3 Enzymes Flashcards
1
Q
What is a protein molecule made up of?
A
long chains of small units called amino acids
2
Q
What functions do proteins carry out in your body?
A
- structural components such as muscles and tendons
- hormones such as insulin
- antibodies, which destroy pathogens
- catalysts in the form of enzymes
3
Q
What does a catalyst do?
A
speeds up a chemical reaction without being used up so it can be used repeatedly
4
Q
What biological catalyst does your body have?
A
enzymes control chemical reaction rates
5
Q
What are enzymes?
A
large protein molecules
- long chains of amino acids are folded to produce a molecule with a specific shape
- the special shape allows other molecules (substrates) to fit into the enzyme protein
- we call this the active site and the shape is vital for the way it works
6
Q
What are enzymes involved in? (give examples(3))
A
- building molecules from lots of smaller ones
e. g.making glycogen from glucose or proteins from amino acids - changing one molecule into another
e. g.one sugar into another, such as glucose to fructose - breaking down large molecules into smaller ones
e. g.breaking down insoluble food molecules into small soluble molecules, such as glucose
7
Q
Are there different types of enzymes?
A
yes - different ones speed up specific types of reaction
8
Q
How do enzymes work?
A
- the substrate (reactant) of the reaction fits into the active site of the enzyme
- it is like a lock and key
- once in place the enzyme and substrate bind together
- the reaction then takes place rapidly and the products are released from the surface of the enzyme
- (remember enzymes can join small molecules together as well as break up larger ones)
9
Q
What factors affect enzymes activity?
A
- temperature
- pH
10
Q
What is the effect of temperature on enzyme action?
A
- reactions occurring in cells happen at fairly low temperatures
- the rate of enzyme-controlled reactions increases as the temperature increases…
- …this is only true up until around 40 degrees C because after this the protein structure of the enzyme is affected by high temperature and the long amino acid chains begin to unravel
- this changes the shape of the active site and the enzyme is denatured
- it can no longer work as a catalyst so the rate of reaction drops rapidly
11
Q
What is the optimum working temperature for enzymes?
A
37 degrees C
12
Q
What do we call enzymes when their active site has been changed and they are no longer useful?
A
denatured
13
Q
What is the effect of pH on enzyme action?
A
- a change in pH affects the forces holding the enzymes shape together
- this changes the shape of the molecule which causes the active site to be lost
- this means the enzyme no longer works as a catalyst
14
Q
Where does the shape of an enzyme come from?
A
the forces between the different parts of the protein molecule
these forces hold the folded chains in place
15
Q
Do all enzymes require the same pH to function properly?
A
no - different enzymes have different temperatures at which they work best and a change can stop them working completely
16
Q
What would happen if our body did not have enzymes?
A
none of the reactions in your body would happen fast enough to keep you alive
17
Q
Why is it dangerous if your temperature rises when you are ill?
A
once your body reaches 41 degrees C, your enzymes start to be denatured meaning that the reactions in your body aren’t happening quick enough so you’ll die
18
Q
Why does food need to be digested?
A
- food is made up of large, insoluble molecules which your body can’t absorb
- they need to be broken down into smaller, soluble molecules
- these can then be absorbed and used by your cells
19
Q
How are digestive enzymes different from most of the enzymes in your body?
A
- most of your enzymes work inside the cells of your body, controlling the rate of chemical reactions
- digestive enzymes work outside your cells because they must break down the food so that it can be absorbed and used in the cells
20
Q
Where are digestive enzymes produced?
A
in specialised cells in glands (like your salivary glands and pancreas) and in the lining of your gut
21
Q
What happens during digestion?
A
- the enzymes pass out of the cells into the gut itself
- your gut is a hollow, muscular tube that squeezes your food
- it helps to break down food into smaller pieces with a large surface area for your enzymes to work on
- it mixes your food with digestive juices so that enzymes come into contact with the food as much as possible
- the muscles of the gut move food along from one area to the next
22
Q
What are the enzymes which break down carbohydrates called?
A
carbohydrases
23
Q
What is one of the most common carbohydrates consumed and what is it broken down into?
A
starch
broken down into sugars in your mouth and small intestine
24
Q
Which enzymes catalyses the breaking down of starch into sugars? Where is it produced?
A
amylase
produced in your salivary glands (so digestion starts in the mouth) and in your pancreas and small intestine (no digestion takes place in the pancreas)
25
Why does no digestion take place inside the pancreas?
all the enzymes made there flow into your small intestine where food such as starch is digested
26
What enzymes breaks down proteins into amino acids?
proteases
27
Where are proteases produced?
in your stomach, pancreas and small intestine
28
Where does the breakdown of protein take place?
stomach and small intestine
29
What is another name for fats and oils?
lipids
30
What are lipids broken down into?
fatty acids and glycerol
31
Which enzyme catalyses the breaking down of lipids?
lipases
32
Where are lipase enzymes produced?
pancreas and small intestine (enzymes in the pancreas are passed into the small intestine)
33
What happens once food molecules have been completely digested?
