Biology Unit 1 Notes: Types of Cells
(1) Types of Organisms Unicellular Organisms: Multicellular Organisms: Organisms that are made of only one single cell. The single cell completes all characteristics of life and maintains homeostasis on its own. Multicellular Organisms: Organisms made of many different types of specialized cells. Each different body part / organ is made of different types of cells. Each type of cell has a unique structure and function. All of the different cells must work together to complete the characteristics of life, and homeostasis.
(2) Multicellular Organization Smallest Level (Microscopic) Atoms & Molecules Cells (The basic units of life.) Tissues (Similar cells working together on a common function.) Organs (Different types of tissues working together on a common function.) Organ Systems (Different types of organs working together on a common function.) Organism (All organ systems working together to maintain homeostasis.) Largest Level (Macroscopic)
(3) What is a cell? The cell is the most basic unit of living things. The Cell Theory States that: All living things must be made of at least one cell. The cell is the basic unit of life. New cells must come from old cells (pre-existing cells).
The Weird Theory of the Cell Theory https://youtu.be/4OpBylwH9DU
(4) Types of Cells Prokaryotic Cells: Eukaryotic Cells Cells without a nucleus. Example = Bacteria Eukaryotic Cells Cells with a nucleus. Example = Plant + Animal Cells
Prokaryotic Cell
Eukaryotic Cell
Comparing Prokaryotic and Eukaryotic Cells All cells have several basic features. They are bounded by a plasma membrane. They contain a semifluid substance called the cytosol. They contain chromosomes. They all have ribosomes.
Prokaryotic Cells Do not contain a nucleus Are smaller than eukaryotic cells. Lack internal structures surrounded by membranes.
Eukaryotic cells Contain a true nucleus, bounded by a membranous nuclear envelope Are generally quite a bit bigger than prokaryotic cells
Eukaryotic vs. Prokaryotic Eukaryotic Cell Prokaryotic Cell Nucleus Present None Cell Wall Only plant and fungi Cell Types uni- and multicellular Unicellular Organelles Absent Chromosomes More than one; Linear One; Circular Cytoskeleton present absent Examples Animals, Plants, Fungi Bacteria, Archea
The Three Domains of Life At the highest level, life is classified into three domains Bacteria Archaea Eukaryota
The Three Domains of Life Domain Bacteria and domain Archaea Prokaryotes Domain Eukarya Eukaryotes Includes the protists and the kingdoms Plantae, Fungi, and Animalia