Laboratory: Proteins

Question 1

a naturally occurring, unbranched polymer in which the monomer units are amino acids

Answer 1

PROTEINS

Question 2

a peptide in which at least 40 amino acids residues are present

Answer 2

PROTEINS

Question 2

a peptide in which at least 40 amino acids residues are present

Answer 2

PROTEINS

Question 3

Proteins is from the Greek word proteios, meaning ___________

Answer 3

preeminence

Question 4

The most important of all biological substances

Answer 4

PROTEINS

Question 5

List down the protein sources

Answer 5

1. Milk
2. Wheat flour
3. Beans
4. Minced beef
5. Egg

Question 6

the most nutritionally complete food found in nature

Answer 6

MILK

Question 7

WHOLE MILK vs SKIM/SKIMMED MILK:

is an oil-in-water emulsion, containing its 3.9% fat dispersed as micron sized globules

Answer 7

WHOLE MILK

Question 8

WHOLE MILK vs SKIM/SKIMMED MILK:

is made when all the cream (also called milkfat) is removed from whole milk.

Answer 8

SKIM/ SKIMMED MILK

Question 9

WHOLE MILK vs SKIM/SKIMMED MILK:

It tends to contain around 0.1% fat

Answer 9

SKIM/ SKIMMED MILK

Question 10

main protein in milk

Answer 10

Casein

Question 11

is a phosphoprotein which has phosphate groups attached to the hydroxyl groups of some of the amino acids side-chain

Answer 11

Casein

Question 12

a mixture of three similar proteins, alpha, beta and kappa caseins which form a micelle

Answer 12

Casein

Question 13

__________ are both insoluble in water and are solubilized by the micelle surrounding them

Answer 13

Alpha- and beta-casein

Question 14

has a hydrophilic portion is responsible for solubilizing the other two caseins by promoting the formation of and stabilizing the micelles.

Answer 14

kappa-casein

Question 15

responsible for the white opaque appearance of milk

Answer 15

micelles

Question 16

has an isoelectric point of pH 4.6

Answer 16

Calcium caseinate

Question 17

What is the pH of milk?

Answer 17

6.6

Question 18

Is the pH at which an amino acid solution has no net charge because an equal number of positive and negative charges are present.

Answer 18

ISOELECTRIC POINT

Question 19

That pH value is known as the ________ of the protein and is generally the pH at which the protein is least soluble.

Answer 19

isoelectric point (IEP)

Question 20

At this point, almost all amino acid molecules in a solution are present at their zwitterion form.

Answer 20

ISOELECTRIC POINT

Question 21

is a mixture of two proteins, glutenin and gliadin

Answer 21

GLUTEN

Question 22

It is also the composite of a prolamin and glutelin, which exist, conjoined with starch, in the endosperm of various grass-related grains.

Answer 22

GLUTEN

Question 23

is a protein composite found in wheat and related grains, including barley and rye.

Answer 23

GLUTEN

Question 24

_____ gives elasticity to dough, helping it rise and keep its shape and often gives the final product a chewy texture

Answer 24

Gluten

Question 25

The principle involved in the isolation of gluten is difference in solubility. The starch is ________ in water while gluten is _____ in water.

Answer 25

partially soluble, insoluble

Question 26

What solution is used to test the complete removal of starch, which involves the formation of blue-iodo starch complex?

Answer 26

Iodine solution

Question 27

What keeps the protein from degrading?

Answer 27

Refrigeration

Question 28

Detection of Nitrogen: What color indicates no presence of Nitrogen or ammonia?

Answer 28

Red-red

Question 29

Detection of Nitrogen: What color indicates the presence of ammonia (NH3)gas & urine like odor (presence of Nitrogen)

Answer 29

Red-Blue

Question 30

What color precipitation is there in the Detection of Sulfur?

Answer 30

White ppt. (Barium Sulfate BaSO4)

Question 31

What color precipitation is there in the Detection of Phosphorus?

Answer 31

Yellow ppt. (NH4)3PO4.12MoO3 ammonium phosphomolybdate

Question 32

Most of these reactions are catalyzed by ______so that they can proceed at the rate necessary to sustain life.

Answer 32

enzymes

Question 33

Enzymes are ______ found in all living organisms.

Answer 33

proteins

Question 34

In an overall reaction, ______ are not consumed but are converted back into their natural state after a reaction

Answer 34

enzymes

Question 35

reactive site where molecular reaction takes place

Answer 35

Enzymes

Question 36

are molecules that bind in the active site of an enzyme

Answer 36

Substrates