Experiment 8 Properties of Nucleic Acids

(Nucleic acids) (nucleotides) (nitrogenous base, pentose, and a phosphate group) (nitrogenous base) (pentose) (3 or 5)

(__________) are polymers of (____________). A (3) (___________) comprises a (_______, _______, _________). The (_________) is bonded to the (_________) via N glycosidic bond at carbon 1, while the phosphate is bonded to the pentose via ester bond through the –OH group at carbon (_______). Individual nucleotides are bound with phosphodiester bonds between carbons 3 and 5. Nucleic acids can be deoxyribonucleic acids (DNA) or ribonucleic acid (RNA). Structurally, DNA differs from RNA because , while RNA is single stranded.

(nitrogenous bases) (bicyclic purines) (adenine and guanine) (monocyclic pyrimidine) (thymine) (cytosine) (uracil)

The (___________) can be (__________), specifically (_____&______); or (____________), like (_______) (for DNA only), (________), and (_____) (for RNA only).

(ribose or deoxyribose) (deoxyribose) (ribose)

The pentose can be a (_______________). DNA contains (__________), while RNA contains (______).

(acidic character) (phosphate residues) (H+) (dissociation) (polyanions) (polycations) (negative) (positive)

From its name, we can already say that nucleic acids have (________). The acidity of the nucleic acids is caused by the (__________), each of which contains (___) capable of (________). Due to this, nucleic acids are (___________) – carrier of many (_______) charges, and this makes them capable of interacting with (_________), particularly with alkaline proteins (histones) – which are carriers of (________) charges.

(alkaline environment) (nucleates) (water) (ethanol)

RNA, like all nucleic acids, is a polyanion. In an (__________), they form salts – (_________), which are soluble in (_______). They can be precipitated from the solution with (____________).

(pinch) (yeast RNA) (water) (95% ethanol) (diluted HCl solution) (diluted NaOH solution)

PROCEDURE:

1. Place a (______) of (_______) in 5 separate test tubes. Label the test tubes

1-5.

2. Add the following solvents accordingly into each test tube:

i. Test tube 1 – 2 mL (_____)

ii. Test tube 3 – 2 mL (__________)

iii. Test tube 4 – 2 mL (___________)

iv. Test tube 5 – 2 mL (___________)

3. Shake each test tube well.

4. Observe the appearance. Record your observation in Table 1

(Mash) (Ziploc bag) (3) 1(20 mL water) (foaming) (dishwashing liquid) (ice-cold isopropyl) (5-15) (2 liquids) (wooly precipitate)

II. EXTRACTION OF DNA FROM BANANA PROCEDURE:

1. (_____) banana in a (________) for about (___) minutes.

2. Add (_______), 1 tablespoon salt, and 1 tablespoon dishwashing liquid. Continue mashing to mix the components but very carefully to avoid (______) caused by the (_____________)

3. Filter the mixture through filter paper. Collect the filtrate.

4. Superimpose equal volume of (__________) alcohol into the filtrate.

5. Wait for (______) minutes. At the junction of the (______), observe the appearance of (____________). It is the DNA.

6. Using the glass rod, gently swirl the junction

(hydrolysis) (water) (catalysts) (enzymes or acids)

Like any other macromolecules, nucleic acids can also undergo (________). Recall that (1) (_________) is the breakdown of a large molecule into its smaller fragments when reacted with (_____) in the presence of (______), such as (______________).

(nucleic acid hydrolysis) (nucleotides) (nucleotides) (nitrogenous bases, pentose, and phosphate residues)

In this experiment, you will be doing acid hydrolysis of your extracted DNA and yeast RNA.

The first stage of (_____________) is its breakdown into (_________). The (2) (__________)

are further broken down into its corresponding components, namely the (_______, ______, ______)

(10 mL of 10% H2SO4) (Shake and boil) (2) (hydrolysate) (1-3) (DNA)

PROCEDURE:

1. Place a pinch of yeast RNA in a test tube.

2. Add (______________) solution into the test tube. (_____&______) the mixture for (__) minutes.

3. Cool the mixture and save for the chemical tests for the components of nucleotides. The mixture obtained after hydrolysis is called (__________).

4. Repeat procedure (___) using a pinch of your extracted (____).

(hydrolysate) (nucleotide’s components)

III. CHEMICAL TESTS FOR THE COMPONENTS OF NUCLEOTIDES

If the acid hydrolysis was successfully done in the previous procedure, it is safe to assume that the (________) already contains free form of the (__________________). Recall that a (2) (___________) comprises a nitrogenous base, a pentose, and a phosphate residue.

(1 mL) (hydrolysates) (5 drops of ammoniacal silver nitrate) (1 mL of NH4OH.) (white precipitate) (silver ion and purines)

PROCEDURE:

*Test for Purine (Nitrogenous Base)

1. Place (_____) each of the (___________) obtained from DNA and RNA in two separate test tubes.

2. Add (_____________________) solution into each test tube and add (_________)

3. Observe for the formation of (___________), which is an insoluble complex of (________&________) . Record your observation in Table 2.

(2 drops of Molisch’s reagent) (45o angle) (superimpose 1 mL of concentrated H2SO4) (purple ring)

Molisch Test

1. Place 1 mL each of the hydrolysates obtained from DNA and RNA in two separate test tubes.

2. Add (__________) each test tube.

3. Tilt each test tube at (________________) and (_________________ ) along its side. Do not shake.

4. Observe the appearance of a (____________) in the junction between 2 liquids. Record your observation in Table 2.

(2 mL of Bial’s reagent) (boiling water bath) (2) (bluish green color)

Bial’s Test

1. Place 1 mL each of the hydrolysates obtained from DNA and RNA in two separate test

tubes.

2. Add (______________) to each test tube. Mix well.

3. Heat the mixtures in a (______________) for (__) minutes.

4. Observe for the formation of (__________). Record your results in Table 2.

(3 mL of NH4OH) (10% HNO3) (2 mL of 0.2 M ammonium molybdate) (2) (yellow precipitate)

*Test for Phosphate

1. Place 1 mL each of the hydrolysates obtained from DNA and RNA in two separate test

tubes.

2. Add (_________) solution.

3. Add (_________) solution until acidic to litmus.

4. Add (___________________________) solution.

5. Warm in a boiling water bath for (__) minutes. Observe for the formation of (___________).