cellular anatomy #1 M1 V2 Flashcards
cellular function - how does it do that
- membrane separates it from outside world
- membranes within the cell form separate compartments these compartments are called organelles
organelles
provide the right conditions for processes, separate things, allow concentration gradients, many different types
membranes
semi - permeable barrier - controlled movement of a range of molecules
outer cell membrane
the outer cell membrane is a phospholipid bilayer
- this is hydrophobic (repels water)
what is the outer cell membrane composed of
- the outer cell membrane is composed of phosphate groups and fatty acids - the composition can change the fluidity
- the membrane also includes proteins for functions
what does cholesterol do
cholesterol reduces the fluidity at moderate temperatures, increases when its cold
types of cell transport
- active transport
2. passive transport
passive transport
movement of molecules down their concentration gradient (requires no energy)
active transport
movement of molecules up / against their concentration gradient, (requires energy) - involves ATP and pumps
regular diffusion
- is passive transport
- lipid soluble /hydrophobic can diffuse
- water / glucose / ions cant
facilitated diffusion
- is passive transport
- requires “helper” membrane proteins
- water/ glucose/ ions move through channel proteins (“holes” in the membrane)_
- these channels could be gated by charge or chemicals, but still no energy involved
active transport
- direct - directly uses ATP as energy to move molecules up their gradient
- indirect - uses the energy gained as other molecules move down their gradient to power the transport
- if this is done in the same channel (eg sucrose H+ cotransporter) this is called cotransport
- effective cell transport is essential for all functions
membrane proteins are involved in ?
- signal transduction
- recognizing other cells
- joining cells together
- linking the inside of the cell to the outside
(think signal , recognize , join , link)
endomembrane system
system of membranes within a cell
- maintains the separation between compartments
- processes material inside the cell
what does the endomembrane system include
The endomembrane system includes
- the SMOOTH and ROUGH endoplasmic reticulum (ER)
- and the Golgi body
rough ER
rough because of ribosomes (make proteins)
- makes proteins for the membrane and for secretion
- proteins in the cytoplasm are made elsewhere
smooth ER
- No ribosomes
- does everything else (lots of processing)
- detoxification
- makes membrane lipids
- metabolises carbohydrates
- stores calcium
- the amount of the smooth ER can be changed to fit the demands of these processes
Golgi complex
- Lot of membrane sacs and vesicles
- processes and packages proteins
what are the two sides of the Golgi complex
The Golgi complex had two sides
- vesicles from ER arrive at the cis side
- processed vesicles leave at the trans side
Type of Golgi complex packaging
- Glycosylates proteins (adds carbs) - important for specific function
Type of Golgi complex process
- the Golgi complex can add markers to identify and sort into vesicles
- adds tags to direct those vesicles to compartments
- retrieval tag directs back
what is exocytosis
- transport out of cell via vesicles (not across the membrane)
- can deliver to surface of cell (non secretory) - membrane protein ect
- regulated - hormones and neurotransmitters
what is endocystosis
- like exocytosis, but INTO the cell
what are the 2 different types of endocytosis
- Phagocytosis - “food” particles into vacuole which is digested
- Pinocytosis - solutes, non selective
