LAB Flashcards
What does GLP stand for?
Good Laboratory Practice
What should you do with contaminated materials in the laboratory?
Discard all contaminated material appropriately into designated containers.
What is the purpose of wearing PPE in the laboratory?
To ensure safety while working in a laboratory environment.
What must be done with long hair in the laboratory?
Long hair must be tied back.
True or False: Eating and drinking are allowed in the laboratory.
False
What type of equipment must be used for disposing of sharps?
Sharps disposal container
What are the three main functional groups of cells in blood?
- Erythrocytes (Red Blood Cells)
- Leucocytes (White Blood Cells)
- Thrombocytes (Platelets)
What do erythrocytes transport?
Oxygen and carbon dioxide
What pigment do erythrocytes contain that is crucial for oxygen transport?
Haemoglobin
What is the function of leucocytes?
Part of the defence and immune systems
How many types of leucocytes are there?
Five types
What is the primary function of thrombocytes?
To control bleeding and help in blood clotting
What is the purpose of the Giemsa stain?
To stain blood smears for microscopic identification of blood cells
Fill in the blank: Blood consists of various cells suspended in a fluid called _______.
plasma
What are the components of the H&E staining method?
- Haematoxylin
- Eosin
What does haematoxylin stain in tissues?
Nucleic acids of the cell nucleus
What color does eosin stain cytoplasmic components?
Red or pink
What is the importance of using a mordant in haematoxylin staining?
It links the dye to the tissues
What is the function of the microtome in histopathology?
To slice embedded tissue into thin sections
What does histopathology investigate?
Diseased tissue to aid in patient diagnosis and treatment
True or False: The sample must be dehydrated before H&E staining.
True
What is the typical thickness for tissue sections cut using a microtome?
4µm
What must be done after staining with haematoxylin?
Wash with running water
What should be done with slides after staining to prevent them from sticking together?
Position them in separate slots in the Coplin jar
What is the first step in the H&E staining method?
Dewax the sections using Safesolv
What is the final step in the H&E staining method?
Mount under a coverslip with DPX
DPX stands for Distrene, Plasticiser, and Xylene. It is a synthetic mounting medium used in microscopy to preserve stained slides, enhance transparency, and prevent fading.
What is the purpose of using immersion oil when observing blood films?
To enhance the resolution of the microscopic image
What is the purpose of haematoxylin in liver tissue staining?
Haematoxylin stains the nuclei of liver cells
Hematoxylin is a basic dye that binds to acidic components like DNA and RNA (negative charge) in the cell nuclei, turning them blue-purple
What component of liver cells does eosin stain?
Eosin stains the cytoplasm of liver cells
Eosin is an acidic dye that binds to basic (positively charged) proteins in the cytoplasm
List the main components visible in stained rat liver slides.
- Hepatic artery
- Portal vein
- Bile duct
- Hepatocytes
- Terminal hepatic venule
- Hepatic sinusoid
What is the first step in the dehydration after ethanol process during tissue preparation?
Wash with Tap Water
A tap water wash removes fixative residues (like formalin) before dehydration, preventing interference with staining and ensuring proper tissue processing.
What is the second step in the dehydration process?
Alcohol (x2)
What is the purpose of using Safesolv in the clearing process?
To prepare the tissue for mounting under a coverslip
True or False: It is important to adjust the eyepiece of the microscope to suit your eyes.
True
What should you do if the light from the microscope is too bright?
Adjust the light to a lower intensity
Fill in the blank: Always start focusing with the ______ objective in position.
10X
What is the main aim of the mammalian cell culture session?
To practice aseptic techniques in cell culture
What is a primary culture?
The initial culture of cells after being removed from an organism
What is the role of trypsin in cell culture?
To detach cells from the culture vessel
What is the importance of maintaining culture sterility?
To prevent contamination that can alter experimental results
True or False: Laminar flow cabinets are used to provide a sterile environment for cell culture.
True
What should be done to the laminar flow cabinet before use?
Wipe the inner surfaces with 70% ethanol
What is the significance of using a spectrophotometer in DNA analysis?
To measure the concentration and purity of the DNA sample
Fill in the blank: Pure DNA shows an absorption peak at ______ nm.
260
What is the ideal ratio of absorbance readings at 260/280nm for pure DNA?
Approximately 2
What is the purpose of protease in DNA extraction?
