Chapter 10
Which features vary among chromosomes?
size, staining properties, length of two arms, location of the centromere (a constriction found on all chromosomes)
What checkpoint ensures that all chromosomes are attached to the spindle?
spindle checkpoint
The group of proteins involved in the compaction and organization of bacterial DNA in the nucleoid is called _______________ maintenance of ________________, or SMC proteins.
structural / chromosome
The spindle apparatus is broken down during which phase of mitosis?
telophase
What is the final stage of mitosis?
telophase
What phase of mitosis is characterized by the reformation of the nuclear envelope and the production of two separate nuclei?
telophase
Telophase
the final phase of cell division, between anaphase and interphase, in which the chromatids or chromosomes move to opposite ends of the cell and two nuclei are formed.
During segregation of the duplicated bacterial chromosome, which part of the chromosome moves towards opposite ends of the cell first?
the origins of replication
Maximum compaction of the chromosomes occurs when solenoids are coiled around what?
the protein scaffold
Anaphase
the third phase of mitosis, during which the chromosome pairs separate and move toward opposite poles
During anaphase __________, sister chromatids are pulled toward opposite poles as their kinetochore microtubules which are attached to the poles are shortened.
A
During anaphase, two forms of movement take place simultaneously and as a result sister chromatids are pulled towards opposite poles of the cell. The two forms of movement are commonly referred to as anaphase ________ and anaphase _________.
A / B
The process of binary fission is the means by which __________ cells perform cell division.
Bacterial
DNA contained in a eukaryotic nucleus resembles what?
Beads on a string
In yeast, ___________________ is the gene necessary for cells to commit to DNA synthesis, and to commit to mitosis.
Cdc2
Cyclin is a regulatory protein that is necessary to activate what?
Cdk
The __________________ enzymes controls progression through the checkpoints in the cell cycle.
Cdk
Phosphorylation within the cell cycle is regulated by enzymes called
Cdks
_______________ are cellular structures, typically found in animal cells, which are replicated during the G2 phase. They are positioned at the poles of the cell and participate in the movement of chromosomes during mitosis.
Centrioles
The coiling of DNA around histone cores is the result of?
Electrostatic attraction between the negatively charged DNA molecule and the positively charged histone core.
True or false: cell division is complete at the end of mitosis?
False
The ________________ protein is necessary for septation and cell division in bacteria.
FtsZ
Two forms of cyclin have been found in organisms. Identify the peak times of these proteins.
G1/S boundary, G2/M boundary
Centrioles are replicated during which of the following phases?
G2
Condensation of chromosomes is initiated in the ______________ phase of interphase and continues until the end of prophase.
G2
What does cell division in bacterial and eukaryotic cells produce?
Genetically identical cells
How does activated G1/S Cdk act at the G1/S checkpoint?
It phosphorylates a number of targets
The pairs of sister chromatids align themselves in a single row along a plane half-way between the poles during which of the following phases of mitosis?
Metaphase
What is considered a checkpoint phase for the preparation of sister chromatids for cell division?
Metaphase
What is the correct chromosomal abnormality for each human embryonic condition: Monosomy, Trisomy ?
Monosomy: missing a copy of a chromosome. Trisomy: having an extra copy of a chromosome.
Is chromosome number related to organismal complexity?
No it is not. For example, silkworms have 56 chromosomes and humans, which are more complex organisms have 46 chromosomes.
In what cells does cytokinesis involve the formation of a cell plate?
Plant Cells
Bacteria cells divide to produce new cells for?
Population growth and reproduction
Order the steps in binary fission from first to last
(1) The bacterial DNA molecule replicates. (2) The cell elongates and the DNA is partitioned such that the origins are at the 1/4 and 3/4 positions in the cell. (3) Septation begins. (4) The cell pinches in two, forming two daughter cells.
What are the mechanisms that have been proposed to explain the force that moves chromosomes to the equator of the cell?
-Assembly and disassembly of microtubules. -Motor proteins located at the kinetochore & poles of the cell pulling on microtubules.
An unreplicated chromosome consists of _____________ double-stranded DNA molecule(s).
1
Order the steps in binary fission from first to last
1 - The bacterial DNA molecule replicates. 2 - The cell elongates and the DNA is partitioned such that the origins are at the 1/4 and 3/4 positions in the cell. 3 - Septation begins. 4 - The cell pinches in two, forming two daughter cells.
What is the diameter of a solenoid fiber?
30 nm
The diploid number of chromosomes for humans is?
46
The human cell contains a total of how many chromosomes?
46
Prometaphase
The second stage of mitosis, in which the nuclear envelope fragments and the spindle microtubules attach to the kinetochores of the chromosomes.
What decision does a cell have to make at the G1/S checkpoint of the cell cycle?
