of the microtubule-organizing center found in animal cells as an identifiable structure present during all phases of the cell cycle? A) centriole B) centromere C) centrosome
C) centrosome
Cytochalasin B is a chemical that disrupts microfilament formation. How would this interfere with cell division? A) formation of the cell plate B) binary fission C) cleavage furrow D) formation of the mitotic spindle E) DNA replication
C) cleavage furrow In animal cells, the cleavage furrow forms when a ring of microfilaments contracts, causing the parent cell to be pinched in two.
Which of the following molecules is a protein synthesized at specific times during the cell cycle that associates with a kinase to form a catalytically active complex? A) PDGF B) MPF C) cyclin D) Cdk
C) cyclin
In some organisms, such as certain fungi and algae, cells undergo the cell cycle repeatedly without subsequently undergoing cytokinesis. What would result from this? A) a decrease in chromosome number B) a rapid rate of gamete production C) large cells containing many nuclei D) division of the organism into many cells, most lacking nuclei
C) large cells containing many nuclei
Motor proteins require which of the following structures or molecules to function in the movement of chromosomes toward the poles of the mitotic spindle? A) intact centromeres B) intact cohesin C) a microtubule-organizing center D) ATP as an energy source
D) ATP as an energy source
Which of the following is true of kinetochores? A) They are located at the center of the centrosome; their function is to organize tubulin into elongated bundles called spindle fibers. B) They interdigitate at the cell's equator and then move apart, causing the cell to elongate. C)T hey attach to the ring of actin along the cytoplasmic surface of the plasma membrane, causing the actin to contract to form the cleavage furrow D) They are sites at which microtubules attach to chromosomes.
D) They are sites at which microtubules attach to chromosomes. ~As the spindle depolymerizes, the kinetochores appear to move along the spindle fiber, dragging the attached chromosomes with them.~
Through a microscope, you can see a cell plate beginning to develop across the middle of a cell and nuclei forming on either side of the cell plate. This cell is most likely ________. A) an animal cell in the process of cytokinesis B) a plant cell in metaphase of mitosis C) an animal cell in anaphase of mitosis D) a plant cell in the process of cytokinesis
D) a plant cell in the process of cytokinesis
Besides the ability of some cancer cells to over proliferate, which of the following situations might logically result in a tumor? A) failure of cells to enter S phase B) inability to form spindles C) changes in the order of cell cycle stages D) lack of appropriate cell death
D) lack of appropriate cell death
At which phase of the cell cycle do centrioles begin to move apart in animal cells? A) anaphase B) telophase C) metaphase D) prophase
D) prophase
Which of the following does not occur during mitosis? A) separation of the spindle poles B) condensation of the chromosomes C) spindle formation D) replication of the DNA
D) replication of DNA
The mitotic spindle plays a critical role in which of the following processes? A) splitting of the cell (cytokinesis) following mitosis B) dissolving the nuclear membrane C) triggering the compaction and condensation of chromosomes D) separation of sister chromatids
D) separation of sister chromatids
Regarding the role of cohesin protein in maintaining cohesion between sister chromatids, which of the following statements is false?
During meiosis II, cohesion holds sister chromatids together along their lengths as the second meiotic spindle forms.
Metaphase is characterized by ________. A) cytokinesis B) separation of sister C) chromatids D) separation of the centromeres E) alignment of chromosomes on the equator of the cell
E) alignment of chromosomes on the equator of the cell
What is the result when a diploid cell undergoes meiosis?
Four haploid cells
Which of the following occurs in meiosis, but not mitosis?
Homologous chromosomes separate.
Which life cycle stage is found in plants but not animals?
Multicellular haploid
Which of the following is a function of mitosis in humans?
Multiplication of body cells
How many genes are present in the human genome?
Tens of thousands
What kind of protection does the Genetic Information Nondiscrimination Act of 2008 provide the public with regard to the use of genetic information? The law mandates that people who undergo genetic testing are provided professional instruction so that they can make informed family decisions based on their test results. The law guarantees that access to genetic counseling cannot be denied to U.S. citizens based on their race, sex, age, religious beliefs, or sexual orientation. The law prohibits the use of genetic test information to deny insurance coverage or employment to individuals. The law mandates that all expecting mothers must undergo fetal testing for genetic disorders regardless of their demographic status.
The law prohibits the use of genetic test information to deny insurance coverage or employment to individuals.
What is a locus?
The precise location of a gene on a chromosome.
Which of the following statements about homologous chromosomes is correct?
They have genes for the same traits at the same loci
Which of the following events occurs during telophase of mitosis?
