The DNA in a cell's nucleus contains
All the genetic information needed to generate any cell in any organism All the genetic information needed to generate any cell in its particular organism Only the genetic information needed to generate another cell in its particular organ system Only the genetic information needed to generate another cell of its particular histologic type, e.g. endothelial cell, squamous cell, glandular cell, etc Only the genetic information necessary to regenerate an exact copy of itself Nucleus Nuclear Envelope Nuclear Chromatin Nucleolus Function:
directs proteins synthesis via rRNA,mRNA, tRNA Nuclei are basophilic staining.
In H&E, the nuclei appear blue to black, depending upon the amount of chromatin condensation. Nuclei contain nucleic acids (DNA, RNA) and stain with basic dyes (such as hematoxylin). Nucleus Functions: Contains DNA Site of synthesis Messenger RNA (mRNA)
Transfer RNA (tRNA) Ribosomal RNA (rRNA) Nuclear envelope and nuclear pore complex Nuclear Lamina Functions: Maintenance of nuclear shape
Composed of lamins (a group of intermediate filaments) Functions: Maintenance of nuclear shape Spatial organisation of nuclear pores within nuclear membrane Regulation of transcription Anchoring of interphase heterochromatin DNA replication. Nuclear envelope and nuclear pore complex
Nuclear pores: Site where inner and outer layers fuse to form circular gaps with a diameter of 70 nm,bridged by a thin protein diaphragm. Nuclear pores allow some materials andinformation to pass through the nuclear membrane, such as mRNA and subunits of ribosomes. Nuclear envelope and nuclear pore complex- Freeze Etching.
Nuclear pores Transport across nuclear pore complex
Transport across nuclear pore complex dependent on size: Small molecules pass freely in either direction. Larger molecules pass by an active process, dependent on protein recognition. The nuclear membrane is
A single unit membrane Formed from the rough endoplasmic reticulum after cell division Visible on light microscopy Continuous with the outer cell membrane Without interruptions along the nuclear surface The nuclear lamina Extends throughout the cell's nucleus
Is primarily formed from microtubules Supports the chromatin, nuclear membranes and nuclear pores Is identifiable on light microscopy Appears only in the region surrounding the nucleolus Microvesicular transport
Ribosomal proteins and histones synthesized in the cytoplasm have been demonstrated to be incorporated into ribosomes in the nucleolus, or utilized within the nucleus, but without nuclear protein synthesis. Transport of large molecular size materials, such as these proteins through the nuclear pore complex occurs by what process Simple diffusion Selective transport Active transport Passive diffusion Microvesicular transport A mother brings her 7-year-old son to your office because of limited growth, baldness, and thick wrinkled skin. He has a history of prenatal growth retardation and the failure to thrive. On physical examination, you find short stature and low weight for height child with characteristic plucked-bird" appearance with small face and jaw, pinched nose, and diffuse signs of accelerated aging, including hypodontia, hearing loss, hypertension, cardiomyopathy, lipodistrophy, and atherosclerotic changes on the fundus oculi. His intelligence is normal.Stem:You conclude the patient has a rare disease caused by the disturbance in what? DNA repair Nuclear lamins Lysosomal storage Mitochondrial function DNA damage Disease- progeria, Sam berns
https://www.youtube.com/watch?v=36m1o-tM05g Disease- progeria, Sam berns Nucleolus Synthesis of rRNA and its assembly into ribosome
precursors; cell-cycle regulator proteins The Nucleolus (LM) Basophilic staining
LM: usually seen near the center of the nucleus Rich in rRNA Rich in protein More prominent in some cell types(active) than in other cell types(inactive) The purpose of the nucleolus is to
Synthesize ribosomal subunits Synthesize protein Synthesize DNA Synthesize messenger RNA Replicate viral DNA Large nucleoli within a cell's nucleus indicate That the cell is engaged in active protein synthesis That the cell is malignant That there is an approximately 50% chance that the cell is malignant That the cell is engaged in active DNA synthesis The term chromatin refers to
Nuclear DNA only Nuclear DNA and histone proteins All nuclear material All nuclear material that stains with basic dyes Complexes of DNA, histone proteins, and some non-histone proteins Chromatin Structural manifestation of chromosomes during interphase.
Basophilic, due to high DNA content. Composed of coiled strands of DNA and 2 types of basic proteins:histones and nonhistones. Chromatin Nucleosome, the basic structural unit of chromatin,consists of 4 types of histones (H2A, H2B, H3 and H4) and 166 DNA base pairs that wrap the histones. The DNA segment between adjacent nucleosomes contains 48 base pairs, and is bound to histones (H1 or H5). Chromatin Further coiling of chromatin fibres is responsible for different levels and types of packaging. This supercoiling is dependent on the non-histone chromosome proteins. (NHCP) Among the large variety of NHCP are two enzymes which control the supercoiling are topoisomerase II and topoisimerase I. Increased euchromatin indicates increased metabolic activity of cell
Exists in two forms during interphase: Euchromatin: extended chromatin. lightly basophilic. Genes readily available for transcription Heterochromatin: Condensed chromatin. Highly basophilic. 2 types: Constitutive: always condensed Facultative: sometimes condensed Typically cells have a mixture of both types of chromatin. Increased euchromatin indicates increased metabolic activity of cell Chromatin Basophilic. Contains genes and is responsible
for the synthesis of RNA. Two Types: Heterochromatin: appears as course granules. Densely stained and inactive. Euchromatin: lightly stained, visible as an organized structure only under EM. Active. Chromatin Heterochromatin and euchromatin A Barr body is A crystalloid lysosomal inclusion
An acidophilic, degenerated hepatocyte An indicator of a patient's genetic make-up The hallmark of an always-lethal genetic abnormality Found only in the extracellular space Chromatins are condensed into chromosomes during mitosis and meiosis. Chromatin A sex chromatin mass is frequently observed in female cells
due to the inactivation of the second X chromosome, which is usually inactive and present in clumps.- Barr bodies. A nucleosome is A DNA packaging unit found only in chromosomes during mitosis A DNA packaging unit found only in heterochromatin A DNA packaging unit found only in euchromatin The smallest unit of chromatin A complex of DNA and transcribed RNA DNA DNA Genetics DNA RNA Proteins Transcription Translation The cell in the attached photomicrographic image displayed between the two arrows is best described as being in what stage of cell division? Interphase Prophase Metaphase Anaphase Telophase The earliest readily appreciable event in cell division is
Dissolution of the nuclear membrane Condensation of the chromosomes Formation of the mitotic spindle Division of the mitochondria Replication of the centrioles Prophase is characterized by which event?
Alignment of the chromosomes along the middle of the cell DNA replication Separation of the chromatids The chromosomes become visible Re-establishment of the nuclear membrane