Chapter 1 Summary
Chapter 1.1
- Cell Theory states that: one or more cells comprise all living things, the cell is the basic unit of life, and new cells arise from existing cells
- Cells fall into one of two broad categories: prokaryotic and eukaryotic
- All cells share four common components: plasma membrane, cytoplasm, DNA, Ribosomes
Chapter 1.2
- Prokaryotes are a highly diverse group of organisms
- The evolution of prokaryotes is still being debated, but we discussed potential evolutionary events such as abiogenesis, protocells, the RNA world hypothesis, and LUCA.
- Prokaryotic cells are simple in structure, since they don’t have a nucleus or other membrane-bound organelles, they store their DNA in a central region of the cell called the nucleoid.
- Prokaryotes have evolved throughout time, making them a very diverse group.
Chapter 1.3
- Eukaryotes have membrane-bound organelles, including a nucleus and mitochondria
- Eukaryotic cells are extremely diverse and have many differences across phylogenetic kingdoms, including animals, plants and fungi.
- Eukaryotic cells have diverse sizes and shapes, they are considerably larger than prokaryotic cells
- As a cell increases in size, its surface area-to-volume ratio decreases
- The endosymbiosis theory proposes that eukaryotic cells originated from prokaryotic cells that engulfed and established a symbiotic relationship with other prokaryotic cells
Chapter 1.4
- In simple terms, multicellularity refers to a group of cells, each with specialized functions that work as a single unit. This phenomenon has arisen several times throughout a variety of taxa.
- Within animals’ multicellularity is divided into four levels of organization: cell, tissue, organ, and organ system.
- The colonial hypothesis rests on the idea that multicellularity arose from the aggregation of unicellular organisms of the same species, which over time, become reliant on one another.
- The symbiotic hypothesis is based on the idea multicellularity arose because of the aggregation of unicellular organisms of different species.
- Multicellularity comes with numerous advantages, including the division of labour, fewer size constraints, and changes in the predator-prey model.