Cell Ultrastructure Flashcards

1
Q

Plasma Membrane

A
  • phospholipids are amphipathic
  • the bilayer for as a relatively impermeable barrier to most water-soluble molecules
  • protein molecules dissolved in the lipid bilayer mediated most of the other functions of the membrane
  • glycocalyx - oliosaccharides and polysaccharide side chains on the outside of the plasma membrane
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2
Q

Functions of the plasma membrane

A
  • selective permeability
  • transport of materials along cell surface
  • endocytosis and exocytosis
  • intercellular adhesion and recognition
  • signal transduction
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3
Q
Endoplasmic Reticulum 
(is continuous and encloses a single lumen)
A
sER 
- no ribosomes 
- found in liver, mammary gland, ovary, testis and adrenal gland
rER 
- ribosomes synthesise proteins
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4
Q

The Golgi Apparatus

A

cis face - receives vesicles from rough ER
trans face - exports vesicles (signal mediated diversions for lysosomes or regulated secretion - not for constitutive secretion)
The Golgi Apparatus functions to modify, sort, concentrate and package proteins synthesised on the rER

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5
Q

Lysosomes

A
  • are generated by the Golgi apparatus
  • contain many hydrolytic enzymes to break down anything in the cell that is defunked
  • fuse with ,aerial requiring digestion
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6
Q

Peroxisomes

A
  • detoxify (oxidise) a number of molecules including alcohol, phenols, forming acid and formaldehyde
  • abundant in the liver and kidney
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7
Q

Mitochondrion

female lineage - always inherited from mother

A
Matrix
- 100s of enzymes 
- mitochondrial DNA genome (has bacterial like replication - endosymbiosis theory) 
Inner Membrane (cristae)
- enzymes for oxidative phosphorylation (ATP synthesis) 
- impermeable to small ions e.g. H+ 
Outer Membrane 
- permeable by all molecules
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8
Q

Actin Filaments

A

Microfilaments
- 5-9nm in diameter
Intermediate filaments
- 10nm in diameter
- tough supporting mesh work in cytoplasm
- cancer source can be traced by looking at filament type in cancer cell
Microtubules
- 25nm in diameter
- hollow cylinders made of protein tubulin
- found where structures move (nerve fibres, mitotic spindle, cilia and flagella)
- 9+2 arrangement in cilium or flagellum

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9
Q

The limit of resolution

proportional to wavelength

A

The minimum distance at which two objects can be distinguished (seen as distinct)
Theoretical limit of resolution
- light microscope is 0.2um
- electron microscope is 0.002nm

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