Quiz 7: Cell Cycles

Which of the following best relates to dinoflagellates? A) Individual organisms are visible from space. B) Individual organisms are macroscopic. C) All species produce neurotoxins. D) Certain species produce neurotoxins.

Which of the following is the reason why blooms may be harmful? A) They attack fish. B) They are always all toxic. C) They often threaten drinking water supplies. D) They exhaust all food available to fish.

What is the usual process by which organisms reproduce asexually? A) mitosis B) gametogenesis C) meiosis D) spore formation

How are the two chromosomes separated and distributed to the two ends of the cell during prokaryotic cell division? A) by an unknown mechanism B) by attachment to separating membrane regions C) by attachment to actin D) by the action of the mitotic spindle

What is the name of the specific region where replication of a bacterial chromosome begins? A) the rep B) the ori C) the ter D) the beg

Which term refers to the mechanism of prokaryotic growth, DNA replication, and cell division that results in two identical daughter cells? A) meiosis B) binary fission C) budding D) mitosis

Which of the following best compares prokaryotic cells with eukaryotic cells with respect to their chromosomes? A) two circular chromosomes in prokaryotic cells versus numerous circular chromosomes, depending on the species, in eukaryotic cells B) a single circular chromosome in prokaryotic cells versus many linear chromosomes in eukaryotic cells C) one linear chromosome in prokaryotic cells versus many circular chromosomes in eukaryotic cells D) several circular chromosomes in prokaryotic cells versus many linear chromosomes in eukaryotic cells

Which of these statements assesses how binary fission and mitosis differ? A) Binary fission is a division of cytoplasm, after mitosis is complete in any cell. B) Binary fission repairs cells; mitosis only replicates cells. C) Binary fission is a division of whole cells in prokaryotes, and mitosis is a division of the nucleus in eukaryotes. D) Binary fission is a division of the nucleoid region in prokaryotes, and mitosis is a division of the nucleus in eukaryotes.

Which of these statements assesses how binary fission and mitosis differ? A) Binary fission occurs in eukaryotes; mitosis occurs in prokaryotes. B) Mitosis helps any organism to grow; binary fission only helps it to repair. C) Mitosis occurs in many phases; binary fission has only one phase. D) Binary fission helps any organism to grow; mitosis only helps it to repair.

Hereditary information is encoded in a single, circular DNA molecule in most prokaryotes. What is another feature of the prokaryotic hereditary information? A) The bacterial chromosomes do not have genes that control binary fission. B) Bacterial cells cannot replicate their DNA very rapidly. C) Bacterial cells do not utilize a mitotic spindle to segregate their replicated DNA. D) The DNA of the bacterial chromosome is not replicated prior to segregation.

Which of the following are direct results of mitosis in your body? A) 4 haploid reproductive cells B) 4 haploid body cells C) 2 diploid reproductive cells D) 2 diploid body cells

Which term refers to duplication of the complete set of chromosomes in an organism's cell, followed by the separation of the duplicated chromosomes into two new cells? A) zygote formation B) mitotic cell division C) binary fission D) meiotic cell division

What does each of the two daughter cells that result from normal mitotic division of the original parent cell contain? A) the same number of identical chromosomes and genes as the parent cell B) one-half the number of chromosomes as the parent cell, but different genes C) one-half of the number of identical chromosomes and genes as the parent cell D) the same number of chromosomes as the parent cell, but different genes

Suppose that a somatic cell divides to form two genetically identical daughter cells during mitosis. Prior to mitosis occurring, which of the following must occur? A) The cell must first be fertilized. B) Chromatids must be separated. C) The cell must replicate its DNA. D) The nucleus must divide.

How genetically identical are cells produced by mitosis? A) completely genetically different B) two-thirds genetically identical C) half genetically identical D) completely genetically identical

What happens to each daughter cell at the end of mitosis? A) Each has DNA identical to the parent cell. B) Each has twice the cytoplasm and the same amount of DNA as the parent cell. C) Each has twice the amount of DNA and half the cytoplasm of the parent cell. D) Each has half the DNA and half the cytoplasm found in the parent cell.