To digest proteins and release DNA from cells
What is the final step in the DNA extraction process?
Elute the DNA with distilled water
What is the purpose of incubating the DNA extraction mixture at 56°C?
To facilitate the lysis of cells and release DNA
What is a transformed cell line?
A cultured cell line that can divide indefinitely
In the cell culture procedure, what is the purpose of adding PBS?
To wash the cells before adding trypsin
✅ Rinse cells – Removes residual media, serum, and debris.
✅ Maintain pH and osmolarity – Prevents cell damage.
✅ Dissociate cells (with trypsin) – Aids in detaching adherent cells.
It is a non-toxic, isotonic buffer essential for washing and cell handling.
What must be done after using the laminar flow cabinet?
Clean the cabinet with alcohol and dispose of waste properly
What should you observe under the inverted microscope when checking cell cultures?
The appearance of healthy growing cells
What is the approximate ratio of absorbance readings at 260/280nm and at 260/230nm for a pure DNA sample?
Approximately 2
How is the concentration of DNA in a sample determined?
From the absorbance value at 260nm
What does the DNA concentration calculation assume about the sample?
That the sample is pure
What are the three different amplification cycles in a PCR assay?
- Denaturation
- Annealing
- Extension
At what temperature does the initial denaturation stage occur in a PCR process?
95°C
What happens during the denaturation stages at 95°C in PCR?
The DNA strands separate
What happens during the annealing stages at 59°C in PCR?
Primers bind to the DNA template
allowing DNA polymerase to initiate replication
What happens during the extension stages at 72°C in PCR?
Taq polymerase is a heat-stable DNA polymerase synthesizes new DNA strands
What is gel electrophoresis used for?
Separation and analysis of macromolecules based on fragment size and charge
Gel electrophoresis is used to separate, analyse, and purify DNA, RNA, or proteins based on size and charge by applying an electric field through a gel matrix. ✅
Why do larger DNA fragments migrate slower through agarose gel?
They encounter more resistance in the highly cross-linked agarose matrix
What charge does DNA carry and why?
Negatively charged due to phosphate groups
What safety measure should be taken when handling gels?
Wear gloves
What dye is used in the agarose gel instead of ethidium bromide?
GelRed
This dye is used instead of ethidium bromide because it is safer, less toxic, and non-carcinogenic while still providing strong fluorescence for DNA detection under UV or blue light.
What is the purpose of the loading dye in gel electrophoresis?
To help visualize the DNA during loading and tracking the migration
What should be done after adding the gel loading buffer to the PCR product?
Gently mix by flicking or pipetting
What is a DNA Ladder in gel electrophoresis?
A mixture of DNA fragments of known size for size determination
A DNA ladder is a mix of DNA fragments of known sizes used as a molecular weight marker in gel electrophoresis to estimate the size of unknown DNA samples.
What voltage should be set for running the gel in electrophoresis?
75 volts
ensures better resolution
What should be observed during the electrophoresis run to ensure it is functioning correctly?
Check for bubbles
What should be done with the running buffer at the end of the electrophoresis run?
Tip it into the sink
What equipment is used to visualize DNA bands after gel electrophoresis?
Gel Documentation chamber
Where should the gel be disposed of after the experiment?
Into yellow waste bags
PPE?
Personal protective equipment
COSHH
Control of substances hazardous to health
Why only the white blood cells are stained by the Giemsa staining?
White blood cells (WBCs) are stained because they have a nucleus and cellular components (e.g., granules, cytoplasm) that take up the Giemsa stain. Red blood cells (RBCs) lack a nucleus and do not retain the stain, appearing pale or pink due to hemoglobin.
PCR?
PCR (Polymerase Chain Reaction) is a technique used to amplify specific DNA sequences, making millions of copies for analysis in research, diagnostics, and forensics.
The five types of leukocytes (white blood cells) and their key differences:
Neutrophils – Most abundant; phagocytize bacteria; multi-lobed nucleus.
Lymphocytes – Include B and T cells; involved in immunity; large nucleus.
Monocytes – Largest WBC; differentiate into macrophages; kidney-shaped nucleus.
Eosinophils – Combat parasites; involved in allergies; bi-lobed nucleus, red granules.
Basophils – Release histamine; involved in allergic reactions; dark granules obscure nucleus.
