Cell Biology: Prokaryotic and Eukaryotic Cells

Study Notes

Basic Structure of a Cell

Cells are the fundamental units of all living things.
All cells share common features, though they are diverse.
Cells are typically microscopic, needing microscopes to be seen.
Cells have specialized parts called organelles, each with a specific job.
Two major types exist: prokaryotic and eukaryotic.

Prokaryotic Cells

Prokaryotic cells are simpler and smaller than eukaryotic cells.
They lack a nucleus or other membrane-bound organelles.
Examples include bacteria and archaea.
Genetic material (DNA) is stored in a region called a nucleoid.
A cell wall provides support and protection.
Some have flagella for movement or pili for attachment.

Eukaryotic Cells

Eukaryotic cells are more complex and larger than prokaryotic cells.
They have a nucleus, which holds the DNA.
Membrane-bound organelles divide up cell functions, increasing effectiveness.
Animal and plant cells are examples of eukaryotic cells.
Multiple organelles work together, like mitochondria for energy and endoplasmic reticulum for protein production.
Cell membranes control what enters and exits the cell.

Cell Membrane

The cell membrane separates the cell from its surroundings.
It is mainly a phospholipid bilayer with embedded proteins.
The interior of the phospholipid bilayer is hydrophobic.
Proteins on the membrane help move molecules.
Receptors on the membrane allow communication with other cells.

Cytoplasm

The jelly-like substance inside the cell.
Contains and suspends the organelles.
Site of many important cellular reactions.
Supports and cushions organelles.
Includes water, nutrients, and ions.

Nucleus

The control center of the eukaryotic cell.
Contains DNA organized into chromosomes.
Enclosed by a double-layered membrane (nuclear envelope).
DNA replication and transcription (DNA to RNA) happen here.
The nucleolus is a region for ribosome production.

Organelles

Specialized structures within a cell with particular functions.
Examples: mitochondria, endoplasmic reticulum, Golgi apparatus, ribosomes, vacuoles.
These work together for cellular processes.

Mitochondria

Mitochondria are the cell's powerhouses.
They do cellular respiration, creating energy (ATP).
Mitochondria have their own DNA and ribosomes, reflecting an ancient bacterial origin.
They have a double membrane.

Endoplasmic Reticulum (ER)

A network of membranes inside the cell.
Two types:
- Rough ER: studded with ribosomes, involved in protein synthesis.
- Smooth ER: lacks ribosomes, plays a role in lipid synthesis.

Golgi Apparatus

Modifies, sorts, and packages proteins and lipids.
Composed of flattened sacs called cisternae.

Ribosomes

Sites of protein synthesis.
Can be free in the cytoplasm or attached to the rough ER.
Made of two subunits (large and small).

Vacuoles

Membrane-bound sacs for storing water, nutrients, or waste.
Plant cells have a large central vacuole that contributes to structural support.

Cell Wall

Found in plant cells and some others.
Provides support and protection.
Mostly made of cellulose in plant cells.

Cell Division

Mitosis and meiosis result in cell reproduction.
They ensure accurate distribution of genetic material.
Crucial for growth and repair in multicellular organisms.

Description

Explore the fundamental structures and functions of cells in this quiz on cell biology. Learn about the differences between prokaryotic and eukaryotic cells, including their organelles and genetic material. Test your knowledge of the basic units of life and their characteristics.