predicted questions Flashcards
explain why the ileum contains both endopeptidases and exopeptidases for efficient digestion of protein
endopeptidases hydrolyse internal peptide bonds
endopeptidases create more ends/increase surface area for exopeptidases
describe the fluid mosaic model
mosaic because of the phospholipid bilayer
fluid because phospholipids free to move
describe and explain how an artery is adapted to carry out its function
thick muscle wall- to withstand high blood pressure
narrow lumer- to maintain high blood pressure
elastic tissue- to stretch and recoil to maintain blood pressure
describe the function of the coronary arteries
carry oxygen to heart muscle
describe how glycoproteins would be produced in the cell
amino acid chain leaves ribosome in cytoplasm
travels to golgi to be modifiedd
carbohydrate chain added to protein
compare structure of triglycerides and phospholipids
both contain fatty acid chains
both contain glycerol moleculees
both contain ester bonds
phospholipids contain a phosphate group bound to the glycerol and triglycerides do not
triglycerides contain three fatty acid chains and phospholipids contain two
explain the steps in meiosis that lead to an increase in genetic variation
-homologus chromosomes pair up
-independent segreagation in metaphase 1
-maternal and paternal chromosomes are re-shuffled in any combination as to which gametes receive maternal/paternal chromosomes
-crossing over leads to exchange of parts of chromatids between homologus chromosomes in prophase 1
-both create new combinations of alleles
describe the process of semi-conservative replication of DNA
process by which DNA is copied before cell division, resulting in two daughter DNA molecules, each containing one original strand and one newly synthesised strand.
During semi-conservative replication, the parental DNA molecule unwinds and serves as a template for the synthesis of complementary daughter strands
describe how two named examples of polysaccharides are adapted to their function
-Starch molecules are insoluble and therefore don’t affect the water potential of the cell
-Starch molecules are large and therefore can’t leave the cell
-Chains are coiled so they are compact;
-Glycogen is insoluble so it doesn’t affect osmotic pressure
-Highly branched allows it to be hydrolysed to release glucose for respiration
Compare and contrast competitive and non-competitive enzymes inhibitors
Competitive inhibitors have a similar shape to that of the substrate molecules and therefore compete with the substrate for the active site Non-competitive inhibitors bind to the enzyme at an alternative site, which alters the shape of the active site and therefore prevents the substrate from binding to it
describe the structure of proteins
The primary structure is the order of amino acids in the peptide. Secondary structure is the folding of the polypeptide chain due to hydrogen bonding into an alpha helix structure, resembling a coiled spring, or a beta pleated sheet. Tertiary structure is the 3-D folding due to ionic and disulphide bonds between sulphur molecules in distant parts of the chain. These bonds may also be hydrogen bonds which occur between distant parts of the chain. Some proteins, such as haemoglobin, have quarternary structure which is when the protein has two or more polypeptide chains joined together.
compare the action of a competitive inhibitor and non-ccompetitive inhibitor
competitive inhibitor will lower the initial rate of reaction, same amount of product will be produced as would have been produced without the competitive inhibitor. Non-competitive inhibitors lower the initial rate of reaction and the maximal rate of reaction
