Biochemistry Introduction (CHEM105)

Study Notes

Cells are the fundamental units of life, serving as the structural and functional components of all living organisms.
All living organisms are composed of cells, which arise from pre-existing cells, except for viruses, which lack cell structure and depend on hosts for survival.
Cells are the smallest living units, often invisible to the naked eye. They are capable of growth, reproduction, energy utilization, adaptation, and environmental response.
Organisms can be unicellular (single-celled) or multicellular (composed of many cells).

Two primary categories of cells exist: Eukaryotes and Prokaryotes, both sharing common features.
Eukaryotes include plants, animals, and fungi, characterized by a well-defined nucleus and organized organelles.
Prokaryotes, such as bacteria, lack a defined membrane-covered nucleus and many organelles, typically having circular DNA.

Prokaryotic Cells:
- Absence of a membrane-covered nucleus.
- No membrane-bound organelles.
- Circular DNA structure, typically found in bacteria.
Eukaryotic Cells:
- Presence of a well-defined nucleus.
- Contain membrane-covered organelles.
- Linear DNA structure, found in animal and plant cells.

Common Organelles:
- Nucleus, Golgi Complex, Mitochondria, Lysosomes, Endoplasmic Reticulum, Ribosomes, and Cell Membrane present in both cell types.
Unique Organelles in Plant Cells:
- Chloroplasts for photosynthesis.
- Cell wall for structural support.
- Larger vacuoles for storage.

Cell Membrane:
- Outer barrier of the cell, regulating nutrient intake and waste expulsion.
Cytoplasm:
- Jelly-like fluid that holds organelles in place.
Nucleus:
- Control center containing the cell's DNA, overseeing cell operations.
Mitochondria:
- Powerhouse of the cell, generating energy for cellular functions.
Ribosomes:
- Sites for protein synthesis, crucial for cell function and growth.