Micropipettes: Usage and Types

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Questions and Answers

What is the primary function of the plunger on a micropipette?

To aspirate and dispense liquids (correct)

To attach the disposable tip

To display the selected volume

To eject the used tip

Which component allows you to set the desired volume on a micropipette?

Volume adjustment dial (correct)

Tip holder

Tip ejector button

Plunger

What is the first step in using a micropipette correctly?

Press the tip ejector button

Set the desired volume (correct)

Attach the tip

Aspirate the liquid

What type of micropipette allows for transferring multiple samples simultaneously?

Multi-Channel Signup and view all the answers

How does the aspirating action of a micropipette work?

Pressing the plunger down to the first stop and releasing Signup and view all the answers

Which of the following volumes can a typical micropipette range include?

0.1-1 µL Signup and view all the answers

What is essential to do after dispensing liquid from a micropipette?

Press the tip ejector button Signup and view all the answers

Which type of micropipette has a set volume that cannot be adjusted?

Fixed Volume Signup and view all the answers

What is the molecular formula of glucose?

C6H12O6 Signup and view all the answers

Which of the following is NOT a symptom of hypoglycemia?

Increased thirst Signup and view all the answers

Which of the following conditions is characterized by low blood glucose levels?

Hypoglycemia Signup and view all the answers

What is one of the main causes of hyperglycemia?

Not taking enough insulin Signup and view all the answers

Which type of diabetes is classified as insulin-dependent?

Type 1 Diabetes Mellitus Signup and view all the answers

Which glucose blood test requires fasting for eight hours prior to testing?

Fasting blood glucose test Signup and view all the answers

What does the suffix '-ose' in glucose indicate?

It is a carbohydrate Signup and view all the answers

Which symptom is directly associated with hyperglycemia?

Dry skin and mouth Signup and view all the answers

What is the main purpose of a spectrophotometer?

To determine the concentration of a light-absorbing substance in a solution Signup and view all the answers

Which component of a spectrophotometer is responsible for separating different wavelengths of light?

Monochromators Signup and view all the answers

What is the correct angle to insert the needle during venipuncture?

45 degrees Signup and view all the answers

What is the purpose of applying a tourniquet during blood collection?

To restrict blood flow and make veins more prominent Signup and view all the answers

What equipment is necessary for carrying out a blood sampling procedure?

Tourniquet, alcohol swabs, gloves, needles, and blood collection tubes Signup and view all the answers

What should be done before inserting the needle in the venipuncture site?

Palpate the vein to locate it Signup and view all the answers

What sensation should be felt when the needle successfully enters the vein during blood collection?

A 'pop' sensation Signup and view all the answers

Which step is NOT part of the blood sampling procedure?

Use a finger to puncture the vein Signup and view all the answers

What effect does increasing the concentration of a solution have on the transmitted light intensity (It)?

It decreases. Signup and view all the answers

In the context of the Beer-Lambert Law, what do the variables 'a' and 'b' represent?

Molar absorptivity coefficient and light path length respectively. Signup and view all the answers

What is the relationship between absorbance (A) and percent transmittance (%T)?

A is inversely proportional to %T. Signup and view all the answers

How can accurate volume measurement be ensured when aspirating liquid?

By avoiding air bubbles in the tip. Signup and view all the answers

What is the purpose of ejecting the tip after dispensing liquid?

To ensure safety and avoid contamination. Signup and view all the answers

What happens to the percent transmittance (%T) when the absorbance (A) increases?

%T decreases. Signup and view all the answers

Which formula represents the Beer-Lambert Law?

A = a * b * Conc. Signup and view all the answers

What should be done to prevent inaccuracies during liquid dispensing?

Position the tip above the target without touching surfaces. Signup and view all the answers

What purpose does albumin serve in the blood?

It helps maintain blood pressure by attracting water into the blood vessels. Signup and view all the answers

Which of the following conditions is associated with high levels of globulin in the blood?

Multiple myeloma Signup and view all the answers

What is a potential cause of low albumin levels in the blood?

Malnutrition Signup and view all the answers

Which structure refers to the overall shape of a single protein molecule?

Tertiary structure Signup and view all the answers

What is the normal fasting blood glucose range?

70 – 110 mg/dl Signup and view all the answers

Which type of globulin transports metals within the bloodstream?

Alpha globulin Signup and view all the answers

Which of the following fractions is measured in a total serum protein test?

Albumin and globulin Signup and view all the answers

What could be indicated by a high albumin level in a blood test?