When does replication of DNA occur? A) during the S phase B) during the G₁ phase C) during the prophase D) during the G₀ phase

Which of these series is the correct sequence of phases in the cell cycle? A) anaphase B) interphase C) metaphase D) prophase

Which of the following explains cohesins? A) Cohesins are lipids that help separate sister chromatids. B) Cohesins are lipids that hold sister chromatids together. C) Cohesins are proteins that help separate sister chromatids. D) Cohesins are proteins that hold sister chromatids together.

Which term represents two identical copies of a chromosome? A) sister chromosomes B) sister chromatids C) brother chromosomes D) brother chromatids

In which phase do human nerve cells remain once they become mature? A) in G₂ B) in G₁ C) in G₀ D) in S

Which of the following events occurs during interphase? A) formation of the spindle B) alignment of chromosomes at the spindle midpoint C) disappearance of the nuclear envelope D) DNA synthesis

During which phases of the cell cycle does a chromosome consist of two identical chromatids? A) from the beginning of G₂ phase in interphase, through the end of prophase in mitosis B) from the end of G₂ phase in interphase, through the end of telophase in mitosis C) from the beginning of G₁ phase in interphase, through the end of anaphase in mitosis D) from the end of S phase in interphase, through the end of metaphase in mitosis

When growing animal cells in a culture, what must be added to the culture medium for growth to occur? A) growth factors B) RNA C) growth hormone D) DNA

Early in mitosis, chromatin condenses into the compact, rodlike structures known as chromosomes. What process takes place more easily as a result? A) the orderly distribution of DNA into the two new nuclei B) the disappearance of the nuclear envelope C) the formation of the mitotic spindle D) the replication of DNA

The microtubules that make up the mitotic spindle attach themselves to special structures that are found in the centromere region of the chromosome. What term refers to these specialized structures? A) nucleosomes B) chromatids C) kinetochores D) centrosomes

Suppose that, at the beginning of interphase in G₁, a cell has 36 chromosomes. How many chromosomes would be found in that same cell in G₂ of interphase? A) 72 B) 64 C) 36 D) 18

During which phases of mitosis are chromosomes composed of two sister chromatids? A) in anaphase and telophase B) in prophase and metaphase C) in prophase and anaphase D) in prophase and telophase

Where do we find centromeres? A) where the spindle microtubules attach B) where metaphase chromosomes align C) where chromosomes cluster during telophase D) where the mitotic spindle forms

Suppose that a cell containing 84 chromatids at metaphase of mitosis produces two nuclei. How many chromosomes does each nucleus contain in late telophase? A) 21 B) 42 C) 84 D) 168

When does cytokinesis typically begin? A) after anaphase B) after prophase C) after telophase D) after metaphase

Embryonic development begins with a single egg being fertilized by a single sperm, thus forming a zygote; the zygote then undergoes mitosis. How many cells would be present at the conclusion of four mitotic divisions? A) 16 B) 8 C) 4 D) 2

Figure 7-1 Photomicrograph by Dr. Conly L. Rieder, East Greenbush, New York -Which stage of mitosis is depicted in photo A in Figure 7-1? A) interphase B) metaphase C) prophase D) anaphase

Figure 7-1 Photomicrograph by Dr. Conly L. Rieder, East Greenbush, New York -Which stage of mitosis is shown in photo B in Figure 7-1? A) interphase B) metaphase C) prophase D) anaphase

Figure 7-1 Photomicrograph by Dr. Conly L. Rieder, East Greenbush, New York -What do we call the stage of mitosis in photo C in Figure 7-1? A) metaphase B) prophase C) interphase D) anaphase

Figure 7-1 Photomicrograph by Dr. Conly L. Rieder, East Greenbush, New York -Which stage of mitosis is shown in photo D in Figure 7-1? A) telophase B) anaphase C) prophase D) interphase

