1
Q
What element are food molecules based on?
A
Carbon
2
Q
What are the four ways carbohydrates are stored as?
A
- Sugars
- Starch
- Glycogen
- Cellulose
3
Q
What is the solubility characteristic of sugars?
A
All soluble in water
4
Q
What is the general process where complex organic molecules are broken down?
A
Digestion
This process involves the absorption of simpler molecules.
5
Q
What are catabolic pathways responsible for?
A
Digestion and Absorption
6
Q
What are anabolic pathways responsible for?
A
Assimilation
7
Q
What three elements are carbohydrates made of?
A
Carbon, Hydrogen and Oxygen
8
Q
What is the enzyme that breaks down starch into maltose?
A
Amylase
9
Q
What does maltase convert maltose into during digestion?
A
Glucose
10
Q
What is the role of starch in plants?
A
Glucose storage
11
Q
What is glycogen used for in animals?
A
Glucose storage
12
Q
What elements are proteins made of?
A
Carbon, hydrogen, nitrogen, and oxygen
13
Q
What are the subunits of proteins called?
A
Amino acids
There are 20 different types of amino acids.
14
Q
How does the sequence of amino acids in a protein affect its function?
A
Determines the protein’s unique shape
15
Q
What are lipids made of?
A
Glycerol attached to 3 fatty acids
16
Q
What elements do lipids primarily use?
A
Carbon, hydrogen, and oxygen
17
Q
What is the significance of the variety in fatty acids in lipids?
A
Leads to a large number of different lipid types
18
Q
What is the primary function of carbohydrates in the human body?
A
Provides energy for the body & brain
19
Q
What are the effects of carbohydrate deficiency?
A
Low BMI (body mass index)
20
Q
What is the role of protein in the human body?
A
Formation of bones, tissues, muscles, teeth, and skin
21
Q
What can result from protein deficiency?
A
Weakened immune system, slow growth
22
Q
List the functions of lipids in the human body.
A
- Regulation of hormones
- Transmitting nerve impulses
- Cushioning organs
- Storing energy as fat
23
Q
What are the effects of lipid deficiency?
A
Weight loss, dry skin, poor temperature regulation
24
Q
What is Vitamin C (Ascorbate) essential for?
A
- Healthy skin, Blood vessels, Bones
- Allergy protection
- Wound healing
- Iron absorption
25
What are the consequences of Vitamin C deficiency?
Weakened immune system, gums bleed, skin won't heal
26
What benefits does Vitamin A (Retinol) provide?
* Better night vision
* Fighting infections
* Healthy skin
27
What is the primary role of Vitamin D (Calciferol)?
Strengthens bones
28
What are the functions of the Vitamin B group?
Strong metabolism , energy production
29
What is the function of calcium in the body?
* Strong bones/teeth
* Healthy muscles
* Clotting blood
30
What can occur due to calcium deficiency?
Rickets, bending bones
31
What is one of the primary functions of Iron in the body?
Making haemoglobin
32
What condition is caused by Iron deficiency?
Iron deficiency anemia
33
What are the benefits of Fibre for the digestive system?
Helps maintain bowel health, lowers cholesterol, controls blood sugar, helps achieve a healthy weight
34
What does a balanced diet consist of?
The correct amount of each food group to suit your lifestyle
35
What energy needs are associated with more active lifestyles?
Need more energy per day
## Footnote
Increased activity demands higher caloric intake.
36
Who requires more energy based on body weight?
Heavier individuals typically require more energy.
37
What dietary needs do growing individuals have?
More energy per their body mass
38
What do pregnant women need more of to support the foetus?
More calcium for bone development
39
Why might menstruating women need more Iron?
Due to blood loss during menstruation
40
What is digestion?
The break down of large, insoluble molecules into smaller, soluble molecules.
41
What is the purpose of digestion?
To absorb small, soluble molecules into the blood.
42
What type of breakdown relies on chewing and stomach churning?
Mechanical/Physical Breakdown.
43
What aids chemical breakdown in digestion?
Digestive enzymes, which are biological catalysts.
44
How much faster does digestion occur with enzymes?
1,000,000,000 times faster.
45
What enzyme digests starch into maltose?
Amylase.
46
What is maltose further digested into, and using what enzyme?
Glucose, using maltase.
47
What enzyme digests proteins into amino acids?
Protease.
48
Where does protease digest proteins?
In the stomach and small intestine.
49
How are lipids emulsified?
By bile.
50
What products result from the digestion of lipids?
Fatty acids and glycerol.
51
What two processes are involved in digestion?
