Cell Biology: Basic Cell Structure

Study Notes

Cell Biology

Basic Cell Structure

All living organisms are made of cells; cells arise from existing cells.
Types of Cells
- Prokaryotic Cells
  - Lack a nucleus and membrane-bound organelles.
  - Example: Bacteria.
- Eukaryotic Cells
  - Contain a nucleus and organelles.
  - Example: Plant and animal cells.

Cell Organelles

Nucleus
- Contains genetic material (DNA).
- Controls cell activities and reproduction.
Mitochondria
- Powerhouse of the cell.
- Site of ATP production through cellular respiration.
Ribosomes
- Site of protein synthesis.
- Can be free-floating or attached to the endoplasmic reticulum.
Endoplasmic Reticulum (ER)
- Rough ER: Studded with ribosomes; synthesizes proteins.
- Smooth ER: Lacks ribosomes; involved in lipid synthesis and detoxification.
Golgi Apparatus
- Modifies, sorts, and packages proteins and lipids for secretion or use within the cell.
Lysosomes
- Contains digestive enzymes.
- Breaks down waste, macromolecules, and cellular debris.
Plasma Membrane
- Semi-permeable membrane that regulates entry and exit of substances.
- Composed of a phospholipid bilayer with embedded proteins.

Cellular Processes

Cell Division
- Mitosis: Division of somatic cells; results in two identical daughter cells.
- Meiosis: Division of gametes; results in four genetically diverse daughter cells.
Cellular Respiration
- Process by which cells convert glucose and oxygen into ATP, carbon dioxide, and water.
- Involves glycolysis, the Krebs cycle, and the electron transport chain.
Protein Synthesis
- Transcription: DNA is transcribed into mRNA in the nucleus.
- Translation: mRNA is translated into a protein at the ribosome.

Cell Communication

Signal Transduction
- Process by which cells respond to external signals through receptors.
- Involves a series of biochemical events leading to a cellular response.
Cell Junctions
- Structures that facilitate communication and adhesion between cells.
- Types include tight junctions, gap junctions, and desmosomes.

Cellular Adaptation

Cells can undergo changes in response to environmental stimuli, such as hypertrophy (increase in cell size), hyperplasia (increase in cell number), atrophy (decrease in cell size), and metaplasia (change in cell type).

These notes cover fundamental concepts of cell biology, emphasizing the structure and function of cells, organelles, processes, and communication mechanisms.

Cell Theory

All living things are composed of cells
The cell is the fundamental unit of life
All cells arise from pre-existing cells

Cell Types

Prokaryotic Cells
- Lack a nucleus and other membrane-bound organelles
- Example: Bacteria
Eukaryotic Cells
- Contain a nucleus and membrane-bound organelles
- Example: Plant and animal cells

Cell Organelles

Nucleus
- Contains genetic material (DNA)
- Controls cellular activities and reproduction
Mitochondria
- Powerhouse of the cell
- Site of ATP production through cellular respiration
Ribosomes
- Site of protein synthesis
- Can be free-floating or attached to the endoplasmic reticulum
Endoplasmic Reticulum (ER)
- Rough ER: Studded with ribosomes and synthesizes proteins
- Smooth ER: Lacks ribosomes and is involved in lipid synthesis and detoxification
Golgi Apparatus
- Modifies, sorts, and packages proteins and lipids for secretion or use within the cell
Lysosomes
- Contain digestive enzymes
- Breaks down waste, macromolecules, and cellular debris
Plasma Membrane
- Semi-permeable membrane that regulates the entry and exit of substances
- Composed of a phospholipid bilayer with embedded proteins

Cellular Processes

Cell Division
- Mitosis: Division of somatic cells; results in two identical daughter cells
- Meiosis: Division of gametes; results in four genetically diverse daughter cells
Cellular Respiration
- Process by which cells convert glucose and oxygen into ATP, carbon dioxide, and water
- Involves glycolysis, the Krebs cycle, and the electron transport chain
Protein Synthesis
- Transcription: DNA is transcribed into mRNA in the nucleus
- Translation: mRNA is translated into a protein at the ribosome

Cell Communication

Signal Transduction
- Process by which cells respond to external signals through receptors
- Involves a series of biochemical events leading to a cellular response
Cell Junctions
- Structures that facilitate communication and adhesion between cells
- Include tight junctions, gap junctions, and desmosomes

Cellular Adaption

Cells can undergo changes in response to environmental stimuli
- Hypertrophy: Increase in cell size
- Hyperplasia: Increase in cell number
- Atrophy: Decrease in cell size
- Metaplasia: Change in cell type

Description

Test your knowledge on basic cell structure and organelles in cell biology. This quiz covers essential topics such as cell theory, types of cells, and functions of organelles like the nucleus, mitochondria, and ribosomes. Perfect for students learning about cellular biology.