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2.11 Origins of Cell Compartmentalization

2 min readjanuary 4, 2023

Caroline Koffke

Caroline Koffke

Haseung Jun

Haseung Jun

Caroline Koffke

Caroline Koffke

Haseung Jun

Haseung Jun

Endosymbiotic Theory

Prokaryotic Cells

Prokaryotic cells are are small cells that simply have a ring of circular floating inside the cell. These small, tiny cells are believed to the earliest forms of life found on Earth. Even 4 billion years ago, prokaryotes existed on earth. , on the other hand, only appeared 1.8 billion years ago. Most biologists think the ancestor of are prokaryotic cells. But are much more complex than prokaryotic cells. also have a , unlike prokaryotic cells.

Endosymbiotic Theory

Ever wonder why we have mitochondria in our cells but the has its own membrane? The endosymbiotic theory is the current theory of how eukaryotic membrane-bound organelles existed in .The endosymbiotic theory states that an early ancestor of engulfed a prokaryotic cell, and the prokaryotic became an , a cell living in another cell. These smaller cells were capable of producing extra energy for the other cell, leading to a selective advantage. Overtime, cells with an extra cell inside were able to become more able to survive and reproduce quickly. The eukaryotic cell was born!While prokaryotes generally lack internal membrane bound organelles, they still have internal regions with specialized structures and functions. These regions are just not defined by outer membranes. The plays a key role in keeping the prokaryotic cells

Evidence

There is quite a bit of evidence to support this claim. In 1883, a botanist named discovered that divided just like bacteria did. During the 1950s and 60s, many biologists found that mitochondria and had their own . They even found that the was more like those of prokaryotes rather than eukaryotes. The even had its own membrane, which is what a free-living cell would have.

This makes us conclude that the was once a prokaryote.

https://firebasestorage.googleapis.com/v0/b/fiveable-92889.appspot.com/o/images%2FScreen%20Shot%202020-04-21%20at%202.21-8ns6CVWqKVwX.png?alt=media&token=6519df9a-96c5-4417-b2f4-2f2e91fe28dd

Key Terms to Review (7)

Andreas Schimper

: Andreas Franz Wilhelm Schimper was a German botanist and phycologist who made significant contributions to botany with his research on photosynthesis and chloroplasts.

Cell Wall

: The cell wall is a rigid layer of polysaccharides lying outside the plasma membrane of the cells of plants, fungi, and bacteria. In algae and higher plants, it consists mainly of cellulose.

DNA

: DNA (Deoxyribonucleic Acid) is a molecule that carries most of the genetic instructions used in development, functioning and reproduction of all known living organisms.

Endosymbiont

: An organism that lives inside another organism, often benefiting both parties. In biology, this term often refers to how certain organelles were once free-living bacteria that got incorporated into early eukaryotic cells.

Eukaryotic Cells

: These are complex cells with a nucleus and other organelles, all enclosed within membranes. They make up organisms in the Protista, Fungi, Plantae, and Animalia kingdoms.

Mitochondrion

: An organelle found in large numbers in most cells, where it generates energy for cellular activities through respiration.

Plastids

: Plastids are major double-membrane organelles found within the cells of plants and algae. They are responsible for manufacturing and storing food including sugars created during photosynthesis (chloroplasts).

2.11 Origins of Cell Compartmentalization

2 min readjanuary 4, 2023

Caroline Koffke

Caroline Koffke

Haseung Jun

Haseung Jun

Caroline Koffke

Caroline Koffke

Haseung Jun

Haseung Jun

Endosymbiotic Theory

Prokaryotic Cells

Prokaryotic cells are are small cells that simply have a ring of circular floating inside the cell. These small, tiny cells are believed to the earliest forms of life found on Earth. Even 4 billion years ago, prokaryotes existed on earth. , on the other hand, only appeared 1.8 billion years ago. Most biologists think the ancestor of are prokaryotic cells. But are much more complex than prokaryotic cells. also have a , unlike prokaryotic cells.

Endosymbiotic Theory

Ever wonder why we have mitochondria in our cells but the has its own membrane? The endosymbiotic theory is the current theory of how eukaryotic membrane-bound organelles existed in .The endosymbiotic theory states that an early ancestor of engulfed a prokaryotic cell, and the prokaryotic became an , a cell living in another cell. These smaller cells were capable of producing extra energy for the other cell, leading to a selective advantage. Overtime, cells with an extra cell inside were able to become more able to survive and reproduce quickly. The eukaryotic cell was born!While prokaryotes generally lack internal membrane bound organelles, they still have internal regions with specialized structures and functions. These regions are just not defined by outer membranes. The plays a key role in keeping the prokaryotic cells

Evidence

There is quite a bit of evidence to support this claim. In 1883, a botanist named discovered that divided just like bacteria did. During the 1950s and 60s, many biologists found that mitochondria and had their own . They even found that the was more like those of prokaryotes rather than eukaryotes. The even had its own membrane, which is what a free-living cell would have.

This makes us conclude that the was once a prokaryote.

https://firebasestorage.googleapis.com/v0/b/fiveable-92889.appspot.com/o/images%2FScreen%20Shot%202020-04-21%20at%202.21-8ns6CVWqKVwX.png?alt=media&token=6519df9a-96c5-4417-b2f4-2f2e91fe28dd

Key Terms to Review (7)

Andreas Schimper

: Andreas Franz Wilhelm Schimper was a German botanist and phycologist who made significant contributions to botany with his research on photosynthesis and chloroplasts.

Cell Wall

: The cell wall is a rigid layer of polysaccharides lying outside the plasma membrane of the cells of plants, fungi, and bacteria. In algae and higher plants, it consists mainly of cellulose.

DNA

: DNA (Deoxyribonucleic Acid) is a molecule that carries most of the genetic instructions used in development, functioning and reproduction of all known living organisms.

Endosymbiont

: An organism that lives inside another organism, often benefiting both parties. In biology, this term often refers to how certain organelles were once free-living bacteria that got incorporated into early eukaryotic cells.

Eukaryotic Cells

: These are complex cells with a nucleus and other organelles, all enclosed within membranes. They make up organisms in the Protista, Fungi, Plantae, and Animalia kingdoms.

Mitochondrion

: An organelle found in large numbers in most cells, where it generates energy for cellular activities through respiration.

Plastids

: Plastids are major double-membrane organelles found within the cells of plants and algae. They are responsible for manufacturing and storing food including sugars created during photosynthesis (chloroplasts).


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© 2024 Fiveable Inc. All rights reserved.

AP® and SAT® are trademarks registered by the College Board, which is not affiliated with, and does not endorse this website.