Reading...
Play button
Play button
Use LEFT and RIGHT arrow keys to navigate between flashcards;
Use UP and DOWN arrow keys to flip the card;
H to show hint;
A reads text to speech;
53 Cards in this Set
- Front
- Back
|
What are the 2 phases of the cell cycle?
|
Interphase and Mitosis
|
|
|
Gap1 (G1)
|
Start at the end of mitosis
longest and most variable stage G1 DNA Damage Checkpoint G1 restriction checkpoint evaluates replication potential |
|
|
S Phase
|
DNA Synthesis (Replication)
DNA is doubled new sister chromatids are formed replication of the centrosome S DNA damage checkpoint |
|
|
Gap2 G2
|
Cell prepares for division
Unreplicated DNA checkpoint prevents progression into mitosis before completion of DNA synthesis G2 DNA-damage checkpoint |
|
|
Mitosis
|
Karyokinesis and Cytokinesis
spindle assembly checkpoint prevents pre-mature entry into anaphase chromosome segregation checkpoint Cyclin B, CDK 1, APC |
|
|
What is the cell cycle driven by?
|
Proteins
cyclically synthesized and degraded |
|
|
Cyclin
|
Levels increase and decrease
|
|
|
Cyclin dependent kinase
|
Cdk levels remain fairly stable
kinase = phosphorylation Cyclin/CDK regulate cell cycle dependent functions |
|
|
Retinoblastoma protein
|
Tumor suppressor gene
inhibitor of cell cycle progression Binds gene regulatory protein E2F Cyclin gene regulation Cdk suppressor= CKI |
|
|
What will DNA damage activate at the checkpoints
|
p53
arrest cell cycle |
|
|
What does the G2 unreplicated DNA checkpoint do
|
Prevents progression until DNA replication is complete
Signal unknown, but results in inactivation of M cyclin/cdk |
|
|
M-Phase Spindle assembly checkpoint
|
prevents premature anaphase
|
|
|
P53 activation
|
Tumor suppressor gene
regulates gene transcription Mutations in p53 found in at least 50% of human cancers Initiation of apoptosis |
|
|
APC
Anaphase-Promoting Complex |
Separation of sister chromatids
degradation of securin Activation of separase Clevage of Cohesion complexes degradation of M-Phase Cyclin B |
|
|
Proto-oncogenes
|
Genes that can be converted into cancer promoting oncogenes by mutation
|
|
|
Tumor suppressor genes
|
Genes that prevent the formation of cancer
Loss of function mutations enhance susceptibility to cancer ex- p53 and Rb |
|
|
DNA damage in normal cells
|
cell cycle arrest by p53
DNA repaired Normal cell division or apoptosis |
|
|
DNA damage in cancer cells
|
No cell cycle arrest
lack of p53 Cell division with damaged DNA Continued mutation, selection, and tumor progression Increased genetic instability |
|
|
Telomerase
|
Enzymes that elongates telomere sequences in chromosomal DNA
most human cells lack some cancer cells are able to reactivate - chromosomes stabilized - progeny inherit highly abnormal chromosome set - continue to acquire new mutations driving tumor progression - possible metastasis |
|
|
Centromere
|
Centric heterochromatin
persists through interphase constricted region that holds sister chromatids together site of kinetochore formation |
|
|
Kinetochore
|
Large protein complex
forms near centromere attach chromosome to mitotic spindle |
|
|
The mitotic spindle consist of
|
Centrosomes
Microtubules - overlap - kinetochore - astral Motor proteins -Dynein - -Kinesin + |
|
|
Prophase
|
Beginning of Mitosis
condensation of replicated chromosomes mitotic spindle assembly Kinetochores form near centromeres |
|
|
Prometaphase
|
Breakdown of nuclear envelope
Chromosomes attach to mitotic spindle via kinetochores |
|
|
Metaphase
|
Chromosomes align at equatorial plate
Kinetochore microtubules motor proteins |
|
|
Anaphase
|
Sister chromatids separate
-each pulled to opposite poles |
|
|
Telophase
|
Sister chromatids arrive at opposite poles and decondense
reassembly of the nuclear envelope -completion of nuclear division assembly of contractile ring |
|
|
Cytokinesis
|
Division of the cytoplasm
furrowing of PM Creation of 2 daughter cells- Diploid 2n |
|
|
Non-Disjunction
|
A chromosome may fail to separate during anaphase
one daughter cell will receive both chromosomes and the other will receive none cells are considered aneuploid -often associated with cancer |
|
|
Deletion
Translocation Inversion |
Chromosome fragment lost
fragment attaches to another chromosome fragment attaches to same chromosome but orientation is reversed |
|
|
Polyploids
|
Whole sets of extra chromosomes
Triploids 3n Tetraploids 4n |
|
|