* Mechanical/Physical Breakdown
* Chemical Breakdown.
52
What is the role of bile in emulsification?
Bile breaks down fat into smaller fat droplets, increasing the surface area for lipase to digest.
53
What is emulsification?
A physical process where bile breaks down fat into smaller fat droplets.
54
What does bile do to stomach acid and why?
Bile neutralises acid from the stomach. This creates the optimum pH for enzymes to function.
55
What is peristalsis?
The process by which food passes through the gut via waves of muscle contraction.
56
How does fibre affect peristalsis?
Fibre provides more grip/friction, improving the effectiveness of peristalsis.
57
Where is bike made and stored?
Made in the liver, stored in the gall bladder
58
What are 6 steps of digestion
(PIG DIAGRAM)
59
What is absorption in the context of digestion?
Movement of the products of digestion (glucose, amino acids, glycerol & fatty acids) from the lumen of the small intestine into the blood or lymph nodes by diffusion or active transport.
60
What are the products of digestion that are absorbed?
* Glucose
* Amino acids
* Glycerol
* Fatty acids
61
What are the two mechanisms of transport for absorption?
* Active transport
* Diffusion
62
What adaptations increase the exchange surface for absorption?
* Large surface area (villi & microvilli)
* Length of approximately 10 meters
* Narrow structure to prevent food from getting stuck
* Extensive blood supply to maintain high concentration gradient
* Lacteals to remove fatty acids and glycerol
* Short diffusion distance (1 cell thick)
* Muscle action to push food along
63
What maintains a high concentration gradient in the small intestine?
Extensive blood supply
64
What are enzymes?
Proteins made of amino acids that act as biological catalysts
65
What is the role of enzymes in chemical reactions?
They lower the activation energy required, speeding up the reaction
66
What is activation energy?
The energy required for particles to collide and initiate a chemical reaction
67
Give an example of how enzymes speed up the reaction of starch.
Starch digestion takes two weeks without enzymes but only a few seconds with amylase
68
What is the unique feature of each enzyme?
Each enzyme has a unique shape with an active site
69
What is the active site?
A groove on the enzyme that fits the substrate like a lock and key
70
Why are enzymes specific?
Only one substrate fits the active site of an enzyme
71
What is formed when an enzyme binds to its substrate?
Enzyme/Substrate Complex
72
What does the enzyme do to the bond between the substrate molecules?
Weakens and breaks the bond
73
What happens to the enzyme after the reaction?
It remains unchanged and can be used again
74
How does temperature affect the rate of reaction for enzymes?
Initially increases the rate due to more collisions, but after reaching its optimum it decreases as the enzyme gets denatured.
75
What is the optimum temperature for enzyme activity?
The temperature at which the reaction is fastest
## Footnote
This can vary depending on the specific enzyme.
76
What is denaturation in the context of enzymes and how do they become denatured?
A permanent change in protein shape, with extreme temperatures and pH levels.
77
What factors affect enzyme activity?
Light intensity, Carbon Dioxide availability, pH level, temperature
78
How does light intensity affect the rate of photosynthesis?
As light intensity increases, so does the rate of photosynthesis until something else is limiting
79
What is the approximate level of Carbon Dioxide (CO2) in the atmosphere?
0.04%
80
At what CO2 level is it no longer the limiting factor?
approximately 1%
81
What is the optimum pH for enzymes in the stomach, mouth and intestines?
Varies, but typically around 1-2 in the stomach, 7 in the mouth, and 8 in the intestines
82
What can happen to enzymes under too alkaline or acidic conditions?
They can denature
83
What is the reagent used to test for starch?
Iodine
84
What color indicates a positive test for starch?
Black
85
What is the reagent used to test for glucose?
Benedict's solution
86
What color change indicates a positive test for glucose using Benedict's solution?
Orange --> red
87
What is the reagent used to test for protein?
Biuret
88
What color indicates a positive test for protein?
Purple
89
What is the method for testing lipids?
Emulsion test by mixing with ethanol and water
90
What color indicates a positive test for lipids?
Milky white
## Footnote
A milky white emulsion indicates the presence of lipids.
91
How do you test for starch?
Use a dimple dish and add iodine to food and mix
92
How do you test for glucose?
Use a test tube and add Benedict's to food then mix & heat
93
How do you test for protein?
Use a dimple dish and add Biuret and alkali to food and mix
94
How do you test for lipids?
Use a test tube, add ethanol, and then add water
95
Fill in the blank: A negative test for glucose shows a color change of _______.