Figure 7-1 Photomicrograph by Dr. Conly L. Rieder, East Greenbush, New York -Which stage of mitosis is shown in photo E in the figure? A) interphase B) metaphase C) prophase D) anaphase

Which of these series is the sequence of the cell cycle? A) anaphase B) prophase C) prometaphase D) interphase

At what point during the cell cycle do chromosomes decondense into chromatin? A) at the end of telophase B) at the beginning of metaphase C) at the beginning of interphase D) at the end of interphase

At what stage of the cell cycle is DNA found in its condensed form, which is known as a chromosome? A) throughout prophase only B) throughout prophase and metaphase C) throughout the cell cycle D) throughout mitosis until late telophase

Which of the following occurs during metaphase of mitosis? A) Centrioles migrate to opposite poles of the cell. B) Chromatin condenses into chromosomes. C) The nuclear envelope disappears. D) Chromosomes decondense into chromatin.

In general, microtubules disassemble and consequently pull the chromatids to the ends of the spindle. When does this occur? A) during interphase B) during prophase C) during metaphase D) during anaphase

Which of these phases of mitosis is used for karyotype analysis? A) prophase B) anaphase C) metaphase D) prometaphase

Which of these activities is included in the stages of cytoplasmic division? A) cytokinesis B) condensation of DNA into chromosomes in the cytoplasm C) separation of sister chromatids in the cytoplasm D) alignment of chromosomes in the cytoplasm

Certain cell types in humans, such as skeletal muscle cells, have several nuclei per cell. Based on what we know about mitosis, how could this happen? A) The cell undergoes repeated mitosis with associated cytokinesis. B) The cell undergoes repeated cytokinesis, but not mitosis. C) The cell undergoes anaphase twice before entering telophase. D) The cell undergoes repeated mitosis, but not cytokinesis.

Which of the following best compares animal and plant cell division? A) A cleavage furrow is found in plant cells, while cell plate is found in animal cells. B) A cleavage furrow is found in animal cells, while a cell plate is found in plant cells. C) A cleavage furrow is made possible by vesicles, while a cell plate is made possible by means of microtubules. D) A cleavage furrow is made possible by vesicles, while a cell plate is made by means of the nucleus.

Which sentence best describes the difference between plant cell division and animal cell division? A) In animal cells, but not plant cells, cytokinesis is accomplished by formation of a cleavage furrow. B) In animal cells, replication of chromosomes occurs during interphase, while in plant cells replication occurs when the nuclear envelope disintegrates. C) In plant cells, centrosomes have an important role in spindle formation, while in animal cells centrosomes do not function during cell division. D) In plant cells, but not animal cells, cytokinesis is accomplished by formation of a cleavage furrow.

Which of the following best compares animal and plant cell division? A) A cleavage furrow is initiated in animal cells, and a cell plate begins to form in plant cells during telophase. B) The nuclear envelope disintegrates in prophase in animal cells, but remains intact in plant cells. C) Sister chromatids are identical in animal cells, but they differ from one another in plant cells. D) In animal cells, chromosomes do not become attached to the spindle until anaphase whereas in plant cells they become attached to the spindle at prophase.

How is cytokinesis different in plant and animal cells? A) It forms a cleavage furrow in animal cells, and a cell plate in plant cells. B) It helps create four daughter cells in animal cells, and two in plant cells. C) It forms a cleavage furrow in plant cells, and a cell plate in animal cells. D) It helps create two daughter cells in animal cells, and four in plant cells.

