Zhong BIOL 1020 Chapter 12*

Both bacteria and eukaryotes

bacteria only, eukarytoes only, or both bacteria and eukaryotes? Replicated chromosomes separate by attaching to some other structural feature of the cell.

cleavage furrow

In animal cells, the ____ forms when a ring of microfilaments contracts, causing the parent cell to be pinched in two.

interphase

In dividing cells, most of the cell's growth occurs during ______.

cytokinesis

In most eukaryotes, division of the nucleus is followed by ____, when the rest of the cell divides.

Eukaryotes only

bacteria only, eukarytoes only, or both bacteria and eukaryotes? Two copies of the duplicated chromosome are attached at their centromeres before separating.

Eukaryotes only

bacteria only, eukarytoes only, or both bacteria and eukaryotes? Nuclear envelope fragments, permitting chromosome separation.

DNA replicates

c

yes

does the cell contain twice as much DNA in this phase as it did in the G1 phase? beginning of M (prophase -> early anaphase)

yes

does the cell contain twice as much DNA in this phase as it did in the G1 phase? end of M (late anaphase -> telophase)

prophase

during ____, chromatin fibers become discrete chromosomes

uncoiled

during interphase, chromatin fibers are in an _____ state

mitotic spindle begin to form

e

cell divides, forming two daughter cells

f

yes

does the cell contain twice as much DNA in this phase as it did in the G1 phase? S

centromere

A

sister chromatids

C

-formation of telophase nuclei

-synthesis of chromatids -spindle fiber formation -formation of telophase nuclei -nuclear envelope breakdown

prokaryotes, cytoskeleton

Binary fission occurs in ______, which do not have a ______.

a groove in the plasma membrane between daughter nuclei

A cleavage furrow is _____. -a groove in the plasma membrane between daughter nuclei -the space that is created between two chromatids during anaphase -a ring of vesicles forming a cell plate -the separation of divided prokaryotes

92

A human bone marrow cell, in prophase of mitosis, contains 46 chromosomes. How many chromatids does it contain? -46 or 92, depending on the portion of prophase examined -23 or 46, depending on the portion of prophase examined -23 -46 -92

centromere(s)

After chromosomes condense, the ______ is the region where the identical DNA molecules are most tightly attached to each other.

no

Are sister chromatids present in all or part of this phase? G1

yes

Are sister chromatids present in all or part of this phase? G2

yes

Are sister chromatids present in all or part of this phase? S

yes

Are sister chromatids present in all or part of this phase? beginning of M (prophase -> early anaphase)

no

Are sister chromatids present in all or part of this phase? end of M (late anaphase -> telophase)

kinetochores

As the spindle depolymerizes, the ____ appear to move along the spindle fiber, dragging the attached chromosomes with them.

prometaphase

Attachment of spindle fibers to kinetochores is one of the events of _____.

kinetochore

B

anaphase

Centromeres divide and sister chromatids become full-fledged chromosomes during _____.

-cleavage

Cytochalasin B is a chemical that disrupts microfilament formation. How would this interfere with cell division? -cleavage -binary fission -formation of the cell plate -formation of the mitotic spindle -DNA replication

-The cell plate consists of the plasma membrane and cell wall that will eventually separate the two daughter cells. -Vesicles from the Golgi apparatus move along microtubules, coalesce at the plane of cell division, and form a cell plate.

Cytokinesis in animal cells is accomplished by constriction of the cell along the plane of cell division (formation of a cleavage furrow). In plant cells, which have cell walls, a completely different mechanism of cytokinesis has evolved. Which of the following statements are true of cytokinesis in plant cells? Select the two that apply. -The cell plate consists of the plasma membrane and cell wall that will eventually separate the two daughter cells. -Vesicles from the Golgi apparatus move along microtubules, coalesce at the plane of cell division, and form a cell plate. -The plasma membrane of the parent cell grows inward, eventually joining with the cell plate. -After chromosome separation is complete, a network of microfilaments forms near the plane of cell division that will separate the two new cells.

cohesion proteins

D

sister chromatid(s)

DNA replication produces two identical DNA molecules, called ________, which separate during mitosis.

the mitotic phase

During _____ both the contents of the nucleus and the cytoplasm are divided. -mitosis -G1 -the mitotic phase -S -G2

interphase

During _____ the cell grows and replicates both its organelles and its chromosomes. -mitosis -interphase -S -cytokinesis -G1

anaphase

During ______, sister chromatids separate and daughter chromosomes migrate to opposite poles

chromatin

During interphase, most of the nucleus is filled with a complex of DNA and protein in a dispersed form called _____.

kinetochore(s)

During mitosis, microtubules attach to chromosomes at the ______.

