Term
| nuclear material organized as euchromatin or heterochromatin. It contains DNA associated with roughly equal mass of various nuclear proteins |
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Definition
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Term
| small area within nucleus that contains DNA in form of transcriptionally active active rRNA genes, RNA, and proteins. where rRNA synthesis occurs |
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Definition
| nucleolus (it is involved in regulation of the cell cycle) |
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Term
| bilayer membrane around nucleus that has nuclear pores and is usually continuos rER |
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Definition
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Term
| nuclear content other than chromatin and nucleolus |
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Definition
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Term
| disappearance of of nuclei due to complete dissolution of DNA by increase activity of DNAase |
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Definition
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Term
| condensation of chromatin leading to shrinkage of the nuclei (they appear as basophilic masses) |
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Definition
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Term
| fragmentation of nuclei (these changes usually are preceded by pyknosis) |
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Definition
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Term
| proteins important to formation of chromatin |
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Definition
| histones (5different types) plus nonhistone proteins |
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Term
| highly condensed chromatin, dark staining part of nucleus due to phosphate groups of DNA...normally found in metabolically inactive cells such small circulating lymphocytes, sperm, or cells that make one major product such as plasma cells |
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Definition
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Term
| where most transcribed genes are located and lighter stained part of nucleus...dispersed form of chromatin...active transcription of DNA here...usually seen in neurons and liver cells |
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Definition
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Term
| found at the periphery of the nucleus |
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Definition
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Term
| discrete bodies of chromatin irregular in size and shape that are found through out the nucleus |
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Definition
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Term
| chromatin found associated with the nucleolus |
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Definition
| nuclear-associated chromatin |
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Term
| What dyes can stain heterochromatin for light microscopes? |
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Definition
1) hematoxylin
2) Feulgen procedure
3) fluorescent vital dyes such as Hoechst dyes and propidium iodide |
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Term
| smallest unit of chromatin structure are molecular complexes of DNA and histones |
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Definition
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Term
| core of the nucleosome made by 8 histone molecules |
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Definition
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Term
| each chromosome is formed by two of these (a), which are joined together at this point (b) |
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Definition
(a) chromatids
(b) centromere |
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Term
| area at the end of each chromosome |
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Definition
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Term
| What enzyme adds repeated nucleotide sequences to the telomere ends, usually found in malignant cells...although expression of this can extend the lifespan of the cell |
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Definition
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Term
| Of the 46 homologous paris of chromosomes 2 are sex chromosomes and the others have an identical chromosome pair, this group of 44 is called? |
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Definition
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Term
| What test is useful for prenatal screening for genetic disorders including nondisjunctions, transpositions, deletions, and duplications plus for fetal determination of sex. |
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Definition
| karyotype- this is when chromosomes are sorted according to their size and shape, and emitted fluorescent color |
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Term
| When a chromosome is repressed in the interphase nucleus and exist only in tightly packed heterochromatic form. What is this called? What chromosome is this usually? And how does it appear? |
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Definition
1) Barr body
2) X chromosome in females (one of two)- can be used to determine fetus sex
3) appears as a drumstick next to one of the nuclear lobes |
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Term
| What are the three morphologically distinct regions of the nucleolus and describe them? |
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Definition
1) Fibrillar centers- contain DNA loops of five different chromosomes (13,14, 15, 21, 22) that contain rRNA genes, RNA polymerase I, and transcription factors
2) Fibrillar material (pars fibrosa) contain ribosomal genes that are actively undergoing transcription and large amounts of rRNA
3) Granular material (pars granulosa)- represents the site of initial ribosomal assembly and contains densely packed preribosomal particles |
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Term
| network formed by the granular and fibrillar materials |
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Definition
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Term
| What is a newly identified protein found in the nucleolus, it is a p53 binding protein that regulates the cycle and influences cell differentiation. How is this protein relevant clinically? |
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Definition
| nucleostemin...its presence in malignant cells suggests it plays a role in uncontrolled cell proliferation |
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Term
| Viruses target this part of the cell to favor viral transcription and translation and also perhaps alter the cell cycle to promote viral replication |
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Definition
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Term
| Does Feuglen dye the nucleolus? |
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Definition
| No, so when examined in a light microscope appear Feuglen negative with a positive nucleus around it |
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Term
| when part of a chromosome breaks off and attaches to another chromosome |
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Definition
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Term
| What is formed by intermediate filaments and lies adjacent to the inner nuclear membrane |
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Definition
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Term
| How can the mitotic activity of a cell be assessed? |
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Definition
| by the number of mitotic metaphases visible in a single high-magnification light microscopic field or by autoradiographic studies of the incorporation of tritiated thymidine into newly synthesized DNA before mitosis |
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Term
| What consist of cells that no longer divide (postmitotic cells)? Give me some examples. |
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Definition
| static cell population, such as cells of central nervous system, skeletal and cardiac muscle cell. exception is cardiac myocytes may enter mitotic division |
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Term
| What consist of cells that divide episodically and slowly to maintain normal tissue or organ structure. Give me some examples |
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Definition
| stable cell populations, such as periosteal and perichondrial cells, smooth muscle cells, endothelial cells of blood vessels, and fibroblasts of connective tissue |
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Term
| What may be slowly or rapidly renewing but display regular mitotic activity? |
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Definition
| Renewing cell populations...typically division results in two daughter cells that differentiate both morphologically and functionally |
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Term
| What population include smooth muscle cells of most hollow organs, fibroblasts of the uterine wall, and epithelial cells of the lens of the eye? |
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Definition
| slowly renewing populations- they may slowly increase in size during their lifetime |
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Term
| What include blood cells, epithelial cells and dermal fibroblasts of the skin, and the epithelial cells and subepithelial fibroblasts of the mucosal lining of the alimentary tract? |
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Definition
| rapidly renewing populations |
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Term
| What are the 5 main phases of the cell cycle? |
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Definition
1) interphase- continuous growth of the cell
2) M phase-(mitosis) - partition of the genome
3) G1 phase (Gap 1)
4) S phase (synthesis)
5) G2 phase (Gap 2) |
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Term
| What phase is usually the longest and most variable of the cell cycle? And what are two of the checkpoints? |
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Definition
G1 phase-regulated by...
