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Biology > Biological Molecules, Enzymes and Human Nutrition > Flashcards

Biological Molecules, Enzymes and Human Nutrition Flashcards

(103 cards)

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1
Q

True or False? Carbohydrates, proteins, and lipids contain carbon.

A

True.

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2
Q

What are the chemical elements present in carbohydrates?

A

Carbohydrates are made of carbon, oxygen and hydrogen.

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3
Q

True or False? Starch, glycogen, and cellulose are all made of glucose.

A

True.

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4
Q

What are the chemical elements present in proteins?

A

Proteins contain carbon, oxygen, hydrogen and nitrogen. Some contain small amounts of other elements such as sulfur.

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5
Q

What is the product when proteins are broken down into smaller molecules?

A

When proteins are broken down into smaller molecules amino acids are produced.

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6
Q

What are the chemical elements present in lipids?

A

Lipids are made of carbon, oxygen and hydrogen.

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7
Q

True or False? Fats and oils are built from many glycerol molecules.

A

False.

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8
Q

What is the test for starch?

A

The test for starch involves adding iodine solution to a food sample. A positive result is a colour change from orange-brown to blue-black.

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9
Q

True or False? A positive iodine test will turn the solution from red to blue-black.

A

False.

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10
Q

What is the test for glucose (a reducing sugar)?

A

The test for glucose involves adding Benedict’s solution to a sample and heating it in a boiling water bath. A positive result is a colour change from blue to brick red.

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11
Q

What is the starting colour of Benedict’s solution?

A

The starting colour of Benedict’s solution is blue.

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12
Q

What is the test for the presence of protein?

A

The protein test involves adding Biuret solution to a food sample. A positive result is a colour change from blue to violet/purple.

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13
Q

What is the starting colour of Biuret solution?

A

The starting colour of Biuret solution is blue.

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14
Q

What is the test for lipids?

A

The test for lipids involves mixing a sample with ethanol and then adding the ethanol solution to cold water. A positive result is a cloudy white emulsion forming.

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15
Q

What does the DCPIP test for vitamin C involve?

A

The DCPIP test for vitamin C involves the addition of a food sample to blue DCPIP solution. If vitamin C is present then the DCPIP will become colourless.

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16
Q

Which of the food tests must be heated to observe the results?

A

The Benedict’s test for glucose (a reducing sugar) must be heated to observe the results.

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17
Q

Describe the structure of DNA. (Extended Tier Only)

A

DNA consists of two strands coiled around each other to form a double helix. The strands are held together by a series of paired bases with bonds in between.

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18
Q

Identify the four nucleotide bases found in DNA. (Extended Tier Only)

A

The four nucleotide bases in DNA are: A, T, C, G.

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19
Q

True or False? Nucleotide base A pairs with G in DNA. (Extended Tier Only)

A

False.

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20
Q

Describe how bases pair together in DNA. (Extended Tier Only)

A

Bases in DNA pair together via complementary base pairing: A pairs with T, C pairs with G.

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21
Q

What sequence of bases would pair with the DNA base sequence below (Extended Tier Only): ACCGTTTGCAA

A

The base sequence would be paired as follows: TGG CAA ACG TT.

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22
Q

Define the term enzyme.

A

An enzyme is a protein that acts as a biological catalyst to speed up the rate of a chemical reaction.

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23
Q

What does a catalyst do?

A

A catalyst speeds up the rate of a chemical reaction without being used up or changed in the reaction.

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24
Q

True or False? Enzymes are necessary for all living organisms.

A

True.