Two distinct daughter nuclei form in the cell. The nuclear envelope fragments during prometaphase of mitosis. The chromosomes align on the metaphase plate during metaphase of mitosis. The sister chromatids separate during anaphase of mitosis. The chromosomes condense during prophase of mitosis. DNA replicates during interphase.
The region of a chromosome holding the two double strands of replicated DNA together is called __________.
a centromere
Which of the following structures is/are part of the mitotic spindle?
a) kinetochore microtubules b) centrosome c) the aster d) nonkinetochore microtubules all of the above
Which event or events occur during anaphase?
all of the above b) the centrioles are at opposite poles c) identical chromatids move to opposite poles d) the centromeres divide e) a spindle made of microtubules is present
The life cycle called __________ in plants has two multicellular stages: the __________ and the __________.
alternation of generations; haploid gametophyte; diploid sporophyte
Somatic cells in animals differ from gametes in that somatic cells __________.
are all of the cells of the body except for the gametes and their precursors
The function of the mitotic cell cycle is to produce daughter cells that __________.
are genetically identical to the parent cell (assuming no mutation has occurred)
Sister chromatids differ from nonsister chromatids in that sister chromatids __________.
are products of the S phase of the cell cycle and are two copies of one chromosome
Which of the following statements correctly describes the difference(s) between mitosis and binary fission?
binary fission involves the replication and division of a single chromosome, whereas mitosis involves the division of multiple, replicated chromosomes
What is the difference between a benign tumor and a malignant tumor?
cells of benign tumors do not metastasize; those of malignant tumors do
The complex of DNA and protein that makes up a eukaryotic chromosome is properly called __________.
chromatin
__________ are a group of genetically identical individuals produced by a process called __________.
clones; asexual reproduction
In addition to the ABO system, humans have other blood groups, including the MN system. Individuals who have alleles for both M and N show __________ for the M and N red blood cell surface antigens. incomplete dominance codominance epistasis polygenic inheritance complete dominance
codominance
A red bull is crossed with a white cow and all of the offspring are roan, an intermediate color that is caused by the presence of both red and white hairs. This is an example of genes that are __________. completely dominant polygenic epistatic codominant nonhomologous
codominant
Somatic cells in humans differs from gametes in that human somatic cells __________.
contain two sets of each of the 23 chromosome types
In animal cell mitosis, the cleavage furrow forms during which stage of the cell cycle?
cytokinesis
Regardless of whether an organism is an animal, a plant, a fungus, or an algal cell, all zygotes are __________ and are formed during the __________ of two __________ gametes.
diploid; fertilization; haploid
During interphase, the genetic material of a typical eukaryotic cell is __________.
dispersed in the nucleus as long strands of chromatin
Cytokinesis refers to __________.
division of the cytoplasm
Observations of cancer cells in culture support the hypothesis that cancer cells __________.
do not exhibit density-dependent inhibition
Achondroplasia, a type of dwarfism, and Huntington's disease are examples of __________, with the exception that the Huntington's allele is __________. recessive inherited disorders; nonlethal dominant inherited disorders; lethal recessive inherited disorders; lethal incomplete dominance; lethal dominant inherited disorders; nonlethal
dominant inherited disorders; lethal
Darwin realized the importance of heritable variation to evolution __________.
even though he never read any of Gregor Mendel's work
A life cycle in which the only multicellular form is haploid is most typical of __________.
fungi
Allelic variation is an important source of __________ in a population.
genetic diversity
A pair of genetic structures carrying genes that control the same inherited characters are called __________.
homologous chromosomes
Chromatids are __________.
identical copies of each other if they are part of the same chromosome
If a plant variety is true-breeding for a dominant trait, then __________. if the plant were crossed with a heterozygote, one-half of the progeny would show the dominant trait, and one-half would show the recessive trait the plant is heterozygous for the trait if the plant were allowed to self-pollinate, the dominant and recessive traits would consistently appear in a 3:1 ratio among the progeny the variety is unable to mutate if the plant were allowed to self-pollinate, all of the progeny would have the dominant trait
if the plant were allowed to self-pollinate, all of the progeny would have the dominant trait
Characteristic of the bdelloid rotifer is that it __________.
is an example of an animal that has not reproduced sexually in 40 million years
You would know a dividing cell was a plant cell rather than an animal cell if you saw that __________.
it formed a cell plate
The major contribution of sex to evolution is that __________.
it provides a method to increase genetic variation
The process called __________ reduces the chromosome number by __________.
meiosis; two consecutive cell divisions.