1) restriction checkpoint- sensitive to size of cell
2) G1- DNA checkpoint- if there is high amount of tumor supressing protein p53, apoptosis should occur
checkpoints are monitored by retinoblastoma susceptibility protein (pRb) and essential transcription factors (E2F) |
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Term
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Definition
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Term
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Definition
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Term
What is another name for Lamin associated proteins?
Give me som examples |
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Definition
Laminopathies
Hutchinson-Gilford progeria syndrome (HGPS)
Dilated cardiomyopathy
Familial partial lipodystrophy
Emery-Dreifuss muscular dystrophy (EMD1)
Limb-girdle muscular dystrophy
Charcot-Marie-Tooth disease
Mandibuloacral dysplasia |
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Term
What nuclear sequence is this?
*Analysis of large (>50 Kda) nuclear proteins revealed the presence of a common stretch of amino acids
- Basic amino acid rich sequence
- Lys-Lys-Lys-Arg-Lys: optimal core consensus
*These sequences were judged to be required for nuclear import, if they are mutated they will no longer direct a protein into the nucleus |
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Definition
| Nuclear Localization Sequence (NLS) |
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Term
| A protein with the NLS sequence is bound by what protein molecule in order to bring it into the nucleus? |
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Definition
| importin alpha/beta complex |
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Term
| What a.a. is frequently seen in the export sequence of a protein that is destined to be sent out of the nucleus? |
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Definition
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Term
| How can you visualize sub-nuclear bodies? |
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Definition
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Term
sub-nuclear bodies
speckles are? 1
Cajal bodies are? 2
PML bodies are? 3 |
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Definition
1- RNA processing centers
2- possible splicing centers/RNA processing/associate with nucleolus
3- protein repositories |
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Term
The outer membrane is continuous
with the endoplasmic reticulum
System |
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Definition
| nucleus (nuclear envelope) |
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Term
| Underlying the nuclear envelope a mesh-work of filaments |
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Definition
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Term
| Provides underlying structure to the nucleus |
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Definition
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Term
| What are two Lamin Associated proteins? |
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Definition
1. Inner-nuclear membrane proteins- tether to the nuclear envelope
2. DNA binding proteins- tether to chromatin |
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Term
Involved in passage of nuclear and cytosolic molecules
Free diffusion of small molecules (proteins <50 Kda)
Active transport of larger molecules (Export/Import) |
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Definition
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Term
| Protein with the NLS sequence will be bound by this protein before entering the nucleus |
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Definition
| Importin alpha/beta complex |
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Term
| transport factors involved with the nuclear pores and importing of protein |
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Definition
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Term
| What protein binds to the face of the pore? |
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Definition
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Term
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Definition
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Term
| What is the consensus sequence of the NES? |
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Definition
| Leu-X1-2-Leu-X2-3-Leu-X-Leu (X=any amino acid) |
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Term
| Which Histone proteins help form the octamer? |
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Definition
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Term
| Which histone is a linker between octamers? |
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Definition
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Term
In Euchromatin:
DNA CpG is (1)
Histones are (2)
Histones H3: Lysine 9 is (3) |
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Definition
1) hypomethylated
2) hyperacetylated
3) unmethylated |
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Term
In Heterochromatin:
DNA CpG is (1)
Histones are (2)
Histones H3: Lysine 9 is (3) |
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Definition
1) hypermethylated
2) hypoacteylated
3) methylated |
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Term
| These proteins activate the CDK and oscillate throughout the cell cycle (cycles) |
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Definition
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Term
| Starting in G1 phase going to S, then G2 and finally M, what cyclins peak at these times? |
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Definition
Cyclin D
Cyclin E
Cyclin A
Cyclin B |
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Term
This protein is...
*protein present throughout the cell cycle
*requires binding of cyclin for activity |
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Definition
| CDK (Cyclin Dependent Protein) |
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Term
What stage of Meiosis is...
Chromosomes not discernible
Nuclear envelope
G1, S, G2 Microscopically similar |
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Definition
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Term
What stage of Meiosis...
Chromosomes become discernible
Nuclear envelope breaks down |
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Definition
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Term
What stage of Meiosis has...
Chromosomes line up on metaphase plate
Mitotic Spindle (microtubules) apparent |
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Definition
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Term
What stage of Meiosis has...
Sister chromatids separate “Pulled” along spindle |
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Definition
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Term
What stage of Meiosis has...
Chromatids are in separate poles
Cleavage furrow apparent
Cytokinesis: actin-driven process |
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Definition
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Term
What
*Allows detection of chromosome from DNA-sequence
*Fluorescently labeled piece of DNA
*Hybridize with the chromosome spread |
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Definition
| FISH (Fluorescence in situ hybridization) |
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