Whether or not to divide
During the ______________ of mitosis, the centromeres of sister chromatids split apart allowing sister chromatids to move away from each other.
anaphase
What is the shortest phase of mitosis?
anaphase
Cytokinesis in ________________ cells involves the formation of a cleavage furrow around the cell.
animal
During cytokinesis in plants, the newly formed cell plate is coated with ________________ to create two new cell walls. At this point the space between the two daughter cells is called the middle _________________.
cellulose / lamella
The three critical regulatory points found in the cell cycle of the eukaryotic cells are called _________________. (one word)
checkpoints
The separation of sister _______________ and the partitioning of ________________ material are the most significant events in mitosis.
chromatids / genetic
The separation of sister _________________ and the partitioning of __________________ material are the most significant events in mitosis.
chromatids / genetic
Centromeres occur at a specific location along a:
chromosome
During interphase of the cell cycle, the cell grows and copies which of the following in preparation for cell division?
chromosomes
During interphase of the cell cycle, what does the cell grow and copy in preparation for cell division?
chromosomes
The key event in anaphase is the removal of _______________ proteins from the centromeres of sister chromatids.
cohesin
The complex of proteins involved in the compaction of eukaryotic chromosomes onto protein scaffolds is called _________________. These proteins are evolutionarily related to the bacterial SMC that compact the nucleoid.
condensin
What is the complex of proteins involved in the coiling of solenoids?
condensin
In the cell cycle, a key issue is that the chromosomes must be properly replicated and sorted to new ______________ cells.
daughter
In an organism that is ____________, the members of a pair of chromosomes are called homologous.
diploid
In an organism that is ________________, the members of a pair of chromosomes are called homologous.
diploid
Cytokinesis
division of the cytoplasm to form two separate daughter cells
Which of the following is characteristic of the DNA fiber found within each chromosome?
double-stranded
During cell division in both bacterial and eukaryotic cells, genetic information is ________________ and segregated and the contents of the cell are divided between the daughter cells.
duplicated
During telophase, chromosomes uncoil to allow for gene __________________.
expression
Prophase
first and longest phase of mitosis, during which the chromosomes become visible and the centrioles separate and take up positions on the opposite sides of the nucleus
In animal cells, the cleavage ______________ pinches the cell until it is divided in two.
furrow
Cells, such as gametes, that contain one set of chromosomes are called _______ cells.
haploid
The type of chromatin which is not genetically expressed is called ____________, while the type of chromatin which is genetically expressed is called ____________.
heterochromatin / euchromatin
If an organism is diploid, the two members of a pair of chromosomes are called
homologues
If an organism is diploid, the two members of a pair of chromosomes are called __________________.
homologues
What chromosomes consist of two slightly different copies of the same chromosome?
homologues chromosomes
A replicated chromosome consists of two _______________ DNA molecules held together by a complex of proteins called cohesins.
identical
The particular array of chromosomes that an individual organism possesses is called its ________________?
karyotype
The centromere contains repeated DNA sequences that can bind specific proteins. These proteins form the ______________, which is shaped like a disc.
kinetochore
____________________ is the phase of the cell cycle when the cell divides into two equal halves.
Cytokinesis
The G1 and G2 checkpoints check for the damage of what?
DNA
The chromatin in eukaryotic chromosomes is composed of a complex of ________________ and protein.
DNA
A nucleosome is a complex of ________________and _________________ proteins.
DNA / histone
MPF is sensitive to chemicals that affect:
Delay replication and damage DNA
At the end of the ___________ phase, the replicated chromosomes are fully extended and uncoiled.
S
Replication of each chromosome and its centromere takes place during the _______________ phase to produce two complete DNA molecules.
S
After a chromosome is replicated, the two copies are referred to as _____________ _____________.
Sister chromatids
True or false: Bacterial cell division produces genetically identical daughter cells.
True
An organism is said to be diploid when its cells carry how many sets of chromosomes?
Two
The number of chromosomes in eukaryotic cells
Varies considerably between different species
During anaphase B, microtubules slide past each other pulling the poles anchored to them away from the center of the cell. At the same time, chromosomes are also pulled apart because
a different set of microtubules attaches the chromosomes to the poles.
What does an unreplicated chromosome contain?
a single DNA molecule
The FtsZ protein is necessary for bacterial cells to perform which of the following activities?
cell division, septation
Nuclear division occurs after ________________ is complete in most fungi and some protists.
mitosis
Cyclin plus cdc2 protein
mitosis-promoting factor (MPF)
The _____________ membrane does not break down before mitosis in most fungi and some protists, therefore mitosis occurs within the ______________.
nuclear / nucleus
The region in a bacterial cell where DNA is located is called the _____________.
nucleoid
In bacterial cells, the replication of DNA begins at a specific site called the ______________ of replication, and proceeds in both directions around the circular DNA until a specific ______________ site is reached.
origin / termination
In bacterial cells, the replication of DNA begins at a specific site called the _________________ of replication, and proceeds in both directions around the circular DNA until a specific _________________ site is reached.
origin / termination
What is the primary molecular mechanism of cell cycle control?
phosphorylation of proteins
Histone proteins are ________________ charged.
positively
During telophase, the changes made to the cell during _________________ are reversed.
prophase
What describe cyclins that are produced at different times in the cell cycle of sea urchin embryos?
proteins
Binary fission involves _______________ and partitioning of cells for cell division.
replication
Maximum compaction of the chromosomes occurs when chromatin fibers are coiled around a ______________ of proteins like the fibers of a wire brush.
scaffold
Maximum compaction of the chromosomes occurs when chromatin fibers are curled around a _________________ of proteins like the fibers on a wire brush.
scaffold
Metaphase
second phase of mitosis, during which the chromosomes line up across the center of the cell
