What tool is used to cut thin slices of s waxed specimen to put on a slide
Give a rough 5 point step by step for slide preparation and the most common stain
- Tissue is preserved
- Tissue is dehydrated
- Embedding with paraffin wax or epoxy
- Mounted on glass slide
Hematoxylin & eosin
What kind of charged particles react with hematoxylin and which with eosin?
A negative charged particle is often? while a positive charged is?
Hematoxylin is a (base/acid) and stains (purple/red) and has a (+/-) charge? What about eosin
- base, purple, +
- acid, red, -
5 types of microscopes
- Bright field (light)
- Fluoresent (follows fluorescently stained molecules)
- Phase contrsast (works on diffraction can see live)
- Confocal (scans at different planes to get 3D)
- Electron (uses short wave electron beams to get high mag and resolution)
What are the 2 types of electron microscopes
- Scanning - scans e- beam across specimen covered in heavy metal, makes 3D image
- Transmission - electromagnetically focused beam at high voltage scans through tissue, still needs heavy metal preparation
What is autoradiography
uses radioactive precursors on silver grains to localize cell components
What is meant by histochemical techniques
When specific enzymes activities are used to produce visible products at specific enzyme locations
What is immunohistochemistry
based on reaction between an antigen and antibody
Direct immunohistochemistry is? indirect?
- if cell or tissue antigen is detected directly by binding to primary antibody
- unlabled primary antibody is detected as bound by a labled secondary antibody
What is in situ hibridization
detect microscopically a specific gene or mRNA sequence using a labelled complementary probe
is tissue composed of only intracellular material?
NO extracellular as well
While many cells may appear similar in structure what could makre them behave very differently
Different receptors (ex. uterine smooth muscle compared to normal)
All tissues in the body are derived from what cells?
Stem cells or blastomeres during the first differentiation forming the inner cell mass
What is cytosol?
Fluid filling the cyytoplasm
in addition to organelles what else can be found in the cytoplasm of a cell
- inclusions (fat, pigment, carbs)
List 5 or so functions of the cell membrane
- Selective barrier
- Constant ion gradient
- Interactions with environment
Polar on one side and non polar on the other
What is the glycocalyx
Cell surface coating coming from extended lipids and glycoproteins
integral proteins vs peripheral proteins
- integral = directly incorporated into lipid bilayer
- peripheral = looser association with 1 of 2 membranes
Which type of membrane protein would be harder to extract, integral or peripheral
integral, would need to break the membrane essentially
What do you call a protein that spans the embrane multiple times
Multipass transmembrane protein
Are all proteins bound tightly in spot by the membrane?
No many are loose and active in the fluid mosaic membrane
give 3 ways proteins can become more anchored in spot in the membrane
- Cytoskeletal attachment
- tight junction attachment can solidify the structure
- Large enzyme complexes are kept on lipid raft of high cholesterol to decrease mobility
What jkind of molecules pass through the membrane through simple diffusion
Small lipophilic molecules
How do most ions get in pass the membrane (2)
ion channels or ion pumps
Channnel proteins would be what kind of membrane protein
osmosis would occur mostly through the use of what trans membrane protein
3 general types of endocytosis
- fluid phase endocytosis
- receptor mediated endocytosis
What is transcytosis
- if it simply engulfes and moves to other side of the cell and spills back out.
- Essentially transportation to the basolateral membrane
WHat two things often coat pits about to perform endocytosis
How do endosomes break what they engulf apart?
BY using ATP driven H pumps to acidify
Are most membrane receptors used for endocytosis reused? HOw do they break them from their ligand?
Yes through the acidicfication fo the endosome
WHat kind of cell would we mostly expect to see transcytosis in?
bulk movement of large molecules OUT of the cell is called?
Exocytosis is often caused by?
TRansient increase in Ca+
Which memebrane wpould we expect epithelial cells to do exocytosis at and what would this be classified as?
!!What are the two types of secretion!!
- Constitutive secretion - constamnt as soon as done being produced
- Regulated secretion - only released when appropriate signal comes
What is the process of membrane trafficking?
When a cell does endocytosis the memebrane shrinks as the membvrane becomes part of the vesicle, the opposite happens when exocytosis occurs
When a vacuole undergoes further invagination and gets a subpopulations of vesicles within it we call this? When they merge with lysosomes what happens? When this vacuole undergoes exocytosis what will happen
- multi vesicular bodies
- Selective dregradation
- Small exosomes will be released (packets)
What are gap junctions
Direct channels with which cells can communicate through without ever reaching the ECM
what are 5 kinds of route signal molecules can take to get to their receptors
- Endocrine - carried by blood
- Paracrine - metabolized quickly so only act on very local cells
- Synaptic - special kind of paracrine used in synapses
- autocrine - signals bind receptors on the same cell type that produced the message
- juxtacrine - signal molecules remain part of the membrane and bind their receptor when the 2 cells make physical contact (mostly used in early embryonic development)
hydrophilic signalling molecules receptors are mostly?
transmembrane proteins found in the plasmalemma
!!!what are 3 important functional classes of receoptors?!!!
- Channel linked receptors - open upon binding to allow ions to transfer
- Enzymatic receptor - ligand binding induces catalytic activity in associated peripheral proteins
- G-protein coupled receptors - ligand binding changes the associated g p[rotein that then binds GTP and is released to activate other cytoplasmic proteins in a chain reaction
Signal transduction is?
Actiovation of a series of intermedieraires to move a message
Hydrophobic signaling molecules do what to move through the blood?
BInd to carrier proteins to move through plasma
What is different about hydrophobic signaling molecules and why can they do this to enter?
- THey diffuse through the membrane to their receptor
- Because they are hydrophobic just the inside of the membrane
often hydrophobic hormones will bind to what?
DNA to induce or stop transcription
Ribosomes do what?
Ribosomes are formed where
partially in the nucleaus and in the cytoplasm however assembled in the nucleus
Ribosomes work on what substrate primarily? Can multiple ribosomes work on one?
Why do areas stained heavily blue with hematoxylin indicate an area of active protein synthesis
- polyribosomes are intensely basophilic because of the phosphate groups on the RNA core.
- they act as polyanions thus attracting basic dyes
What are the channels and sacs of the ER called?
IS the membrane surface of the ER bigger or smaller than the cell membrane? Where does it stretch from?
- Yes 30X bigger
- From nucleus to the cell membrane
functions of the ER?
- Biosynthesis of the proteins ands lipids
- modification and delivery of proteins
2 types of ER
Smooth and rough
Rough ER have ribosomes on them, when they produce proteins where does the chain go to?
IT is secreted as its made into the ER cisterna
RERmain functions include
synthesis and segregation of proteins not destined for cytosol
RER looks like
sac like or parralell stacks of flattened cisternae
Both chaperones and enzymes are found in the RER
What is a signal sequence? What protein binds the newly translated signal sequence? What does it do
- first part on the 5 prime end of the mRNA that starts translation
- Signal-recognition particle
- binds the newly forming polypeptide to the translocator complex which allows the polypeptide into the lumen of the RER
is the smooth ER continuous or separate from the RER
Continuous, just the sections with no ribosomes
How can you best see the SER? RER?
- Light microscope with hematoxylin stain
What are some main functions of the SER
- temporary Ca2+ sequestration
- phospholipid synthesis
What is the specialized form of the SER in muscle cells and what is its specialized function?
- Sarcoplasmic reticulum
- Sequester and control the release of Ca2+