Chapter 3: Cellular Biology Techniques and Technology

What is microscopy?

A technique used to observe and magnify small objects or structures such as cells.

What are organelles?

Specialized structures inside cells that perform specific functions.

Give three examples of organelles.

Nucleus, mitochondria, and Golgi apparatus.

What is the cytoskeleton?

A network of protein filaments that maintains cell shape and enables movement.

What cellular process can microscopy be used to observe?

Cell division, including mitosis and meiosis.

What are molecular interactions?

What are molecular interactions?

What does a light microscope use?

Visible light.

What type of cells can light microscopes observe particularly well?

Live cells.

What are two common light microscopy techniques?

Brightfield and phase-contrast microscopy.

What do electron microscopes use?

Beams of electrons.

Why do electron microscopes provide greater resolution than light microscopes?

Electrons have much shorter effective wavelengths than visible light.

What is the approximate resolution limit of a light microscope?

About 200 nm.

What resolution can electron microscopes achieve?

Below 1 nm.

What is the main purpose of fluorescence microscopy?

To highlight specific cellular components using fluorescent dyes or tagged proteins.

What is magnification?

How much larger a specimen appears compared with its actual size.

What is resolution?

The ability to distinguish two closely spaced points as separate.

Does higher magnification always produce a clearer image?

No. Resolution determines how much detail can be distinguished.

Which is more directly related to image detail: magnification or resolution?

Resolution.

Why is resolution important?

It determines whether closely spaced structures can be seen as separate.

Why is sample preparation important?

It helps produce accurate observations and prevents artifacts.

What is staining?

Applying dyes to samples to increase contrast.

What is a wet mount?

A preparation in which a live specimen is placed in liquid on a microscope slide.

What is fixation?

Preserving a biological specimen by stabilizing its structure.

What preparation steps are commonly required for electron microscopy?

Fixation, dehydration, conductive coating, and, for TEM, thin sectioning.

What is used to label structures for fluorescence microscopy?

Fluorescent dyes or fluorescently tagged proteins.

What is an advantage of live-cell imaging?

It allows researchers to observe dynamic processes in real time.

What is an advantage of fixed cells?

Fixation preserves cellular structures for detailed observation.

Which is better for observing cell movement over time: live or fixed cells?

Live cells.

Which is useful for preserving structures for electron microscopy?

Fixed cells.

What is super-resolution microscopy?

A technique that surpasses the resolution limits of traditional light microscopy.

What can super-resolution microscopy reveal?

Nanoscale structures such as protein clusters and DNA organization.

What does confocal microscopy do?

Focuses on a single plane and reduces background noise to produce sharp images.

What is a major advantage of confocal microscopy?

It can produce sharp 3D images of cellular layers.

What is multiphoton microscopy particularly useful for?

Imaging deeper within living tissues.

Where might multiphoton microscopy be used?

Brain tissue or tumors.

What does FRAP stand for?

Fluorescence Recovery After Photobleaching.

What does FRAP study?

Movement and diffusion of molecules within cells.

What can FRAP tell researchers about membranes?

Information about membrane fluidity.

What does FRET stand for?

Fluorescence Resonance Energy Transfer.

What does FRET study?

Molecular interactions.

How does FRET detect molecular interactions?

By measuring energy transfer between fluorescent molecules or tags.

What is live tissue imaging?

Imaging cells within complex living systems.

What are organoids?

Artificially grown masses of cells that mimic aspects of organs.

What is microenvironment analysis?

Studying interactions between cells and their surrounding environment.

What can cellular pathway imaging help identify?

Potential targets for drug therapies.

How is microscopy used in developmental biology?

It can track cell differentiation and tissue formation in developing embryos.

What is digital pathology?

Digital analysis of high-resolution scans of pathology slides.

What is point-of-care microscopy?

Portable microscopy that brings diagnostic capabilities closer to patients, including in underserved areas.

How can fluorescent markers help in diagnostics?

They can bind to disease-specific molecules and help detect disease.

How is microscopy used in forensic science?

By analyzing microscopic evidence such as fibers and residues.

What is cell culture?

Growing cells in controlled environments outside their natural body.

What is cell culture media?

A nutrient-rich solution that supports cell growth.