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25
Define the term substrate.
A substrate is the reactant of an enzyme-catalysed reaction.
26
State the meaning of the term active site.
The active site is the region on an enzyme where a specific substrate attaches for the reaction to be catalysed.
27
What happens after a reaction has occurred in the active site of an enzyme?
After the reaction has occurred the products leave the enzyme's active site and the enzyme is free to take up another substrate.
28
True or False? Enzymes are changed or used up in the reactions they catalyse.
False.
29
Define the term optimum temperature.
The optimum temperature is the temperature at which an enzyme works fastest.
30
Define the term denatured.
When an enzyme is denatured its active site changes shape and can no longer bind to its specific substrate.
31
In a practical that investigates the effect of temperature on rate of reaction in amylase, what is the variable being changed?
The variable being changed (independent variable) is the temperature of the amylase and starch reaction mixture.
32
In a practical that investigates the effect of temperature on rate of reaction in amylase, what is the purpose of adding iodine solution?
Iodine is added to detect the presence of starch. When all the starch has been digested into sugar the iodine will no longer turn blue-black.
33
True or False? In a practical that investigates the effect of temperature on rate of reaction in amylase, the iodine solution will stop turning blue-black fastest at the optimum temperature.
True.
34
In a practical that investigates the effect of temperature on rate of reaction in enzymes, what happens to the rate at low temperatures?
The rate of reaction will be slow at low temperatures due to low kinetic energy.
35
In a practical that investigates the effect of temperature on rate of reaction in enzymes, what happens to the rate at high temperatures?
The rate of reaction will decrease to zero at high temperatures because the amylase enzyme has become denatured.
36
In a practical that investigates the effect of temperature on rate of reaction, which variables should be kept constant?
The concentration and volume of starch solution, the concentration and volume of enzyme solution, and the pH.
37
In a practical that investigates the effect of temperature on rate of reaction in enzymes, why must the starch and amylase solutions be placed in a water bath at optimum temperature before being used?
The reactants and enzymes must be placed in a water bath at optimum temperature to be brought up to the correct temperature before the investigation.
38
In a practical investigating the effect of pH on rate of reaction in amylase, why does the iodine solution stop turning blue-black at certain pH levels?
The iodine solution stops turning blue-black because the starch is fully broken down by the amylase.
39
In a practical investigating the effect of pH on rate of reaction in amylase, what impact does the optimum pH have on the rate of amylase activity?
At the optimum pH the iodine solution will stop turning blue-black and remain orange-brown within the shortest time period.
40
In a practical investigating the effect of pH on rate of reaction in amylase, what impact does a very low pH, such as pH2, have on the rate of amylase activity?
At very low pH values the iodine solution will continue turning blue-black because the enzymes are denatured.
41
What is a buffer solution?
A buffer solution is a solution that resists changes in pH upon the addition of small amounts of an acid or base.
42
What is the role of a buffer solution when investigating the effect of pH on enzyme activity?
Buffer solutions are used to maintain a specific pH environment for the amylase enzyme.
43
True or False? The starch and amylase solutions need to be at room temperature to investigate the effect of pH on the activity of amylase.
False.
44
Define the term specificity in the context of enzymes. (Extended Tier Only)
Enzyme specificity means that enzymes only bind to/catalyse the reaction of one specific substrate.
45
What is an enzyme-substrate complex? (Extended Tier Only)
An enzyme-substrate complex is formed when a substrate attaches to the active site of an enzyme.
46
True or False? Enzymes can bind to several types of substrate. (Extended Tier Only)
False.
47
True or False? The substrate is the same shape as the active site. (Extended Tier Only)
False.
48
Why is enzyme activity low at low temperatures? (Extended Tier Only)
Enzyme activity is low at low temperatures due to a lack of kinetic energy.
49
Why does increasing temperature towards the optimum temperature increase reaction rate? (Extended Tier Only)
Increasing the temperature towards the optimum increases enzyme activity as the molecules have more kinetic energy.
50
Why does increasing temperature too far beyond the optimum temperature result in a reaction rate that decreases to zero? (Extended Tier Only)
Increasing temperature too far beyond the optimum reduces reaction rate to zero because heat breaks the bonds that hold the enzyme together.
51
What happens to an enzyme or substrate if its kinetic energy increases? (Extended Tier Only)
If an enzyme or substrate gains kinetic energy it moves around faster.
52
Why does the rate of an enzyme-controlled reaction decrease as the pH level moves further from the enzyme's optimum pH? (Extended Tier Only)
The rate of an enzyme-controlled reaction decreases as the pH level moves further from the enzyme's optimum because extremes of pH break the bonds that hold the amino acid chain together.
53
True or False? All enzymes denature in acid. (Extended Tier Only)
False.
54
A balanced diet includes all nutrients in equal quantities.
False. A balanced diet consists of all nutrients in their correct proportions, not necessarily equal quantities.
55
Define the term balanced diet.
A balanced diet consists of all essential nutrients in their correct proportions.
56
What are the key components of a balanced diet?
The key components of a balanced diet are: Carbohydrates, Proteins, Lipids, Dietary fibre, Vitamins, Minerals, Water.
