Spectrophotometry

Question 1

A ________ is used to provide a source of light at certain energy, _______, and to measure the quantity of light that is absorbed by the sample.

Answer 1

Spectrophotometer, wavelength

Question 2

______ is the amount of light that has been absorbed by the sample; and the relationship between sample concentration and absorbance is _____ up to a certain concentration.

Whereas, ____ is the fraction of incident light that passes completely through the sample; and the relationship between the sample concentration and transmittance is _________

Answer 2

Absorbance
Linear (directly proportional)

Transmittance

Exponential (inversely proportional)

Question 3

A spectrophotometer is designed to detect _________ of light at different __________when the light passes through a solution of some given concentration.

Answer 3

Absorbance, wavelength

Question 4

A spectrophotometer is a method of analyses that involves how _______ interacts with the atoms (or molecules) in a sample of matter.

Answer 4

Light

Question 5

The _______ spectrum consists of electromagnetic radiation whose wavelengths range from 400 nm to nearly 800 nm.

Answer 5

Visible

Question 6

When this light passes through a substance, certain energies (or colours) of the light are _____ while other colour(s) are allowed to pass through or are _______ by the substance.

Answer 6

Absorbed

Reflected

Question 7

A substance appears white if it does not absorb ________

Answer 7

Any colour

Question 8

We see _____ colour when the substance doesn’t absorb any white light.

Answer 8

White

Question 9

We see ______ colour when the substance does absorb all colours except red colour

Answer 9

Red

Question 10

The visible range is from ______ nm.

Answer 10

400 - 780

Question 11

The ultraviolet range is ______ nm.

Answer 11

Below 400

Question 12

The visible light is used to detect _____ substances, whereas the ultra-violet is used for ______ substances.

Answer 12

Coloured

Colourless

Question 13

A ______ is either a prism or a diffraction grating that seperates the white light into all colours of the visible spectrum

Answer 13

Monochrometer

Question 14

A _____ Lamp is used for Vis spectrophotometer

Answer 14

Tungstin

Question 15

A _______ Lamp is used for UV spectrophotometer

Answer 15

Deuterium/Hydrogen/Mercury

Question 16

Conjugated aromatic compounds, such as aromatic amino acids absorb _______ radiation

Answer 16

Ultraviolet

Question 17

Compounds that absorb UV radiation are normally measured in cuvettes made of _______

Answer 17

Quartz

Question 18

What is the optimum pH of pepsin?

Answer 18

2 or 3

Question 19

The enzyme’s theory that state that “Enzyme structure is flexible, not rigid substrate binding induces appropriate conformational changes in the enzyme Increases range of substrate specificity.” is termed: ————————.

Answer 19

Induced-fit theory

Question 20

The enzyme’s theory that state that “The shape of the active site is complementary to that of the substrate molecule.” is termed: ————–.

Answer 20

Key-Lock theory

Question 21

What is the optimum pH of trypsin?

Answer 21

8

Question 22

In non competitive inhibitors, the inhibitor fits into ————– site

Answer 22

allosteric

Question 23

In non competitive inhibitors, the inhibitor fits into _______ site

Answer 23

Active site

Question 24

The extinction coefficient of a solution containing 1g molecule of solute per 1 liter of solution is termed _______

Answer 24

Molar absorptivity or molar extention coefficient

Question 25

The maximum ---------is the one at which a compound gives its highest absorbance.

Answer 25

Wavelength

Question 26

The slope of a standard curve divided by the cuvette’s path length is equal to \_\_\_\_\_\_\_\_\_

Answer 26

Molar absorptivity of molar extention coeficient

Question 27

The equation for Beers-Lambert law is \_\_\_\_\_\_\_

Answer 27

A = (wierd E boi) x C x L

Question 28

The cuvette with a path length of 0.4 cm gave an absorbance of 0.6. What is the absorbance when the path length is doubled?

Answer 28

1.2

Question 29

Best results for unknown concentration is obtained when the absorbances are between -----------

Answer 29

0.1 - 1.0

Question 30

The molar absorptivity deviates at concentrations

Answer 30

\> 0.01 M

Question 31

The enzyme’s uses the process termed "\_\_\_\_\_\_ "to (i) prevent waste of cell raw materials (substrates), (ii) prevent overproduction of cell products and (iii) prevent wastes of cell energy

Answer 31

"switching on/off"

Question 32

The ability of a compound to absorb light is termed \_\_\_\_\_\_\_\_\_

Answer 32

Molar absorptivity or molar extinction coefficient

Question 33

Conjugated aromatic compounds such as aromatic amino acids are absorbed at which spectra?

Answer 33

Ultra violet

Question 34

According to Beers-Lambert law, the relationship between the absorbance and transmittance is ______ proportional

Answer 34

Indirectly

Question 35

The relationship between the absorbance and transmittance is \_\_\_\_\_\_\_\_\_\_

Answer 35

A = 2 - Log %T or A = Log (1/T)

Question 36

------ light is actually a mixture of all the colors of light.

Answer 36

White