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AS Biology - Unit 1 > Unit 1: Section 2 - The Digestive System > Flashcards

Unit 1: Section 2 - The Digestive System Flashcards

0
Q

Polymers are long chains of?

A

Monomers

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1
Q

Digestion is the process in which……………?

A

Large molecules are hydrolysed by enzymes to produce smaller molecules that can be absorbed and assimilated

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2
Q

Are protein and most carbohydrates polymers or monomers?

A

Polymers

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3
Q

In carbohydrates the monomers are called?

A

Monosaccharides

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4
Q

In proteins the monomers are called?

A

Amino acids

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5
Q

What elements to monosaccharides contain?

A

Carbon, hydrogen and oxygen

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6
Q

What elements do amino acids contain?

A

Carbon, hydrogen, oxygen and nitrogen

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7
Q

Which element is present only in monomers in protein?

A

Nitrogen

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8
Q

What’s the difference between absorption and assimilation?

A

Absorption is when molecules move from the digestive system into the blood where as assimilation is where absorbed molecules are incorporated into body tissues

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9
Q

What’s is assimilation?

A

Assimilation is where absorbed molecules are incorporated into body tissues

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10
Q

How does physical digestion happen in the mouth and stomach?

A

By the teeth in the mouth, and by the churning movement of the stomach muscles in the stomach

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11
Q

Why does physical digestion make digestion easier?

A

It breaks down food into smaller pieces giving a larger surface area for chemical digestion to take place on

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12
Q

What happens during chemical digestion?

A

Polymers are hydrolysed into smaller more soluble molecules which can be absorbed

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13
Q

How is the digestive process started in the mouth?

A

Teeth begin to break down the food (physical digestion) and the tongue is used to push food down the oesophagus

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14
Q

Why is saliva secreted?

A

Makes food easier to swallow and it contains enzymes which start chemical digestion

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15
Q

How is the digestive process continued in the oesophagus?

A

It takes food from the mouth to the stomach using peristalsis

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16
Q

What is peristalsis?

A

Wave like movements caused by contraction and relaxation of muscles, pushing food down the digestive tract

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17
Q

Why is mucus secreted in the oesophagus?

A

To lubricate the foods passage downwards

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18
Q

How is the digestive process continued in the stomach?

A

The stomach walls produce gastric juice to break down the food in the stomach (chemical digestion). Any the peristalsis of the stomach turn food into an acidic fluid called chyme

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19
Q

What do gastric juices contain?

A

Hydrochloric acid, pepsin and mucus

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20
Q

What are the two main parts of the small intestine?

A

Duodenum and ileum

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21
Q

The duodenum and ileum are parts of the?

A

Small intestine

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22
Q

What happens in the duodenum?

A

Bile and pancreatic juice neutralise the acidity of the chyme and break it down into smaller molecules

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23
Q

What happens in the ileum?

A

Small soluble molecules are absorbed through villi in the lining of the walls

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24
Q

What’s another name for the large intestine?

A

Colon

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25
Q

What happens in the large intestine?

A

Water, salts and minerals are absorbed

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26
Q

What final part of the digestive process happens in the rectum?

A

Faeces are stored in the rectum and then pass through the anus on defecation

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27
Q

What is the name of the glands in the digestive system?

A

The salivary glands and the pancreas

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28
Q

What do the salivary glands do?

A

Secrete saliva

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29
Q

What does saliva contain?

A

Mucus, mineral salts and salivary amylase

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30
Q

What does the pancreas release into the duodenum and why?

A

Pancreatic juice, to provide enzymes for digestion and to neutralise the hydrochloric acid from the stomach

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31
Q

Why does the acidity of the chyme have to be neutralised?

A

So that the digestive enzymes can work in the small intestine

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32
Q

What enzymes are within the pancreatic juice?

A

Amylase, trypsin, chymotrypsin and lipase

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33
Q

What does bile contain that neutralise the stomach acid?

A

Sodium hydrogencarbonate

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34
Q

What three classes can digestive enzymes be divided into?