The spread of cancer cells to other locations in the body is known as __________.
metastasis
Human ABO groups are best described as an example of __________. a pleiotropic effect autosomal dominant alleles multiple alleles codominant alleles Mendelian dominant and recessive alleles
multiple alleles
In meiosis, __________ of __________ cross over and form __________.
nonsister chromatids; homologous pairs; chiasmata
Unless the chromosomes were stained to show band patterns, a karyotype would be least likely to show which of the following?
part of a chromosome turned around
In humans, height and skin color have continuous variation in the population because of __________. incomplete dominance epistasis multiple alleles codominance polygenic inheritance
polygenic inheritance
The zipper-like complex that forms in meiosis occurs during __________ and is called the __________.
prophase I; synaptonemal complex
Checkpoints in the cell cycle control system __________.
regulate the cell cycle through a variety of stop and go signals
Which of the following events does not occur during interphase of the cell cycle?
separation of the sister chromatids This DOES happen in the interphase of the cell... a) production of new mitochondria b) production of the endoplasmic reticulum c) growth of the cell d) protein production
Genetic diversity requires __________.
sexual reproduction, independent assortment, crossing over between nonsister chromatids of homologous chromosomes, and random fertilization
Which of the following phases of mitosis is essentially the opposite of prometaphase in terms of the nuclear envelope?
telophase
A cell biologist examined the DNA content of a cell from a fruit fly larva during the G1 phase and determined that it had 150 units of DNA. After measuring the DNA content of the same type of cell after the G2 phase, it was discovered that the cell had 300 units of DNA. How is this possible?
the DNA was replicated during the S phase of interphase, which occurs between the two G phases
DNA replication occurs in __________.
the S phase of interphase in both somatic and reproductive cells
One event occurring during prophase is __________.
the beginning of the formation of a spindle apparatus
Which of the following statements describes a cell that undergoes mitosis but not cytokinesis?
the cell contains more than one nucleus
Which of the following events occurs during metaphase of mitosis?
the chromosomes align along the metaphase plate of the cell
Which of the following events does not occur during prophase of mitosis?
the mitotic spindle breaks down These DO occur during prophase of mitosis a) nucleoli disappear b) the mitotic spindle forms c) each duplicated chromosome appears as two identical sister chromatids d) the chromosomes condense e) the centrosomes move away from each other
Which of the following events occurs during prometaphase of mitosis?
the nuclear envelope fragments
How does the process of mitosis differ between most eukaryotes and other eukaryotes such as diatoms and dinoflagellates?
the nuclear envelope fragments in most eukaryotes but remains intact in diatoms and dinoflagellates
During binary fission in a bacterium __________.
the origins of replication move apart
Which of the following events occurs during anaphase of mitosis?
the sister chromatids are pulled apart toward opposite sides of the cell
Mendel's law of segregation states that __________. the two alleles for a heritable character do not segregate during gamete formation and end up in the same gametes non-true-breeding plants can be bred with non-true-breeding plants The law of segregation does not apply to pea plants. the two alleles for a heritable character segregate (separate from each other) during gamete formation and end up in different gametes only true-breeding plants can be bred with true-breeding plants
the two alleles for a heritable character segregate (separate from each other) during gamete formation and end up in different gametes
Somatic cells in humans contain __________ set(s) of chromosomes and are therefore termed __________.
two; diploid
At the end of mitosis, __________ daughter cells that are genetically __________ are formed, while at the end of meiosis, __________ daughter cells that are genetically __________ are formed.
two; identical; four;
In incomplete dominance, the offspring __________. will have an appearance that's intermediate between those of the two parental types will resemble the recessive type 25% of the time will resemble the dominant type 75% of the time will resemble the recessive type 50% of the time will resemble the dominant type 50% of the time
will have an appearance that's intermediate between those of the two parental types
If the two traits that Mendel looked at in his dihybrid cross of smooth yellow peas with wrinkled green peas had been controlled by genes that were located near each other on the same chromosome, then the F2 generation __________. None of the listed responses is correct. would have contained no individuals that were heterozygous at both loci would have deviated from the 9:3:3:1 phenotypic ratio that is predicted by the law of independent assortment would have contained only individuals that were heterozygous at both loci would have contained four phenotypes in a 9:3:3:1 ratio
would have deviated from the 9:3:3:1 phenotypic ratio that is predicted by the law of independent assortment
In Labrador retrievers, a dog that has the genotype BBee, where BB produces black-pigmented fur and ee produces yellow-pigmented fur, would have __________ fur and would exhibit __________. yellow; incomplete dominance yellow; epistasis black; dominance brown; epistasis brown; codominance
yellow; epistasis
