TOB L1 Flashcards
Nucleosome comprises of
Histone protein and Chromosomes
What is in the nucleus
DNA, RNA and nucleoproteins
Types of nucleoproteins? Are they both positively charged?
Histone proteins and non histone proteins but only histone proteins are positive.
What are non histone proteins?
enzymes for the synthesis of DNA, RNA and other regulatory proteins.
types of Nuclear RNA
mRNA, tRNA and rRNA
what controls DNA transcription?
miRNA, smRNA, siRNA
electron dense area of the nuclei
heterochromatin
electron Lucent area of nuclei
Euchromatin
what small discrete mass is present in the inactivated X chromosome of females?
Barr body
what nuclear material is active in RNA synthesis?
Euchromatin
what do nucleosomes do?
control the uncoiling and expressions of the genes encoded by the DNA strand.
Acidic dye used for staining
Eosin
Is Haematoxylin acidic or basic
basic dye
What is present in muscular mucosal? where is it present?
Smooth muscle cells. GI tract
What is lamina propria?
layer of connective tissue that sits beneath the epithelium of mucous membranes
what has bilobed nuclear form
eosinophils (WBC)
What is present on the outer lipid bilayer of the nuclear envelope?
Endoplasmic reticulum with ribosomes on the cytoplasmic face
What is present on the intermembranous space of nuclear membrane?
lumen of the ER
what is present in the inner nuclear membrane?
nuclear lamina with intermediate filaments called lamins
what do the lamins in the nuclear membrane do?
link proteins and heterochromatin
what is in a nuclear pore
nuclear pore complex with 30 nucleoporins.
what do nuclear pores do
permit the exchange of metabolites, macromolecules and ribosomal subunits between nucleus and cytoplasm.
role of nucleolus
synthesis of rRNA and tRNA. Controls cell cycle and stress responses.
what is the region where ribosomal genes are found and how many chromosomes?
nucleolar organiser regions and 5.
transcription
copy of DNA to form a complementary pre messenger RNA
post transcription processing
excision of introns I (non coding regions) by (spliceosome)
snRNA + proteins
spliceosomes
Translation
mRNA + ribosomes to determine the specific amino acid sequence;.
ribozymes
RNA molecules which catalyze peptide bonds between amino acids.
difference between RER proteins and free ribosomal proteins
RER- exporting and integral membrane protein. (held by hydrophobic attraction) proteins form tertiary structure, intrachain disulphide bonds are formed and glycosylation takes place.
Free ribosomal proteins- proteins destined for the cytoplasm, nucleus and mitochondria. post translational modifications take place here.
what happens to damaged proteins
binds to ubiquitin and is taken by a proteasome(proteolytic enzymes).
what is synthesized in the SER
phospholipids and cholesterol
what is synthesized in the cytosol
fatty acids and triglycerides
what does cytochrome P450 do and where is it?
Detoxification of by-products, drugs and alcohol. metabolism of glycogen.
which cells have prominent SER
liver, adrenal glands and gonads ( for lipid synthesis)
passive diffusion
needs gradient and depends on the size and polarity.
facilitated diffusion
through protein carrier molecules- pores or particular ion. Eg: aquaporins
active transport
pumps. independent of electrochemical gradients. (Eg: Na-K ATPase pump).
Bulk transport
through vesicles
Different types of transportation across cell membranes
passive diffusion, facilitated diffusion, active transport, bulk transport and transmembrane signalling.
example of transmembrane signalling
neurotransmitters at nerve synapses bind to ion channels in the postsynaptic membrane.
antibody given for over-expression of Her2 (human epidermal growth factor type 2) in breast tissue
trastuzumab
how are RER proteins transported to the golgi
coated vesicles (coat protein complex II)
what happens to the proteins in the Golgi
addition of sugar residues.
how are proteins transported out of the Golgi
secretory vesicles and they fuse with SNAREs to get to their target membrane.
why is the Golgi unstained
lipids get dissolved during preparation.
acinus
a cluster of cells producing digestive enzymes
What role do porosomes play in the regulated secretion of digestive enzymes in the pancreas?
Porosomes form a transient opening in the plasma membrane through which secretory granules discharge their contents during regulated exocytosis.
How do secretory vesicles in pancreatic cells transport digestive enzymes to the plasma membrane for secretion?
Secretory vesicles are moved along microtubules toward the plasma membrane, where they dock and fuse with the membrane to release their contents.