What is the primary function of centrioles in animal cells? A) to provide a point of attachment for spindle fibres on chromosomes B) to connect the two sister chromatids C) spindle formation D) the generation of flagella and cilia

What is the main structure of the mitotic spindle? A) actin filaments B) intermediate filaments C) keratin D) microtubules

During which of the following phases of the cell cycle does centriole replication occur? A) S phase B) G₁ phase C) prophase D) G₂ phase

In which type of cell do duplicated centrioles move to opposite poles, and during which part of the cell cycle does this occur? A) in a plant cell, during prophase B) in an animal cell, during prophase C) in a plant cell, during metaphase D) in an animal cell, during metaphase

In both plant cells and animal cells, where do the microtubles of the mitotic spindle originate? A) in the centromere B) in the organizing centres C) in the chromatid D) in the centriole

What is another term for an identifiable structure known as the microtubule organizing centre (MTOC) of an animal cell? A) a cell plate B) a centrosome C) a kinetochore D) a centromere

Which of the following terms is synonymous with restriction point? A) G₂ checkpoint B) G₁ checkpoint C) G₀ checkpoint D) S checkpoint

When does a cell commit to undergoing mitosis? A) once it transitions from S to G₂ B) once it transitions from G₁ to S C) once it transitions from G₁ to G₀ D) once it transitions from G₂ to prophase

What will happen in a cell if it becomes damaged by radiation or chemicals? A) It will not pass the G₂ checkpoint. B) It will not enter S from G₁. C) It will not synthesize cyclin-dependent kinases. D) It will not enter G₁ from mitosis.

Consider vinblastine, a chemotherapeutic drug used to treat breast and testicular cancers. This drug interferes with the assembly of microtubules. How does this drug most likely work to inhibit growth in a cancer cell? A) It inhibits transition from G₁ to S. B) It disrupts mitotic spindle formation, and consequently mitosis. C) It inhibits cytokinesis. D) It inhibits transition from S to mitosis.

What would happen if you add mitosis-promoting factor (MPF) to germinal cells in the skin arrested in G₂? A) Cell division would cease. B) The cells would enter prophase. C) The cells would undergo cytokinesis. D) Cell death would occur.

Suppose that, at the G₁-to-S checkpoint, one of the cyclins has reached a concentration great enough to complex with one of the CDKs to initiate DNA synthesis. Which cyclin and which CDK are the ones most likely involved? A) cyclin G₁/S and CDK2 B) cyclin G₁/S and CDK1 C) cyclin S and CDK2 D) cyclin S and CDK1

Which of the following regulates progression through the phases of the cell cycle? A) fluctuating concentrations of cyclin-dependent kinases B) fluctuating concentrations of microtubules C) fluctuating concentrations of cyclins D) fluctuating concentrations of actin

During which phase of the cell cycle is cyclin degraded, resulting in the transition to G₁? A) during interphase B) during metaphase C) during prophase D) during anaphase

Suppose that, at the G₂-to-M checkpoint, one of the cyclins has reached a concentration great enough to complex with one of the CDKs to initiate DNA synthesis. Which cyclin and which CDK are most likely involved? A) cyclin M and CDK1 B) cyclin S and CDK1 C) cyclin M and CDK2 D) cyclin S and CDK2

Signalling molecules, such as peptide hormones and growth factors, bind to receptors on the cell surface, which subsequently trigger reactions in the cell. Which of the following is among the reactions? A) causing cells to enter the G₀ state B) stopping cell division C) initiating cell division D) slowing the rate of cell division

Contact inhibition is an important mechanism for maintaining cell growth in developed organs and tissues. Suppose that the organ and tissue cells remain in contact with each other. In order to prevent the cells from dividing, which phase of the cell cycle must they be in? A) in G₁ B) in G₀ C) in G₂ D) in prophase

Which statement best explains contact inhibition? A) Contact between neighbouring cells triggers reactions that lead to inhibition of mitosis. B) As cell number increases, the level of waste products increases, consequently slowing metabolism and leading to mitosis. C) As cell number increases, the protein kinases they produce compete with neighbouring cells, thus inhibiting mitosis. D) As neighbouring cells become more tightly packed together, their size is restricted and cytokinesis can no longer occur.

Which of the following would be revealed by a comparison of a cancer cell and a normal cell? A) Regulation of mitosis is strictly regulated in cancer cells; mitosis is unregulated in normal cells. B) Cancer cells undergo contact inhibition; normal cells do not. C) Cancer cells do not undergo contact inhibition; normal cells do. D) Cancer cells cannot metastasize; normal cells can.