2 chromosomes and 4 chromatids

During prophase a homologous pair of chromosomes consists of _____.

anaphase

During which phase of mitosis do the chromatids become chromosomes? -metaphase -anaphase -telophase -prophase

homologogous chromosomes

E

DNA and proteins

Eukaryotic chromosomes are composed of which of the following macromolecules? -DNA and RNA -DNA and phospholipids -DNA only -DNA and proteins

protein synthesis.

Except during the M phase, the DNA is extended, allowing its genes to be transcribed for ______.

Cancer cells may be immortal.

How do cancer cells differ from normal cells? -Cancer cells may be immortal. -Cancer cells trigger chromosomal changes in surrounding cells. -Cultured cancer cells exhibit anchorage dependence.

Plant cells deposit vesicles containing cell wall building blocks on the metaphase plate; animal cells form a cleavage furrow.

How is plant cell cytokinesis different from animal cell cytokinesis? -The contractile filaments found in plant cells are structures composed of carbohydrates; the cleavage furrow in animal cells is composed of contractile proteins. -Plant cells deposit vesicles containing cell wall building blocks on the metaphase plate; animal cells form a cleavage furrow. -Plant cells divide after metaphase but before anaphase; animal cells divide after anaphase. -The structural proteins of plant cells separate the two cells; in animal cells, a cell membrane separates the two daughter cells.

large cells containing many nuclei

In some organisms, such as certain fungi and algae, cells undergo the cell cycle repeatedly without subsequently undergoing cytokinesis. What would result from this? -large cells containing many nuclei -inability to duplicate DNA -a rapid rate of gamete production -division of the organism into many cells, -most lacking nuclei -a decrease in chromosome number

attachment of microtubules to kinetochores

In the cells of many eukaryotic species, the nuclear envelope has to disappear to permit which of the following events in the cell cycle? -condensation of the chromosomes -separation of the centrosomes -attachment of microtubules to kinetochores -DNA synthesis

G2

Measurements of the amount of DNA per nucleus were taken on a large number of cells from a growing fungus. The measured DNA levels ranged from 3 to 6 picograms per nucleus. In which stage of the cell cycle did the nucleus contain 6 picograms of DNA? -G0 -G2 -S -G1

alignment of chromosomes on the equator of the cell

Metaphase is characterized by ________. -cytokinesis -alignment of chromosomes on the equator of the cell -separation of sister chromatids -separation of the centromeres

shortening of microtubules

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? -elongation of microtubules -shortening of microtubules -formation of a cleavage furrow -nuclear envelope breakdown

-in the S phase of the cell cycle

Part complete Scientists isolate cells in various phases of the cell cycle. They isolate a group of cells that have 1 1/2 times more DNA than G1 phase cells. What is the most likely part of the cell cycle from which these cells were isolated? -in the G2 phase of the cell cycle -between the G1 and S phases in the cell cycle -in the M phase of the cell cycle -in the S phase of the cell cycle

promethaphase

Spindle fibers attach to kinetochores during _____.

the mitotic spindle

Taxol is an anticancer drug extracted from the Pacific yew tree. In animal cells, Taxol prevents microtubule depolymerization. Thus, Taxol stops mitosis by interfering with which of the following structures or processes? -centriole duplication -chromosome condensation -cytokinesis -the mitotic spindle

centrosome(s)

The ______ are the organizing centers for microtubules involved in separating chromosomes during mitosis.

mitotic spindle(s)

The _______ is a cell structure consisting of microtubules, which forms during early mitosis and plays a role in cell division.

cleavage furrow formation and cytokinesis

The drug cytochalasin B blocks the function of actin. Which of the following aspects of the animal cell cycle would be most disrupted by cytochalasin B? -cell elongation during anaphase -spindle attachment to kinetochores -cleavage furrow formation and cytokinesis -DNA synthesis -spindle formation

46

Typical human cells, e.g., normal skin cells, have ______ chromosomes.

