AP Biology Chapter 12 Notes
centrioles
(animals) located at the centrosome center
How many chromosomes do bacteria have?
1
GO / NO GO enzymes
CDK, MPF, cyclins
What occurs first in binary fission?
DNA replication
WHY IS MITOSIS IMPORTANT?
TO DIVIDE THE NUCLEUS, NOT ASKING ABOUT THE ROLE OF THE MITOTIC CYCLE
chromosomes
a cellular structure consisting of one DNA molecule and associated protein molecules
binary fission
a method of asexual reproduction by "division in half"
mitosis
a process of nuclear division in eukaryotic cells divided into five phases
chemical cues for cell cycle
absence of essential nutrients, presence of growth factors (PDGF)
cell cycle
an ordered sequence of events in the life of a cell, from its origin in the division of a parent cell until its own division into two
late anaphase image
anaphase and not telophase because there is no cleavage furrow visible
How long does chromosome synthesis take?
anywhere between 2-12 hours depending on genetic material
aster
area that mitotic spindles come out of, array of microtubules, the centrosome extends from this
How are spindle fibers arranged?
between 2 centrosomes
How do all prokaryotic cells reproduce?
binary fission (asexual reproduction)
difference between benign and malignant
blood supply
somatic cells
body cells (any cell but a sex cell)
What is the common role of kinetochores and nonkinetochores?
both move the chromatids apart
How are checkpoints synchronized?
by rhythmic changes in protein kinases
mitotic cycle aka
cell cycle
G2 phase
cell disassembles cytoskeleton, begins formation of spindle proteins
What do single celled organisms do to reproduce themselves (protists)?
cell division, not bacteria (binary fission)
anaphase
centromeres divide, separating from the chromatids, forming individual chromosomes, the chromosomes are led by the centromere, the poles move apart (reason for this is unknown), spindle fibers pull apart but we don't know why
Each eukaryotic species has a ___ number of chromosomes in each cell's nucleus.
characteristic
two types of external cues for the cell cycle
chemical and physical
metaphase
chromatids align at the cell's midpoint aka metaphase plate, chromosomes appear to have an X shape (stiches), the nuclear envelope is completely gone, easiest to identify, two identical sister chromatids connected by centromere in the middle, centromere is a protein (magenet), kinetochore pulls centromere and thus chromatids apart
prophase
chromosomes become distinct, chromatids are joined by centromeres, nucleoli begin to disappear and nuclear membrane begins to break down
cytokinesis image
cleavage furrow visible, pinches inward
mitotic spindles
composed of microtubules, assembly begins in centrosomes
cleavage furrow
contractile ring of actin microfilaments, pinching inward
____ activate kinases
cyclins
Which phase differs in plant and animal cells?
cytokinesis (cytoplasmic division)
physical cues for cell cycle
density dependent inhibition, anchorage dependence
prometaphase
each chromatid forms a kinetochore, there are overlapping non-kinetochore microtubules that form, chromosomes move toward the middle
nonkinetochores
elongate cell
Checkpoints integrate....
external and internal information
What happens to plans in cytokinesis?
form a cell plate
What happens to animals in cytokinesis?
form a cleavage furrow
genome
genetic material of an organism or virus along with its noncoding nucleic acid sequences
Once the chromosomes replicate, the cell must
go through mitosis (nuclear division)
cell plate
golgi apparatus produces vesicles
G1 phase
growth, cell functioning as a normal cell, grows/expans, organelles replicate, preparing to go forward (has to decide if it wants to replicate chromosomes or not), GO or no go
How fast can DNA replicate in binary fission?
in 20 minutes
Which phase is the longest?
interphase (doubling everything)
What does the mitotic cycle alternate?
interphase and mitotic phase (mitosis)
two types of mitotic spindles
kinetochore and nonkinetochore microtubules
internal cues for the cell cycle
kinetochores cue M-phase checkpoint (identify the state of spindle attachment)
telophase
last phase of mitosis, nuclei form, nucleoli reappear, chromosomes coil into chromatin
What is the role of the proteins associated with DNA?
maintain the structure of the chromosome and help control the activity of the genes
image of checkpoints
maturation-promoting factor at G2 checkpoint
interphase
metabolic activity is high, organelles duplicating, cell size may increase, not dividing
What is the mitotic spindle composed of?
microtubules
M phase
mitosis and cytokinesis
meiosis (I & II)
modified type of cell division consisting of two rounds of cell division but only one round of DNA replication
regulation of the cell cycle
molecule control system drives the cell, consists of a set of checkpoints
anchorage dependence
need to be connected (desmosomes, gap junctions)
What type of mutation in a cell causes it to be a cancer cell?
nitrogenous base, translocation of chromosomes
How do cancer cells not respond to normal control mechanisms?
no density dependent inhibition, make their own growth factors, abnormal cell cycle, unusual number of chromosomes possible, aberrant metabolism, lost attachment to neighboring cells and to ECM
G0 phase
no go cells, cells that did not replicate chromosomes, sterile, won't make new cells, metabolically active ex: brain cell, some cells never progress past this phase, mitotically inactive
How does a cancer metastasize?
once it gets a blood supply (ups a stage)
each chromosome consists of...
one very long, linear DNA molecule associated with many proteins
centrosomes
opposite poles, separated by the spindle fibers, opposite sides of the cell (N, S, E, W)
telophase image
plant cell because cell plate is visible
phases of mitosis
prophase, prometaphase, metaphase, anaphase, telophase PRETTY PEOPLE MAKE ANGRY TIGERS
What molecule controls checkpoints?
proteins
role of cell division
reproduction, growth, and repair (tissue renewal)
gametes
sex cells, haploid reproductive cell
kinetochore microtubules
specialized microtubules (proteins), attach to the kinetochore
chromosome numbers are ____ specific
species
What does the mitotic spindle form?
spindle fibers
kinetochores
spindle fibers that attach to chromosomes, separate and organize chromosomes, protein located by the centromere
S phase
synthesis phase, occurs when DNA is replicated, all chromosomes replicate
cohesins
the attachment of two chromatids containing an identical DNA molecule along their lengths by protein complexes, "sister chromatid cohesion"
chromatin
the complexes of DNA and proteins that make up eukaryotic chromosomes, dispersed mass of long thing fibers not visible when the cell is not dividing
cytokinesis
the division of the cytoplasm to form two separate daughter cells immediately after mitotis or meosis I/II
arm of the chromatid
the portion of a chromatid to either side of the centromere
centromere
the region on each sister chromatid where it is most closely attached to the other chromatid by proteins that bind to the centromeric DNA
cell division
the reproduction of cells
density dependent inhibition
there is no room for more cells to grow in that space so they stop, too crowded in the cell
human somatic cell chromosome #
46
human gamete cell chromosome #
23
T/F: Nuclear division is the same as cellular division.
FALSE, cells can have multiple nuclei ex: skeletal muscle cells, a lot of plant cells
phases of interphase
G1, S, G2
T/F: Binary fission is similar to the cell cycle.
true
T/F: Daughter cells are clones.
true
T/F: Mitosis is well-ordered.
true
T/F: Some cells rarely divide.
true
an abnormal number of chromosomes indicates
tumors/genetic mutation if the cell is not killed
sister chromatids
two copies of a duplicated chromosome attached to each other by proteins at the centromere, make up one chromosome when joined
interphase vs. prophase image
visible condensing of chromosomes
