SCIENCE_PRE-ASSESSMENT (4TH QUARTER)

• Biomolecules


  any molecules that are produced by a living organism, including large macromolecules such as proteins, polyssachrides, lipids, and nucleic acids
• Carbohydrates


  most common biomolecule

  primary energy source of the body

  Formula: (CH20) where n is the number of molecules
• Monosaccharides


  Simple Sugars

  ex. Glucose, fructose, galactose
• Disaccharides


  Double sugars

  ex. maltose, lactose, glucose+fructose
• polysaccharides


  Examples.

  1. starch

  2. glycogen

  3. cellulose
• Starch


  used for energy storage in plants

  they provide a quick form of energy for the body
• Glycogen


  Used for energy storage in animals

  when the body doesn't need glucose for energy, it stores it into the liver and muscles in the form of glycogen
• Cellulose


  found in plants, in cell walls and bark of trees

  gives us fiber
• Chitin


  forms the exoskeleton of certain insects and crustaceans
• Iodine test


  test used to determine the oresence of starch in materials

  A positive result for the iodind test (starch is present) was a color change ranging from violet to black; a negative result (no starch) was the yellow color (no change) of the iodine solution
• Benedicts test


  test used for simple carbohydrates.

  
  

  Green: then there would be 0.1 to 0.5 percent sugar in solution.

  
  

  Yellow: then 0.5 to 1 percent sugar is present.

  
  

  Orange: then it means that 1 to 1.5 percent sugar is present.

  
  

  Red: then 1.5 to 2.0 percent sugar is present.

  
  

  Brick red: it means that more than 2 percent sugar is present in solution.
• Proteins


  Body-building molecules which helps us grow

  Transport molecules in and out of the cell

  Control the speed of chemical reactions

  Used for growth and repair
• Biuret test


  Tests for proteins
• Biuret Test


  a chemical test used to determine the presence of a peptide bond (chemical bond between amino acids) in a substance. The test yields a negative result if the Biuret reagent remains blue, and it yields a positive result if the reagent changes from blue to purple.
• Nucleic acids


  these biomolecules are not necessarily from food

  
  

  Biomolecular components of hereditary materials and are present in DNA

  
  

  • Building blocks: nucleotides
• Lipids


  Are also energy-giving molecules, but they are more commonly referred as the stored-energy molecules

  
  

  They store more energy than carbohydrates and proteins.

  
  

  Building block: fatty acids
• Ethanol emulsion


  Ethanol is added to the sample. Lipids are not present if the substance remains colorless and no emulsion is formed. Lipids are present in the substance, however, if a layer of cloudy white suspension forms above the solution.
• Combined Gas Law


  Deals with changes in pressure, volume, and temperature.

  
  

  Use when you have initial and final conditions for a gas undergoing changes.

  
  

  For problems involving processes where a gas changes from one set of conditions to another.
• Ideal Gas Law


  Applies to ideal gases under various conditions.

  
  

  Use when you have values for pressure (P), volume (V), temperature (T), and the number of moles (n).

  
  

  Problems where you know the state variables for a gas at a particular point in time.
• Combined Gas Law

  V2=0.64 L


  A gas occupies 2.3 liters at a pressure of 1.3 atm. What is the volume when the pressure is increased to 4.7 atm? The temperature remains constant.

  What formula will be used and what is the answer?
• Combined Gas Law

  V2=3.13L


  3.22 L of a gas is collected at 23.0 °C. What will be its volume after it cools to 15.0 °C if pressure remains constant?

  What formula will be used and what is the answer?
• Combined Gas Law

  V2=8.6L


  A sample of gas has a volume of 15.0L at a pressure of 1.0 atm and a temperature of 27.2 degrees Celsius. What is the new volume if the pressure is raised to 1580 mmHg and the temperature is raised to 356.2K degrees Celsius?

  What formula will be used and what is the answer?