(2.7-2.9) Carbs, Proteins, Lipids + testing

What are carbohydrates?

The main source of energy

What elements are found in carbohydrates?

Carbon, Hydrogen, Oxygen

What are the two types of carbohydrates?

Simple carbs

Complex carbs

What type of energy release do simple carbs cause?

Quick energy release due to quick digestion

What type of energy release do complex carbs cause?

Slow energy release due to gradual digestion.

What are the 2 main classifications that come under simple carbs?

Monosaccharides (monomers) and disaccharides (2 monomers)

Name the monosaccharides.

Glucose

Fructose

Galactose

(GFG)

Name the disaccharides.

Maltose

Lactose

Sucrose

(meet the mls!)

Name the monomers of sucrose. (sugar)

Glucose + Fructose

Name the monomers of lactose. (milk)

Galactose + Glucose

Name the monomers of maltose.

Glucose + Glucose

Name the types of complex carb. (polysaccharides, many monomers)

Cellulose

Starch

Glycogen

What is cellulose used for?

The cell walls in plants.

What is starch used for?

Storage in plants.

What is glycogen used for?

Storage in animals.

Describe the test for the presence of glucose.

• Put samples of food in test tubes with Benedict’s Reagent.

• Heat the test tubes in a water bath set to 60-80 degrees for 5 mins.

• Remove test tubes and observe colour change.

Describe the colour change for Benedict’s Reagent.

red → orange → green → blue

none → some → more → lots

(NOT YELLOW)

Describe the test for the presence of starch.

• Add drops of iodine solution onto a sample on white tile

• Observe colour change

What is the colour change for iodine?

Red-Brown → Blue-Black

no starch → starch

What are lipids?

Fats when solid, Oils when liquids

What are the properties of lipids?

Hydrophobic

Good insulators

Energy dense

What elements are lipids made up of?

Carbon, Hydrogen, Oxygen

What is the structure of lipids?

They are triglycerides:

made up of 3 fatty acid chains chemically bonded to a glycerol molecule

Name the saturation levels of lipids.

Saturated Lipids

(Mono)unsaturated Lipids

(Poly)unsaturated Lipids

What are saturated lipids?

• Least healthy

• No double bonds

• They have the most hydrogen in the fatty acid chains.

• Very energy dense

• Solids

• Animal fats

What is a monounsaturated lipid?

• Healthier than saturated fats

• 1 double bond

• Less hydrogen→ less energy dense

• Liquids/oils

• animals/plants

What is a polyunsaturated lipid?

• More than one double bond

• Least hydrogen→ least energy dense

• Plants + fish

• Healthiest

Describe how to test for lipids.

• Crush around 5g of the sample and put in a test tube

• Add around 2ml of ethanol and 2ml of water

• Shake and observe colour change

If there is cloudy white emulsion, lipids are present.

What are proteins?

Polymers of amino acid monomers with different levels of structure and functions

What elements are present in proteins?

Carbon, Hydrogen, Oxygen, Nitrogen

How are proteins formed?

There are 20 different amino acids. The order of their arrangement affects the type of protein that is formed when they form a chain. The shape affects their functions.

Describe the experiment to test for presence of proteins.

• Add sample into test tube

• Add Biuret solution

• Observe colour change

What is the colour change for Biuret solution?

Blue → Violet

no protein → protein

Describe the structure of carbs, proteins and lipids in one sentence.

Large molecules made up from smaller basic units.