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REVIEWER OF BIOCHEMISTRY, Cheat Sheet of Biochemistry

Virgen Milagrosa University Foundation (VMUF)Biochemistry

ALL ABOUT PROPERTIES OF BIOLOGY AND CHEMISTRY IT

Typology: Cheat Sheet

2023/2024

Uploaded on 10/21/2023

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BIOCHEMISTRY LABORATORY
[reviewer]
Experiment #1 pH and Buffer
OBJECTIVE: To explain some factors
affecting the biochemical reactions that take
place in living systems.
Materials/Reagents:
Beaker
Test tubes
Test tube rack
Pipette
Medicine dropper
Graduated cylinder
pH meter
pH paper
Litmus paper
Samples:
1. Fresh milk
2. Tea
3. Pure water
4. Vinegar
5. Coke
6. Chlorox
7. Soap solution
8. Calamansi
9. Rubbing alcohol
10. Shampoo
Procedure:
1. Determine the pH of the assigned
sample. If fruit or vegetables is desired, a
small sample of juice may be obtained by
grinding and squeezing.
2. Use a wide range paper (pH 1-14) to get
the approximate idea of the pH. (pH paper
or the test strips for pH)
3. Subsequently, use narrow range paper to
determine the pH to within 0.2 unit. (Litmus
paper
4. Check the pH obtained from the pH paper
with the use of a pH meter.
pf3
pf4
pf5
pf8

Partial preview of the text

Download REVIEWER OF BIOCHEMISTRY and more Cheat Sheet Biochemistry in PDF only on Docsity!

BIOCHEMISTRY LABORATORY

[reviewer]

Experiment #1 pH and Buffer OBJECTIVE: To explain some factors affecting the biochemical reactions that take place in living systems. Materials/Reagents: Beaker Test tubes Test tube rack Pipette Medicine dropper Graduated cylinder pH meter pH paper Litmus paper Samples:

  1. Fresh milk
  2. Tea
  3. Pure water
    1. Vinegar
    2. Coke
    3. Chlorox
    4. Soap solution
    5. Calamansi
    6. Rubbing alcohol
    7. Shampoo Procedure:
    8. Determine the pH of the assigned sample. If fruit or vegetables is desired, a small sample of juice may be obtained by grinding and squeezing.
    9. Use a wide range paper (pH 1-14) to get the approximate idea of the pH. (pH paper or the test strips for pH)
    10. Subsequently, use narrow range paper to determine the pH to within 0.2 unit. (Litmus paper
    11. Check the pH obtained from the pH paper with the use of a pH meter.

QUESTIONS:

1. How does the pH of your assigned sample as obtained from the pH paper compared with the pH obtained from the pH meter?  pH obtained in pH paper is only limited in acquiring pH range (wide range) pH paper and in classifying the samples as acid or base only (narrow range pH in meter but corresponds to the obtained in pH meter is specific for it shows the (H+) 2. Blood has a (H+) = 5x10-8. Calculate the pH. pH= kg (H+) pH--log ( 5 * 10 to the 8 power) pH = 7. 3. Calculate the pH of 0.15 Macetic acid. Ka = 2x10- (HA) solution concentration (H+) hydrogen ion concentration (A) = antilog concentration Given: (HA) = 0.15I molarity) Ka = 2 * 10.5 I Formula: Ka=(H+) (A)/(HA) = (H+)2/(HA) (H+)=square root of Ka (HA) (H+) square root of (0,15) (2 x 10-5) = 1.732050807 * 10 - 3 pH=-log (H+),-log (1.732050807 x 10-3) pH=2. **QUESTIONS BUFFER:

  1. Which is the best at resisting pH change when acid is added: water, acetic acid, acetate ion or buffer?**  Buffer is the best at resisting pH change when acid is added. It is a solution that resists change in pH following the addition of an acid or base 2. Which is the best at resisting pH change when base is added: water, acetic acid, acetate ion or buffer.  Buffer is the best at resisting pH change when base is added. 3. Why would it be useful to "buffer" as Aspirin tablet? (Aspirin is acetylsalicylic acid)  The pH of buffer aspirin was a lot of higher than others.  Keeping the acetylsalicylic acid in ionic form or preventing it from dissolving until it reached the small intestine would prevent it from causing bleeding. 4. Explain the significance of buffer.  Butters are vital in health and biological sciences for virtually all chemical reactions in living systems take place in buffered solution.  This includes reaction in intracellular and extracellular fluid as well as in the blood.

