Answers to Review Questions in Pipetting

1. Give the reasons why the thumb is not used in pipetting.

The thumb should not be used because, it is more convenient to use the index finger. You can manipulate the pipette properly and easily.

2. Convert the following milliliters to microliters.

5 ml - 5,000 uL
20 ml - 20,000 uL
0.05 ml - 50 uL
100 ml - 100,000 uL
0.025 ml - 25 uL

3.Name sources of error in pipetting.

Broken tips can reduce the total volume TV) of the pipet.

Not wiping the sides of the pipet before delivering will add to the TV.

Dirty and contaminated pipets can affect the test reaction.

Reading at the lower meniscus for opaque solutions instead of the upper meniscus and vice versa.

Improper pipetting will lead to unreliable results.

Review Questions in Pipetting

1. Give the reasons why the thumb is not used in pipetting.

2. Convert the following milliliters to microliters.

5 ml
20 ml
0.05 ml
100 ml
0.025 ml

3.Name sources of error in pipetting.

ANSWERS to Review Questions- Spectrophotometry

1. State Beer's law

The concentration of the solution is directly proportional to the absorbance and inversely proportional to the transmitted light.

2. What is the relationship between the intensity of color of a solution to its concentration?

The intensity of color of a solution is directly proportional to its concentration.

3. What is the formula in solving the Cu?

Cu = Au X Cs/ As

Where: Cu -Concentration of the unknown
Au -Absorbance of the unknown
Cs -Concentration of the standard
As -Absorbance of standard

4. What are the other methods in computing for your unknown concentration?

a. Ratio of standard to known, using the formula in No. 3
b. Absorptivity value
c. Standard curve

5. Give the types of wavelength and the ranges by which they occur.

Ultraviolet (UV) - Below 350 nm
Visible - 350 to 800 nm
Infrared (IR) - above 800 nm

6. List the specific colors for each wavelength.

Blue - 475 nm
Green - 510 nm
Yellow - 570 nm

7. List and describe briefly the basic components of the spectrophotometer.

Light source- provides a continuous source of light.

Entrance slit - prevents entry of extraneous light.

Monochromator - selects the wavelength of choice in reading the unknown.

Exit slit - purifies and intensifies the light entering the cuvette.

Cuvette - contains the unknown solution.

Detector - detects the light absorbed or transmitted and converts it to a reading.

Readout device or digital display window - reflects the readings or concentration of the unknown solution.

Review Questions- Spectrophotometry

1. State Beer's law
2. What is the relationship between the intensity of color of a solution to its concentration?
3. What is the formula in solving the Cu?
4. What are the other methods in computing for your unknow concentration?
5. Give the types of wavelength and the ranges by which they occur.
6. List the specific colors for each wavelength.
7. List and describe briefly the basic components of the spectrophotometer.

Questions for Endocrinology and Toxicology

I. ESSAY: DISCUSS BRIEFLY BUT CONCISELY:

1. DISCUSS THE PORTER SILBER METHOD. ( 5 PTS.)
2 DISCUSS THE DIALYSIS METHOD OF TOTAL T4 PROCEDURE.
( 5 PTS.)
3. HOW IS THE CHAIN OF CONFIDENTIALITY MAINTAINED IN DRUG ABUSE SCREENING? ( 5 PTS.)


II. MATCHING TYPE: ( 1 PT.EACH)

MATCH COLUMN A WITH COLUMN B

CHOICES:

A. HYPOTHYROIDISM
B. HYPERTHYROIDISM


1. Muscle weakness
2. Amenorrhea
3. Goiter
4. Dry skin
5. Brittle nails
6. Constipation
7. Cold Intolerance
8. Heat intolerance
9. Tremors
10. Profuse bleeding


III. PROBLEM SOLVING: ( 5 pts.)

1. WHAT IS THE HALF LIFE OF A DRUG WITH AN ORIGINAL CONCENTRATION OF 500 mg IF IT WAS REDUCED TO 400 mg AFTER AN HOUR.


IV. TRANSCRIPTION ( 1 PT. EACH)

1. OGTT
2. 9-THC
3. VMA
4. HVA
5. FBS
6. ALT
7. DHEA
8. DTL
9. PRL
10. ASC