Biochemistry

Question 1

Difine spectrophotometer?

Answer 1

Is used to measure the amount of light that the chemical substances absorbs by measuring the intensity of light as a beam of light passes through sample solution

Question 2

What is the basic principle of spectrophotometer?

Answer 2

Is that each compound absorbs or transmits light over a certain range of wavelength

Question 3

F of light source in spectrophotometer?

Answer 3

Emits radiant E that contains many wavelength

Question 4

F of monochromator ?

Answer 4

Prism , to beak the polychromatic radiation into component of wavelength or bands of wavelength .

Question 5

F of adjustable aperture?

Answer 5

Exit slit that allows only one color to pass to the sample .

Question 6

F of sample ?

Answer 6

Absorbs a portion of the light and transmits the rest through the sample .

Question 7

F of output?

Answer 7

Detector , that convert the radiant E into electrical E .

Question 8

F of transport vessels ( cuvettes )?

Answer 8

To hold the sample .

Question 9

What is the components of spectrophotometer?

Answer 9

1. A stable and cheap radiation energy source .
2. Monochromator .
3. Transport vessels * cuvettes* .
4. A photosensitive detector and an associated readout system .

Question 10

How the simple beam spectrophotometer work ?

Answer 10

To measure the intensity of the incident light , the sample must be removed , so that the reference can be placed each time .

Question 11

What is the advantages of simple spectrophotometer?

Answer 11

Less expensive and less complicated.

Question 12

How the double beam spectrophotometer work ?

Answer 12

Before it reaches the sample , the light source is split into tow separate beams , from this one passes through the sample and the second one is used for the reference.

Question 13

What is the advantages of double beam spectrophotometer?

Answer 13

The reference reading and the sample reading can take place at the same time .

Question 14

What is the type of spectrophotometer?

Answer 14

Simple beam spectrophotometer.

Double beam spectrophotometer.

Question 15

Types of spectrophotometer based to the wavelength of light and write the range of each type ?

Answer 15

1. Visible spectrometer ( 400 _ 700 nm) of electromagnetic radiation spectrum .
2. UV spectrometer (180 _400nm) of electromagnetic radiation spectrum .
3. IM spectrometer (700_1500 nm) of electromagnetic radiation spectrum .

Question 16

What is the realation between the amount of light absorbs and the concentration of a substance.?

Answer 16

Directly propotional .

Question 17

What tube do we need in our spectrophotometer experiment?

Answer 17

Blank tube , reagent and water
Standard tube , reagent and standard
Test tube , reagent and test

Question 18

What’s the beer’s law ?

Answer 18

The concentration of the substances is directly proportional to the light absorbed or inversely proportional to the logarithm of the transmitted light.
A = abc 
A for absorbance 
a for absorptivity 
b for light path in centimetres 
C for concentration of the substances.

Question 19

What is the absorptivity ?

Answer 19

It is a constant for a particular substance that means the amount of light absorbed per unit concentration.

Question 20

What is the equation of law ?

Answer 20

Ct =( At / Ast )× C st .

Question 21

Where do we get a specimen from the total calcium ?

Answer 21

Serum and heparinized plasma .

Serum is prefered.

Question 22

How do we get a sample from the free calcium ?

Answer 22

1. should be collected and handled anaerobically .

2. Take care of the heparinized in the tube .

Question 23

What are the precautionary steps for taking a calcium sample?

Answer 23

1. Without tourniquet.
2. In sitting position .
3. Use wide bore needle . ابرة ذات تجويف واسع
4. Fasting .

Question 24

What is the analytical method for assessing calcium in the serum?

Answer 24

By using calcium _binding reagent which exhibit high affinity for calcium and forming a coloured reaction product .

Question 25

List the calcium binding reagent ?

Answer 25

1. O_cresolphathalein complexone . | 2. Arsenazolll .

Question 26

What is the OCPC method?

Answer 26

Ca+OCPC_____red complex (570_580 nm ) | At alkaline pH 10_12 .

Question 27

What is the arsenazolll method ?

Answer 27

1. Measured at acidic pH 6\has much affinity for Ca than other. 2. Utility of the OCPC assay is limited by the fact that absorption of carbon dioxide by the alkaline reagent causes considerable calibration drift. 3. Arsenazo III is highly sensitive and specific for calcium, generating a sensitive absorbance peak at (600-660 nm).Because the Arsenazo III reacts under slightly acidic conditions. 4. Measured at wavelength 650nm.

Question 28

How calculate the ionized calcium ?

Answer 28

``` iCa= 0.9+(0.55×tCa_ 0.3 × albumin ). iCa= (6×tCa _TP/3)/(6+TP). ```

Question 29

How calculate the corrected serum calcium ?

Answer 29

1. Serum calcium / (0.6 + ( total protein/ 8.5)). 2. Cacium + 0.8 ( normal albumin _ patient albumin ) Normal albumin = 4.0

Question 30

What is the optimal ph for the enzyme reaction ?

Answer 30

9 _ 10.5

Question 31

What is the activators of ALP enzyme ?

Answer 31

Mg +2 / zn +2

Question 32

Where is the highest concentration of ALP found?

Answer 32

``` Intestine Live Kidney Placenta Bone ```

Question 33

Where the ALP found mainly ?

Answer 33

In the cells lining the biliary tract . | In the osteoblasts .

Question 34

List the ALP isozymes?

Answer 34

ALPL _Intestinal. ALPL_ tissue non specific live / bone / kidney . ALPP_ placental.

Question 35

When does ALP increase ?

Answer 35

1. Gut ALP rises after meals . 2. Bone ALP increase at the time of physiological growth. 3. Placental ALP normally increase at the third trimester.

Question 36

What is the method and the substrate that use to assay enzyme activity?

Answer 36

Kinetic method

Question 37

What is the principle of assay enzyme activity by ALP ?

Answer 37

ALP catalyzes the hydrolysis of colourless organic phosphate ester substrate ( p_Nitrophenylphosphate) to the yellow coloured product ( p_Nitrophenol) and phosphate .

Question 38

What is the suitable environment to assay enzyme activity by ALP ?

Answer 38

Alkaline ph at 37 ⁰C