#4 0.5 M urea #5 Chloroform

  1. Centrifuge the blood sample for 5 minutes at a reasonable speed. Pipet off and discard the liquid portion.
  2. Add 3 drops of the blood cells remaining in the conical tube to each of the 5 test tubes above. Mix by inverting and allow to stand for about 30 minutes or until next laboratory meeting
  3. Ask for the room temperature reading from the laboratory technician. Room temperature: ___________
  4. Examine a drop of the blood sample in the conical tube under the microscope,
  5. Examine also the contents of each of the live test tubes under the microscope, and compare the results obtained in No. 6
  6. On a separate sheet of paper make a drawing of each observation (6 in all) describing what happened in each or the appearance of each **IV. PRESENTATION OF RESULTS OBTAINED/OBSERVATIONS: Drawing: QUESTIONS
  7. a.) Why do cells tend to shrivel when placed in a concentrated salt solution?**  Cells tend to shrivel when placed in a concentrated salt solution because the osmosis of high concentration to low concentration causes the cells to shrivel or shrink from lack of water balance. b.) What will happen when cells are in contact with 0.9% NaCl solution (NSS)?  A solution of 0.9% NaCl is isotonic to the cytoplasm of cells. There will be equal movement of water by osmosis. The cells would maintain their size and shape. 2. What is osmotic pressure? Explain its significance in biochemistry.  Osmotic pressure which needs to be applied to a solution to prevent the inward flow of water across a semi-permeable membrane. In the molecular level, storage cells maintain osmotic pressure by storing energy in forms of macromolecules such as polysaccharide, rather than micro molecules, such as glucose.

Experiment #13 Saponification of Fats Characteristics of Fats

  1. saturated fatty acids
  2. glycerol
  3. solid at room temperature except Theobroma oil
  4. heavy to digest due to quality of fat
  5. not soluble in water.
  • Theobroma oil is also called cocoa butter and cacao oil. Procedure: Weigh 1.5 g of fresh coconut oil in a dry beaker. Add 10 ml of 10% alcoholic KOH. Cover the beaker with a watch glass. Fill the watch glass with crushed ice. Boil over a water bath until a drop of hot solution added to cold water in a test tube do not form globules of fat. Remove the watch glass to drive off the alcohol. Add 20 ml of water to the gelatinous mass and warm it to dissolve the soap. **PROPERTIES OF SOAP
  1. Separation by Salting-out** Place 10 ml of the soap solution in a beaker and add Sodium chloride gradually while stirring until no more NaCl dissolves. Remove the solid mass of soap formed on top of the liquid. Wash the mass with water. Transfer a small amount of the soap in a test tube and shake with distilled water to produce suds. Observation: Explain the principle in "salting out". **ANSWER: Salting out - addition of high salt concentration causes precipitation.
  2. Formation of fatty acid** Place 5 ml of the soap solution in a test tube and add 2 mL. 10% HCI drop until a precipitate form 3. Insoluble soaps A. Prepare two test tubes containing 4 ml of distilled water and 1 ml of soap solution. To test tube # 1, add 2 ml of 5% CaCl and to test tube #2 add 2 ml of 5% Magnesium chloride. Observation: B. Repeat the test using 4 ml of distilled water and 1 ml of liquid detergent. Observe and compare the results with that of Procedure A. Observation: 4. Separation of Fatty acids
  3. To the remainder of the solution, add 1:4 Sulfuric acid in excess (about 15 ml) and heat at or near the boiling temperature for 2 minutes (CAUTIONI). Note the oily layer of fatty acid that gradually forms on the surface.
  4. Cool until the top layer solidifies. Rub some of it on a piece of paper. 5. Separation of Glycerol
  5. Neutralize 2 ml of the filtrate from #4 with dilute NaOH using litmus paper as indicator. Add a pinch of potassium bisulfate and heat. Note the odor: