The activity of two types of protease enzymes was measured in two different species of fish; species X and species Y. The results of the research are shown in the graph.
The unit U denotes the enzyme required for the production of 1 μmol of product per minute. The bars represent the standard deviation.
Which statement about protease enzymes is correct?
The activity of the stomach protease of species Y is 2.5 times greater than that of species X.
The activity of the intestinal protease of species X is significantly higher than the stomach protease of species X.
Endopeptidase proteases hydrolyse peptide bonds at the ends of polypeptides.
The activity of the intestinal proteases of both species X and Y are significantly higher than the stomach proteases.
Sucrase-isomaltase is a membrane-bound disaccharidase located in the cell surface membranes of the cells lining the small intestine. It digests the following molecules:
Dextrins
Glucose-glucose disaccharides
Glucose-frustose disaccharides
A recessive mutation leads to congenital sucrase-isomaltase deficiency (CSID). Which of the following are likely to be symptoms of CSID?
I. Diarrhoea due to water retention in the digestive tract.
Inhibition of a transport protein known as SGLT1 has been studied as a possible treatment option for the treatment of type 2 diabetes. The diagram shows the location of SGLT1, alongside two other types of transport protein.
Which statement regarding the impact of inhibiting SGLT1 is likely to be true?
It will prevent the active transport of glucose into the epithelial cell.
It will increase the release of insulin from the pancreas.
It will prevent the formation of a glucose gradient between the epithelial cell and the capillary.
It will prevent the formation of a sodium ion gradient between the intestine lumen and the epithelial cell.
The micrograph image below shows a transverse section through the wall of the small intestine.
Image courtesy of Ed Uthman, licensed under the Creative Commons Attribution-Share Alike 2.0 Generic license, and adapted and redistributed under conditions found at https://creativecommons.org/licenses/by/2.0/
Which tissue layers can be identified in the image?
