Biological molecules Flashcards

1
Q

What are organic nutrients?

A
  • carbohydrates
  • fats
  • proteins
  • vitamins
  • dietary fibre
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2
Q

What are inorganic nutrients?

A
  • mineral salts
  • water
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3
Q

What are micronutrients?

A
  • vitamins
  • mineral salts
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4
Q

What are macronutrients?

A
  • carbohydrates
  • fats
  • proteins
  • dietary fibre
  • water
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5
Q

What are the compounds of carbohydrates and what ratio are they in?

A
  • carbohydrates are made up of oxygen, carbon and hydrogen
  • hydrogen and oxygen atoms are in a ratio of 2:1
  • e.g. glucose: C6H12O6, Sucrose: C12H22O11
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6
Q

What are the functions of carbohydrates?

A
  • energy respiration (glucose)
  • energy storage (glycogen and starch)
  • supporting structures (cellulose cell wall)
  • to be converted to other organic compounds (e.g. fats)
  • lubricants
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7
Q

What are the types of carbohydrates?

A
  • monosaccharides
  • disaccharides
  • polysaccharides
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8
Q

What are the different types of monosaccharides?

A
  • glucose
  • galactose
  • fructose
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9
Q

What is the name of the test for reducing sugars?

A
  • benedict’s test for reducing sugars
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10
Q

What is used in the test for reducing sugars?

A
  • sample solution
  • benedict’s solution (copper (ll) sulphate)
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11
Q

How is the test for reducing sugars carried out

A
  • add equal volume of benedict’s solution to sample solution
  • shake the test tube
  • place test tube into boiling water bath for 5 minutes
  • observe colour of precipitate formed
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12
Q

What are the different colors of precipitate in the test for reducing sugars and what do they indicate?

A
  • Blue (no reducing sugars present)
  • Green (trace amounts of reducing sugars present)
  • yellow (moderate amount of reducing sugar present)
  • orange
  • brick red (high amount of reducing sugar present)
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13
Q

What are some examples of disaccharides?

A
  • lactose
  • sucrose
  • maltose
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14
Q

What are some examples of polysaccharides?

A
  • starch
  • glycogen
  • cellulose
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15
Q

How is maltose formed?

A
  • glucose + glucose → maltose
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16
Q

How is sucrose formed?

A
  • glucose + fructose → sucrose
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17
Q

How is lactose formed?

A
  • glucose + galactose → lactose
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18
Q

How are monosaccharides combined to form disaccharides?

A
  • condensation
19
Q

What is condensation?

A
  • when 2 simple molecules join together
  • with the removal of 1 water molecule
20
Q

How are disaccharides and polysaccharides turned back into monosaccharides?

A
  • hydrolysis
21
Q

What is hydrolysis?

A
  • when a water molecule is used to split a complex molecule into its component parts with acid or enzyme
22
Q

What are proteins made of?

A
  • proteins are made up of carbon, hydrogen, oxygen and nitrogen
  • sulfur is also often present
23
Q

What are proteins made up of (basic unit)?

A
  • amino acids
24
Q

How do amino acids form a polypeptide chain?

A
  • they are linked up
  • in a condensation reaction
25
Q

What are the bonds between amino acids known as?

A
  • peptide bonds
26
Q

What are proteins made up of (final product)?

A
  • 1 or more polypeptide chains
  • they are twisted or coiled into a unique 3-d structure
27
Q

Why do enzymes (proteins) denature easily?

A
  • bonds that hold the 3-d coiled structure together are weak
  • thus by heat, or changes to pH, enzymes denature easily
28
Q

What does denaturation cause?

A
  • it causes proteins to lose their functions
29
Q

What are the functions of proteins?

A
  • synthesis of new cells
  • growth and repair of cells
  • serve as chemical messengers (hormones etc)
  • transportation
  • structural function
  • defence of the body (antibodies)
  • energy
30
Q

What is the test for proteins known as?

A
  • Biuret’s test
31
Q

What are used in the test for proteins?

A
  • sample solution
  • sodium hydroxide
  • 1% copper (ll) sulfate
32
Q

What is the procedure for the test for proteins and what colour is observed?

A
  • add 1cm cube of sodium hydroxide to 2cm cube of sample
  • shake
  • add 1% copper (ll) sulfate, drop by drop
  • add drops and shake until a colour change is observed
  • blue to violet indicates the presence of proteins
  • blue indicates the absence of proteins
33
Q

What are fats made of?

A
  • carbon
  • hydrogen
  • oxygen
34
Q

What is less than what in fats?

A
  • less oxygen compared to hydrogen
35
Q

What are the properties of fats?

A
  • insoluble in water
  • less dense than water
  • conduct heat slowly
36
Q

What are the functions of fats?

A
  • they store energy
  • they store food in animals and humans
  • heat insulator
  • absorbs shock
37
Q

What is the test for fats known as?

A
  • ethanol emulsion test
38
Q

What are used in the ethanol emulsion test?

A
  • sample
  • ethanol
  • water
39
Q

What is the procedure of the ethanol emulsion test?

A
  • add 2cm cube of ethanol to sample
  • shake
  • add 2 cm cube of water
40
Q

What is the test for starch known as?

A
  • iodine test
41
Q

What are used in the test for starch?

A
  • iodine
  • sample
42
Q

What is the procedure for the test for starch?

A
  • place the substance on a white tile
  • add 2-3 drops of dilute iodine solution to the substance
  • observe colour changes
43
Q

What are the different colours in the test for iodine and what do they mean?

A
  • yellowish-brown to blue-black means starch is present
  • is the solution remains yellowish-brown, starch is absent
44
Q

What to do in case of testing solid foods?

A
  • chop food into smaller pieces
  • allow solid particles to settle
  • decant liquid only and test