Blue
## Footnote
Blue indicates the absence of reducing sugars.
96
Fill in the blank: A negative test for starch shows a color change of _______.
Brown
## Footnote
Brown indicates that starch is not present.
97
Fill in the blank: A negative test for lipids shows a color change of _______.
Clear
## Footnote
Clear indicates that no lipids are present.
98
What is the chemical equation for photosynthesis?
6CO₂ + 6H₂O → C₆H₁₂O₆ + 6O₂
99
What role does chlorophyll play in plants?
Chlorophyll traps light energy, which is turned into chemical energy
## Footnote
Chlorophyll is located inside chloroplasts and is essential for photosynthesis.
100
How do plants utilise glucose?
* To make amino acids for growth and repair
* To make cellulose, which strengthens cell walls
* To make fats and oils, especially in seeds
* For respiration, where glucose is broken down to release energy
* Stored as starch for efficient storage because it is more compact and insoluble
101
What are the deficiency symptoms of nitrate in plants?
Stunted growth, older leaves turning yellow
## Footnote
Nitrate is essential for making amino acids, which are crucial for growth.
102
What deficiency symptoms occur due to a lack of magnesium in plants?
Leaves turn yellow with dead spots
## Footnote
Magnesium is important for chlorophyll production.
103
What happens to young leaves when there is a phosphorus deficiency?
Young leaves turn purple
## Footnote
Phosphorus is vital for DNA production and energy transfer.
104
What is the effect of potassium deficiency in plants?
yellow leaves with dead spots
## Footnote
potassium is used to make enzymes
105
How do you test leaves for starch?
* Place the leaf in a beaker and fill it with boiling water to stop further reactions. Boiling water softens and kills the leaf.
* Half-fill a boiling tube with ethanol and use tweezers to move the leaf into the boiling tube. The ethanol dissolves the membrane and removes its chlorophyll.
* Place the boiling tube into the beaker of water for 5 mins
* Remove the leaf from the tube and rinse it
* This means you can see the colour change when iodine is added- ethanol would decolourise iodine
* If the iodine turns brown, no starch is present and the leaf has respired recently, and if it is black, then the leaf hasn't respired recently.
106
Name a factor that may affect photosynthesis.
* Light intensity
* Chlorophyll
* CO2 Level
107
What could you do to test the effect of carbon dioxide on photosynthesis?
Use one leaf with KOH, which absorbs CO2, and one normal leaf
108
What is the function of the waxy cuticle in plants?
Prevents water loss
## Footnote
The waxy cuticle is a protective layer that helps retain moisture in plants.
109
What are palisade cells primarily responsible for?
Contain many chloroplasts, site of photosynthesis
## Footnote
Palisade cells are located beneath the epidermis and are crucial for capturing sunlight.
110
What is the role of the spongey layer in leaves?
Contains many air spaces for gases to diffuse through
## Footnote
This layer aids in gas exchange within the leaf.
111
What do guard cells do?
Open and close stomata
## Footnote
Guard cells control the exchange of gases and water vapor in and out of the leaf.
112
What are the components of a vein in plant leaves?
Xylem and phloem
## Footnote
Xylem transports water and minerals, while phloem transports sugars.
113
Where are stomata primarily located in leaves?
Lower epidermis
## Footnote
Stomata are pores that facilitate gas exchange.
114
What is the primary function of the epidermis in leaves?
Protective layer with few chloroplasts
## Footnote
The epidermis acts as a barrier and helps protect internal tissues.
115
What is the main purpose of stomata in leaves?
Allows gases in and out of the leaf
## Footnote
Stomata are essential for photosynthesis and respiration.
116
How do you investigate the energy content of food?
* Weigh the mass of food
* Measure 20ml of water and measure its temperature
* Set fire to the food ad hold it under the test tube
* Once it is completely burned, take the temperature again
117
What formula is used to calculate the energy of food?
Energy = change in temp. x mass of water (g) x 4.2
## Footnote
The constant 4.2 represents the specific heat capacity of water.
118
Hoe do you investigate the effect of temperature on enzymes?
* Add a drop of iodine into the depressions on the dimple dish
* Measure 3ml of starch solution into a test tube and 3ml of amylase solution in another
* Place both in a water bath (5°C, 20°C, 40°C, 60°C and 75°C)
* Wait 5 mins for the solutions to equilibriate to that temperature
* Mix the two and start a timer
* Immediately add a drop to the first depression
* Repeat every 15 seconds
* Note the time when the colour changes
119
What is the optimum temperature for enzymes to work?
40°C
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