EXERCISE 3 - 5

Question 1

• Process of separating substances in a complex mixture by their different affinities to an adsorbent
• One of the most useful methods of separating the components of minute amount of mixtures
• Discovery with plant samples
• Commonly used for analyzing mixtures of colored chemicals

Answer 1

CHROMATOGRAPHY

Question 2

who invented chromatography

Answer 2

MIKHAIL SEMYONOVICH TSVET

Question 3

chroma means

Answer 3

color

Question 4

graphein means

Answer 4

to write

Question 5

• Either a liquid or solid that is fixed in place during the process
• Usually a high-quality filter paper, or an adsorbent

Answer 5

STATIONARY PHASE

Question 6

• Either liquid or gas which moves the samples through the stationary phase during the process
• Solvent or a mixture of solvents

Answer 6

MOBILE PHASE

Question 7

CHROMATOGRAPHY

forces of attraction for non-polar

Answer 7

weak VAN DER WAALS

Question 8

CHROMATOGRAPHY

forces of attraction for polar

Answer 8

dipole-dipole
hydrogen bonding

Question 9

CHROMATOGRAPHY

Polar compounds adsorb strongly on what phase

Answer 9

STATIONARY PHASE

Question 10

CHROMATOGRAPHY

Non-polar compounds have higher affinity with what phase

Answer 10

MOBILE PHASE

Question 11

CHROMATOGRAPHY

The extent of separation is measured by

Answer 11

RETENTION FACTOR
Rf value

Question 12

This value depends on the relative solubility and adsorptive properties of the components of the sample

Answer 12

RETENTION FACTOR
Rf value

Question 13

Rf value formula

Answer 13

distance travelled by the substance / distance travelled by the solvent

Question 14

Largely depends on adhesion and cohesion forces which allows the mobile phase to move along the stationary phase due to surface tension

Answer 14

PAPER CHROMATOGRAPHY

Question 15

PAPER CHROMATOGRAPHY

It is important that the solvent level is ____ the spots with samples

Answer 15

BELOW

Question 16

in paper chromatography, what should be the shape of the paper

Answer 16

COILED / FORMED INTO CYLINDER

Question 17

why does the container needs to be covered during paper chromatography

Answer 17

to prevent volatilization

Question 18

PAPER CHROMATOGRAPHY

solution used as spray to allow the visualization of spots

Answer 18

NINHYDRIN

Question 19

ninhydrin solution reacts with amino acids giving colored compounds known as

Answer 19

RUHEMANN’S PURPLE

Question 20

Building blocks of proteins

Answer 20

AMINO ACIDS

Question 21

Amino acids may react as an acid or a base

Answer 21

AMPHOTERIC

Question 22

The pH at which the amino acid exists in its zwitterionic form is called as

Answer 22

ISOELECTRIC pH

Question 23

• General test in nature
• Used to detect the presence of peptide bond
• Complexes turn the solution from blue to purple
• The deeper the purple color, the higher is the number of the peptide-cupric ion
• Negative for single amino acids

Answer 23

BIURET TEST

Question 24

BIURET TEST

In the presence of an ____ solution, the blue-colored cupric ions form complexes with peptide bonds

Answer 24

ALKALI

Question 25

* The **general test for amino acids** * Used to **detect** the **presence** of **amine group**, which includes α-amino acids * Positive results are **not exclusive** to proteins or amino acids * Amino acid undergoes **oxidative deamination**

Answer 25

NINHYDRIN TEST

Question 26

in **ninhydrin test**, Amino acid undergoes ___

Answer 26

oxidative deamination

Question 27

# NINHYDRIN TEST **Proline** produces what complex

Answer 27

YELLOW

Question 28

# NINHYDRIN TEST **Asparagine** produces what complex

Answer 28

BROWN

Question 29

* Used to **detect** the **presence** of **aromatic amino acids**—the presence of **benzene** (Tyr, Trp, and Phe) * Aromatic benzene undergoes **nitration** (+NO2) upon reacting with conc. Nitric acid produces **yellow color** in the solution * Upon addition of an **alkali**, these nitro derivative salts produce an **orange color** in solution due to ionization of the phenolic group

Answer 29

XANTHROPOTEIC TEST

Question 30

# XANTHOPROTEIC TEST **Aromatic benzene** undergoes ____ upon reacting with **conc. Nitric acid**

Answer 30

NITRATION

Question 31

# XANTHORPOTEIC TEST Aromatic benzene + conc. Nitric acid **result**

Answer 31

YELLOW SOLN

Question 32

# XANTHOPROTEIC TEST Aromatic benzene + conc. Nitric acid + **alkali**

Answer 32

ORANGE SOLN

Question 33

* Used to **detect** the **presence** of **phenolic amino acid**—**tyrosine** * Tyrosine reacts with mercury and mercuric nitrate to form **red-colored complex**

