Eukaryotic cells are believed to have evolved about 1.6 - 2.1 billion years ago and are more complex than prokaryotic cells and contain many more organelles. Eukaryotic cells distinctly contain free and membrane bound organelles such as...
- Cellular Membrane
- Endoplasmic Reticulum
- Golgi Apparatus
- Cell Wall
- Plant Cell Organelles
A major defining difference between prokaryotic cells and eukaryotic cells for the MCAT is the presence of the Nucleus in eukaryotic, whereas prokaryotes have a nuclear membrane. The nucleus in a eukaryotic cell allows for the compartmentalization and storage of DNA.
All multi-cellular organisms (humans, fungi, plants) are eukaryotes, however there are some single celled eukaryotic organisms. There are many differences between each type of eukaryotic cell, for example in the plant cell there exists a chloroplast to aid in photosynthesis which is lacking in an animal cell.
Eukaryotic cells also divide differently than prokaryotes. For example, some simple bacteria replicate via asexual replication such as binary fission, however eukaryotic cells must undergo either mitosis (autosomal cells) or meiosis (sex cells).
Click here to see the differences between prokaryotic cells and eukaryotic cells. The major eukaryotic cells that will be tested on the MCAT are plant and animal cells. Understanding the differences between them are very important and each serve different functions.
Animal vs. Plant Cells
|Animal Cells||Plant Cells|
|Lack cell wall||Has cell wall|
|Lack chloroplasts||Has chloroplasts|
|Smaller vacuoles||Has large central vacuole|
|Can morph shape easily||Has rigid structure|
|Have centrioles||Lacks centrioles|
|Gets energy via consumption||Gets energy via photosynthesis|
The MCAT will also test you on basic concepts of Fungi. Fungi have a cell wall composed of chitin. All fungi are heterotrophs and many exist as parasites. This means they rely on a host in order to live. Examples of fungi involve yeast and mold. Fungi reproduce asexually or sexually via spores and have both a haploid and diploid life cycle.
Scale of the World
It is important to understand the scale of the living world from atoms, all the way to the interactions of live animals on Earth. By understanding the interactions between the different levels of science you will be able to build bridges between the concepts and facilitate better learning and understanding. Groups of similar cells organize themselves into tissues. Tissues have the same origin and thus carry out the same function. Eventually, organs are formed from the grouping together of multiple tissues.
Epithelial tissue provides primary immune protection, covers the body and lines cavities. It is involved in absorption, secretion, protection and sensation. Epithelial tissue is derived from the ectoderm and endoderm during growth and development.
Connective tissue supports the body and provides framework, examples are...
Nervous tissue uses an electrochemical gradient to allow cellular signaling and the coordinated control of multiple tissues, organs and organ systems
Muscle tissue is composed of muscle fibers that respond and react to neural stimulation to perform a certain action
- Isotonic means when there is no net movement of particles
- Hypertonic means there is a higher concentration of particles in the cell compared to the surroundings. This will eventually cause the cell to lyse
- Hypotonic means the opposite, that there is a lower concentration of particles in the cell compared with the surroundings. This will cause the cell to shrivel and atrophy.
Osmosis moves water from an area of lower solute concentration to an area of higher solute concentration (opposite of solute movement). This means that nutrients move from high water to low water concentration, because water will always be even in equilibrium.