4.2.2.1 The Human Digestive System Flashcards
1
Q
What is the role of the digestive system?
A
- breaks down food
- absorbs food
2
Q
What are enzymes?
A
- biological catalysts produced by living things
- a substance that increases speed of a reaction without being changed or used up
3
Q
What do the thousands of chemical reactions in a living thing need to be?
A
- carefully controlled
- to get right amount of substances
4
Q
What are enzymes helpful for?
A
- reducing the need for high temperatures
- speed up useful chemical reactions
5
Q
What is the nature of enzymes?
A
- large proteins
- chains of amino acids
- chains folded into unique shapes
6
Q
What does every enzyme have?
A
- an active site
7
Q
What is an active site?
A
- a unique shape that fits onto substrate involved in a reaction
- only catalyse one specific reaction
- if doesn’t match then reaction won’t be catalysed
8
Q
What is the ‘lock and key’ diagram?
A
- simplified model of enzyme action
- reaction will only be catalysed if shape of substrate exactly matches active site
- active site changes a little for an induced fit
9
Q
What does a higher temperature do to a reaction?
A
- increases rate at first
- if too hot some bonds that hold enzymes together break, which changes active site, making it denatured
10
Q
What happens when the pH isn’t the right level?
A
- interferes with bonds, also making them denatured
11
Q
What do all enzymes have that makes them work the best?
A
- optimum pH
- often neutral, pH 7
12
Q
What are examples of large molecules?
A
- starch
- proteins
- fats
13
Q
What are examples of small molecules that have been broken down from big molecules
A
- sugars (glucose, maltose)
- amino acids
- glycerol
-fatty acids
14
Q
How are smaller molecules absorbed into the bloodstream?
A
- they are soluble so they can pass easily through walls
- diffusion
- active transport
15
Q
What do carbohydrases convert carbohydrates into?
A
- simple sugars