Answer 33

MILLON'S TEST

Question 34

# MILLON'S TEST tyrosine + mercury & mercuric nitrate

Answer 34

RED-COLORED COMPLEX

Question 35

* Used to **detect** the **presence** of the **guanidino group** found in the amino acid **arginine** * Arginine reacts with α-naphthol in ethanol and an oxidizing agent (e.g. sodium hypobromite, sodium hypochlorite) to give a **red-colored** product

Answer 35

SAKAGUCHI TEST

Question 36

# SAKAGUCHI TEST arginine + a-naphthol + oxidizing agent

Answer 36

RED COLORED PRODUCT

Question 37

* Used to **detect** the **presence** of **indole-containing** amino acid—**tryptophan** * The **indole group** of tryptophan **reacts** with **glyoxylic acid** in the presence of sulfuric acid to give a **purple-colored complex**

Answer 37

HOPKIN'S-COLE TEST

Question 38

prepared from **glacial acetic acid** being **exposed** to **sunlight**

Answer 38

GLYOXYLIC ACID

Question 39

* Used to detect **sulfur-containing** amino acid—**cysteine** * When **cysteine** is **heated** with **sodium hydroxide**, it will **yield sodium sulfide**, this chemical reaction converts organic sulfur into an inorganic one * Sodium sulfide is then reacted with Lead (II) Acetate, producing **black precipitate** in the solution

Answer 39

LEAD ACETATE TEST

Question 40

# LEAD ACETATE TEST cysteine heated w/ NaOH → NaS NaS + Lead (II) acetate will produce

Answer 40

BLACK PPT

Question 41

are **polymers** of **monomers** of **amino acids**

Answer 41

PROTEINS

Question 42

* **Helper proteins** that provide **favorable conditions** for protein **folding** to **take place** * **Clump around** the forming protein and **prevent** other polypeptide chains from **aggregating** * Once the target protein **folds**, these proteins **disassociate**

Answer 42

CHAPERONE PROTEINS

Question 43

* Any process that **temporarily** or **permanently** changes the **protein conformation** which results in **loss of protein activity** and **function** * **Destruction** of the **quaternary**, **tertiary**, and **secondary** levels of the structure of proteins

Answer 43

PROTEIN DENATURATION

Question 44

# PROTEIN DENATURATION **Destruction** of the **primary** level of protein structure

Answer 44

HYDROLYSIS

Question 45

Denaturing a protein is occasionally ____

Answer 45

IIREVERSIBLE

Question 46

**visualizes** the process of protein denaturation

Answer 46

PAPER CLIP ANALOGY

Question 47

# PROTEIN DENATURATION * Causes the atoms to **vibrate more rapidly** by kinetic energy * **Disruption** of **relatively weak forces** such as **H-bonds** and **hydrophobic interactions** * **mostly** employed technique in **sterilization** which **destroys enzymes** in bacteria

Answer 47

HEAT

Question 48

# PROTEIN DENATURATION are often **charges** and **can form ionic bonds** with a **group of opposite charge**

Answer 48

R GROUPS in amino acids

Question 49

# PROTEIN DENATURATION Chemicals like **ethanol** can form ____ with protein molecules which **disrupts** the **intramolecular H-bonds** of the **protein itself**

Answer 49

H BONDS

Question 50

used as a **disinfectant** because it **denatures proteins of bacteria** (can penetrate the bacterial cell wall)

Answer 50

70% ETHANOL

Question 51

**coagulates proteins** at the **cell wall surface**, forming a **crust** that **prevents** the **alcohol** from **penetrating bacterial cell**

Answer 51

95% ETHANOL

Question 52

# PROTEIN DENATURATION can form **strong groups** with **disulfide groups** of proteins

Answer 52

MERCURY II LEAD II SILVER

Question 53

# PROTEIN DENATURATION cause the protein to **precipitate** out of the solution as **insoluble metal-protein salt**

Answer 53

DISRUPTED DISULFIDE BRIDGES & SALT LINKAGES

Question 54

# PROTEIN DENATURATION are used as **antidotes** for **heavy metal poisoning**

Answer 54

HIGH PROTEIN SUBSTANCES | egg whites, milk

Question 55

# EGG ALBUMIN provides **nourishment** and **binds digestive enzymes**; approximately **54%** of the protein content

Answer 55

OVALBUMIN

Question 56

# EGG ALBUMIN **most heat-labile**; approximately **12%** of the protein content

Answer 56

OVOTRANSFERRIN