57
Not having a balanced diet can lead to malnutrition.
True.
58
Calcium is part of a balanced diet.
True. Calcium is an important mineral required in the formation of teeth and bones.
59
What disease causes bowing of the legs due to vitamin D deficiency?
The disease that can arise from vitamin D deficiency which causes bowing of the legs is rickets.
60
Carbohydrates are a source of energy.
True.
61
Why are proteins needed in the body?
Proteins are essential for repair and growth.
62
What is the function of lipids in the body?
Lipids, e.g. fats and oils, act as an energy store, protect vital organs, and help reduce heat loss.
63
What are minerals?
Minerals are chemical elements essential for many processes in the body. Examples include iron and calcium ions.
64
Vitamins A is important for maintaining good eyesight.
True. Vitamins A is needed for the production of pigments in the retina.
65
Why is dietary fibre an important component of a balanced diet?
Dietary fibre provides bulk in the intestines, aiding the movement of solid waste and preventing constipation.
66
Water is the main component of blood, and of cell cytoplasm.
True.
67
Name two foods that are sources of carbohydrate.
Carbohydrates can be obtained from: Pasta, Rice, Potatoes, Cereals, Bread, Sugary foods, e.g. fruit juice, chocolate, biscuits.
68
Why is iron important in the diet?
Iron is essential for production of haemoglobin, which carries oxygen in the blood.
69
Why is vitamin D needed in the body?
Vitamin D aids absorption of calcium, so is essential for strong bones and teeth.
70
What is scurvy?
Scurvy is caused by a lack of vitamin C and leads to anaemia, exhaustion, bleeding, pain in the limbs, swelling, tooth loss.
71
What is the function of the digestive system?
The function of the digestive system is to break down large, insoluble food molecules into small, soluble molecules that can be absorbed.
72
Name the organs of the digestive system through which food passes during digestion.
The organs of the alimentary canal through which food passes are: Mouth, Oesophagus, Stomach, Small intestine (duodenum and ileum), Large intestine, Rectum.
73
Mechanical digestion takes place in the mouth.
True.
74
What is the role of saliva in digestion?
Saliva contains amylase enzymes that begin the chemical breakdown of starch into sugars.
75
What is the role of the oesophagus in digestion?
The oesophagus is the tube through which food passes between the mouth and the stomach.
76
Both mechanical and chemical digestion take place in the stomach.
True.
77
What is the role of the large intestine in digestion?
The role of the large intestine is to allow absorption of water from solid waste before it is egested.
78
The pancreas is part of the alimentary canal.
False.
79
Name three organs of the digestive system that release enzymes.
Three organs of the digestive system that release enzymes include: Salivary glands, Stomach, Small intestine.
80
Which organ is bile released from?
Bile is released from the liver.
81
Physical digestion is the same as mechanical digestion.
True.
82
How does physical digestion aid chemical digestion?
Physical digestion increases the surface area of food for the action of enzymes in chemical digestion.
83
Give an example of physical digestion in the human digestive system.
Physical digestion includes chewing food in the mouth, churning food in the stomach and emulsification of fats in the intestine.
84
Define physical digestion.
Physical digestion is the breakdown of food into smaller pieces without chemical change to the food molecule.
85
Which of the following shows the tooth designed for biting and cutting?
Tooth number 3 is an incisor which is shaped specially to facilitate biting and cutting.
86
Which tooth is a premolar?
Number 1 is a premolar which is designed for chewing and grinding food up.
87
Name the four human teeth types.
Human teeth include: Canines, Incisors, Premolars, Molars.
88
Teeth are used in chemical digestion.
False.
89
Describe the structure of a tooth.
Teeth are made up of enamel, dentine, pulp, nerves, blood vessels and cement.
90
Define the term organ.
An organ is a collection of tissues working together to perform one function.
91
What is the function of the stomach?
The stomach has three roles: To mechanically digest food through the churning of food, To produce the enzyme protease, To produce hydrochloric acid (stomach acid).
92
Name the organ system the stomach is part of.
The stomach is part of the digestive system.
93
What is the role of mucus-producing cells in the stomach?
The role of mucus-producing cells in the stomach is to protect the stomach lining from hydrochloric acid (stomach acid).
94
Name two organs of the digestive system, other than the stomach.
Two other organs of the digestive system: Mouth/tongue/salivary glands, Oesophagus.
95
What are the two main roles of bile? (Extended Tier Only)
Bile's main roles are neutralising stomach acid and emulsifying fats.
96
Define the term emulsification.(Extended Tier Only)
Emulsification is the process of breaking apart large fat droplets into smaller ones, increasing the available surface area for enzyme action.
97
What is the significance of emulsification in digestion? (Extended Tier Only)
Emulsification increases the surface area of fat droplets, increasing the efficiency of fat digestion by lipase enzymes in the small intestine.
98
Emulsification is a type of chemical digestion. (Extended Tier Only)
False.
99
Where is bile produced? (Extended Tier Only)
Bile is produced by cells in the liver.
100
Name the organ that stores bile before releasing it.(Extended Tier Only)
Bile is stored in the gall bladder before it is released into the small intestine.
101
The liver and the gall bladder are part of the alimentary canal. (Extended Tier Only)
False.
102
What is the role of chemical digestion?
The role of chemical digestion is to break down large insoluble molecules into small soluble molecules which can be absorbed.
103
Glucose is a small soluble molecule which can be absorbed in the small intestine.
True.

Biology (3 decks)

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