Food and energy Flashcards by Aria Lo Nigro

Is heat required in the glucose food test

Yes

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What reagent is used in the glucose food test

Benedict’s

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What is the initial colour of the solution before adding the reagent in the glucose food test

Blue

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What is the final colour of the solution after adding reagent in the glucose food test

Brick red precipitate

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Is heat required in the starch food test

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What is the reagent used in the starch food test

Iodine

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What is the initial colour before reagent is added in the starch food test

Yellow-Brown

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What is the final colour after reagent is added in the starch food test

Blue-Black

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Is heat required in the food test for protein

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What reagent is used in the test for protein

Biuret

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What was the initial colour before reagent was added in the protein food test

Blue

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What was the final colour after reagent was added in the protein food test

Purple

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Is heat required in the food test for fats

Warm

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What reagent is used in the test for fats

Ethanol

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What was the initial colour before the reagent was added in the fats food test

Clear

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What was the final colour after the reagent was added in the fats food test

White emulsion

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Method for the food test for glucose

-Add a few drops of glucose to a boiling tube
-Add a few drops of benedict’s to the boiling tube
-Heat in water bath

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Method for starch food test

-Add a few drops of starch to a spotting tile
-Add a few drops of iodine to the starch

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Method for protein food test

-Add a few drops of protein to a spotting tile
-Add a few drops of biuret to the protein

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Method for fats test

-Add 2ml of oil to a boiling tube
-Add 2ml of ethanol to the oil
-Mix together and warm in hands
-Add some water

What health conditions are associated with a poor diet

*Obesity -taking in too much energy
*Heart disease and strokes- build up of fatty substances in the walls of arteries
*Type 2 diabetes- Caused by poor diet or obesity leading to the body being unable to control blood sugar levels

List the three important food groups

-Carbs
-Protein
-Fats

What does carbs, protein and fats all have in common

-Carbon
-Hydrogen
-Oxygen

What do proteins contain that carbs and fats don’t

Nitrogen

2 examples of simple sugars

Glucose and lactose

2 characteristics of simple sugars

Soluble in water Tastes sweet

3 examples of complex sugars

-cellulose -glycogen -starch

Why is starch important in our diet

Starch is broken down into glucose during digestion and this is stored as glycogen

What is the role of cellulose

Cellulose is found in plant cell walls and it adds bulk to the food allowing the muscles in the intestine wall to push the food along

Name 3 types of food rich in simple sugars

Biscuits, cake, fizzy drinks

What foods can starch be found in

Potatoes, rice, pasta

Function of carbs

-Provide energy -Provide energy store

Why are proteins important in our diet

-Growth of cells -Repair of cells Only used as an energy source when carbs and fats are low

What are proteins made up of

Amino acids

What happens after the digestion of proteins in the body happens

Amino acids are absorbed into the blood and reassembled in our body cells into protein the body needs

Name 3 proteins our body makes

*Haemoglobin- required for red blood cells *Enzymes- required for digestion *Antibodies- required for immunity

Name 3 types of foods that are rich in protein

-Lean meat -Beans -Fish

Why are fats important in the diet

Act as an energy store so are a source of energy

What is produced when fats are broken down by enzymes

Glycerol, fatty acids

Name 2 foods rich in fat

Streaky bacon and cheese

Independent variable for burning biscuit practical

Type of biscuit

Dependent variable for burning biscuit practical

Temperature increase of the water

Controlled variable for bb practical

-Mass of biscuit -Same vol of water -Hold food same distance from boiling tube -Same amount of stirring

Method for bb practical

1.Measure mass of biscuit and volume of water(25ml) 2.Record initial temp of water 3.Set food alight using bunsen 4.Burn food completely and relight if it goes out 5.Hold food sample at a set distance under boiling tube 6.Stir water using stirring rod 7.Record final temp of water 8.Repeat with other food samples 9.Calculate energy content using values in the table 10.Repeat results from each group so you can repeat and take an average to ensure reliable results

Calculation for Energy(J)

Mass of water(g) x rise in temp(degrees) x 4.2

Calculation for energy in 1g (KJ/g)

Energy released by food sample(KJ) ÷ Mass of food sample(g)

How is a valid test achieved

Only one variable is changed and all rest are kept the same

Extra points for bb practical

-Use balance to weigh foods -Measure water with measuring cylinder

Why did the biscuits in the experiment contain less energy than the value contained in industry

-Not whole biscuit burnt -Heat energy lost to atmosphere and boiling tube