Cell Biology & Experimental Approaches transcript DS

Cell Biology

The scientific study of the structure and function of cells. It is not just a body of knowledge but an experimental approach to asking questions and gathering new information about cellular processes.

Scientific Method in Cell Biology

The process of discovery: 1) Form a question/hypothesis, 2) Select a model system, 3) Design and execute an experiment, 4) Observe and interpret results, 5) Use results to answer the question, refute/confirm the hypothesis, and generate new questions.

Model Systems

Organisms or cell types used to study biological processes because they are convenient, well-characterized, or share conserved features with humans. Common examples: Yeast, Fruit flies (Drosophila), Worms (C. elegans), Mice, Cultured cells.

Biochemistry (Experimental Approach)

The study of molecules and chemical processes in living organisms. It focuses on the structure, behavior, and interactions of specific biomolecules (like proteins, lipids, nucleic acids).

Examples of Biochemical Techniques

1) Purifying or separating biomolecules for study (e.g., chromatography). 2) Detecting proteins using antibodies (e.g., Western blot, ELISA). 3) Identifying interactions between biomolecules (e.g., co-immunoprecipitation). 4) Monitoring biochemical reactions (e.g., enzyme assays).

Microscopy (Experimental Approach)

Techniques used to visualize objects too small to be seen by the naked eye. It reveals the shape, location, and behavior of organisms, cells, organelles, and molecules.

Examples of Microscopy Applications

1) Observation of molecules, cells, tissues, or organisms. 2) Detection of specific molecules or cellular structures (e.g., immunofluorescence). 3) Live imaging to study the dynamics and real-time behavior of molecules and cells.

Genetics (Experimental Approach)

The study of inheritance and variation of genetic material. It allows evaluation of a cell's structure and function when its DNA sequence is altered.

Genetic Techniques: Forward Genetics

Starting with an interesting phenotype (observable trait) in a diverse population, then identifying the gene(s) responsible for that phenotype through genetic mapping and sequencing.

Genetic Techniques: Reverse Genetics

Starting with a known gene/DNA sequence of interest, creating a specific mutation in it, and then analyzing the resulting effect on the cell's phenotype or function.

Genetic Techniques: Altering Expression

Manipulating the expression levels of a specific RNA or protein (e.g., through knockout, knockdown, or overexpression) to determine its effect on cellular processes.

Genetic Techniques: Fusion/Tagged Proteins

Modifying a gene by adding a nucleic acid sequence that encodes an additional amino acid sequence. This creates a fusion protein or tagged version (e.g., GFP-tagged, FLAG-tagged) of the protein, which is useful for tracking, purification, or localization experiments.

Interplay of Experimental Approaches

Major discoveries in cell biology often result from integrating biochemical, microscopy, and genetic approaches. For example, using genetics to create a GFP-tagged protein (genetics), purifying it to find interacting partners (biochemistry), and visualizing its location in a living cell (microscopy).