A

Carbohydrases, proteases and lipases

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35
Q

Carbohydrases catalyse the……….?

A

Hydrolysis of carbohydrates

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36
Q

Proteases catalyse the……….?

A

Hydrolysis of proteins

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37
Q

Lipases catalyse the……….?

A

Hydrolysis of lipids

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38
Q

What enzymes is produced by the salivary glands?

A

Amylase

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39
Q

What enzymes is produced by the stomach?

A

Pepsin

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40
Q

What enzymes are produced but the pancreas?

A

Amylase, trypsin, chymotrypsin, carboxypeptidase and lipase

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41
Q

What enzymes are produced in the ileum?

A

Maltese, sucrase, lactase and peptidase

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42
Q

Where is amylase produced?

A

In the salivary glands and pancreas

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43
Q

Where is pepsin produced?

A

In the stomach

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44
Q

Where is trypsin produced?

A

In the pancreas

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45
Q

Where is carboxypeptidase produced?

A

In the pancreas

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46
Q

Where is chymotrypsin produced?

A

In the pancreas

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47
Q

Where is lipase produced?

A

In the pancreas

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48
Q

Where is maltase produced?

A

In the ileum

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49
Q

Where is sucrase produced?

A

In the ileum

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50
Q

Where is lactase produced?

A

In the ileum

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51
Q

Where is peptidase produced?

A

In the ileum

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52
Q

What are four examples of a carbohydrase?

A

Amylase, maltase, sucrase and lactase

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53
Q

What are four examples of a protease?

A

Pepsin, trypsin, chymotrypsin and carboxypeptidase

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54
Q

What is an example of a lipase?

A

Lipase

55
Q

Amylase hydrolysis what? into?

A

Starch into maltose

56
Q

Pepsin, trypsin and chymotrypsin hydrolyse what? Into?

A

Protein into peptides

57
Q

Carboxypeptidase and peptidase hydrolyse what? Into?

A

Peptides into amino acids

58
Q

Lipase hydrolyses what? Into?

A

Lipids into fatty acids and glycerol

59
Q

Maltase hydrolyses what? Into?

A

Maltose into glucose

60
Q

Sucrase hydrolyses what? Into?

A

Sucrose into glucose nod my fructose

61
Q

Lactase hydrolyses what? Into?

A

Lactose into glucose and galactose

62
Q

What is a dipeptide?

A

When two amino acids are joined together

63
Q

What’s the difference between dipeptides and polypeptides?

A

Dipeptides only contain two amino acids and polypeptides contain three or more

64
Q

What’s the same general structure that all amino acids have?

A

A carboxyl group, and an amino group attached to a carbon atom

65
Q

What is the difference between different amino acids ?

A

The variable group

66
Q

What reaction forms polypeptides from amino acids?

A

Condensation reactions

67
Q

What molecules is released during a condensation reaction?

A

Water

68
Q

What are the bonds between amino acids called?

A

Peptide bonds

69
Q

What’s the opposite of a condensation reaction?

A

Hydrolysis

70
Q

What happens during hydrolysis of polypeptide?

A

The peptide bond between the amino acids is broken down and a water molecules is added to form separate amino acids

71
Q

What’s the difference between hydrolysis and a condensation reaction?

A

In condensation reactions a water molecule is formed, hydrolysis reactions use a water molecule

72
Q

What are the names of the different structures of protein?

A

Primary, secondary, tertiary and quaternary

73
Q

What is the primary structure?

A

A sequence of amino acids in a polypeptide chain

74
Q

What is a secondary structure?

A

Hydrogen bonds form between amino acids in the polypeptide chain causing it to coil into an alpha helix or fold into a beta pleated sheet

75
Q

What two things do polypeptide chains from in the secondary structure?

A

Alpha helixs and beta pleated sheets

76
Q

What is the tertiary structure?

A

The coiled or folded chain of amino acids are coiled up and folded even further, and many more bonds form between different parts of the polypeptide chain

77
Q

Do all proteins have a quaternary structure and why?

A

No as some are only made up of one polypeptide chain

78
Q

What is the quaternary structure?

