Cell and Molecular Biology Overview

Study Notes

This course aims to provide students with a comprehensive understanding of cell and molecular biology.
The content will cover topics including cell structure, molecular processes, and laboratory methods.
Students will gain knowledge about the fundamental building blocks of life and the principles governing their interactions.

Cell Theory: All living organisms are composed of one or more cells, cells are the fundamental unit of life, and all cells arise from pre-existing cells.
Microscopy:
- Light Microscope: Uses visible light and glass lenses to magnify images, enabling visualization of cells and some organelles.
- Electron Microscope: Uses beams of electrons and electromagnetic lenses to provide higher resolution, allowing for detailed observation of cellular structures and even molecules.
Cell Types: There are two main types of cells: prokaryotes and eukaryotes.
- Prokaryotes: Lack a nucleus and other membrane-bound organelles, including bacteria and archaea. They are generally smaller than eukaryotes.
- Eukaryotes: Possess a nucleus and other membrane-bound organelles, including animals, plants, and fungi.

Size: Eukaryotic cells are larger than prokaryotic cells.
Organelles: Eukaryotes have membrane-bound organelles, while prokaryotes do not.
Cytoskeleton: Eukaryotes have microtubules, intermediate filaments, and exocytosis/endocytosis mechanisms, which are absent in prokaryotes.
Cell Division: Prokaryotes divide by fission, while eukaryotes use mitosis and meiosis.
Genetic Information: Prokaryotic DNA is bound with few proteins, while eukaryotic DNA is packaged with histones to form chromosomes.
RNA Processing: Eukaryotic cells have complex RNA processing compared to prokaryotic cells.
Ribosomes: Prokaryotes and eukaryotes have different ribosomes.
Function: Prokaryotic cells tend to be single, identical entities, while eukaryotic cells are specialized for specific functions.

Structure: Lack a nucleus and membrane-bound organelles.
Genetic Material: Contains a single circular DNA molecule located in the nucleoid region.
Ribosomes: Smaller than eukaryotic ribosomes (70S).

Structure: Possess a nucleus and other membrane-bound organelles.
Genetic Material: DNA is organized into linear chromosomes within the nucleus.
Ribosomes: Larger than prokaryotic ribosomes (80S).

Function:
- Regulates the passage of molecules into and out of the cell.
- Maintains cell shape and integrity.
- Participates in cell signaling and communication.
- Provides a platform for enzyme activity.
- Facilitates cell adhesion and interactions.

Function:
- Stores the cell's genetic information (DNA) in the form of chromosomes.
- Regulates gene expression.
- Synthesizes ribosomal RNA (rRNA).
- Assembles ribosomes.

Function:
- Generates ATP (adenosine triphosphate), the cell's primary energy currency.
- Plays a role in cell signaling and apoptosis.
- Contains its own DNA, which is distinct from the nuclear DNA.

Types:
- Rough ER: Covered with ribosomes, involved in protein synthesis and secretion.
- Smooth ER: Lacks ribosomes, involved in lipid synthesis, steroid hormone production, detoxification of drugs and toxins, and calcium storage.
Function (Overall):
- Synthesis of proteins, lipids, and steroids.
- Detoxification of harmful molecules.
- Storage and release of calcium ions.

Structure: Consists of flattened, stacked membrane-enclosed sacs called cisternae.
Function:
- Modifies, sorts, and packages proteins and lipids synthesized in the ER.
- Synthesizes complex polysaccharides.
- Produces lysosomes.