Biuret Test for Proteins

Testing for the Presence of Proteins

Aim:
To test to see if a sample of food contains proteins.

Equipment:

• Test tube
• Sodium Hydroxide (0.1 mol/L)
• Copper sulfate (0.1 mol/L)
• Food sample (milk and eggs)

Method:

1. Place about 2mL of sample into a test tube.
2. Add 5 drops of sodium hydroxide
3. Add 5 drops of copper sulfate
4. Shake the test tube gently from side to side.
5. Record your observations.

Results:
The egg whites when tested with the Biuret solution turned a light blue colour and on further addition of sodium hydroxide turned a dark purple colour.

The milk did also turn a light blue colour but then stayed light blue. Due to the original colour of the milk the solution stayed a blue with a slight hint of pruple.

Conclusion:
Both the milk and eggs turned the blue biuret solution a purple colour which shows the presence of protein. Both milk and eggs are good examples of everyday foods which we expect to be high in protein and this test had confirmed that.

Simple and Complex Sugars Tests

Testing for Simple Sugars

Aim:

To test a sample of food to determine if it contains simple sugars.

Equipment:

Bunsen burner, test tube tongs, Benedict's solution, a sample of food.

Method:

1. Place about 2mL of sample (orange juice) into a test tube and then add 5 drops of Benedict's solution.
2. Heat with a Bunsen burner until it changes colour. Do not boil.

Results:

When the blue Benedict's solution was added to the orange juice a green solution was formed. However after heating the solution turned a a orange/brown colour.

Conclusion:

The Benedict's solution will turn from a blue to a yellow to a red/ orange if a simple sugar is present. When the colour of the orange juice was taken into account this colour change was observed. Hence orange juice must contain simple sugars.

Testing for Complex Sugars

Aim:

To test if a food sample contains complex sugars or not.

Equipment:

Test tube, food sample, iodine solution

Method:

1. Place about 2mL of the sample (frozen bread and water) in a test tube.
2. Add 3-5 drops of iodine solution.

Results:

When i added the brown solution to the bread it turned a black colour. 

Conclusion:

Because the iodine turned from a brown to a black colour then the bread must contain a complex sugar (starch).

Biology Research

Arthritis

Arthritis is a disease which affects the mobility of joints, causing painful inflammation and stiffness of the joints. The two most common forms of the disease are osteoarthritis and rheumatoid arthritis.

Osteoarthritis is a form of the disease where the cartilage between bones is worn away, causing the bones to rub against each other- very painful!


There are certain activities which can increase the risk of someone feeling the affects of osteoarthritis:

• Continual wear and tear
• Fractures and infections
• Overuse
• Physical inactivity
• Being overweight

Interesting fact: The term arthritis  refers to about 120 different diseases that can affect the joints, muscles and other soft tissues. The three most common forms are osteoarthritis, fibromyalgia and rheumatoid arthritis. .

Heart Attack

What is a heart attack?

A heart attack happens when there is a sudden complete blockage of an artery that supplies blood to an area of your heart. A heart is a muscle, and it needs a good blood supply to keep it healthy.

The causes of heart attacks and how to prevent one?

The underlying cause of a heart attack is coronary heart disease. Some people may not know they have coronary heart disease until they have a heart attack. For others, a heart attack can happen after weeks, months or years of having coronary heart disease. 

Medical treatments and healthy lifestyle choices can help your heart attack recovery, greatly reduce your risk of further heart problems, and relieve or control symptoms such as angina.

Symptoms of a heart attack?

Discomfort or pain in your chest. This can often feel like a heaviness, tightness or pressure. People who have had a heart attack have commonly described it as like “an elephant sitting on my chest”, “a belt that’s been tightened around my chest” or “bad indigestion”. The discomfort may spread to different parts of your upper body. Discomfort in your arm(s), shoulder(s), neck, jaw or back is common. You may have a choking feeling in your throat. Your arms may feel heavy or useless.

DNA Extraction from a Banana

Aim:

To find a valid method online and then to successfully extract strands of DNA from a banana.

Equipment:

1/2 peeled ripe banana, 1/2 cup water, 1 tsp salt, 1/2 tsp liquid dishwashing soap, resealable zip-top bag, very cold rubbing alcohol, coffee filter, funnel, stirrer.

Method:

1. Mush the banana in the resealable bag for about a minute until all the lumps are gone.
2. Fill a cup with water and salt.
3. Pour the saltwater mix into the bag. Close the bag and very gently squeeze and move the saltwater and banana mush together. Do this for 30 to 45 seconds.
4. Add the dishwashing soap into the bag and gently mix the contents. Try to avoid making too much foam.
5. Place the coffee filter in a funnel.
6. Pour the mix into the filter and let it sit until all of the liquid drips down into the beaker.
7. Remove and discard the used coffee filter.
8. Tilt the glass and slowly add cold alcohol down the side of the cup. You want the alcohol to form a layer on top of the banana mix, staying separated, so be careful not to pour it too fast. Make a layer of alcohol that is 2.5-5cm (1-2in) thick.
9. After the alcohol layer is set up, wait for eight minutes. You may see some bubbles and cloudy material moving around in the alcohol. This is the DNA pieces clumping together.
10. Use the wooden stirrer to start poking the cloudy stuff in the alcohol layer. Spin the stirrer it in place to start gathering the cloudy stuff. When you are done, take a closer look at the stuff on the stirrer. You are looking at DNA!

Method source: https://askabiologist.asu.edu/activities/banana-dna 

Results: