Enzymes

Question 1

How does a ph that is very different to the optimum affect enzyme activity?

Answer 1

The change in ph will distort the enzymes active site denaturing it so that it can no longer fit the specific substrate

Question 2

Describe the effect of the ph on the rate of an enzyme controlled reaction

Answer 2

• the rate of enzyme catalysed reaction is the fastest at the optimum ph
• if the ph is too high or low, the enzyme will work less efficiently and the active site may be denatured

Question 3

If the temperature increases above the optimum, how does this affect enzyme function?

Answer 3

The active site will be distorted as the enzyme denatures and so it will no longer fit the substrate

Question 4

Why doe the rate of an enzyme controlled reaction increase when the temperature increases?

Answer 4

• as the temperature increases the particles have more kineti energy
• this increases the chance of collisions between molecules being successful and leading to a reaction

Question 5

Describe the effect of temperature on the rate of an enzyme controlled reaction

Answer 5

• as the temperature increases, so doe he rate of reaction
• once the temperature exceeds the optimum, the enzyme denatures and the rate of reaction decreases

Question 6

What are the fur factors that affect the rate of enzyme controlled reactions

Answer 6

• ph
• temperature
• substrate concentration
• enzyme concentration

Question 7

What does the statement enzymes are highly specific mean?

Answer 7

The active site of the enzyme must bind to a substrate that has a complementary shape and so only specific reactions can be catalysed.

Question 8

Describe enzyme action

Answer 8

• a substrate that fits the specific active site of the enzyme binds to create and enzyme-substrate complex, a reaction occurs catalysed by the enzyme and the products are released

Question 9

Why are enzymes necessary in biological systems?

Answer 9

They speed up reactions so that less energy is needed for the reaction to occur

Question 10

Describe the structure of enzymes

Answer 10

• enzymes are proteins that contain a highly specific active site that fits a specific substrate

Question 11

What are enzymes?

Answer 11

Biological catalysts that speed up the rate of reactions

Question 12

What is a catalyst?

Answer 12

A substrate which increases the rate of reaction without being used up

Question 13

Pepsin

Answer 13

Breaks proteins into polypeptides.
Protein digesting enzymes produced by the pancreas

Question 14

Three types of digestive enzymes

Answer 14

• Carbohydrates
• proteases
• lipeases

Question 15

Example of a carbohydrate enzyme

Answer 15

Amylase

Question 16

Where is amylase made?

Answer 16

• Salivary glands
• pancreas
• small intestine

Question 17

What are carbohydrates such as starch broken down into?

Answer 17

Simple sugars such as glucose

Question 18

Where are proteases made?

Answer 18

• stomach
• pancreas
• small intestine

Question 19

What are the products of protein digestion?

Answer 19

Amino acids

Question 20

Where do proteases work?

Answer 20

Stomach and small intestine

Question 21

What are the products of lipid digestion?

Answer 21

Glycerol and fatty acids

Question 22

Where are lipeases made/

Answer 22

Pancreas and small intestine

Question 23

Where is bile made?

Answer 23

In the liver

Question 24

Where is bile stored?

Answer 24

The gall bladder

Question 25

Two functions of bile

Answer 25

• neutralises hydrochloric acid from the stomach
• emulsifies fat

Question 26

What does the term emulsifying fats mean?

Answer 26

• break fats into tiny droplets

Question 27

Why does emulsification of fats make digestion faster?

Answer 27

Gives a bigger surface area for lipeases enzymes to work on

Question 28

Why is it important that bile is an alkaline?

Answer 28

To neutralise stomach acid and create optimum conditions for enzymes in small intestine

Question 29

What is the test for starch? And colour change

Answer 29

• Iodine solution
• brown/orange - blue/black

Question 30

Test for presence of proteins and colour change?

Answer 30

• biuret
• blue - purple

Question 31

Test for lipids and colour change

Answer 31

• Sudan III / ethanol
• Sudan III - mixture will separate into two layers top one is red
• ethanol - cloudy white emulsion

Question 32

Test for presence of reducing sugars and colour change

Answer 32

• Benedict’s test
• blue/green - yellow - brick red with increasing amounts of sugar

Question 33

What is the name of the protease that is found in the stomach called?

Answer 33

• pepsin

Question 34

Where does the gall bladder release bile into?

Answer 34

• small intestine

Question 35

Where does the absorption of products of digestion happen?

Answer 35

• small intestine

Question 36

Function of hydrochloric acid

Answer 36

• kills bacteria
• makes acidic conditions for pepsin
• works best at ph 2

Question 37

Function of digestion

Answer 37

• breaks big molecules into smaller ones tat can easily be absorbed