Name four components that may be found in cell culture media.

Glucose, amino acids, vitamins, and growth factors.

What temperature is typically used for mammalian cell culture?

Approximately 37°C.

What pH is typically maintained for mammalian cell culture?

Approximately 7.4.

Why is carbon dioxide controlled in cell culture?

To help maintain appropriate culture conditions, including pH.

What is the purpose of an incubator?

To maintain stable temperature, humidity, and gas conditions.

What is the purpose of a laminar flow hood?

To provide a sterile environment for handling cells.

What are culture vessels?

Sterile containers such as Petri dishes and flasks used to grow cells.

Why is sterility important in cell culture?

Contamination can compromise experiments and damage or kill cells.

What is aseptic technique?

Sterile practices used to prevent contamination.

What are primary cells?

Cells taken directly from tissues.

What is an advantage of primary cells?

They closely resemble cells in their natural state.

What is a disadvantage of primary cells?

They have a limited lifespan.

What are continuous cell lines?

Cell lines derived from transformed cells that can grow indefinitely under appropriate conditions.

Give an example of a continuous cell line.

HeLa cells.

What is the major difference between primary cells and continuous cell lines?

Primary cells have a limited lifespan and more closely resemble natural cells, while continuous cell lines can keep growing under appropriate conditions.

How is cell culture used in drug development?

Cells can be used to test how potential drugs affect cellular function.

How is cell culture used in cancer research?

Tumor cell lines can be used to screen potential cancer treatments.

How is cell culture used in vaccine production?

Cells can be used to grow viruses needed to produce vaccines.

How is cell culture used in genetic engineering?

Cultured cells can be genetically manipulated to study gene function and genetic diseases.

What ethical issues can arise in cell culture?

Issues involving cell sources, human embryonic cells, and genetic manipulation.

What is genetic engineering?

The deliberate modification of an organism's DNA to achieve a specific outcome.

What are three major areas where genetic engineering is used?

Medicine, agriculture, and research.

What is CRISPR-Cas9?

A genome-editing system that uses guide RNA and the Cas9 enzyme to target and cut specific DNA sequences.

What does guide RNA do in CRISPR?

It directs the editing system to a specific DNA sequence.

What does Cas9 do?

It cuts targeted DNA.

What can CRISPR be used to do?

Add, delete, or modify genetic material.

What is gene cloning?

Copying a specific gene to study its function or produce a protein.

What is a transgenic organism?

An organism containing a gene from another species.

What are restriction enzymes?

Enzymes that cut DNA at specific sequences.

What are vectors?

DNA carriers, such as plasmids or viruses, that deliver genes into cells.

What is PCR?

A technique used to amplify specific DNA sequences.

What is DNA sequencing?

Determining the exact order of nucleotides in a DNA molecule.

What are the four DNA nucleotides/bases?

Adenine, thymine, cytosine, and guanine.

What is Sanger sequencing?

A sequencing method that uses chain-terminating nucleotides to create DNA fragments of different lengths.

What is NGS?

Next-generation sequencing, a high-throughput approach for sequencing large amounts of DNA.

What is one major advantage of NGS?

It can analyze large numbers of DNA sequences simultaneously.

How can DNA sequencing help diagnose disease?

It can identify mutations associated with genetic disorders.

How can DNA sequencing be used in evolutionary studies?

Researchers can compare DNA sequences between organisms to study evolutionary relationships.

What is the purpose of PCR?

To make millions of copies of a specific DNA sequence.

What is denaturation?

Heating DNA to separate its two strands.

What is annealing?

The stage when primers bind to specific DNA sequences.

What is extension?

The stage when DNA polymerase adds nucleotides to extend the primers.

What enzyme performs DNA synthesis during PCR?

DNA polymerase.

What is the correct order of PCR steps?

Denaturation → annealing → extension.

Why is PCR useful in forensic science?

It can amplify tiny amounts of DNA so they can be analyzed.

Name three applications of PCR.

Genetic testing, infectious disease detection, and forensic analysis.

What is gel electrophoresis?

A technique used to separate DNA fragments based on size and charge.

Why does DNA move during gel electrophoresis?

DNA is negatively charged and moves through the gel in an electric field.