Paper 1

• The nucleus contains the genetic material of the cell and controls the activities of the cell.
• The cytoplasm is where chemical reactions occur
• The cell membrane controls what enters and exits the cell.
• The mitochondria is the site of aerobic respiration and is where most of the energy is released.
• The ribosome is the site of protein synthesis in the cell.
• Plant cells have three extra structures: chloroplasts, cell wall and permanent vacuole.
• Cells exposed to light have chloroplasts for photosynthes.
• Eukaryotic cells are animal and plants cells and have a nucleus
• Prokaryotic cells hold genetic information in circular DNA and plasmids
• Light microscopes use light to form an image of the specimen.
• Magnification = image size / actual size x 1000
• Magnification is the amount that an image of something scaled up when viewed through a microscope.
• The electron microscope has higher magnification and higher resolution than the light microscope.
• Levels of organisation:

  1. Cells
  2. Tissues
  3. Organ
  4. Organ systems
• Gaseous exchange happens in the lungs.
• Alveoli are tiny air sacs in the lungs that are filled with air and have a large surface area to volume ratio
• Proteins are used for growth and repair.
• Lipids can be used as a source of energy.
• Lipids are found in cell membranes
• A substrate is a substance that is used by an enzyme to catalyse a reaction
• Proteins are made up amino acids
• Glucose is used for respiration and to make starch and glycogen which is stored in the liver
• Glucose food test:

  • Benedict test
  • If positive gives orange-red colour
• Starch food test:

  • iodine solution
  • if positive gives a blue-black colour
• Protein food test:

  • biuret test
  • if positive gives a purple colour
• Lipids food test:

  • a couple drops of ethanol
  • Turns a cloudy milky colour of positive
• The function of the digestive system is to breakdown and absorb food.
• Amylase are enzymes that break down starch, they are found in the mouth and small intestine
• Protease are enzymes that breakdown proteins, they are found in the stomach and small intestine
• Lipase are enzymes which breakdown lipids into fatty acids and glycerol, they are found in the pancreas and small intestine
• Enzymes are biological catalysts that speed up chemical reactions in the body.
• Denatured enzymes will no longer catalyse the reaction
• An enzyme is specific to one chemical reaction
• An enzyme has a unique shape and binds to a specific substrate to the active site
• The active site is the part of the enzyme that binds to the substrate.
• The optimum temperature for photosynthesis is 25-30 degrees Celsius
• The optimum PH for digestion in the stomach is 1.5 - 2.0
• Substances such as antibodies, carbon dioxide, hormones and wastes are dissolved into the blood plasma
• Red blood cells transport oxygen
• The pulmonary circuit is the blood flow through the lungs and the pulmonary artery on the right side of the heart.