2.2 Flashcards
why do people with CF have stickier mucus?
contains less water
why do people with CF’s mucus contain less water?
abnormal salt and water transport across the cell surface membranes caused by a faulty transport protein channel in the membrane
what is the general structure of an amino acid?
a carbon with an amine group to the left (N-H-N), a carboxylic acid group to the right and a residual group at the bottom
how do amino acids join together?
in a condensation reaction forming a peptide bond
what is the primary structure of a protein?
the sequence of amino acids joined together by peptide bonds
what is the secondary structure?
When the polypeptide chain coils into a shape
what are the two types of secondary structure?
a - helix
b - pleated sheets
what is the tertiary structure?
when the secondary structures folds into a three dimensional shape due to the interactions between amino acids in the chain
what is a quaternary structure?
proteins with more than one polypeptide chain
what bond occurs between two inward facing amino acids?
a covalent disulphide bond between R groups
what kind of R groups face the inside of the protein?
hydrophobic
what do ionised R groups form?
ionic bonds
what are the pros and cons of disulphide and ionic bonds compared to hydrogen bonds?
they are much stronger but also more sensitive to pH change
what are conjugated proteins?
they have another chemical group associated with their polypeptide chain
what are globular proteins?
they have a polypeptide chain that is folded into a compact spherical shape and are soluble
what are fibrous proteins?
they remain as long chains that can be cross linked and are insoluble
what is a cell membrane?
a phospholipid bilayer
what part of the phospholipid is hydrophilic?
the phosphate head
what part of the phospholipid is hydrophobic?
the fatty acid tail
what two structures can phospholipids form?
micelles and bilayers
where are the hydrophobic areas of the membrane proteins found?
within the membrane bilayer
describe the fluid mosaic model?
some of the proteins are fixed within the membrane, but others are not and can move around in the fluid phospholipid bilayer
what makes the membrane more fluid?
having a greater ratio of phospholipids that contain unsaturated fatty acids to those with saturated
name the six ways substances can pass through a cell membrane?
diffusion, facilitated diffusion, osmosis, active transport, exocytosis and endocytosis
what is the definition of diffusion?
the net movement of molecules or ions from a region where they are at a higher concentration to a region of their lower concentration
what is facilitated diffusion?
when larger hydrophilic molecules or ions cross the membrane with aid of channel or carrier proteins
how do carrier proteins work?
the ion or molecule bonds into a specific site on the protein, the protein changes shape and it can move across
what is the definition for osmosis?
the net movement of water molecules from a solution with a lower concentration of solute to a solution with a higher concentration of solute through a partially permeable membrane
when will osmosis stop?
when the solutions are isotonic
what is active transport?
substance moving from a low to high concentration which requires energy
where is the energy for active transport supplied from?
ATP
