Biological Molicules And Food Tests Flashcards

1
Q

What are biological molecules

A

Carbohydrates, lipids and proteins. They are long complex molecules made up from smaller basic units.

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2
Q

What are carbohydrates made up of

A

Simple sugars

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3
Q

What elements do carbohydrates contain

A

Carbon, hydrogen, oxygen

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4
Q

What are proteins made up of

A

Amino acids

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5
Q

What elements do proteins contain

A

Carbon, nitrogen, hydrogen and oxygen

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6
Q

What are lipids made up of

A

Three fatty acids and glycerol

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7
Q

What elements do lipids contain

A

Carbon, hydrogen, oxygen

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8
Q

How do you prepare a food sample

A

Get food and break it up with pestle and mortar
Transfer food to beaker and add water
Stir mixture with glass rod to dissolve some food
Filter solution using funnel lined with filter paper to get rid of solid food

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9
Q

Which food test tests for glucose

A

Benedicts

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10
Q

Which food test tests for starch

A

Iodine solution

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11
Q

Which food test tests for protein

A

Biuret

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12
Q

Which food test tests for lipids

A

Sudan III

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13
Q

What food contains glucose

A

Biscuits, cereal, bread,

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14
Q

What food contains starch

A

Pasta, Rice, potatoes

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15
Q

What food contains protein

A

Meat, cheese

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16
Q

What food contains lipids

A

Olive oil, margarine, milk

17
Q

What is benedicts solutions normal colour

A

Blue

18
Q

How to test for glucose with benedicts solution

A

Prepare food sample
Transfer 5cm cubed to a test tube
Prepare water bath to 75 celcius
Add benedicts solution to test tube (10 drops) with pipette
Put test tube in water bath using a test tube holder and leave for 5 minuets and make sure the tube is facing away from you

If the food sample contains glucose the solution will change to green or yellow in low concentrations and brick red in high concentrations.

19
Q

What colour does benedicts solution change to if glucose is present

A

Green or yellow in low concentrations and brick red in high consentrations

20
Q

How to test for starch with iodine

A

Make food sample and transfer 5cm cubed to test tube
Add a few drops of iodine and gently shake to mix
If sample contains starch the solution will cha he to black or blue black

21
Q

What is iodine solutions normal colour

A

Brown orange

22
Q

If starch is present what colour will iodine solution change to

A

Black or blue black

23
Q

What is biuret solution normal color

A

Blue

24
Q

How to test for protein with biuret solution

A

Prepare food sample and transfer 2cm cube to test tube
Add 2cm cube if biuret solution to sample and gently shake to mix
If the sample contains protein the solution will change to pink or purple

25
Q

What colour will biuret solution change to if protein is present

A

If the sample contains protein the solution will change to pink or purple

26
Q

How to test for lipids with Sudan III stay solution

A

Prepare food sample ad transfer 5cm cubed to test tube (no need to filter solid food)
Add 3 drops of Sudan III with pipette and shake gently to mix
If the sample contains lipids the mixture will separate into two layers and the top layer will be bright red

27
Q

What colour will Sudan III stain solution turn if lipids are present

A

If the sample contains lipids the mixture will separate into two layers and the top layer will be bright red

28
Q

What is the chemical formula for glucose

A

C6 H12 O6

29
Q

How do you experiment to see how well enzymes work at different temps

A

Potatoes contain enzyme catalase which breaks down hydrogen peroxide.

  1. Place a 1cm cube if potato in 2 test tubes
  2. Cover with water
  3. Keep first tube at room temp and place second in a water bath
  4. Ad 5ml of hydrogen peroxide to both tubes and record the amount of bubbling in each tube

There should be more bubbling in room temp as room temp is closer to body temp.