Chapter 9 Flashcards
The continuity of life is based on?
cell division
Cell division enables multicellular eukaryotes to develop from a _____ and once fully grown to ____, ___, or, ___
single cell, renew, repair, replace cells
cell division is an integral part of the?
cell cycle
cell cycle
the life of a cell from its formation to its own division
Most cell division results in?
genetically identical daughter cells
all DNA in a cell constitutes?
the cells genome
DNA molecules in a cell are packaged into?
chromosomes
Eukaryotic chromosomes consist of?
chromatin
chromatin
complex of DNA and Protein
somatic cells have ___ chromosomes
46
somatic cells are _____ and gametes are ____.
nonreproductive, reproductive
gametes have ___ chromosomes
23
When a cell is not dividing, each chromosomes is?
a long, thin chromatin fiber
Each duplicated chromosome has?
2 sister chromatids
sister chromatids
joined copies of the original chromosomes
Centromere
where the two chromatid are most closely attached.
Once separated, the chromatids are considered?
individual chromosomes
Eukaryotic cells division consists of?
mitosis and cytokinesis
mitosis
distribution of chromosomes into two daughter nuclei.
mitosis only occurs if you have?
a nucleus
cytokinesis
the division of the cytoplasm producing two daughter cells
Meiosis yields?
non identical daughter cells
daughter cells from meiosis have only ___ sets of chromosomes.
1
The cell cycle consists of?
-mitotic phase
-interphase
Mitotic phase includes?
mitosis and cytokinesis
Interphase includes?
cell growth and copying chromosomes in prep for cell division
Interphase subphases
-G1 phase
-S phase
-G2 phase
Mitosis is divided into 5 stages
-prophase
-Prometaphase
-Metaphase
-Anaphase
-Telephase
G1 phase
metabolic activity and growth
G2 phase
metabolic activity, growth, and preparation for cell division
S phase
metabolic activity, growth, and DNA synthesis
Miotic phase includes?
mitosis and cytokinesis
Prophase
Chromosomes condense and become visible, the nuclear membrane begins to break down, and the spindle apparatus starts to form
Prometaphase
Microtubules from the spindle fibers attach to the centromeres of the chromosomes.
Metaphase
Chromosomes line up along the equator of the cell.
Anaphase
Sister chromatids of each chromosome separate and are pulled to opposite poles of the cell.
Telophase
Two new nuclear membranes form around the separated chromosomes, and the cell begins to divide into two daughter cells
miotic spindle
structure made of microtubules and associated proteins
what does the miotic spindle do?
controls chromosome movement during mitosis
In animal cells, assembly of spindle microtubules begins in?
the centrosome
centrosome
Type of microtubule organizing center
Kinetochores
protein complexes that assemble on section of DNA at centromeres
metaphase plate
imaginary structure at the midway point between the spindle’s two poles
In anaphase, _______ and ___ the kinetochore microtubles toward ____.
chromatids separate, move along, opposite ends of the cell
Cytokinesis begins during _____ and the _____.
anaphase or telophase, spindle eventually disassembles
In animal cells, what forms during cytokinesis?
clevage
cleavage furrow
shallow groove in the cell surface
In plant cells what forms during cytokinesis?
cell plate
binary fission
How prokaryotes perform cell division
In bacteria, ___ beginning at the ___.
the single chromosome replicates, origin of replication.
The frequency of cell division varies with?
the type of cells
The cell cycle is driven by ____ present in ____.
specific signaling molecules, the cytoplasm
The sequential events of the cell cycle are directed by?
distinct cell cycle control system
cell cycle control system is similar to?
control device of a washing machine
The clock has specific ____ where the cell cycle ___.
checkpoints, stops until a go-ahead signal is received.
Which checkpoint is the most important?
G1
G0 phase
nondividing state due to not receiving a go-ahead signal.
cyclins
set of regulatory proteins and protein complexes.
example of cyclins
kinases and proteins
Attachment of all the kinetochores activates ___ which then activates ___
a regulatory complex, enzyme seperase
Examples of external signals
growth factors, density-dependent inhibition
growth factors
proteins released by certain cells that stimulate other cells to divide.
density-dependent inhibition
crowded cells stop dividing
Most animal cells exhibit ___?
anchorage dependence
anchorage dependence
cells must be attached to something inside a culture flask or extra cellular matrix of a tissue in order to divide.
What do cancer cells not exhibit?
density-dependent anchorage nor anchorage dependence.
Cancer cells do not?
respond to signals that normally regulate the cell cycle.
Transformation
cells in culture that can divide indefinitely
benign tumor
abnormal cells remain only at the original site.
malignant tumors
abnormal cells invade surrounding tissues and undergo metastasis
metastasis
cancer cells go to other parts of the body and form additional tumors.
What is used to treat known or suspected metastatic tumors?
chemotherapy
