1st paper 1 knowledge i got wrong

• Blood enters the heart through the atria
• .Blood from the pulmonary veins enters the left atrium
•  Blood from vena cavae enters the right atrium.
• Blood leaves the heart in the body's main artery - the aorta - from the left side, and the pulmonary artery, from the right.
• The pulmonary circulation transports blood to the lungs. At the lungs:

  • oxygen diffuses into the blood from the alveoli - the blood becomes oxygenated
  • carbon dioxide diffuses from the blood into the lungs
• The systemic circulation transports:

  • oxygen and nutrients to the body
  • carbon dioxide and other wastes away from cells
• Heart valves may become faulty. A valve may not:

  • open as wide as it should, restricting blood flow through the heart - this means less blood reaches the body, pressure builds up and the lungs can swell with fluid
  • close properly and allow blood to leak back through into the atrium
• The operation is usually successful. Mechanical valves last longer, but blood can clot on them. A patient may need long-term medication that prevents blood clots developing. Biological valves are more likely to wear out.
• An artificial pacemaker is a small, battery-operated electronic device implanted in a person's chest that sends out regular, adjustable electrical impulses to produce normal contractions of the heart.
• Anaerobic digestion is the process by which organic matter such as animal or food waste is broken down to produce biogas and biofertiliser. This process happens in the absence of oxygen in a sealed, oxygen-free tank called an anaerobic digester
• 1. Prepare Food Solutions

  • Grind each food sample thoroughly using a pestle and mortar with a small amount of water.
  • Filter the resulting mixture to produce a testable food solution.
• 1. Benedict’s Test for Sugars
  2. Set Up the Water Bath

  • Fill a 250ml beaker with water and heat it to around 80°C using heating equipment. Monitor with a thermometer.

  1. Perform the Test

  • Place a small amount of food solution into a test tube.
  • Add a few drops of Benedict’s solution to the tube.
  • Place the test tube into the water bath for approximately 5 minutes.

  1. Observe and Record

  • Note any colour change in the solution:
  • A brick-red colour indicates the presence of sugars.
• 1. Iodine Test for Starch
  2. Perform the Test

  • Add a small amount of food solution to a test tube.
  • Add a few drops of Iodine solution to the tube.

  1. Observe and Record

  • Note any colour change:
  • A dark blue/black colour indicates the presence of starch.
  • Repeat this procedure for other food samples.
• 1. Test for Lipids (Fats)
  2. Ethanol Emulsion Test

  • Add a small amount of food solution to a test tube.
  • Add a few drops of Ethanol (take care: highly flammable, avoid naked flames).
  • Shake the tube gently, then add a few drops of water.

  1. Filter Paper Test (Optional)

  • Rub a piece of each food sample onto filter paper and hold it up to light.

  1. Observe and Record

  • Note any observations:
  • If an emulsion forms (cloudy or milky appearance), lipids are present.
  • If the filter paper becomes slightly translucent, the food contains lipids.
• 1. Biuret Test for Proteins
  2. Two-Step Procedure

  • Add a small amount of food solution to a test tube.
  • Add 1ml of Biuret Solution A and 1ml of Biuret Solution B to the tube.
  • Shake the test tube gently to mix the contents.

  1. Observe and Record

  • Note any colour change:
  • A purple colour indicates the presence of proteins
• Independent variable – the variable that is altered during a scientific experiment. Dependent variable – the variable being tested or measured during a scientific experiment. Controlled variable – a variable that is kept the same during a scientific experiment.