What are the differences between Prokaryotes and Eukaryotes? In this blog we will find out:
- The recap of cellular functions
- The definition of prokaryotes and its function
- The definition of eukaryotes
- The structures and the differences between the two cellular organisms
Main functions of Cells
In IBDP Biology Topic, we are expected to know the 7 main functions of cells in general, here's the recap:
- Metabolism: includes all the chemical reactions that occur within an organism
- Growth
limited but is always evident
- Reproduction
involves hereditary molecules that can be passed to offspring
- Response
To the environment is imperative to the survival of the organism
- Homeostasis
Maintaining a constant internal environment e.g. acid-base levels/temperature
- Nutrition
Providing a source of compounds with many chemical bonds which can be broken to provide the organism with energy and nutrients necessary to maintain life
- Excretion
Letting out of waste within the organism
Prokaryotes
Prokaryotes are unicellular organisms that lack a membrane-enclosed nucleus, lacking organelles.
- Flagella
- : Solid
- protein structures,
- projecting from the cell wall and causes locomotion
- Pilus:
- Hairlike structures projecting from the cell wall, that can be ratcheted in and out; when connected to another bacterial cell they can be used to pull cells together
- Nuclei
- : Region of cytoplasm that contains
naked DNA which is the genetic information of the cell
- Cytoplasm
Contains enzymes that catalyse the chemical reactions of metabolism
- Ribosomes
Small granular structures that synthesize proteins by transplanting messenger RNA. Some proteins stay in the cell and others are secreted.
- Plasma Membrane: Controls entry and exit of substances, pumping some of them in by active transport.
- Cell wall: Forms a protective outer layer that prevents damage from outside and also bursting if internal pressure is high.
Prokaryotic cells divide by Binary Fission:
During this process, the DNA is copied, then two daughter chromosomes become attached to different regions on the plasma membrane, and the cell divides into two genetically identical daughter cells through elongation of the cell and a partitioning of the newly produced DNA by fibres made of protein.
Eukaryotes
In IBDP Biology, we need to know that eukaryotes are multicellular organisms with organelles and a membrane-bound nucleus
- Rough Endoplasmic Reticulum (RER):
- Synthesizes proteins for secretion from the cell
- Mitochondrion:
- Carries out aerobic respiration
- Golgi apparatus:
- Processes proteins before secretion
- Plasma Membrane
- : Controls energy and exit of substances
- Free ribisosmes:
- Synthesise protein for the use in cytoplasm
- Lysosome:
- Stores digestive enzymes
- Nucleus
: Stores the genetic material
- Central Vacuole:
Storage and hydrolic functions
- Lysosomes:
Contain and transport enzymes.
- Nucleolus:
Involved in ribosome synthesize
- Centrioles:
Associated with nuclear division
- Smooth Endoplasmic Reticulum:
ER without ribosomes
Differences between Eukaryotes and Prokaryotes
There are a few differences between the two cellular organisms, the main points which are enlisted below:
- Pro has
naked loop of DNA, Eu has DNA with proteins as chromosomes/chromatin
- Pro has
- no mitochondria
- , Eu have
- mitochondria present
- Pro has
- small ribosomes (70s)
, Eu has bigger ribosomes (80s)
- Pro has
no internal compartments, Eu is internally compartmentalized
And that's the end of the discussion between Eukaryotes and Prokaryotes! YAY!
Photo References:
https://biologydictionary.net/wp-content/uploads/2016/12/The-Anatomy-of-a-Bacterial-Cell-1
https://www.google.com/url?sa=i&url=http%3A%2F%2Fib.bioninja.com.au%2Fstandard-level%2Ftopic-1-cell-biology%2F12-ultrastructure-of-cells%2Feukaryotic-cells.html&psig=AOvVaw0mP4IkD0af74pPQIUAECyU&ust=1624859923809000&source=images&cd=vfe&ved=0CAoQjRxqFwoTCOjF5YaRt_ECFQAAAAAdAAAAABAD
Drafted by Venetia (Biology)