cell membrane & major components
the cell membrane is a ________ bilayer
phospholipid
which membrane lipids are most abundant?
phospholipids
which transport processes do not require energy
simple diffusion, osmosis, faciliated diffusion
what type of curve does a [s] graph have?
michaelis - menten or logarithmic curve
which organelles have double membrane
mitochondria, nucleus, chloroplast
cell membrane composes of?
lipids, proteins & carbohydrates
what are the 3 main classes of membrane lipids
phospholipids , glycolipids, sterols
define simple diffusion
Flow of molecules from [high] to [low]
which curves involve 'connecting the dots' of the plot points?
compare & contrast smooth ER & rough ER
smooth:
- lipid/steroid synthesis
- carbohydrate metabolism
- inactivate & detox drugs
- store & release Ca2+
100*:
what type of model represennts the cell membrane
fluid mosaic
what is does oligosaccharides attach to & what is their function?
attached to proteins or lipids:
- Help in signalling
- Act as molecular markers (antigen) for the recognition of substances
define osmosis & what it is dependent on
Diffusion of water across a selective permeable membrane
• Dependent on relative osmolarity (total solute concentration)
discuss the 3 points of cell theory
All organisms consist of one or more cells.
The cell is the basic unit of structure and organization in all organisms.
All cells come from pre-existing, living cells.
what is the composition of a phospholipid?
Consists of a polar head (attached to phosphate), backbone and non-polar fatty acids tails
compare & contrast saturated fatty acids & unsaturated fatty acids
Single bonds v Double bonds → bends/kinks chain Pack tightly v Do not pack tightly
Solidify at room temperature (RT) v Remains liquid at RT
Cell in a hypertonic solution
• Higher solute concentration OUTSIDE cell
• Hence, water will move out of cell
Cell in an isotonic solution
• Same solute concentration to cell
• No nett movement of water
Cell in a hypotonic solution
• Higher solute concentration INSIDE cell
• Hence, water will diffuse into cell
what factors limit size?
Diffusion rates of molecules
Maintaining concentrations of substances in cell
surface area/vol ratio
describe integral proteins
Hydrophobic regions embedded within lipid bilayer Classified by mode of attachment
• Integral monotopic proteins
• Transmembrane protein that acts as proton pump/channel
describe active transport
Requires membrane carrier protein (pump) Requires energy (ATP)
Molecules able to move against concentration gradient
• Uptake scarce essential nutrients
• Remove waste and secretory products
• Maintain [ions]
Example: Na+/K+ pump (Na+ out and K+ in)
compare & contrast plant & animal cells
imilarities:
- Cell membrane, Cytosol, Nucleus
- Organelles: ribosomes, cytoskeleton, peroxisomes, golgi complex, endoplasmic reticulum, mitochondria,
differences:
- plant cell: cell wall, chloroplasts, large vacuole, glyoxysomes (type of peroxisomes)
- animal cell: lysosomes, centrosome, cilium