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Chapter 11: How Cells Reproduce
Multiplication By Division:
____________________: a series of events from the time a cell forms until its cytoplasm
divides
A typical cell spends most of its life in __________: interval between mitotic divisions
when a cell grows
During interphase, a cell roughly doubles the number of its __________
__________, and ______________________________
Three stages of interphase:
__________: cell is just going about its metabolic activities
__________: cells preparing to divide enter this stage and undergo DNA
replication
__________: protein need for cell division are synthesized
__________: process of nuclear division that maintains chromosome number
Mitosis and cytoplasmic division are the basis of:
________________________ (e.g., increases in body size and tissue remodeling)
____________________________________________________________
_________________________________ (offspring are produced by one parent)
Prokaryotes do not undergo mitosis because they have no __________
When a cell divides by mitosis, it produces ______________________________; each
with the same number and type of ____________________ as the parent
Human body cells are __________ (contain pairs of chromosomes)
Excluding the sex chromosomes, the chromosomes of each pair are
____________________: have the same length, shape, and genes
Distribution of the homologous chromosomes to descendant cells:
__________: chromosomes are ____________________, each cell contains 1
chromosome from father and 1 chromosome from mother. Together this paternal
chromosome and maternal chromosome form a ____________________.
__________: Each homologous chromosome in the cell is __________ during
DNA replication
__________: each chromosome consists of two double-stranded DNA molecules
called ____________________which are connected to each other at the
____________________
Now each _________________contains ___________________________
______________: maternal sister chromatid and paternal sister chromatid
During mitosis, the sister chromatids are ____________________and each
sister chromatids end up in ____________________that are packaged into
separate cells resulting in two cells each with a ____________________
Control Over the Cell Cycle:
Whether or not a cell divides is determined by mechanisms of _____________________
“Brakes” on the cell cycle normally keep the vast majority of cells in __________
During the cell cycle “________________” monitor progression and put the brakes on if:
____________________________________________________________
____________________________________________________________
____________________________________________________________
Sequence of Events During Mitosis
____________________:
Chromosomes are loosened to allow ____________________________________
Nuclear envelope is intact
____________________:
______________________________
DNA replication has been completed, ____________________have formed
Chromosomes begin to ____________________in preparation for nuclear
division
____________________begins to break up
____________________:
Chromosomes further____________________to point where they are now visible
under a light microscope
One of the two ____________________ move to the opposite end of cell
____________________ assemble and lengthen, from the centrosome, forming a
__________which will functions to move chromosomes during nuclear division
____________________breaks up completely
____________________are attached to opposite centrosomes via the spindle
projections
____________________:
All chromosomes are aligned ____________________ between spindle poles
____________________:
Sister chromatids __________ and move toward __________________________
____________________:
Chromosomes arrive at opposite spindle poles and ____________________
________________________________________
Eukaryotic Cellular Division:
In most eukaryotes, ____________________ (cytoplasmic division) occurs between late
anaphase and the end of telophase
______________________________: typical animal cells pinch themselves in two after
nuclear division ends
The spindle begins to disassemble during telophase
____________________drag the plasma membrane inward
______________________________ (indentation) forms and continues until the
cytoplasm is pinched in two
______________________________: dividing plant cells face a challenge because a cell
wall surrounds their plasma membrane
By the end of anaphase short microtubules form on either side of the future plane
of division
Disk-shaped structure called the ____________________forms and eventually
partitions the cytoplasm
The cell plate forms into ______________________________
The Function of Telomeres:
1997: geneticist Ian Wilmut and his team cloned the first mammal, a lamb named Dolly,
from an adult somatic cell. Although Dolly was healthy at first, she showed signs of
premature aging (arthritis, lung disease, etc.)
Dolly’s early demise may have been the result of abnormally ____________________
____________________ are noncoding repeat DNA sequences (repeated thousands of
times) found at the ends of eukaryotic chromosomes
Telomere sequences provide a ______________________of more valuable internal DNA
Typically, a eukaryotic chromosome shortens by about ____________________with
each DNA replication
When chromosomes contain telomeres that are too short, _________________________
____________________ halt the cell cycle and cell death soon follows
Most body cells can divide only a certain number of times before this happens, because
each time it divides its telomere becomes ______________________________
Telomeres-dependent cell division limits may protect against uncontrolled cell division,
keeping “____________________” cells from overrunning the body
Cell division limits vary by species and may set an organism’s ____________________
A few normal adult cells retain the ability to divide indefinitely, replacing cell lineages
that die out, these immortal cells are called ____________________
Stem cells continuously produce enzymes called ____________________ which reverse
the telomere shortening that normally occurs after DNA replication
Types of mutations that affect cell cycle:
________________________________________can cause the loss-of function of their
protein products which regulate cell cycle checkpoints
When enough checkpoint mechanisms fail, a cell loses control over its cell cycle and
unchecked ______________________________
Signaling mechanisms that cause abnormal cells to die may stop working
____________________: accumulation of abnormally dividing cells
____________________: neoplasm that forms a lump
______________________________: operates as a positive growth regulator and in
involved in promoting the growth and division of normal cells, if mutated protooncogenes become oncogenes
Proto-oncogene example: ____________________which are molecules that
stimulate mitosis and differentiation
____________________: mutated proto-oncogene that has the ability to transform a
normal cell into a tumor cell
Oncogene example: ______________________________whose overactivity
causes unchecked cellular division
Checkpoint gene products that inhibit mitosis are called ____________________
__________because tumors form when checkpoint gene products are missing
Examples: Tumor cells often have mutations in the BRCA1and BRCA2
checkpoint genes
HPV (human papillomavirus) cause cells to make proteins that interfere with
tumor suppressors
Cancer:
____________________neoplasms such as warts are not usually dangerous because of
slow growth, but a ____________________ neoplasm get progressively worse and is
dangerous to health
Characteristics of malignant cells:
________________________________________ (unchecked division, increased
vascularization)
__________________________________________________________________
________________________________________: process in which malignant
cells spread from one part of the body to another
____________________: disease that occurs when a malignant neoplasm physically and
metabolically disrupts body tissues
Mutations in ______________________________genes are required to transform a
normal cell into a malignant one, and such mutations may take a lifetime to accumulate
Lifestyle choices can reduce one’s risk of acquiring mutations
Some neoplasms can be detected with ______________________________such as
gynecology or dermatology exams, and if detected early enough, many types of
malignant neoplasms can be removed before metastasis occurs