Cell Membranes Flashcards
What does the protein coating contain in a virus?
Nucleic acids
What does the nucleic acid of the virus encode
RNA or DNA of normal cells to duplicate the virus
What does the bacterial genome bind to using what?
Sees protein and binds with its tail fibres
What injects the viral DNA
Sheath injects viral DNA through spikes
What will the viral DNA do to the cell?
Will rupture the cell membrane causing it to die
What are the two types of viral life cycle ?
Nonlytic and lytic
Non lytic
Reproduce
Lytic
Kill
What are membranes made of?
Phospholipids and proteins which are embedded in the membrane to help with function
Lipid bilayer is known as a ———— structure
Trilaminar
Fluid
Components are moveable
Mosaic
Consists of diverse particles such as proteins carbohydrates and cholesterol
Structure of a phospholipid
Polar head and nonpolar tails
Why is one of the tails kinked
Double bonds
Why do phospholipids configure spontaneously
To be more stable, the polar head is outdid and the tails are inside, two layers
Where does phospholipid synthesis happen?
Interface of the cytoskeleton and outer endoplasmic reticulum membrane
What does the ER membrane contain
Molecular machinery for synthesis and distribution
3 classes of membrane proteins
1) intregal/transmembrane proteins
2) peripheral proteins
3)lipid anchored proteins
Transmembrane
proteins that span the entire membrane
Peripheral
proteins that associate with the surfaces of the lipid bilayer
lipid anchored
proteins attach to a lipid in the bilayer
Transmembrane function
1) transport of nutrients and ions
2) Cell-Cell communication (gap junction)
3) Attachment
Lipids move easily
within leaflet
Lipid movement is difficult and slow
between the leaflets
An important feature for signal transduction
Biochemical modification can alter protein mobility in the membrane
Structure of biological membranes
6nm thick
stable
flexible
Capable of self assembly
The mitochondria contains very high concentration of
Proteins in the inner membrane which is necessary for ETC and ATP synthesis
The outer leaflet contains
glycolipids and glycoproteins which are lipids and proteins with carbohydrates attached to them
Warming the membrane will result in
increased fluidity
Cooling the membrane will result in
decreased fluidity
What do unsaturated lipids do to fluidty
increase
What do saturated lipids do to fluidity
decrease
Lipid composition can be changed by
1) desaturation of lipids
2) exchange of lipid chains
Fluidity is important in the membrane because
1) support and flexibility
2) assembly and modification
3) dynamic interactions
What helps maintain membrane fluidity
Cholesterol