Severe dehydration Signup and view all the answers

Study Notes

Micropipettes

Essential laboratory tools for measuring and transferring small liquid volumes (microliters)
Components: Plunger, Volume Adjustment Dial, Tip Ejector Button, Tip Holder
How they work:
- Set the desired volume
- Attach a sterile tip
- Press plunger down to the first stop, then slowly release to aspirate liquid
- Press plunger down to the first stop to dispense liquid, then further to second stop for complete delivery
- Eject the tip
Types:
- Single Channel: One sample at a time
- Multi-Channel: Multiple samples simultaneously (e.g., 8, 12, 16 channels)
- Variable Volume: Adjustable within range
- Fixed Volume: Set volume, cannot be changed
How to use:
- Select micropipette with volume range encompassing desired volume
- Set desired volume using plunger or dial adjustment
- Attach tip by pressing tip ejector and inserting
- Aspirate liquid by submerging tip, pressing to first stop and avoiding air bubbles
- Dispense liquid by positioning tip and pressing to second stop, avoiding contact with surfaces
- Eject the tip

Beer Lambert Law

Describes the relationship between absorbance, concentration, and light path length of a solution
Absorbance is directly proportional to concentration
Formula: A = a b c
- A = Absorbance
- a = Molar absorptivity coefficient
- b = Path length
- c = Concentration
Spectrophotometer measures light transmitted by a solution, used to determine concentration of light-absorbing substance

Blood Drawing and Sampling

Performed by trained phlebotomists or medical personnel
Requires proper training to avoid complications like infections and tissue damage
Blood samples collected from blood vessels: capillaries, veins, arteries
Samples obtained via needle puncture and withdrawn by suction into collection tubes or by finger pricking
Equipment: Tourniquet, Alcohol Swabs, Gloves, Needles, Blood Collection Tubes, Bandage
Steps:
- Prepare the patient: Ensure comfort, arm extended, well-hydrated
- Gather supplies
- Apply tourniquet: 3-4 inches above site, tight enough to restrict blood flow without pain
- Locate vein: Palpate with index and middle fingers, look for a prominent, rolling vein
- Clean site: Use alcohol swab in circular motion, allow to air dry
- Insert needle: Angle at 45 degrees, gently insert, “pop” indicates entry into vein
- Collect blood: Attach collection tube, allow to fill
- Remove needle: Carefully remove once tube is full
- Apply pressure: Apply pressure to site until bleeding stops
- Secure site: Place bandage

Glucose

Main source of energy for most living organisms
Belongs to carbohydrates
Simple chemical structure (C6H12O6) allows for direct absorption through intestines
Also known as dextrose or grape sugar
Hexose (6 carbon atoms)
Monosaccharide

Hypoglycemia

Low blood sugar (glucose) level
Common causes:
- Too much insulin
- Too much exercise
- Not enough food
Symptoms:
- Sweating
- Weakness
- Hunger
- Headache

Hyperglycemia

High blood glucose level
Commonly found in individuals with diabetes
Causes:
- Not taking enough insulin
- Illness
- Eating too much
- Certain medications
Symptoms:
- Blood glucose over 240 mg/dl
- Increased urine output
- Increased thirst
- Dry skin and mouth

Diabetes Mellitus

Group of metabolic diseases characterized by hyperglycemia
Results from defects in insulin secretion, insulin action, or both.
Categories:
- Type 1 (insulin-dependent diabetes mellitus: IDDM)
- Type 2 (non-insulin-dependent diabetes mellitus: NIDDM)
- Gestational diabetes
Glucose blood tests:
- Fasting blood glucose (8 hour fast)
- Oral glucose tolerance test (OGTT)
- Random blood sugar
- Hemoglobin A1c (HbA1c)

Protein

Large biological molecules (macromolecules)
Consist of one or more long chains of amino acid residues
Vast array of functions:
- Catalyzing metabolic reactions
- Replicating DNA
- Responding to stimuli
- Transporting molecules
Total serum protein test measures total protein in blood, including albumin and globulin
Albumin: Made in liver, maintains blood vessel integrity, carries substances, important for tissue growth and healing.
Globulin: Various proteins (alpha, beta, gamma), some made in liver, some by immune system, roles include binding with hemoglobin, transporting metals.

Protein Structure

Four aspects:
- Primary Structure: Amino acid sequence
- Secondary Structure: Local folding patterns (alpha helix, beta sheet, turns) stabilized by hydrogen bonds
- Tertiary Structure: Overall 3-dimensional shape of a single protein molecule
- Quaternary Structure: Arrangement of multiple protein molecules (subunits) in a complex

High Protein Levels

High albumin may indicate:
- Severe dehydration
High globulin may indicate:
- Blood diseases (multiple myeloma, lymphoma, leukemia, hemolytic anemia)
- Autoimmune diseases (rheumatoid arthritis, autoimmune hepatitis)
- Kidney disease
- Liver disease

Low Protein Levels

Low albumin may indicate:
- Poor diet (malnutrition)
- Kidney disease
- Liver disease
- Autoimmune disease
- Uncontrolled diabetes
- Hyperthyroidism
- Heart failure

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Description

This quiz covers essential information about micropipettes, including their components, types, and how to use them effectively in a laboratory setting. Test your knowledge on single-channel and multi-channel micropipettes, as well as variable and fixed volume options.