Organizing Principles Flashcards
Who was Robert Hooke?
Stablished the term cell to refer to the functional units of eukaryotes. Also published the first depiction of a microorganism.
Francesco Redi proved that…
…Spontaneous generation was not true through an experiment with meat.
Primordial Soup
Is one of the main hypothesis to explain how life was formed on Earth. Some scientists like Oparin and Haldane were able to demonstrate this by adding some gases together (such as nitrate, nitrite, ammonia, water vapor, oxygen) and lit it up with a sparkle. The result were some amino acids, which are the monomers of proteins.
What is the RNA-world idea?
It suggests that life arose from self-replicating, RNA based genes, and that only later did organisms develop the ability to store genetic information in the molecule’s close relative, DNA.
What are protocells?
They are a membrane-enclosed collection of molecules, including self-replicating RNA.
What are the two cell variations we find in our world?
Eukaryotes and Prokaryotes.
What is the most defining feature of a Prokaryote?
It lacks a nucleus; also, it is always unicellular
How are eukaryotic and prokaryotic cells similar?
Both have ribosomes; however, prokaryotic cells have a 70-s ribosome, while eukaryotic cells havea 80-s ribosome.
What is the one key feature found in Eukaryotes?
Cholesterol
How old is the oldest fossilized eukaryotic cells?
1.8 billion years old but there are proofs that they might have existed about 2.7 billion years ago because of cholesterol markers found in rocks.
What is the endosymbiotic theory and what are the features that support it?
It is the theory that affirms that mitochondrias used to be aerobic bacterias that were engulfed by cells. Not only their DNA is similar to the bacterial one, they also have 70-s ribosomes, which do not exist freely in eukaryotic cells
Nucleus
Controls the cellular processes and holds the DNA.
Mitochondria
Break down sugars and produce ATP; in the process it kicks off carbon dioxide.
Cell membrane
It regulates what enters and leaves the cell
Cytoskeleton
Provides structure and support for the cell; it aids in cellular movement using the micro tubules and micro filaments.
Golgi apparatus
It is considered the packing and shipping center of the cell. It will use vesicles to transport substances. Vesicles are identical to the cell membrane, so once they reach it, they will merge, fold outwardly, and release the contents into the cell membrane. (Stack of pancakes)
Lysosomes
The recycling center for eukaryotic cells. They do not produce energy, so cannot be compared to mitochondria
Smooth endoplasmic reticulum
Has a maze-like appearance and stays not far away from the nucleus. Its main job is to produce and transport lipids.
Rough endoplasmic reticulum
Its surface is covered with ribosomes and its main job is to produce and transport proteins.
The main difference between human cells and plant cells is…
…the presence of a cell wall. They also don’t have Lysosomes.
What is a vacuole?
A watery structure that holds water and other important substances the cell can use.
What is the chloroplasts main function?
Taking sunlight, carbon dioxide, and water and transforming them in energy to charge ATP and NADPH. They also cleave CO2 and turn it into a 6-glucose.
What is Plasmodesmata?
Channels connecting one cell to the next.
What is the Endomembrane System?
It is a system of membranes that involve the organelles. Everything in a cell are membrane bound. Except ribosomes; they are non-membrane bound organelles.
