Enzymes and the digestive system- topic 6 Flashcards
(27 cards)
What is the function of enzymes in digestion?
They speed up chemical reactions by breaking down large food molecules into smaller ones.
What is the optimum temperature for enzymes in humans?
37°C.
What happens to enzymes at temperatures above their optimum?
They become denatured (the active site changes shape).
What is the Lock and Key model?
A model that explains enzyme specificity — each enzyme fits only one substrate.
What enzyme breaks starch into maltose and where?
.
Amylase in the mouth and small intestine
Where is bile produced and what are its two main functions?
Made in the liver; it neutralizes stomach acid and emulsifies lipids.
What does the active site do
It’s the part of the enzyme where the substrate binds.
What are villi and what is their function?
Tiny finger-like projections in the small intestine that increase surface area for absorption.
What enzyme breaks maltose into glucose?
Maltase in the small intestine
What enzyme breaks lipids into glycerol and fatty acids?
Lipases in the small intestine
What breaks proteins into amino acids?
Proteases in the stomach and small intestine.
What is meant by “denatured enzyme”?
An enzyme whose shape has changed so the substrate can no longer fit.
what is peristalsis?
Muscle contractions that push food through the digestive tract.
what are enzymes
Proteins that act as biological catalysts to speed up metabolic reactions without being used up.
how do enzymes work
They have an active site with a specific shape that matches only one substrate, like a lock and key.
What happens to enzymes at low temperatures?
Molecules have less kinetic energy, so there are fewer successful collisions between enzyme and substrate.
What happens to enzymes at high temperatures?
The enzyme becomes denatured; the active site changes shape and no longer fits the substrate.
How does pH affect enzyme activity?
Each enzyme has an optimum pH; too high or too low a pH denatures the enzyme.
What is the practical method for investigating enzyme activity and temperature?
Use starch and amylase at different temperatures, then test with iodine to measure starch breakdown.
What is the practical method for investigating enzyme activity and pH?
Use buffers to set different pH levels and observe how enzyme activity (e.g. amylase on starch) changes.
What organs make up the human alimentary canal?
Mouth, oesophagus, stomach, small intestine (duodenum and ileum), large intestine (colon and rectum), and anus.
What is the function of the pancreas in digestion?
It produces digestive enzymes like amylase, protease, and lipase.
What is the role of amylase and maltase?
Amylase breaks starch into maltose; maltase breaks maltose into glucose.
What is the role of lipases?
Break down lipids into fatty acids and glycerol.
