Chapter 3 & 4 Flashcards
Forms a selectively permeable barrier between the nuclear and cytoplasmic compartments
Nuclear envelope
It is the command center of the cell also contains the molecular Machinery to replicate the DNA and to synthesize and process all types of RNA
Nucleus
A narrow space that separates the two concentric membranes of the nuclear envelope
Perinuclear space
And organized meshwork of proteins which stabilizes the nuclear envelope
Nuclear lamina
Class of intermediate filament proteins that bind to the membrane proteins and associate with chromatin and non-dividing cells
Lamins
Inner and outer nuclear membranes are bridged at this
Nuclear pore complexes
Various core proteins of a nuclear pore complex
Nucleoporins
A sex chromatin
Barr Body
A basic protein that extensively packages DNA and chromatin
Histones
Hey structural units of DNA and histone which has a core of eight histones
(2 copies each of histones H2A H2B H3 and H4) around which is wrapped DNA with about 150 base pairs
Nuclesome
Each long DNA double helix with it’s associated proteins
Chromatid
Two chromatids held together by complexes of cohesion proteins
Chromosome
Barr bodies or gender chromatin permit gender to be determined microscopically in patients whose external sex organs do not permit as in ______________ & _______________
Hermaphroditism , pseudohermaphroditism
The presence of XXY chromosomes __________________ which causes testicular abnormalities and __________ ( absence of sperm)
Klinefelter syndrome, azoospermia
Contains pairs of chromosomes
Diploid
Although from different parents they contain forms ( alleles) of the same genes
Homologous
Stained chromosomal regions ( bands) that can be analyzed
Karyotypes
___________Is important for many prenatal diagnosis in which home is on analysis of cultured cells from the fetus or Amnion can detect certain genetic anomalies. as with karyotypes of adults, missing or extra chromosomes chromosome deletions or translocations are readily seen
Karyotyping
A spherical highly basophilic subdomain of nuclei in cells, actively making proteins
Nucleolus
Is the sequence of events that controls cell growth and division
Cell cycle
Is the longest part of the cycle begins immediately after mitosis and includes all preparations for DNA replication
G1 Phase
The period of DNA and histone syntheses
S Phase
A short phase where the cell prepares for division during mitosis
G2 Phase
Cell cycling is controlled by the sequential appearance of Cytoplasmic proteins the _________ which bind ______________
Cycling, cyclin-dependent kinases (CDKs)
Phosphorylate and activate the enzymes and transcription factors whose functions characterize each phase of the cell cycle
CDKs
When cell cycle activities may be temporarily or permanently suspended the cells are referred to as being in the ______ space
G0
The stages of mitosis
Prophase, metaphase, anaphase, telophase,cytokinesis
Occur in all tissues with rapid cell turnover they divide slowly in a asymmetric manner with one daughter cell remaining a stem cell and becoming committed toward differentiation
Stem cells
Cells committed to differentiate typically divide more rapidly than stem cells before slowing stopping division to differentiate
Transit amplifying or progenitor cells
Is the process by which two successive cells divisions produce cells gametes containing half the number of chromosomes found in somatic cells
Meiosis
Prophase of the fist meiotic division is a unique, extended period in which homologous chromosomes pair and undergo genetic recombination during the process called ______
Synapsis
Is the process by which redundant or defective cells are rapidly eliminated in a manner that does not provoke a local inflammatory reaction in the tissue
Apoptosis
Apoptosis involves a cascade of events controlled by the _______ family of proteins regulating the release of death-promoting factors from mitochondria
Bcl-2
Cytochrome c from mitochondria activates cytoplasmic Proteases called __________ which degrade proteins of the cytosol, cytoskeleton and cell membrane
Capases
Degrade all nuclear DNA
Endonucleases
Late In apoptosis the cell into many small _____________ that undergo ______________ by neighboring cells
Apoptotic bodies, phagocytosis
___________ typically follows damage to the DNA of proto-oncogenes and failure of the cells to be eliminated ________ growth can either be benign or malignant ( commonly called cancer)
Neoplastic proliferation, neoplastic
Certain mutants in the gene __________ are associated with a subtype of the disorder progeria which causes ______________ in this and other rare laminopathies the nuclear envelope is abnormal
Lamin A, premature aging
Many mitogenic growth factors for research are produced commercially from microorganisms or cells with recombinant DNA have important med uses ex. Include analogs of _________________
granulocyte colony-stimulating factor (G-CSF)
Many genes coding proteins important in the control of cell proliferation and differentiation are often called ________________
Proto-oncogenes
Changing in the structure or expressing of these can convert them to _____________ causing uncontrolled cell and a potential for cancer
Oncogenes
A type of cancer occurring in the eyes, usually in young children one form of the disease is inherited or familial. Lead to the discovery of the gene Rb, which blocks the cell cycle progression until a mitogenic stimulus arrives
Retinoblastoma