Enzymes and human nutrition Flashcards
1
Q
What chemical elements are present in carbohydrates?
A
C,H,O
2
Q
What chemical elements are present in lipids
A
C,H,O
3
Q
What chemical elements are present in proteins?
A
C,H,O,N,S
4
Q
What are complex carbohydrates like starch and glycogen made up of?
A
Simples sugars
5
Q
What are proteins made up of?
A
Amino acids
6
Q
What are two molecules of lipids made up of?
A
Glycerol and fatty acid tails
7
Q
What are enzymes?
A
Biological catalysts that increase the rate of metabolic reactions
8
Q
State 4 factors that affect enzyme function
A
Temperature, pH, substrate concentration, enzyme concentration
9
Q
Describe the effect of temperature on the rate of an enzyme-controlled reaction
A
- As the temperature increases, so does the rate of reaction
- Once the temperature exceeds the optimum, the enzyme denatures and the rate of reaction decreases
10
Q
Why does the rate of an enzyme controlled reaction increase when the temperature increases?
A
- As the temperature increases the particles have more kinetic energy
- This increases the chance of collisions between molecules and leading to a reaction
11
Q
If temperature increases above the optimum, how does this affect enzyme function?
A
The active site will be distorted as the enzyme denatures and so it will no longer fit the substrate
12
Q
Describe the effect of pH on the rate of an enzyme-controlled reaction
A
- The rate of an enzyme catalysed reaction is fastest at its optimum pH
- If the pH is too high or low, the enzyme will work less efficiently and the active site may be denatured at extremes of pH
13
Q
Why is a balanced diet important?
A
The body needs different substances in different proportions to function properly, too much or too little of different things can be harmful
14
Q
What 7 groups are needed for a balanced diet?
A
Carbohydrates, proteins, lipids, minerals, water,vitamins and dietary fibre
15
Q
What is the function of carbohydrates in the diet?
A
Carbohydrates are the body’s main source of energy
16
Q
What are the functions of proteins in the body?
A
helps repair and build bodys tissues
17
Q
What are the functions of lipids in the body?
A
structural components of cell membranes, energy storehouses, important signalling molecules
18
Q
What is vitamin A used for?
A
Keeping skin healthy, improved vision in the dark, strengthening immune system
19
Q
What is vitamin C used for
A
Growth and repair
20
Q
What is vitamin D used for
A
Absorption of calcium
21
Q
What is calcium used for in the body?
A
Strengthens bones and teeth
22
Q
What is iron used for in the body
A
Haemoglobin to transport oxygen in the blood
23
Q
What is water used for in the body?
A
A reaction medium, temperature control, transport
24
Q
What is dietary fibre used for?
A
Helps keep everything flowing through the digestive system
25
Compare the energy requirements of more and less active people
The more active a person is, the greater their energy requirement
26
What is the alimentary canal?
The complete tube that food passes through as it passes through the body
27
What is the difference between the alimentary canal and the digestive system?
The alimentary canal involves tubes that the food passes through whereas the digestive system also includes digestive glands
28
Describe the passage of food through the alimentary canal
Mouth>oesophagus>stomach>small intestine>large intestine>rectum
29
What is the function of the mouth?
To chew and break down food, to secrete digestive enzymes
30
What is the oesophagus?
The tube that carries food from the mouth to the stomach
31
What does the stomach do?
The stomach is a muscular sac containing acid that breaks the food down further
32
What role does the pancreas play in digestion?
The pancreas secretes digestive enzymes into the small intestine
33
What are the two parts of the small intestine called?
Duodenum and ileum
34
What is the function of the duodenum
The duodenum receives food directly from the stomach and uses enzymes and chemical digestion to break the food down
35
What is the function of the ileum?
where Most nutrients are absorbed from the food into the blood
36
How is the ileum adapted for absorption?
The ileum is lined with villi which provide a large surface area for reabsorption
37
How are villi adapted for absorption?
Thin walls, large surface area, good blood supply close to the surface
38
What is the function of the large intestine (colon)
Water is reabsorbed into the blood in the large intestine
39
What is the function of the rectum?
The rectum stores faeces before egestion
40
What enzymes break starch down into glucose?
Maltase and amylase
41
What group of enzymes break proteins down into amino acids?
Proteases
42
What group of enzymes break lipids down into glycerol and fatty acids?
Lipases
43
What does bile do?
Neutralises the stomach acid and provides alkaline conditions for the digestive enzymes in the small intestine, emulsifies fats
44
Where is bile produced?
In the liver
45
Where is bile stored
In the gallbladder
46
How does peristalsis work to push food through the gut?
