Theme 1 Cell Structure Flashcards

Question

amphipathic

Answer 1

having hydrophobic and hydrophilic parts

Answer 2

saturated: each available carbon has hydrogen bonded to it, making FA chain straight unsaturated: contains double bonds b/w carbon atoms in FA chain, leaving it kinked

Answer 3

ie cholesterol | - 4 hydrocarbon ring structure

Answer 4

polar molecules are hydrophilic meaning they can interact with water non polar molecules are hydrophobic

Answer 5

lipids w bulky heads and single hydrophobic FA tails are arranged in to ball like spherical structures - important for nutrient absorption

Answer 6

lipids w less bulky heads are arranged in 2 layers where heads are on outside and hydrophobic tails are on inside - this is how the cell membrane is arranged - explains how cell membrane is self healing

Answer 7

enclosed bilayer structure that forms spontaneously when phospholipids are thrown into env'ts w neutral pH like water can trap macromolecules in the middle

Answer 8

the ability of the phospholipids to move laterally within the cell membrane NOTE: phospholipids can't easily flip from upper to lower layers in a bilayer without using too much energy

Answer 9

1. unsaturated or saturated FAs: double bonds produce kinks that increase fluidity 2. number of carbons in the FA tails (shorter tails = more fluid) 3. temp (higher temp = more fluid) 4. amt of cholesterol present (less is more fluid)

Answer 10

it makes up 30% of membrane lipids - at low temp, it prevents phospholipids from packing too tightly thus increasing fluidity - - ie prevents dramatic changes in membrane from fluid to solid state

Answer 11

less fluid regions of the lipid membrane: not always uniform - can gather proteins in these areas too - less fluid bc of longer and saturated FA tails packing together and also making taller; also higher conc of cholesterol here

Answer 12

less fluid membrane results in lower permeability | more fluid membrane results in higher permeability

Answer 13

cell membranes can control the movement of substances into and out of the cell: - sm hydrophobic molecules and ions move w conc. gradient - large polar molecules can't move through

Answer 14

are embedded in the cell membrane and allow hydrophilic molecules to move across has hydrophobic middle region and hydrophilic ends allowing it to interact w cell membrane and its env't

Answer 15

permanently assoc w cell membranes, can't be removed w/o destroying the cell - most are transmembrane proteins

Answer 16

temporarily assoc w cell membrane through weak bonds, etc. they can be removed easily - can associate on internal or external side of the membrane

Answer 17

when a molecule moves along its concentration gradient, crosses phospholipid bilayer - does NOT use energy ex. small molecules, water

Answer 18

movement along a conc. grad. , requires proteins molecules that assist in transmembrane movement of the solutes - NO energy required ex. ions, most hydrophilic molecules

Answer 19

movement AGAINST a concentration gradient, fuelled by hydrolysis of ATP

Answer 20

the passive transport of water across membranes | - water diffuses from less concentrated solutions to more concentrated solution

Answer 21

protein channels that only transport water through osmosis | dependent upon conc grad., NO use of energy

Answer 22

extracellular fluid concentration is the same as it is inside the cell - no net movement of water

Answer 23

extracellular fluid has a lower concentration than inside the cell - net movement of water inside cell, can cause swelling and bursting of cell

Answer 24

extracellular fluid has higher solute concentration than inside cell - net loss of water in cell to exterior env't

Answer 25

dependent on the direct expenditure of ATP

Answer 26

indirect expenditure of ATP where neighbouring transport proteins follow action of pump

Answer 27

pumps 3 Na+ out and 2 K+ in