Chapter 12 Mastering Biology
cell divides, forming two daughter cells
f
During anaphase, the nonkinetochore microtubules _______________ and move past each other, and the kinetochore microtubules _______________ .
lengthen....shorten
Which of the following statements are true of cytokinesis in plant cells? Select the two that apply.
-- Vesicles from the Golgi apparatus move along microtubules, coalesce at the plane of cell division, and form a cell plate. -- The cell plate consists of the plasma membrane and cell wall that will eventually separate the two daughter cells.
eukaryotes only
-before separation duplicated chromosomes condense, -nuclear envelope fragments permitting chromosome separation -two copies of the duplicated chromosome are attached at their centromeres before separating
prophase:
-cohesions join sister chromatids of duplicated chromosome, - tubulins assemble into spindle microtubules
cells divide by construction of ring of protein
Bacteria- true animals- true plant- false
A human bone marrow cell, in prophase of mitosis, contains 46 chromosomes. How many chromatids does it contain? See Concept 12.1 (Page 236)
92
at this point, cell commits to go through the cycle
B
Tubulin or tubulin-like molecules function binary fission or cytokinesis.
Bacteria - true animals - false plants- true
DNA replicates
C
two centrosomes have formed
D
Which of the following is found in binary fission but not in mitosis? See Concept 12.2 (Page 242)
Duplicated chromosomes attach to the plasma membrane.
Which statement provides the best description of the interphase portion of the cell cycle?
During interphase, a cell is metabolically active.
If a eukaryotic cell is in the G1 phase of the cell cycle, which statement about the cell's chromosomes must be correct?
Each chromosome is made of a complex of DNA and associated proteins.
Cells will usually divide if they receive the proper signal at a checkpoint in which phase of the cell cycle? See Concept 12.3 (Page 244)
G1
Is the DNA condensed in all or part of this phase?
G1- no S-no G2-no Beginning of M-yes End of M-yes
Does the cell contain twice as much DNA in this phase as it did in the G1 phase?
G1- no S-yes G2-yes Beginning of M- yes End of M-yes
Are sister chromatid present in all or part of this phase?
G1-no S-yes G2-yes Beginning of M-yes End of M-no
Which of the following correctly matches a phase of the cell cycle with its description? See Concept 12.2 (Page 237)
G1: follows cell division
Spindle fibers attach to kinetochores during _____.
Prometaphase
Chromosomes become visible during _____.
Prophase
mitotic spindle begins to form
e
Which of the following is true of kinetochores? See Concept 12.2 (Page 240)
They are sites at which microtubules attach to chromosomes.
What is true of all cancers?
They have escaped normal cell cycle controls.
Why is it difficult to observe individual chromosomes with a light microscope during interphase? See Concept 12.1 (Page 235)
They have uncoiled to form long, thin strands.
Which of the following is true of benign tumors, but not malignant tumors? See Concept 12.3 (Page 248)
They remain confined to their original site
non- dividing cell exit cell cycle
a
non-dividing cells exit cell cycle
a
Centromeres divide and sister chromatids become full-fledged chromosomes during _____.
anaphase
The presence of a cell wall prevents the cell from dividing by contrition.
bacteria- false animals- false plants- true
After chromosomes condense, the____________ is the region where the identical DNA molecules are most tightly attached to each other.
centromere
The _____________ are the organizing centers for microtubules involved in separating chromosomes during mitosis.
centrosome
During interphase, most of the nucleus is filled with a complex of DNA and protein in a dispersed form called .________________
chromatin
Bacteria only
chromosome separation begins at the origin of replication on DNA
Which of these is NOT a carcinogen?
cigarette smoke UV light fat testosterone all of the above are carcinogens
anaphase:
cohesions break down, kinetochores move toward poles of cell
In most eukaryotes, division of the nucleus is followed by _____________, when the rest of the cell divides.
cytokinesis
During telophase, the nonkinetochore microtubules _______________
disassemble
Which of these phases encompasses all of the stages of mitosis but no other events?
e
_____ is a carcinogen that promotes colon cancer.
fat
both bacteria and eukaryotes
hromosomes replicate before cell division, replicated chromosomes separate by attaching to some other structural feature of the cell
During _____ the cell grows and replicates both its organelles and its chromosomes.
interphase
In dividing cells, most of the cell's growth occurs during ___________
interphase
Nucleoli are present during _____.
interphase
During mitosis, microtubules attach to chromosomes at the ___________________ .
kinetochore
metaphase:
kinetochores are motionless in relation to poles of cell
In some organisms, such as certain fungi and algae, cells undergo the cell cycle repeatedly without subsequently undergoing cytokinesis. What would result from this? See Concept 12.2 (Page 241)
large cells containing many nuclei
During prophase, the microtubules of the mitotic spindle _______________
lengthen
prometaphase:
microtubules attach to kinetochores
The ______________ is a cell structure consisting of microtubules, which forms during early mitosis and plays a role in cell division.
mitotic spindle(s)`
Will the chromosomes move to the poles of the cell?
no
DNA replication produces two identical DNA molecules, called _____________ which separate during mitosis.
sister chromatid(s),
telophase:
spindle microtubules disassemble
Cytokinesis often, but not always, accompanies _____.
telophase
During _____ both the contents of the nucleus and the cytoplasm are divided.
the mitotic phase
During prophase a homologous pair of chromosomes consists of _____.
two chromosomes and four chromatids
Will the sister chromatids separate from each other?
yes
Will this cell elongate during mitosis?
yes