23

Typical human cells, e.g., normal skin cells, have ______ pairs of chromosomes.

23

Typical human cells, e.g., normal skin cells, have ______ pairs of homologous chromosomes.

92

Typical human cells, if normal, have ______ chromosomes during anaphase in mitosis.

-They have escaped normal cell cycle controls

What is true of all cancers? -They have escaped normal cell cycle controls. -They are caused by chemical carcinogens. -They are inherited.

replication of the DNA

Which of the following does not occur during mitosis? -replication of the DNA -separation of the spindle poles -condensation of the chromosomes -spindle formation -separation of sister chromatids

replication of the DNA

Which of the following events occurs during interphase of the cell cycle? -condensation of the chromosomes -replication of the DNA -separation of the spindle poles -spindle formation

replication of the DNA

Which of the following events occurs during interphase of the cell cycle? -spindle formation -separation of the spindle poles -condensation of the chromosomes -replication of the DNA

They are sites at which microtubules attach to chromosomes.

Which of the following is true of kinetochores? -They are the primary centromere structures that maintain the attachment of the sister chromatids prior to mitosis. -They interdigitate at the cell's equator and then move apart, causing the cell to elongate. -They attach to the ring of actin along the cytoplasmic surface of the plasma membrane, causing the actin to contract to form the cleavage furrow. -They are sites at which microtubules attach to chromosomes. -They are located at the center of the centrosome; their function is to organize tubulin into elongated bundles called spindle fibers.

E

Which of these phases encompasses all of the stages of mitosis but no other events?

They have uncoiled to form long, thin strands.

Why is it difficult to observe individual chromosomes with a light microscope during interphase? -Sister chromatids do not pair up until division starts. -They have uncoiled to form long, thin strands. -They leave the nucleus and are dispersed to other parts of the cell. -The spindle must move them to the metaphase plate before they become visible. -The DNA has not been replicated yet.

non-dividing cells exit the cell cycle

a

Both bacteria and eukaryotes

bacteria only, eukarytoes only, or both bacteria and eukaryotes? Chromosomes replicate before cell division.

at this point, cell commits to go through the cycle

b

Eukaryotes only

bacteria only, eukarytoes only, or both bacteria and eukaryotes? Before separation, duplicated chromosomes condense.

bacteria only

bacteria only, eukarytoes only, or both bacteria and eukaryotes? Chromosome separation begins at the origin of replication on DNA.

the division of cytoplasm

cytokinesis involves...

telophase

cytokinesis often, but not always, accompanies...

two centrosomes have formed

d

no

does the cell contain twice as much DNA in this phase as it did in the G1 phase? G1

yes

does the cell contain twice as much DNA in this phase as it did in the G1 phase? G2

no

is the DNA condensed in all or part of this phase? G1

no

is the DNA condensed in all or part of this phase? G2

no

is the DNA condensed in all or part of this phase? S

yes

is the DNA condensed in all or part of this phase? beginning of M (prophase -> early anaphase)

yes

is the DNA condensed in all or part of this phase? end of M (late anaphase -> telophase)

interphase

nucleoli are present during...

false

true or false for animals? the presence of a cell wall prevents the cell from dividing by constriction

false

true or false for animals? tublin or tublin-like molecules function in binary fission (in bacteria) or cytokinesis (in plants and animals)

true

true or false for animals? cells divide by construction pf a ring protein

false

true or false for bacteria? the presence of a cell wall prevents the cell from dividing by constriction

true

true or false for bacteria? tublin or tublin-like molecules function in binary fission (in bacteria) or cytokinesis (in plants and animals)

true

true or false for bacteria? cells divide by construction pf a ring protein

true

true or false for plants? the presence of a cell wall prevents the cell from dividing by constriction

true

true or false for plants? tublin or tublin-like molecules function in binary fission (in bacteria) or cytokinesis (in plants and animals)

false

true or false for plants? cells divide by construction pf a ring protein

microtubules

what are mitotic spindles constructed from

Cancer cells can go on dividing indefinitely in culture if they are given a continual supply of nutrients

why are cancer cells "immortal"