- the soluble molecules: glucose, amino acids, fatty acids and glycerol leave your small intestine
- they pass out into your bloodstream to be carried around the body to the cells which need them
34
Why does your body make a variety of different chemicals? (digestion)
in order to help keep conditions ideal for your enzymes all the way through the gut
- protease enzymes in stomach works best in acidic conditions
- protease enzymes in pancreas need alkaline conditions to work at their best
keeping the pH levels in your gut is difficult
35
How does the pH change through your gut in the process of digestion?
1) - stomach proteases function best in acidic conditions so the stomach produces a concentrated solution of hydrochloric acid from your glands (around 3 litres per day) the acid allows the enzymes to work effectively whilst also killing bacteria taken in with food
- your stomach also produces a thick layer of mucus which coats your stomach walls, protecting them from being digested by the acid and enzymes
2) - after a while the food travels to the small intestine which have enzymes working best in alkaline conditions (also pancreas)
- acidic liquid from stomach becomes an alkaline mix by squiring bile which neutralises and makes the mixture alkaline, providing the ideal conditions needed for enzymes
- bile is produced in your liver and stored in gall bladder until needed
36
Why is it important for enzymes digesting food to have the largest possible surface area to work on?
- fats eaten don't mix with water liquids in the gut so they stay as large globules that can make it hard for lipases to act
- not a problem with carbohydrates and proteins
37
What are the 2 important functions of bile?
1) to turn the acidic liquid from stomach passing into the small intestine alkaline for enzymes to work optimally
2) to emulsify the fats in your food to allow lipases to act more efficiently
38
How does bile help lipases to break down fats?
- emulsifies the large globules of fat which don't break down in watery liquids in gut
- breaking down the fats into smaller droplets provides a larger surface area for the lipase enzymes to work on
- the larger surface area helps lipases chemically break down the fats much more quickly into fatty acids and glycerol
39
How can enzymes be used in the home?
- people use biological detergents to remove stains
- they contain enzymes like proteases and lipases in order to break down proteins and fats in stains which gives a cleaner wash
- biological detergents work better than non-biological detergents because enzymes work best a lower temperatures so you can use cooler water and less electricity
40
How can pure enzymes be used in industry?
- baby food) proteases are used to make baby food as they 'predigest' some of the proteins in the food to allow the baby's digestive system to cope with it and make it easier to get the amino acids they need
- sugar syrup (+ ethanol) )carbohydrases are used to convert starch into sugar (glucose syrup) which is used in food production and plants like corn containing starch are very cheap (it is also an important for the process of making fuel from plants)
- slimming foods) glucose syrup can be passed though another process using a different set of enzymes - isomerase is used to change glucose syrup into fructose syrup (although containing the same amount of calories, fructose is sweeter so less can be used)
41
What are the advantages and disadvantages of using enzymes?
A:
- enzyme-based processes are fairly cheap to run because they catalyse reactions at relatively low temperatures and normal pressures (solving problems in energy use and expensive equipment in industry)
- pure enzymes use substrate more efficiently
D:
- enzyme conditions must be carefully controlled so that they don't become denatured which costs money e.g. temperature (below 45 degrees C) and no change in pH
- enzymes are expensive to produce because they must be supplied with food and oxygen, have waste products removed and use substrate to grow more micro-organisms
- pure enzymes are even more expensive to produce
42
What are the pros and cons of biological detergents?
pros:
- break down biological stains such as sweat and are very effective at cleaning
- work at lower temperatures so therefore use less energy and electricity which is cheaper and environmentally friendly
cons:
- originally caused allergies (from enzyme dust in the air-proteins can cause allergies) but this was solved by putting the enzymes in tiny capsules
- the lower-temperature washes are less good at killing pathogens (but higher temperatures denature the enzymes)
- some worry about enzymes going into rivers and seas from sewage systems
43
How can enzymes be used in medicine? (and examples (3))
- to diagnose a disease
e. g.liver can be checked by testing blood for enzymes in your liver which leak if it is damaged
- to diagnose and control a disease
e. g.can be used to test for diabetes as they have too much glucose in their blood so there will be excess in the urine and an enzyme can catalyse the breakdown of any found in the urine proving that glucose was present
- to cure disease
e. g.if pancreas is damaged...more enzymes must be made which are transported in special capsules so they aren't digested by stomach, if you have a heart attack...streptokinase enzyme will be injected into blood to dissolve clots etc, childhood blood cancer...enzyme speeds up breakdown of amino acid which cancer cells can't produce (having taken it from bodily fluid) so the cancer cells can't get any and die
