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- what was being looked at?
- what did he use?
- what was the objection?
- it existed in the late 1890s by a man named Golgi
- nerve cells
- a particular stain (silver stain)
- its an artifact (not really resolved until observed with EM until 1950
Cells have how many Golgi?
- which cells?
- at least one; others may have hundreds
- mature cells (plants and animals)
- RBC prob have it to begin with, but get rid of it
- animals tend to have more than plant cells
Appearance of Golgi
- cisterna (same that are found in ER) (flattened sacs)--> stacked
- no ribosomes
- different in size from one end to another (not as big)
What was another controversy concerning the Golgi?
- movement between organelles
- split between two models
What does movement within the Golgi depend on?
Steps in the synthesis of cholesterol showing hte location in the cell of the various enzymes
The two membrane-bound enzymes that have been __ and studied in detail are __ and __.
Enzymes embedded in the SER membrane have their active site where?
Where does the product end up?
- HMG-CoA reductase
- squalene synthesase
- in the cytosol of the SER
- in the cytosol
Conversion of cholesterol to steroid hormones in the adrenal cortex:
The intermediates of the biosynthetic pathways are __ to complete the appropriate transformations. Wherease all cells o the __ carry out the pathway to __, the formation of __ occurs int eh __, and __ and __ are made in the __ (regions demarcated by dashed lines).
- shuttled back and forth between organelles to compete the appropriate transformations
- adrenal cortex
- inner cortex
Where are mitochondrial enzymes?
in the matrix
Pathway for making steroid hormones in the adrenal cortex?
intermediates must go back and forth between organelles
What is the main function of the Golgi?
How would you figure it out?
Who was this done by?
- label with heavy metal stains or radioactivity (radioactive label)
- by Caro and Palade
Caro and Palade
- interested in what?
- what did they do?
- - 1950s
- - interested and knew proteins were being secreted
- - they exposed cells with radioactively labelled amino acids
- --- incubated sections in mix of radioactively labelled amino acids
What did the cells do?
What did Caro and Palade do in response?
- absorbed and carried on with cell processes
- they followed radioactivity= pulse-chase experiment
Explain the pulse-chase experiment.
wHAT WAS THE PROBLEM WITH THIS?
- pulse: expose cells to radioactive chemical
- - can vary the time
chase: vary time of chase period as well; radioactivity should move
problem with this: you can't see the radioactivity directly
Palade and Caro used a pulse period of what, and did what?
What did they see?
- 3 minutes, stained, and emulsified, and followed
- first saw grains in RER (proteins made in connection with the rough ER)
In the case of pancreatic cells, there are __. When they reach surface, then they're __.
- condensing vacuoles
- secretory vesicles
In a pancreatic cell, what is the pathway an amino acid takes from the RER to outside of the cell?
made in the RER--> transport vesicle--> Golgi cis network--> Golgi cis region--> medial region--> trans region--> Golgi trans network--> condensing vacuoles-->secretory vesicles (or zymogen granules)--> outside
How can protiens be modified?
- it continues in the Golgi (starts in the RER)
- - portions are more modified in the Golgi
How would you find out if glycosylation occurs in the Golgi?
Who was it done by? Where was it seen?
label the onosaccharides and find out where they end up
Neutri and Lablond
over the Golgi
The protein portion is made in the __, but most carbs are made in the __.
What else can you see?
- is the progression of the molecules
Another function of the Golgi?
- what can be done to follow it?
- can add phosphorus in the form of phosphate
- - radioactive phosphorus to see if it goes through
- - the one that is used is P32
What else can the Golgi add?
What has been shown in the end?
sulfate (detect by radioactive surfur)
- proteins go to the ER--> Golgi--> modified
- - P or S added to the Carb portion
Calcium is housed in the elaborate network of internal membranes that make up the __. When an impulse arrives by means of a __, it is carried into the interior of the fiber along hte membrane of the __ to the __. The __ of the __ open, releasing __ into the __. The binding of calcium ions to __ molecules of the thin filaments lead to other events and __.
- sarcoplasmic reticulum
- motor neuron
- transverse tubule
- calcium gates
- calcium ions
- contraction of the fiber