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P face

P face --> freeze fracture

method of specimen preparation for the electron microscope in which rapidly frozen tissue is cracked so as to produce a fracture plane through the specimen. The surface of the fracture plane is then shadowed by heavy metal vapour, strengthened by a carbon film and the underlying specimen is digested away, leaving a replica that can be picked up on a grid and examined in the transmission electron microscope. The great advantage of the method is that the fracture plane tends to pass along the centre of lipid bilayers and it is therefore possible to get en face views of membranes that reveal the pattern of integral membrane proteins. The e face is the outer lamella of the plasma membrane viewed as if from within the cell, the p face the inner lamella viewed from outside the cell. Fracture planes also often pass along lines of weakness such as the interface between cytoplasm and membrane, so that outer and inner membrane surfaces can be viewed. Further information about the structure can be revealed by freeze etching. Extremely rapid freezing followed by deep etching has allowed the structure of the cytoplasm to be studied without the artefacts that might be introduced by fixation.


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Hypothetical question about vampires

... in the field of biology is about highschool level, so if I'm missing something please point it out gently (and whatever you do, don't hit the face) and if there is any other way, I would be grateful if you could share it with me.

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by eugene2k
Mon Jul 28, 2014 2:30 pm
 
Forum: General Discussion
Topic: Hypothetical question about vampires
Replies: 1
Views: 449

Why similar features are preserved in a gigantic population?

... (except the native Ainu) resemble each other. All have common characteristics as epicanthic fold, oblique eyes, slightly marked brow ridges, flat face, high orbits, etc. .. The teeth are Characterized by sinodonty. But this is very rare when you consider the number of people, absolutely gigantic. ...

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by Goldentiger
Mon Jul 14, 2014 1:22 am
 
Forum: Human Biology
Topic: Why similar features are preserved in a gigantic population?
Replies: 2
Views: 473

Re:

Hi Golden tiger, How about a pug dog or a Persian cat? HI ! :D I have noticed that Persian cats are very flat face and nose, and have changed a lot in a short time, it's true. How is this obtained? A mutation caused them to have this type of face? Or were selecting cats with ...

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by Goldentiger
Mon Jul 07, 2014 5:32 pm
 
Forum: Zoology Discussion
Topic: Examples of Mutations ?
Replies: 3
Views: 448

Examples of Mutations ?

... change the facial features. Until now I only see examples of changes in pigmentation or aberrations. So if anyone has photos of mutations in the face of an animal (but which are not aberrations) I like to see them. Thank you.

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by Goldentiger
Fri Jun 27, 2014 2:43 pm
 
Forum: Zoology Discussion
Topic: Examples of Mutations ?
Replies: 3
Views: 448

Changes on our face when we grow

What changes does parts of our face make when we grow up ? Lets see on nose, eye or ear ? Can we find out the age of person by measuring or seeing any parts of any person ??

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by sshasi009
Thu Mar 13, 2014 5:20 am
 
Forum: Human Biology
Topic: Changes on our face when we grow
Replies: 1
Views: 1152
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