A

Several polypeptide chains are held together by bonds.

79
Q

Name three quaternary structure proteins?

A

Haemoglobin, insulin and collagen

80
Q

Why enzymes usually spherical in shape?

A

Due to the tight folding of the polypeptides

81
Q

What polypeptides are antibodies made up of?

A

Two light polypeptide chains and two heavy polypeptide chains

82
Q

Why structural proteins strong?

A

They consist of long polypeptide chains lying parallel to each other with cross links between them making them strong

83
Q

What test can you do to identify a protein?

A

Biuret

84
Q

What is the biuret test for proteins?

A

1.) add a few drops of sodium hydroxide to the solution
2.) then add some copper sulfate to the solution
3.) positive results - changes to purple
negative results - solution stays blue

85
Q

When doing a biuret test for protein why do you need to add sodium hydroxide to the solution?

A

To make it alkaline

86
Q

What causes lactose intolerance?

A

When you don’t have enough of the enzyme lactase you can’t break down the lactose properly, causing lactose intolerance

87
Q

When you have lactose intolerance what happens to the undigested lactose?

A

It is fermented by bacteria in the stomach causing intestinal problem

88
Q

What intestinal problems does lactose intolerance cause?

A

Stomach cramps, excessive flatulence and diarrhoea

89
Q

How does lactose intolerance cause diarrhoea?

A

Having a high concentration of lactose in the intestine causes water to move out of the blood into the intestines by osmosis. Meaning your faeces are more runny

90
Q

What’s another name for lipids?

A

Triglyceride

91
Q

What bonds form between fatty acids and glycerol to form lipase?

A

Ester bond

92
Q

What are three examples of monosaccharides?

A

Glucose, fructose and galactose

93
Q

What type of bond forms between two monosaccharides?

A

Glycosidic bond

94
Q

What is a disaccharide?

A

Two monosaccharides joined together

95
Q

What’s the difference between disaccharides and polysaccharides?

A

Polysaccharides contain more than two monosaccharides, disaccharides only contain two

96
Q

What are the two forms a glucose called?

A

Alpha and beta

97
Q

What reaction joins together two monosaccharides?

A

Condensation reaction

98
Q

What is a general term for monosaccharides and disaccharides?

A

Sugars

99
Q

What two groups can sugars be classified into?

A

Reducing and non reducing sugars

100
Q

What is the test called you can do for sugars?

A

Benedict’s test

101
Q

What’s the test you can do to find reducing sugars and what are the results?

A

Add Benedict’s reagent and heat it

If it contains reducing sugars it will turn brick red, if no reducing sugars are present it will stay blue

102
Q

If reducing sugars are present what do you expect to happen after the Benedict’s test?

A

It will turn brick red

103
Q

If reducing sugars aren’t present what can you do next to see if there are any non reducing sugars?

A

You have to break them down into their monosaccharides by boiling it with dilute Hydrochloric acid, you then add sodium hydrogen carbonate to neutralise the solution and carry out the Benedict’s test again

104
Q

What two polysaccharides are starch made up of?

A

Amylose and amylopectin

105
Q

How is starch hydrolysed into alpha glucose molecules?

A

Starch is hydrolysed by amylase into maltose

Maltose is then hydrolysed by maltase into alpha glucose molecules

106
Q

What test can you do to see if starch is present?

A

Add iodine dissolved in potassium iodide solution
If starch is present it will change to a dark blue black colour, if no starch is present it will remain a browny orange colour

107
Q

What’s the definition of a catalyst?

A

A substance that speeds up chemical reactions without being used up or changed in the reaction itself

108
Q

What are enzymes?

A

They are biological catalysts, catalysing metabolic reactions in your body

109
Q

What’s the part of an enzymes where the substrate binds to?

A

Active site

110
Q

What is activation energy?

A

The minimum amount of energy that needs to be supplied to the chemicals before the reaction will start

111
Q

Do enzymes increase or decrease activation energy?

A

Decrease

112
Q

Why can enzymes lower the temperature that some reactions can happen!

