Term
|
Definition
| An aggregate of bile salts in aqueous solution- they stick together with a +ve inside (hydrophobic) and -ve outside (hydrophilic) and thus can transport lipids to the brush border |
|
|
Term
| What is the function of a micelle? |
|
Definition
| To transport lipids to the brush border, and away from the site of degradation |
|
|
Term
|
Definition
| A triacyclglycerol and esterified cholesterol surrounded by protein, cholesterol and phospholipids, making a lipoprotein for lipid transport |
|
|
Term
| What is the function of bile constituents? |
|
Definition
|
|
Term
|
Definition
| Lipase that is found in the mouth and begins lipid breakdown during mastication. |
|
|
Term
| True or false: Glycerol forms triacylglycerol in a hydrolysis reaction with three fatty acid chains |
|
Definition
| False. Glycerol forms triacylglycerol in a CONDENSATION reaction with three fatty acids! |
|
|
Term
| What is the function of co-lipase? |
|
Definition
| To anchor pancreatic lipase at the fat-water interface and allow it to work |
|
|
Term
| True or false? Pancreatic lipase catalyses the hydrolysis of the triacylglycerol, forming glycerol and 3 fatty acids. |
|
Definition
| FALSE: Pancreatic lipase catalyses the hydrolysis of triacylglycerol, forming 2-monoacylglycerol and 2 free fatty acids. |
|
|
Term
| Describe the appearance of the pancreas. |
|
Definition
Lobulated structure attached to flexure of duodenum.
Pale pink to yellow
Likely to be self-digesting in necroscopy unless very soon after death. |
|
|
Term
| True or false? The islets of langerhans in the pancreas produce endocrines. |
|
Definition
|
|
Term
| True or false, the exocrine pancreas consists of alpha, beta, and delta cells. |
|
Definition
| False- the endocrine pancreas consists of alpha, beta and delta cells, the exocrine pancreas consists of acini cells. |
|
|
Term
| True or false: Carboxypeptidase is an exopeptidase? |
|
Definition
|
|
Term
| What is the action of carboxypeptidase on a protein chain? |
|
Definition
| Attacks the carboxyterminal at the end of the amino acid |
|
|
Term
| True or false: Trypsinogen cleaves bonds in the middle of a peptide molecule, after a positively charged amino acid. |
|
Definition
| False. Trypsinogen is a zymogen and has no action on peptides. |
|
|
Term
|
Definition
|
|
Term
| How is trypsin activated? |
|
Definition
| Trypsinogen is squeezed from the pancreas into the pancreatic ducts, when it reaches SI, enterokinase in the SI activates it. Trypsin further cleaves trypsinogen and other zymogens so speeds up the process, resulting in an 'explosion' of enzymes. |
|
|
Term
| Describe the structure of starch? |
|
Definition
| A spiral shaped, unbranched amylose chain with a 1-4 linkages and a branched amylopectin chain with a 1-4 and a 1-6 linkages. |
|
|
Term
| What is the percentage of average liver mass is glycogen? |
|
Definition
|
|
Term
| True or false: Only D-isomers of monosaccharides can be metabolised |
|
Definition
|
|
Term
| What are the functions of glucosidases in the brush border? |
|
Definition
| To digest disaccharides to monosaccharides. |
|
|
Term
| How are glucose and galactose transported across the mucosa? |
|
Definition
| Na+k+ATPase causes a conc gradient, when Na+ then moves into cell it releases energy and glucose gets a 'free ride'. The high intracellular level of glucose then means that it can move through basolateral membrane by facilitated diffusion. |
|
|
Term
| How is fructose absorbed? |
|
Definition
| By facilitated diffustion independant of Na+ |
|
|
Term
| True or false: Absorption of monovalent ions (Na+, K+, CL- etc) is independant of the needs of the body. |
|
Definition
| TRUE! They are all absorbed easily through the paracellular route, but excretion is tightly regulated. |
|
|
Term
| True or false? Vitamin C increases the absorption of iron? |
|
Definition
| True, because it reduces Fe3+ to Fe2+ which is absorbed more easily. |
|
|
Term
|
Definition
| The transport molecule for iron |
|
|
Term
| How is iron uptake regulated? |
|
Definition
| If there is too much iron and tranferrin is saturated, the iron taken up all binds to ferritin within the epithelial cells, which inhibits further uptake of iron. If it is low, tranferrin has all it's binding sites free and more iron can be absorbed. |
|
|
Term
| How is calcium uptake regulated? |
|
Definition
| When Ca2+ is low, calcitriol is formed, which increases the Ca2+ channels on both apical and basal membrane and increases the sythesis of the protein that Ca2+ binds to to transport it across the cell between these two channels. When there is too much calcium, there are fewer transport proteins and channels and so uptake is slow. |
|
|
