Exchange Flashcards
Amylase breaks down …
polysaccharides
Endopeptidase hydrolyzes…
peptide bonds within polypeptides
Exopeptidases hydrolyzes…
peptide bonds at the end of proteins
Features of an efficient exchange surface
large SA
thin (short diffusion)
good blood supply/ventilation
Define digestion
Hydrolysis of large, insoluble molecules into smaller molecules that can be absorbed across cell membranes
Which enzymes are involved in carbohydrate digestion? Where are they found?
Amylase (mouth)
Maltase, sucrase , lactase (small intestine)
What are the substrates and products of the carbohydrate digestive enzymes?
Amylase -> starch into smaller polysaccharides
Maltase -> maltose into x2 glucose
Sucrase-> Sucrose into glucose + fructose
Lactase -> Lactose into glucose and galactose
Lipids are digested in…
the small intestine
What needs to happen before lipids can be digested?
They must be emulsified by bile salts produced by the liver. This breaks down large fat molecules into smaller, soluble molecules called micelles, increasing SA
How are lipids digested?
Lipase hydrolyses the ester bond between the monoglycerides and fatty acids
Dipeptides…
break dipeptides into amino acids
Role of Na+ in co-transport
Na+ is actively transported out of the cell into the lumen, creating a diffusion gradient. Nutrients are then taken up into the cells along with Na+ ions.
how does an organism size relate to their surface area to volume ratio
The larger the organism, the lower the SA:V
How does an organisms SA:V relate to their metabolic rate?
The lower the SA:V, the lower the metabolic rate
How might a large organism adapt to compensate for its small surface area to volume ratio?
Changes that increase SA like:
Foldings
Developing a specialised gas exchange surface