General Physiology Prelims Notes

Study Notes

Principles of Cell Theory

All living organisms consist of one or more cells.
Cells serve as the fundamental structural and organizational units of life.
Cell division through mitosis or meiosis is responsible for the formation of new cells from pre-existing ones.

Universal Features of Cells

Cell Membrane: Encloses the cell and maintains internal conditions.
Cytoplasm: Gel-like substance where cellular components are suspended.
DNA: Contains genetic instructions for cell functions and reproduction.
Ribosomes: Sites for protein synthesis essential for cellular activities.

Types of Cells

Prokaryotic Cells: Simple structure, no nucleus, circular DNA in nucleoid; examples include bacteria and archaea.
- Possess a cell wall for protection and structure.
- Reproduce quickly via binary fission, important in evolutionary biology.
Eukaryotic Cells: More complex with a defined nucleus and membrane-bound organelles.
- Organelles include mitochondria, endoplasmic reticulum, Golgi apparatus, and lysosomes.
- Reproduce through mitosis for identical cells or meiosis for gametes.
- Endosymbiotic Theory posits that mitochondria and chloroplasts originated from prokaryotes.

Animal and Plant Cells

Animal Cells:
- Nucleus manages DNA and regulates cell activities.
- Mitochondria produce ATP via cellular respiration.
- Endoplasmic Reticulum: Rough ER processes proteins; Smooth ER synthesizes lipids and detoxifies substances.
- Golgi Apparatus modifies and packages proteins and lipids.
- Lysosomes digest waste; centrioles assist in cell division; smaller vacuoles handle storage.
Plant Cells:
- Contain chloroplasts for photosynthesis and a stiff cell wall made of cellulose.
- Feature a large central vacuole for storage and structural integrity.
Key Differences:
- Only plant cells have chloroplasts and cell walls.
- Plant cells have larger vacuoles compared to animal cells.

Important Organelles and Their Functions

Nucleus: Regulates cellular activities and holds genetic material.
Mitochondria: Produce ATP, essential for energy.
Endoplasmic Reticulum (ER):
- Rough ER synthesizes proteins due to ribosome attachments.
- Smooth ER focuses on lipid production and detoxification.
Ribosomes: Key for protein synthesis; can be free in cytoplasm or bound to ER.
Golgi Apparatus: Processes and transports proteins and lipids.
Lysosomes: Contain enzymes for waste breakdown.
Centrosomes/Centrioles: Aid in microtubule organization during cell division.
Peroxisomes: Detoxify harmful substances and break down fatty acids.

Cellular Energy and Reactions

ATP: The primary energy currency composed of adenine, ribose, and three phosphate groups.
Photosynthesis: Process by which plants generate glucose from sunlight, producing oxygen as a byproduct.
Energy Cycling: Continuous recycling of chemicals through various organisms.
Coupled Reactions: Energy released in one reaction is harnessed to fuel another.

Specialized Cells and Functions

Axons & Dendrites: Function in signal transmission in nerve cells.
Microvilli & Cell Junctions: Important for maintaining barriers in epithelial tissue.
Sarcomere: Structural unit in muscle cells responsible for contraction.

Function and Structure of Ribosomes

Essential for translating genetic information from mRNA into proteins.
Types of ribosomes:
- Free Ribosomes: Floating in cytoplasm; synthesize proteins for internal cell use.
- Bound Ribosomes: Attached to the rough ER; synthesize proteins for export or insertion into membranes.

Description

This quiz covers key principles of cell theory and the universal features of cells. Understand how cellular structures and processes form the foundation of life. Test your knowledge on these essential concepts in physiology.