Muscles contract in a wave like function which pushes food along
47
Describe the test for glucose
1. Add sample to test tube
2. Add drops of Benedict’s solution
3. Heat in a water bath at 60-70 degrees Celsius for 5 mins
4. Take the test tube out and record the colour
48
What colours can the solution turn in the glucose test
If glucose is presently the solution will turn brick red. If glucose is not present the solution will remain blue
49
Describe the starch test
1. Pipette the sample solution into a tile
2. Add drops of iodine solution and leave for 1 min
3. Record any colour change
50
What colours can the solution turn in the starch test
If starch is present the solution will turn blue-black. If starch is not present the solution will remain brown
51
Describe the test for protein
1. Add the sample solution into a test tube
2. Add drops of Biuret solution into the test tube
3. Leave for 1 min and then record the colour
52
What colour can the solution turn in the protein test
If protein is present the solution will turn purple. If protein is not present the solution will remain blue
53
Describe the test for fat
1. Add 2cm cubed of ethanol to the test solution
2. Add 2cm cubed of distilled water
3. Leave for 3 mins and then record the colour
54
What colours can the solution turn in the fat test
If fat is present a milky white emulsion will form. If fat is not present the solution will remain colourless
55
What is ingestion?
The taking of substances eg food and drink, into the body through the mouth
56
What is digestion?
The breakdown of food from large insoluble molecules to small soluble molecules
57
What is absorption?
The movement of digested food molecules through the wall of the intestine into the blood
58
What is assimilation?
The movement of digested food molecules into the cells where they are used
59
What is egestion?
Egestion happens when faeces pass out of the body through the anus
60
Why is food moved through the gut by peristalsis?
It helps water from undigested food be absorbed into the bloodstream
61
What are digestive enzymes?
Enzymes that break down proteins, carbohydrates and fats into their basic building blocks such as amino acids, simple sugars and fatty acids
62
What is an active site?
Part of the enzyme that is complementary to the shape of the substrate. The shape of the active site may change if the enzyme is exposed to high temperatures or extremes of pH
63
What are amino acids?
Small molecules from which proteins are assembled
64
What is glycogen?
A large carbohydrate made from many glucose molecules joined together. It serves as an energy store in animals.
65
What are lipids?
A group of large molecules that are made from long fatty acid chains and glycerol. Lipids include fats and oils
66
What are proteins?
Large molecules made up of amino acids
67
What is starch?
A large carbohydrate molecule made up of many glucose molecules joined together. It serves as an energy storage molecule in plants
68
What is amylase?
An enzyme produced in the salivary glands and pancreas that breaks down starch into maltose
69
What is the colon?
The first part of the large intestine where water is reabsorbed
70
What is the duodenum?
The first section of the small intestine where digestive enzymes and bile are added to the ingested food
71
What is the ileum?
The second section of the small intestine where the products of digestion are absorbed
72
What is lipase?
An enzyme produced in the pancreas that breaks down lipids into fatty acids and glycerol
73
What is maltase?
An enzyme produced in the small intestine that breaks down maltose into glucose
74
What is the oesophagus?
A muscular tube that takes food from the mouth to the stomach
75
What is the pancreas?
An organ that produces digestive enzymes and releases them into the small intestine
76
What is peristalsis?
The ‘squeezing’ movement of muscles that pushes the bolts of food along the digestive tract
77
What is protease?
An enzyme produced in the stomach and pancreas that breaks down proteins into amino acids
78
What is the rectum?
Part of the large intestine where faeces is stored
79
What is villi?
Small, finger-like structures on the surface of the small intestine that increase the surface area for absorption
80
What is the purpose of proteins?
To give structural support, growth and repair
81
What is the purpose of carbohydrates?
Can be useful for structural support and as a source of stored energy
82
What is the purpose of lipids?
Make up cell membranes, important source of stored energy
83
Examples of carbohydrates
Bread, cereals, pasta, rice, potatoes
84
Examples of proteins
Meat, fish, eggs, pulses
85
Examples of lipids
Butter, oil, nutes
86
Examples of dietary fibre
Vegetables, bran
87
Purpose of dietary fibre
Provides of roughage to keep food moving through gut
88
What does deficiency of dietary fibre cause?
Diarrhoea and constipation
89
Examples of vitamin A
Carrots, green vegetables
90
Examples of vitamin C
Helps to absorb iron
91
Examples of vitamin D
Margarine, oily fish
92
Example of calcium
Milk
93
What can deficiency of calcium cause?
Rickets (curving of bones)
94
Examples of iron
Red meat
95
What can deficiency of iron cause
Anaemia
96
Examples of water
Water, juice, milk
97
What are the factors that affect energy requirements?
Age, activity levels, pregnancy
98
How does age affect energy requirements?
Energy requirements generally increase as we approach adulthood. Energy needs of adults go down as they age
99
How does pregnancy affect energy requirements?
Energy requirements will increase in order to support growth of the foetus. Energy needs also increase due to extra mass of baby