A

The activation energy for most reactions if given as heat, as enzymes decrease the activation energy they also decreases the temperature at which a reaction will happen

113
Q

What is it called when a substrate fits into the enzymes active site?

A

Enzyme - substrate complex

114
Q

What is the reason why enzymes substrate complexes lower the activation energy when substrate molecules are being joined together?

A

Being binded to the enzyme holds the two substrates closer together, reducing any repulsion meaning they can bond more easily

115
Q

What is the reason why enzymes substrate complexes lower the activation energy when substrate molecules are being broken apart?

A

When the substrate binds to the active site it puts a statin on the bonds in it so they can be broken more easily

116
Q

How many models are there for how enzymes work?

A

Two

117
Q

What are the names of the two models for how enzymes work?

A

The lock and key model

The induced fit model

118
Q

The enzymes and substrate have a what shape?

A

Complementary

119
Q

What does the lock and key model show?

A

The active site of the enzyme and the substrate have a complementary shape and fit together perfectly, they then bind together to form an enzyme-substrate complex. After this the substrate is released as two products. Or alternatively two substrate fit into the active site together and bond and become one product

120
Q

What does the induced fit model show?

A

The active site and substrate have a similar shape and when they bind together the active site changes shape slightly so that they are now complementary, forming an enzyme substrate complex. After this the substrate is released as two products. Or alternatively two substrate fit into the active site together and bond and become one product

121
Q

Why can enzymes only catalyse one reaction?

A

The shape of the active site is specific to the substrate

122
Q

What does the shape of the active site depend on?

A

The enzymes tertiary structure, which is determined by its primary structure

123
Q

Name five things that affect enzyme activity

A

Temperature, pH, substrate concentration, competitive and non competitive inhibitors

124
Q

What two ways can you measure enzyme activity?

A
  1. ) measure the amount of product produced

2. ) measure the amount of substrate left

125
Q

Why does an increase in temperature increase the rate of reaction between enzymes and the substrates?

A

More heat means the substrate molecules have more energy and move faster, meaning they are more likely to collide with the enzymes active site, the energy of these collisions also increases more likely resulting in a reaction

126
Q

What happens if you increase the temperature too high for an enzyme?

A

An increase in temperature makes the enzymes molecules vibrate more, these vibrations eventually cause the peptide bonds holding the enzyme in shape to break. This makes the enzyme and it’s active site change shape so it no longer fits the substrate. Denaturing it

127
Q

When the enzyme changes shape and can no longer catalyse the reaction it is said to be?

A

Denatured

128
Q

What’s the effect of a too high or too low pH on the rate of reaction between enzymes and their substrates ?

A

Above and below the optimum pH the H+ and OH- ions can distrust the ionic and hydrogen binds holding the enzymes tertiary structure in place, making it change shape and become denatured

129
Q

What does an increase in substrate concentration do to the rate of reaction?

A

Increase it up until the saturation point

130
Q

Why does an increase in substrate concentration cause the rate of reaction between the enzyme and substrate but only up till the saturation point?

A

More substrate means there will be more collisions between the substrate and active sites increasing the rate of reaction. However at saturation point all the active sites are occupied and increasing the substrate anymore won’t make any difference

131
Q

What are the molecules called that can prevent enzyme activity?

A

Enzyme inhibitors

132
Q

How do competitive inhibitors prevent enzyme activity?

A

They have a similar shape to the substrate molecules, and compete with the substrate molecules to bind to the active site. However no reaction takes place when they do they just block it for the substrate molecules meaning they can’t react

133
Q

How much the enzyme is inhibited depends on?

A

The relative concentrations of the inhibitors and substrate

134
Q

How do non competitive inhibitors prevent enzyme activity?

A

They bind to the enzyme away from the active site. Causing the active site to change shape so the substrate molecules can no longer bind it it

135
Q

Will increasing the concentration of substrate make any difference to non competitive inhibitors?

A

No as non competitive inhibitors don’t use the active sites and they will still alter the shape of the active sites

AS Biology - Unit 1 (5 decks)

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