What lines the internal surface of the body
|
Epithelium tissue
avascular seperated from conn. tissue by basement membrane |
|
|
Simple Squmous Epithelium
|
single layer of flat cells
Lines blood vessels as endothelium pleural, peritoneal, and other serous cavitites as mesothelium compromises bowmans capsule |
|
|
Simple Cuboidal Epithelium
|
single layer of polyhedral cells that appear cuboidal in histological sections
Lines kidney, Follicles in the thyroid gland, ovary look for round nucleus |
|
|
Simple Columnar Epithelium
|
Consist of polyhedral cells
elongated into one plane line stomach, intestine and excretory ducts of many glands look for long narrow nucleus |
|
|
Stratified Squamous Nonkeratinized Epithelium
|
Several layers
superficial layer consist of flat nucleated cells Lines moist body surfaces such as mouth, esophagus and vagina |
|
|
Stratified Squamous Keratinized Epithelium
|
Several layers
Flattened superficial layers have lost their nuclei and become filled with keratin constitutes the epidermis |
|
|
Stratified Cuboidal Epithelium
|
2 or more layers
lines ducts of sweat glands |
|
|
Stratified Columnar Epithelium
|
Found in large excretory ducts of some glands and cavernous urethra
|
|
|
Pseudostratified Epithelium
|
Falsely stratified
every cell rests on the basal lamina but not all reach the lumen lines trachea, primary bronchi, excretory ducts in parotid gland |
|
|
Transitional Epithelium
|
Stratified epithelium whose superficial cells are domeshaped and bulge into the lumen
lines excretory passages in the urinary system |
|
|
Zona Occludens
|
Region where outer leaflets of adjacent plasma membranes fuse to form zone around entire apical perimeter of the cells
prevents entrance or exit of substances into the intercellular space from the lumen Tight junction |
|
|
Zona adherens (Intermediate junction, Belt Desmosome)
|
Intermediate Junction
Extends completely around the perimeter of the ep cells, just basal to zonula occludens adhesive and structurally supportive junction opposing plasma membranes are reinforced on their cytoplasmic surfaces by a mat of actin filaments Distinguished by the presence of the E-cadherins |
|
|
Macula Adherens (Desmosome)
|
Focal diskshaped adhesive junction between adjacent epithelial cells
dense plaque present keratin filaments loop in and out of the dense plaque intercellular space between 2 desmosomes has dense material and delicate striations representing transmembrane linkers |
|
|
Fasciae occludens
|
ribbon-like structures present in capillaries but do not extend around the entire cell
|
|
|
Gap junction (Nexus, communicating junction)
|
communicating junctions where ions and small molecules are permitted to pass between adjoining cells
plaque like specialization composed of an ordered array of subunits connexons in the opposing plasma membranes extend into the intercellular gap |
|
|
Lateral interdigitations
|
Fingerlike or irregular projections that interlock adjacent epithelial cells
|
|
|
Basal Surfaces
|
acellular supportive structure
2 layers Lamina Rare (Lamina Lucida) Lamina Densa produced by epithelium along with reticular lamina makes up basement membrane |
|
|
Hemidesmosomes
|
incomplete desmosome
attachment speacilization that has the appearance of one half desmosome present along the basal surface of cells in certain epithelium attaches to cells underlying the basal lamina ex- strat squam ep, myoepithelial in mammary gland, and salivary glands |
|
|
Basal plasma membrane infoldings
|
common specialization in ion transporting epithelia
deep invaginatins that compartmentalize mitochondria ion pumps are brought into close association with the energy supply (atp from mitochondria) |
|
|
Microvilli
|
fingerlike projections that extend into a lumen and increase the absorptive surface area
comprise the brush border of kidney proximal tubule cells and striated border of intestinal absorptive cells characterized by glycocalyx(sugar coat) on exterior surface, formed by terminal oligosaccharides of integral mem. proteins and phospholipids bundle of 30 actin extend from core of MV to terminal web of apical cytoplasm |
|
|
Stereocilia
|
not cilia
very long microvilli present in the epidermis and vas deferens of the male repo tract |
|
|
E-Cadherins
|
Transmembrane glycoproteins
Intracellularly, actin filaments form a meshwork that is attached to the E-cadherins by the other molecules |