Which statement characterizes cancer cells? A) They form tumours that remain encapsulated, growing in only one location. B) They form tumours that adhere strongly to surrounding tissues. C) They display uncontrolled cell division. D) They display strictly regulated mitosis.

What are the two most likely reasons for cellular senescence (the loss of proliferative ability)? A) DNA damage and telomere lengthening B) DNA damage and telomere shortening C) DNA intactness and telomere shortening D) DNA intactness and telomere lengthening

What is the Hayflick factor responsible for? A) tissue senescence B) organ senescence C) organ system senescence D) cellular senescence

Which of the following is synonymous with cellular senescence? A) the loss of proliferative ability B) the gain of proliferative ability C) the gain of contact inhibition D) the loss of contact inhibition

Which of the following is synonymous with apoptosis? A) programmed cell life B) the loss of contact inhibition C) programmed cell death D) the gain of contact inhibition

Suppose that, once activated, an enzyme activates other enzymes in a cascade of events leading to apoptosis. Which of the following is this enzyme most likely? A) caspase B) cytokinin C) kinase D) roscovitine

Caspase is the main enzyme that controls apoptosis. Which family of enzymes does this enzyme most likely belong to? A) lipases B) proteases C) endonucleases D) ligases

What are oncogenes? A) genes that control contact inhibition B) genes that control apoptosis C) mutated genes that promote uncontrolled growth D) non-mutated genes that promote controlled growth

What is the purpose of cell division in living organisms?

What is the difference between a chromosome and a chromatid?

Compare spindle formation in animal cells with plant cells. How is this process different?

How is cell cytokinesis in plant cells different than cytokinesis in animal cells? Explain both.

Why are cancer cell lines, rather than normal cells, frequently used to study biological processes?

Identify the stage of mitosis in which each activity occurs. a.prophase b.prometaphase c.metaphase d.anaphase e.telophase -Sister chromatids are pulled to opposite spindle poles.

Identify the stage of mitosis in which each activity occurs. a.prophase b.prometaphase c.metaphase d.anaphase e.telophase -Nuclear envelope disappears.

Identify the stage of mitosis in which each activity occurs. a.prophase b.prometaphase c.metaphase d.anaphase e.telophase -Duplicated chromosomes condense into chromosomes.

Identify the stage of mitosis in which each activity occurs. a.prophase b.prometaphase c.metaphase d.anaphase e.telophase -Daughter chromosomes decondense and the nuclear envelope reforms.

Identify the stage of mitosis in which each activity occurs. a.prophase b.prometaphase c.metaphase d.anaphase e.telophase -Spindle fibre begins to form.

Identify the stage of mitosis in which each activity occurs. a.prophase b.prometaphase c.metaphase d.anaphase e.telophase -Mitotic spindle disassembles.

Identify the stage of mitosis in which each activity occurs. a.prophase b.prometaphase c.metaphase d.anaphase e.telophase -RNA synthesis shuts down.

Identify the stage of mitosis in which each activity occurs. a.prophase b.prometaphase c.metaphase d.anaphase e.telophase -Chromosomes align at the centre of the cell.

For each phrase, choose the most appropriate component of cell cycle regulation. Each component may be used once, more than once, or not at all. a.CDK b.cyclins c.CDK/cyclin complex d.SPF -levels fluctuate throughout the cell cycle

For each phrase, choose the most appropriate component of cell cycle regulation. Each component may be used once, more than once, or not at all. a.CDK b.cyclins c.CDK/cyclin complex d.SPF -levels remain constant throughout the cell cycle

For each phrase, choose the most appropriate component of cell cycle regulation. Each component may be used once, more than once, or not at all. a.CDK b.cyclins c.CDK/cyclin complex d.SPF -turns CDK on or off

For each phrase, choose the most appropriate component of cell cycle regulation. Each component may be used once, more than once, or not at all. a.CDK b.cyclins c.CDK/cyclin complex d.SPF -regulates cell division